Surgery_Schwartz

Surgery_Schwartz. invasive procedure, typically performed via a transfemoral puncture, and involves selective imaging of the carotid and ver-tebral arteries using iodinated contrast. The risk of stroke during cerebral angiography is generally reported at approximately 1% and is typically due to atheroembolization related to wire and catheter manipulation in the arch aorta or proximal branch vessels. Over the last few decades, however, the incidence of neurologic complications following angiography has been reduced, due to the use of improved guidewires and catheters, better resolution digital imaging, and increased experience. Local access compli-cations of angiography are infrequent and include development of hematoma, pseudoaneurysm, distal embolization, and acute vessel thrombosis. Currently, selective angiography is particu-larly used for patients with suspected intracranial disease and for patients in whom percutaneous revascularization is con-sidered. The techniques of carotid angioplasty and


Surgery_Schwartz

Surgery_Schwartz. angiography is particu-larly used for patients with suspected intracranial disease and for patients in whom percutaneous revascularization is con-sidered. The techniques of carotid angioplasty and stenting for carotid bifurcation occlusive disease are described in detail later in this chapter. We generally use CTA or MRA to get informa-tion about the aortic arch anatomy and presence of concomitant intracranial disease and collateral pathway in planning our strategy for carotid stenting or endarterectomy.Treatment of Carotid Occlusive DiseaseConventionally, patients with carotid bifurcation occlusive dis-ease are divided into two broad categories: patients without prior history of ipsilateral stroke or TIA (asymptomatic) and those with prior or current ipsilateral neurologic symptoms BA(symptomatic). It is estimated that 15% of all strokes are pre-ceded by a TIA. The 90-day risk of a stroke in a patient present-ing with a TIA is 3% to 17%.14 According to the Cardiovascular Health


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Surgery_Schwartz. BA(symptomatic). It is estimated that 15% of all strokes are pre-ceded by a TIA. The 90-day risk of a stroke in a patient present-ing with a TIA is 3% to 17%.14 According to the Cardiovascular Health Study, a longitudinal population-based study of coronary artery disease and stroke in men and women, the prevalence of TIA in men was 2.7% for ages of 65 and 69 and 3.6% for ages 75 to 79; the prevalence in women was 1.4% and 4.1%, respectively.24 There have been several studies reporting on the effectiveness of stroke prevention with medical treatment and carotid endarterectomy for symptomatic patients with moderate to severe carotid stenosis. Early and chronic aspirin therapy has been shown to reduce stroke recurrence rate in sev-eral large clinical trials.19Symptomatic Carotid Stenosis. Currently, most stroke neu-rologists prescribe both aspirin and clopidogrel for secondary 1Brunicardi_Ch23_p0897-p0980.indd 91027/02/19 4:14 PM 911ARTERIAL DISEASECHAPTER 23stroke prevention in


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Surgery_Schwartz. most stroke neu-rologists prescribe both aspirin and clopidogrel for secondary 1Brunicardi_Ch23_p0897-p0980.indd 91027/02/19 4:14 PM 911ARTERIAL DISEASECHAPTER 23stroke prevention in patients who have experienced a TIA or stroke.19 In patients with symptomatic carotid stenosis, the degree of stenosis appears to be the most important predic-tor in determining risk for an ipsilateral stroke. The risk of a recurrent ipsilateral stroke in patients with severe carotid ste-nosis approaches 40%. Two large multicenter randomized clinical trials, the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET), have both shown a significant risk reduction in stroke for patients with symptomatic high-grade stenosis (70–99%) undergoing carotid endarterectomy when compared to medical therapy alone.20,21 Although there has been much discussion regarding the different methodologies used in the measurement of carotid stenosis and calculation of


Surgery_Schwartz

Surgery_Schwartz. when compared to medical therapy alone.20,21 Although there has been much discussion regarding the different methodologies used in the measurement of carotid stenosis and calculation of the life-table data between the two studies, both of these studies had similar clinical results. The findings of these two landmark tri-als have also been reanalyzed in many subsequent publications. The main conclusions of the trials remain validated and widely acknowledged. Briefly, the NASCET study showed that for high-grade carotid stenosis, the cumulative risk of ipsilateral stroke was 26% in the medically treated group and 9% in the surgically treated group at 2 years. For patients with moderate carotid artery stenosis (50–69%), the benefit of carotid endar-terectomy is less but still favorable when compared to medical treatment alone; the 5-year fatal or nonfatal ipsilateral stroke rate was 16% in the surgically treated group versus 22% in the medically treated group.22 The risk of stroke was


Surgery_Schwartz

Surgery_Schwartz. compared to medical treatment alone; the 5-year fatal or nonfatal ipsilateral stroke rate was 16% in the surgically treated group versus 22% in the medically treated group.22 The risk of stroke was similar for the remaining group of symptomatic patients with less than 50% carotid stenosis, whether they had endarterectomy or medical treatment alone. The ECST reported similar stroke risk reduc-tion for patients with severe symptomatic carotid stenosis and no benefit in patients with mild stenosis when carotid endarter-ectomy was performed versus medical therapy.21The optimal timing of carotid intervention after acute stroke, however, remains debatable. Earlier studies showed an increased rate of postoperative stroke exacerbation and conver-sion of a bland to hemorrhagic infarction when carotid endarter-ectomy was carried out within 5 to 6 weeks after acute stroke. The dismal outcome reported in the early experience was likely related to poor patient selection. The rate of stroke


Surgery_Schwartz

Surgery_Schwartz. carotid endarter-ectomy was carried out within 5 to 6 weeks after acute stroke. The dismal outcome reported in the early experience was likely related to poor patient selection. The rate of stroke recurrence is not insignificant during the interval period and may be reduced with early intervention for symptomatic carotid stenosis. Con-temporary series have demonstrated acceptable low rates of perioperative complications in patients undergoing carotid end-arterectomy within 4 weeks after acute stroke.22 In a recent ret-rospective series, carotid artery stenting when performed early (<2 weeks) after the acute stroke was associated with higher mortality than when delayed (>2 weeks).23Asymptomatic Carotid Stenosis. Whereas there is univer-sal agreement that carotid revascularization (endarterectomy or stenting) is effective in secondary stroke prevention for patients with symptomatic moderate and severe carotid stenosis, the management of asymptomatic patients remains an important


Surgery_Schwartz

Surgery_Schwartz. or stenting) is effective in secondary stroke prevention for patients with symptomatic moderate and severe carotid stenosis, the management of asymptomatic patients remains an important controversy to be resolved. Generally, the detection of carotid stenosis in asymptomatic patients is related to the presence of a cervical bruit or based on screening duplex ultrasound findings. In one of the earlier observational studies, the authors showed that the annual occurrence rate of neurologic symptoms was 4% in a cohort of 167 patients with asymptomatic cervical bruits followed prospectively by serial carotid duplex scan.24 The mean annual rate of carotid stenosis progression to a greater than 50% stenosis was 8%. The presence of or progression to a greater than 80% stenosis correlated highly with either the development of a total occlusion of the internal carotid artery or new symptoms. The major risk factors associated with disease progression were cigarette smoking, diabetes mellitus, and


Surgery_Schwartz

Surgery_Schwartz. either the development of a total occlusion of the internal carotid artery or new symptoms. The major risk factors associated with disease progression were cigarette smoking, diabetes mellitus, and age. This study supported the contention that it is prudent to fol-low a conservative course in the management of asymptomatic patients presenting with a cervical bruit.One of the first randomized clinical trials on the treatment of asymptomatic carotid artery stenosis was the Asymptomatic Carotid Atherosclerosis Study (ACAS), which evaluated the benefits of medical management with antiplatelet therapy versus carotid endarterectomy.25 Over a 5-year period, the risk of ipsi-lateral stroke in individuals with a carotid artery stenosis greater than 60% was 5.1% in the surgical arm. On the other hand, the risk of ipsilateral stroke in patients treated with medical man-agement was 11%. Carotid endarterectomy produced a relative risk reduction of 53% over medical management alone. The results of


Surgery_Schwartz

Surgery_Schwartz. the risk of ipsilateral stroke in patients treated with medical man-agement was 11%. Carotid endarterectomy produced a relative risk reduction of 53% over medical management alone. The results of a larger randomized trial from Europe, the Asymptom-atic Carotid Surgery Trial (ACST), recently confirmed similar beneficial stroke risk reduction for patients with asymptomatic, greater than 70% carotid stenosis undergoing endarterectomy versus medical therapy.26 An important point derived from this latter trial was that even with improved medical therapy, includ-ing the addition of statin drugs and clopidogrel, medical ther-apy was still inferior to endarterectomy in the primary stroke prevention for patients with high-grade carotid artery stenosis. It is generally agreed that asymptomatic patients with severe carotid stenosis (80–99%) are at significantly increased risk for stroke and stand to benefit from either surgical or endovascular revascularization. However, revascularization for


Surgery_Schwartz

Surgery_Schwartz. with severe carotid stenosis (80–99%) are at significantly increased risk for stroke and stand to benefit from either surgical or endovascular revascularization. However, revascularization for asymptomatic patients with a less severe degree of stenosis (60–79%) remains controversial.Carotid Endarterectomy Versus Angioplasty and StentingCurrently, the argument is no longer whether medical therapy alone is inferior to surgical endarterectomy in stroke preven-tion for severe carotid stenosis. Rather, the debate now revolves around whether carotid angioplasty and stenting produce the same benefits demonstrated by carotid endarterectomy. Since carotid artery stenting was approved by the FDA for clinical application in 2004, this percutaneous procedure has become a treatment alternative in patients who are deemed “high risk” for endarterectomy (Table 23-4). In contrast to many endovascular peripheral arterial interventions, percutaneous carotid stent-ing represents a much more challenging


Surgery_Schwartz

Surgery_Schwartz. who are deemed “high risk” for endarterectomy (Table 23-4). In contrast to many endovascular peripheral arterial interventions, percutaneous carotid stent-ing represents a much more challenging procedure, because it requires complex catheter-based skills using the 0.014-inch guidewire system and distal protection device. Moreover, cur-rent carotid stent devices predominantly use the monorail guide-wire system, which requires more technical agility compared with the over-the-wire catheter system that is routinely used in peripheral interventions. This percutaneous intervention often requires balloon angioplasty and stent placement through a long carotid guiding sheath via a groin approach. Poor techni-cal skills can result in devastating treatment complications such as stroke, which can occur in part due to plaque embolization during the balloon angioplasty and stenting of the carotid artery. Because of these various procedural components that require high technical proficiency, many


Surgery_Schwartz

Surgery_Schwartz. in part due to plaque embolization during the balloon angioplasty and stenting of the carotid artery. Because of these various procedural components that require high technical proficiency, many early clinical investigations of carotid artery stenting, which included physicians with little or no carotid stenting experience, resulted in alarmingly poor Brunicardi_Ch23_p0897-p0980.indd 91127/02/19 4:14 PM 912SPECIFIC CONSIDERATIONSPART IITable 23-4Conditions qualifying patients as high surgical risk for carotid endarterectomyANATOMIC FACTORSPHYSIOLOGIC FACTORS• High carotid bifurcation (above C2 vertebral body)• Low common carotid artery (below clavicle)• Contralateral carotid occlusion• Restenosis of ipsilateral prior carotid endarterectomy• Previous neck irradiation• Prior radical neck dissection• Contralateral laryngeal nerve palsy• Presence of tracheostomy• Age ≥80 years• Left ventricular ejection fraction ≤30%• New York Heart Association class III/IV congestive heart


Surgery_Schwartz

Surgery_Schwartz. neck dissection• Contralateral laryngeal nerve palsy• Presence of tracheostomy• Age ≥80 years• Left ventricular ejection fraction ≤30%• New York Heart Association class III/IV congestive heart failure• Unstable angina: Canadian Cardiovascular Society class III/IV angina pectoris• Recent myocardial infarction• Clinically significant cardiac disease (congestive heart failure, abnormal stress test, or need for coronary revascularization)• Severe chronic obstructive pulmonary disease• End-stage renal disease on dialysisclinical outcomes. A Cochrane review noted that, before 2006, a total of 1269 patients had been studied in five randomized controlled trials comparing percutaneous carotid intervention and surgical carotid reconstruction.27 Taken together, these trials revealed that carotid artery stenting had a greater procedural risk of stroke and death when compared to carotid endarterectomy (odds ratio, 1.33; 95% confidence interval, 0.86–2.04). Addi-tionally, a greater incidence of


Surgery_Schwartz

Surgery_Schwartz. artery stenting had a greater procedural risk of stroke and death when compared to carotid endarterectomy (odds ratio, 1.33; 95% confidence interval, 0.86–2.04). Addi-tionally, a greater incidence of carotid restenosis was noted in the stenting group than the endarterectomy cohorts.However, the constant improvement of endovascular devices, procedural techniques, and adjunctive pharmacologic therapy will likely improve the treatment success of percutane-ous carotid intervention. Critical appraisals of several prospec-tive randomized trials comparing the efficacy of carotid stenting versus endarterectomy are available for review.28 Two recently published randomized controlled trial, the Carotid Revascu-larization Endarterectomy Versus Stent Trial (CREST) and the International Carotid Stenting Study (ICSS) have reported somewhat differing results.29 CREST compared the efficacy of carotid endarterectomy and carotid stenting in both symptom-atic and asymptomatic patients.30 Primary end


Surgery_Schwartz

Surgery_Schwartz. Study (ICSS) have reported somewhat differing results.29 CREST compared the efficacy of carotid endarterectomy and carotid stenting in both symptom-atic and asymptomatic patients.30 Primary end points included 30-day periprocedural composite death, stroke, myocardial infarction, or any ipsilateral stroke up to 4 years. CREST inves-tigators reported no difference between stenting (5.2%) and endarterectomy (4.5%) in terms of primary end point. When each variable was independently analyzed, there was a higher rate of stroke in the stenting group at 30 days (4.1% vs. 2.3%) and a higher rate of myocardial infarction in the endarterectomy group (2.3% vs. 1.1%). The ICSS was a multicenter, interna-tional, randomized controlled trial comparing carotid stenting versus endarterectomy in patients with symptomatic carotid ste-nosis.31 The risk of stroke, death, and myocardial infarction in the stenting group (8.5%) was significantly higher than in the surgical arm (5.2%). The finding that carotid


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Surgery_Schwartz. symptomatic carotid ste-nosis.31 The risk of stroke, death, and myocardial infarction in the stenting group (8.5%) was significantly higher than in the surgical arm (5.2%). The finding that carotid endarterectomy is safer than carotid stenting is also supported by the results of an MRI substudy, which showed significantly more new lesions by diffusion-weighted imaging in the carotid stenting than the carotid endarterectomy patients.All available randomized studies have provided some answers and raised some questions. Some ongoing clinical tri-als will undoubtedly provide more insights on the efficacy of carotid stenting in the near future. Currently, the Society for Vascular Surgeons recommends carotid endarterectomy as first-line treatment for most symptomatic patients with stenosis of 50% to 99% and asymptomatic patients with stenosis of 60% to 99%.32 The perioperative risk of stroke and death in asymp-tomatic patients must be below 3% to ensure benefit for the patient. Carotid


Surgery_Schwartz

Surgery_Schwartz. of 50% to 99% and asymptomatic patients with stenosis of 60% to 99%.32 The perioperative risk of stroke and death in asymp-tomatic patients must be below 3% to ensure benefit for the patient. Carotid artery stenting should be reserved for symptom-atic patients with stenosis of 50% to 99% at high risk for carotid endarterectomy for anatomic or medical reasons. Carotid artery stenting is not recommended for asymptomatic patients at this time. Asymptomatic patients at high risk for intervention or with a life expectancy of less than 3 years should be considered for medical management as the first-line therapy.Surgical Techniques of Carotid EndarterectomyAlthough carotid endarterectomy is one of the earliest vas-cular operations ever described and its techniques have been perfected in the last two decades, surgeons continue to debate many aspects of this procedure. For instance, there is no uni-versal agreement with regard to the best anesthetic of choice, the best intraoperative cerebral


Surgery_Schwartz

Surgery_Schwartz. two decades, surgeons continue to debate many aspects of this procedure. For instance, there is no uni-versal agreement with regard to the best anesthetic of choice, the best intraoperative cerebral monitoring, whether to “rou-tinely” shunt, open versus eversion endarterectomy, and patch versus primary closure. Various anesthetic options are avail-able for patient undergoing carotid endarterectomy including general, local, and regional anesthesia. Typically, the anesthe-sia of choice depends on the preference of the surgeon, anes-thesiologist, and patient. However, depending on the anesthetic given, the surgeon must decide whether intraoperative cerebral monitoring is necessary or intra-arterial carotid shunting will be used. In general, if the patient is awake, then his or her abilities to respond to commands during carotid clamp period determine the adequacy of collateral flow to the ipsilateral hemisphere. On the other hand, intraoperative electroencepha-logram (EEG) or


Surgery_Schwartz

Surgery_Schwartz. abilities to respond to commands during carotid clamp period determine the adequacy of collateral flow to the ipsilateral hemisphere. On the other hand, intraoperative electroencepha-logram (EEG) or transcranial power Doppler (TCD) has been used to monitor for adequacy of cerebral perfusion during the clamp period for patients undergoing surgery under general anesthesia. Focal ipsilateral decreases in amplitudes and slow-ing of EEG waves are indicative of cerebral ischemia. Simi-larly, a decrease to less than 50% of baseline velocity in the ipsilateral middle cerebral artery is a sign of cerebral ischemia. For patients with poor collateral flow exhibiting signs of cere-bral ischemia, intra-arterial carotid shunting with removal of the clamp will restore cerebral flow for the remaining part of the surgery. Stump pressures have been used to determine the need for intra-arterial carotid shunting. Some surgeons prefer to shunt all patients on a routine basis and do not use intraop-erative


Surgery_Schwartz

Surgery_Schwartz. of the surgery. Stump pressures have been used to determine the need for intra-arterial carotid shunting. Some surgeons prefer to shunt all patients on a routine basis and do not use intraop-erative cerebral monitoring.Brunicardi_Ch23_p0897-p0980.indd 91227/02/19 4:14 PM 913ARTERIAL DISEASECHAPTER 23Figure 23-17. To perform carotid endarterectomy, the patient’s neck is slightly hyperextended and turned to the contralateral side. An oblique incision is made along the anterior border of the ster-nocleidomastoid muscle centered on top of the carotid bifurcation.The patient’s neck is slightly hyperextended and turned to the contralateral side, with a roll placed between the shoulder blades. An oblique incision is made along the anterior border of the sternocleidomastoid muscle centered on top of the carotid bifurcation (Fig. 23-17). The platysma is divided completely. Typically, tributaries of the anterior jugular vein are ligated and divided. The dissection is carried medial to the


Surgery_Schwartz

Surgery_Schwartz. top of the carotid bifurcation (Fig. 23-17). The platysma is divided completely. Typically, tributaries of the anterior jugular vein are ligated and divided. The dissection is carried medial to the sternocleido-mastoid. The superior belly of the omohyoid muscle is usually encountered just anterior to the common carotid artery. This muscle can be divided. The carotid fascia is incised, and the common carotid artery is exposed. The common carotid artery is mobilized cephalad toward the bifurcation. The dissection of the carotid bifurcation can cause reactive bradycardia related to stimulation of the carotid body. This reflex can be blunted with injection of lidocaine 1% into the carotid body or reversed with administration of intravenous atropine. A useful landmark in the dissection of the carotid bifurcation is the common facial vein. This vein can be ligated and divided. Frequently the 12th cranial nerve (hypoglossal nerve) traverses the carotid bifurcation just behind the common


Surgery_Schwartz

Surgery_Schwartz. the carotid bifurcation is the common facial vein. This vein can be ligated and divided. Frequently the 12th cranial nerve (hypoglossal nerve) traverses the carotid bifurcation just behind the common facial vein. The external carotid artery is mobilized just enough to get a clamp across. Often, a branch of the external carotid artery crossing to the sternocleidomas-toid can be divided to allow further cephalad mobilization of the internal carotid artery. For high bifurcation, division of the posterior belly of the digastric muscle is helpful in establishing distal exposure of the internal carotid artery.Intravenous heparin sulfate (1 mg/kg) is routinely admin-istered just prior to carotid clamping. The internal carotid artery is clamped first using a soft noncrushing vascular clamp to prevent distal embolization. The external and common carotid arteries are clamped subsequently. A longitudinal arteriotomy is made in the distal common carotid artery and extended into the bulb and past


Surgery_Schwartz

Surgery_Schwartz. distal embolization. The external and common carotid arteries are clamped subsequently. A longitudinal arteriotomy is made in the distal common carotid artery and extended into the bulb and past the occlusive plaque into the normal part of the internal carotid artery. Endarterectomy is carried out to remove the occlusive plaque (Fig. 23-18). If necessary, a tem-porary shunt can be inserted from the common carotid artery to the internal carotid artery to maintain continuous antegrade cerebral blood flow (Fig. 23-19). Typically, a plane is teased out from the vessel wall, and the entire plaque is elevated and Figure 23-18. A. During carotid endarterectomy, vascular clamps are applied in the common carotid, external carotid, and internal carotid arteries. Carotid plaque is elevated from the carotid lumen. B. Carotid plaque is removed, and the arteriotomy is closed either primarily or with a patch angioplasty.Figure 23-19. A temporary carotid shunt is inserted from the com-mon carotid


Surgery_Schwartz

Surgery_Schwartz. carotid lumen. B. Carotid plaque is removed, and the arteriotomy is closed either primarily or with a patch angioplasty.Figure 23-19. A temporary carotid shunt is inserted from the com-mon carotid artery (long arrow) to the internal carotid artery (short arrow) during carotid endarterectomy to provide continuous ante-grade cerebral blood flow.removed. The distal transition line in the internal carotid artery where the plaque had been removed must be examined care-fully and should be smooth. Tacking sutures are placed when an intimal flap remains in this transition to ensure no obstruction to flow (Fig. 23-20). The occlusive plaque is usually removed from the origin of the external carotid artery using the ever-sion technique. The endarterectomized surface is then irrigated and any debris removed. A patch (autogenous saphenous vein, synthetic such as polyester, PTFE, or biologic material) is sewn to close the arteriotomy (Fig. 23-21). Whether patch closure is necessary in all patients


Surgery_Schwartz

Surgery_Schwartz. removed. A patch (autogenous saphenous vein, synthetic such as polyester, PTFE, or biologic material) is sewn to close the arteriotomy (Fig. 23-21). Whether patch closure is necessary in all patients and which patch is the best remain con-troversial. However, most surgeons agree that patch closure is Brunicardi_Ch23_p0897-p0980.indd 91327/02/19 4:14 PM 914SPECIFIC CONSIDERATIONSPART IIFigure 23-20. The distal transition line (left side of the picture) in the internal carotid artery where the plaque had been removed must be examined carefully and should be smooth. Tacking sutures (arrows) are placed when an intimal flap remains in this transition to ensure no obstruction to flow.Figure 23-21. A. An autologous or synthetic patch can be used to close the carotid arteriotomy incision, which maintains the luminal patency. B. A completion closure of carotid endarterectomy incision using a synthetic patch.BAindicated particularly for the small vessel (<7 mm). The ever-sion technique has


Surgery_Schwartz

Surgery_Schwartz. maintains the luminal patency. B. A completion closure of carotid endarterectomy incision using a synthetic patch.BAindicated particularly for the small vessel (<7 mm). The ever-sion technique has also been advocated for removing the plaque from the internal carotid artery. In the eversion technique, the internal carotid artery is transected at the bulb, the edges of the divided vessel are everted, and the occluding plaque is “peeled” off the vessel wall. The purported advantages of the eversion technique are no need for patch closure and a clear visualization of the distal transition area. Reported series have not shown a clear superiority of one technique over the others.33 Surgeons will likely continue to use the technique of their choice. Just prior to completion of the anastomosis to close the arteriotomy, we thoroughly flush the vessels of any potential debris. When the arteriotomy is closed, flow is restored to the external carotid artery first and to the internal carotid


Surgery_Schwartz

Surgery_Schwartz. to close the arteriotomy, we thoroughly flush the vessels of any potential debris. When the arteriotomy is closed, flow is restored to the external carotid artery first and to the internal carotid artery second. Intravenous protamine sulfate can be given to reverse the effect of heparin anticoagulation following carotid endarterectomy. The wound is closed in layers. After surgery, the patient’s neurologic con-dition is asserted in the operating room prior to transfer to the recovery area.Complications of Carotid Endarterectomy. Most patients tolerate carotid endarterectomy very well and typically are discharged home within 24 hours after surgery. Complica-tions after endarterectomy are infrequent but can be poten-tially life-threatening or disabling. Acute ipsilateral stroke is a dreaded complication following carotid endarterectomy. Cerebral ischemia can be due to either intraoperative or post-operative events. Embolizations from the occlusive plaque or prolonged cerebral ischemia


Surgery_Schwartz

Surgery_Schwartz. complication following carotid endarterectomy. Cerebral ischemia can be due to either intraoperative or post-operative events. Embolizations from the occlusive plaque or prolonged cerebral ischemia are potential causes of intraopera-tive stroke. The most common cause of postoperative stroke is due to embolization. Less frequently, acute carotid artery occlu-sion can cause acute postoperative stroke. This is usually due to carotid artery thrombosis related to closure of the arteriotomy, an occluding intimal flap, or distal carotid dissection. When patients experience acute symptoms of neurologic ischemia after endarterectomy, immediate intervention may be indicated. Carotid duplex scan can be done expeditiously to assess patency of the extracranial internal carotid artery. Reexploration is man-dated for acute carotid artery occlusion. Cerebral angiography can be useful if intracranial revascularization is considered.Local complications related to surgery include excessive bleeding and


Surgery_Schwartz

Surgery_Schwartz. man-dated for acute carotid artery occlusion. Cerebral angiography can be useful if intracranial revascularization is considered.Local complications related to surgery include excessive bleeding and cranial nerve palsies. Postoperative hematoma in the neck after carotid endarterectomy can lead to devastating airway compromise. Any expanding hematoma should be evac-uated and active bleeding stopped. Securing an airway is critical and can be extremely difficult in patients with large postopera-tive neck hematoma. The reported incidence of postoperative cranial nerve palsies after carotid endarterectomy varies from 1% to 30%.34 Well-recognized injuries involve the marginal mandibular, vagus, hypoglossal, superior laryngeal, and recur-rent laryngeal nerves. Often these are traction injuries but can also be due to severance of the respective nerves.Techniques of Carotid Angioplasty and StentingPercutaneous carotid artery stenting has become an accepted alternative treatment in the


Surgery_Schwartz

Surgery_Schwartz. but can also be due to severance of the respective nerves.Techniques of Carotid Angioplasty and StentingPercutaneous carotid artery stenting has become an accepted alternative treatment in the management of patients with carotid bifurcation disease (Fig. 23-22). The perceived advantages of percutaneous carotid revascularization are related to the mini-mal invasiveness of the procedure compared to surgery. There are anatomic conditions based on angiographic evaluation in which carotid artery stenting should be avoided due to increased procedure-related risks (Table 23-5). In preparation for carotid stenting, the patient should be given oral clopidogrel 3 days prior to the intervention if the patient was not already taking the drug. The procedure is done in either the operating room with angiographic capabilities or in a dedicated angiography room. The patient is placed in the supine position. The patient’s blood pressure and cardiac rhythm are closely monitored.To gain access to the


Surgery_Schwartz

Surgery_Schwartz. angiographic capabilities or in a dedicated angiography room. The patient is placed in the supine position. The patient’s blood pressure and cardiac rhythm are closely monitored.To gain access to the carotid artery, a retrograde trans-femoral approach is most commonly used as the access site for carotid intervention. Using the Seldinger technique, we insert a diagnostic 5or 6-French sheath in the CFA. A diagnostic arch Brunicardi_Ch23_p0897-p0980.indd 91427/02/19 4:14 PM 915ARTERIAL DISEASECHAPTER 23BAFigure 23-22. A. Carotid angiogram demonstrating a high-grade stenosis of the left internal carotid artery. B. Com-pletion angiogram demonstrating a sat-isfactory result following a carotid stent placement.Table 23-5Unfavorable carotid angiographic appearance in which carotid stenting should be avoided• Extensive carotid calcification• Polypoid or globular carotid lesions• Severe tortuosity of the common carotid artery• Long-segment stenoses (>2 cm in length)• Carotid artery


Surgery_Schwartz

Surgery_Schwartz. should be avoided• Extensive carotid calcification• Polypoid or globular carotid lesions• Severe tortuosity of the common carotid artery• Long-segment stenoses (>2 cm in length)• Carotid artery occlusion• Severe intraluminal thrombus (angiographic defects)• Extensive middle cerebral artery atherosclerosisaortogram is obtained. The carotid artery to be treated is then selected using a 5-French diagnostic catheter, and contrast is injected to show the carotid anatomy. It is important to assess the contralateral carotid artery, vertebrobasilar, and intracranial circulation if these are not known based on the preoperative noninvasive studies. Once the decision is made to proceed with carotid artery stenting, with the tip of the diagnostic catheter still in the common carotid artery, a 0.035-inch, 260-cm long stiff guidewire is placed in the ipsilateral external carotid artery. Anticoagulation with intravenous bivalirudin bolus (0.75 mg/kg) followed by an infusion rate of 2.5 mg/kg per


Surgery_Schwartz

Surgery_Schwartz. 260-cm long stiff guidewire is placed in the ipsilateral external carotid artery. Anticoagulation with intravenous bivalirudin bolus (0.75 mg/kg) followed by an infusion rate of 2.5 mg/kg per hour for the remain-der of the procedure is routinely administered. Next the diagnos-tic catheter is withdrawn and a 90-cm, 6-French guiding sheath is advanced into the common carotid artery over the stiff glide wire. It is critical not to advance the sheath beyond the occlu-sive plaque in the carotid bulb. The stiff wire is then removed, and preparation is made to deploy the distal embolic protection device (EPD). Several distal EPDs are available (Table 23-6). The EPD device is carefully deployed beyond the target lesion. With regard to the carotid stents, there are several stents that have received approval from the FDA and are commercially Table 23-6Commonly used embolic protection devices (EPDs)MECHANISMNAME OF EPDPORE SIZE (μM)Distal balloon occlusionPercuSurge Guard Wire, Export catheter


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Surgery_Schwartz. approval from the FDA and are commercially Table 23-6Commonly used embolic protection devices (EPDs)MECHANISMNAME OF EPDPORE SIZE (μM)Distal balloon occlusionPercuSurge Guard Wire, Export catheter (Medtronic)NADistal filterAngioguard (Cordis)Accunet (Abbott)Emboshield (Abbott)FilterWire (Boston Scientific)SpiderRx (EV3)100150140110<100Flow reversalaParodi Neuro Protection (Gore)NAaClinical trial (EMPIRE) in United States.NA = not applicable.available for carotid revascularization (Table 23-7). All current carotid stents use the rapid-exchange monorail 0.014-inch plat-form. The size selection is typically based on the size of com-mon carotid artery. Predilatation using a 4-mm balloon may be necessary to allow passage of the stent delivery catheter. Once the stent is deployed across the occlusive plaque, postdilatation is usually performed using a ≤5.5-mm balloon. It is noteworthy that balloon dilation of the carotid bulb may lead to immediate bradycardia due to stimulation of the


Surgery_Schwartz

Surgery_Schwartz. occlusive plaque, postdilatation is usually performed using a ≤5.5-mm balloon. It is noteworthy that balloon dilation of the carotid bulb may lead to immediate bradycardia due to stimulation of the glossopharyngeal nerve. The EPD is then retrieved and the procedure is completed with removal of the sheath from the femoral artery. The puncture site is closed using available closure device or with manual compression. Throughout the procedure, the patient’s neuro-logic function is closely monitored. The bivalirudin infusion is Brunicardi_Ch23_p0897-p0980.indd 91527/02/19 4:14 PM 916SPECIFIC CONSIDERATIONSPART IITable 23-7Currently approved carotid stents in the United StatesNAME OF STENTMANUFACTURERCELL DESIGNTAPERED STENTDELIVERY SYSTEM SIZE (FRENCH)AcculinkAbbottOpenYes6ExactAbbottClosedYes6NexStentBoston ScientificClosedSelf-tapering5Protégé RXEV3OpenYes6Precise RXCordisOpenNo6ExponentMedtronicOpenNo6Figure 23-23. Excessive elongation of the carotid artery can result in carotid


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Surgery_Schwartz. ScientificClosedSelf-tapering5Protégé RXEV3OpenYes6Precise RXCordisOpenNo6ExponentMedtronicOpenNo6Figure 23-23. Excessive elongation of the carotid artery can result in carotid kinking (arrow), which can compromise cerebral blood flow and lead to cerebral ischemia.stopped and the patient is kept on clopidogrel (75 mg daily) for at least 1 month and aspirin indefinitely.Complications of Carotid Stenting. Although there have been no randomized trials comparing carotid stenting with and without EPD, the availability of EPDs appears to have reduced the risk of distal embolization and stroke. The results of the various clinical trials and registries of carotid stenting have been reported and compared. It is well known that distal embolization as detected by TCD is much more frequent with carotid stenting even with EPD, when compared with carotid endarterectomy. However, the clinical significance of the distal embolization detected by TCD is not clear because most are asymptomatic. Acute


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Surgery_Schwartz. stenting even with EPD, when compared with carotid endarterectomy. However, the clinical significance of the distal embolization detected by TCD is not clear because most are asymptomatic. Acute carotid stent thrombosis is rare. The incidence of in-stent carotid restenosis is not well known but is estimated at 10% to 30%. Duplex surveillance shows elevated peak systolic velocities within the stent after carotid stenting not infrequently. However, velocity criteria are being formulated to determine the severity of in-stent restenosis after carotid stenting by ultra-sound duplex.35 It appears that systolic velocities exceeding 300 to 400 cm/s would represent >70% to 80% restenosis. Bradycar-dia and hypotension occur in up to 20% of patients undergoing carotid stenting.36 Systemic administration of atropine is usually effective in reversing the bradycardia. Other technical compli-cations of carotid stenting are infrequent and include carotid artery dissection and access site


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Surgery_Schwartz. administration of atropine is usually effective in reversing the bradycardia. Other technical compli-cations of carotid stenting are infrequent and include carotid artery dissection and access site complications, such as groin hematoma, femoral artery pseudoaneurysm, distal embolization, and acute femoral artery thrombosis.Nonatherosclerotic Disease of the Carotid ArteryCarotid Coil and Kink. A carotid coil consists of an excessive elongation of the internal carotid artery producing tortuosity of the vessel (Fig. 23-23). Embryologically, the carotid artery is derived from the third aortic arch and dorsal aortic root and is uncoiled as the heart and great vessels descend into the medi-astinum. In children, carotid coils appear to be congenital in origin. In contrast, elongation and kinking of the carotid artery in adults are associated with the loss of elasticity and an abrupt angulation of the vessel. Kinking is more common in women than men. Cerebral ischemic symptoms caused by


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Surgery_Schwartz. of the carotid artery in adults are associated with the loss of elasticity and an abrupt angulation of the vessel. Kinking is more common in women than men. Cerebral ischemic symptoms caused by kinks of the carotid artery are similar to those from atherosclerotic carotid lesions but are more likely due to cerebral hypoperfusion than embolic episodes. Classically, sudden head rotation, flexion, or extension can accentuate the kink and provoke ischemic symp-toms. Most carotid kinks and coils are found incidentally on carotid duplex scan. However, interpretation of the Doppler fre-quency shifts and spectral analysis in tortuous carotid arteries can be difficult because of the uncertain angle of insonation. Cerebral angiography, with multiple views taken in neck flex-ion, extension, and rotation, is useful in the determination of the clinical significance of kinks and coils.Fibromuscular Dysplasia. Fibromuscular dysplasia (FMD) usually involves medium-sized arteries that are long and have


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Surgery_Schwartz. is useful in the determination of the clinical significance of kinks and coils.Fibromuscular Dysplasia. Fibromuscular dysplasia (FMD) usually involves medium-sized arteries that are long and have few branches (Fig. 23-24). Women in the fourth or fifth decade of life are more commonly affected than men. Hormonal effects on the vessel wall are thought to play a role in the pathogenesis of FMD. FMD of the carotid artery is commonly bilateral, and in about 20% of patients, the vertebral artery is also involved.37 Brunicardi_Ch23_p0897-p0980.indd 91627/02/19 4:14 PM 917ARTERIAL DISEASECHAPTER 23Figure 23-24. A carotid fibromuscular dysplasia with typical characteristics of multiple stenoses with intervening aneurysmal outpouching dilatations. The disease involves the media, with the smooth muscle being replaced by fibrous connective tissue.An intracranial saccular aneurysm of the carotid siphon or mid-dle cerebral artery can be identified in up to 50% of the patients with FMD. Four


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Surgery_Schwartz. muscle being replaced by fibrous connective tissue.An intracranial saccular aneurysm of the carotid siphon or mid-dle cerebral artery can be identified in up to 50% of the patients with FMD. Four histologic types of FMD have been described in the literature. The most common type is medial fibroplasia, which may present as a focal stenosis or multiple lesions with intervening aneurysmal outpouchings. The disease involves the media with the smooth muscle being replaced by fibrous con-nective tissue. Commonly, mural dilations and microaneurysms can be seen with this type of FMD. Medial hyperplasia is a rare type of FMD, with the media demonstrating excessive amounts of smooth muscle. Intimal fibroplasia accounts for 5% of all cases and occurs equally in both sexes. The media and adven-titia remain normal, and there is accumulation of subendothe-lial mesenchymal cells with a loose matrix of connective tissue causing a focal stenosis in adults. Finally, premedial dyspla-sia represents a


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Surgery_Schwartz. remain normal, and there is accumulation of subendothe-lial mesenchymal cells with a loose matrix of connective tissue causing a focal stenosis in adults. Finally, premedial dyspla-sia represents a type of FMD with elastic tissue accumulating between the media and adventitia. FMD can also involve the renal and external iliac arteries. It is estimated that approxi-mately 40% of patients with FMD present with a TIA due to embolization of platelet aggregates.37 DSA demonstrates the characteristic “string of beads” pattern, which represents alter-nating segments of stenosis and dilatation. The string of beads can also be shown noninvasively by CTA or MRA. FMD should be suspected when an increased velocity is detected across a stenotic segment without associated atherosclerotic changes on carotid duplex ultrasound. Antiplatelet medication is the gener-ally accepted therapy for asymptomatic lesions. Endovascular treatment is recommended for patients with documented lateral-izing symptoms.


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Surgery_Schwartz. duplex ultrasound. Antiplatelet medication is the gener-ally accepted therapy for asymptomatic lesions. Endovascular treatment is recommended for patients with documented lateral-izing symptoms. Surgical correction is rarely indicated.Carotid Artery Dissection. Dissection of the carotid artery accounts for approximately 20% of strokes in patients younger than 45 years of age. The etiology and pathogenesis of sponta-neous carotid artery dissection remain incompletely understood. Arterial dissection involves hemorrhage within the media, which can extend into the subadventitial and subintimal layers. When the dissection extends into the subadventitial space, there is an increased risk of aneurysm formation. Subintimal dissections can lead to intramural clot or thrombosis. Traumatic dissection is typically a result of hyperextension of the neck during blunt trauma, neck manipulation, strangulation, or penetrating injuries to the neck. Even in supposedly spontaneous cases, a history of


Surgery_Schwartz

Surgery_Schwartz. is typically a result of hyperextension of the neck during blunt trauma, neck manipulation, strangulation, or penetrating injuries to the neck. Even in supposedly spontaneous cases, a history of preceding unrecognized minor neck trauma is not uncommon. Connective disorders, such as Ehlers-Danlos syndrome, Marfan’s syndrome, α1-antitrypsin deficiency, or FMD, may predispose to carotid artery dissection. Iatrogenic dissections can also occur due to catheter manipulation or balloon angioplasty.Typical clinical features of carotid artery dissection include unilateral neck pain, headache, and ipsilateral Horner’s syndrome in up to 50% of patients, followed by manifestations of the cerebral or ocular ischemia and cranial nerve palsies. Neurologic deficits can result either because of hemodynamic failure (caused by luminal stenosis) or by an artery-to-artery thromboembolism. The ischemia may cause TIAs or infarctions, or both. Catheter angiography has been the method of choice to diagnose


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Surgery_Schwartz. failure (caused by luminal stenosis) or by an artery-to-artery thromboembolism. The ischemia may cause TIAs or infarctions, or both. Catheter angiography has been the method of choice to diagnose arterial dissections, but with the advent of duplex ultra-sonography, MRI/MRA, and CTA, most dissections can now be diagnosed using noninvasive imaging modalities (Fig. 23-25). The dissection typically starts in the internal carotid artery distal to the bulb. Uncommonly, the dissection can start in the com-mon carotid artery or is an extension of a more proximal aortic dissection. Medical therapy has been the accepted primary treat-ment of symptomatic of carotid artery dissection. Anticoagula-tion (heparin and warfarin) and antiplatelet therapy have been commonly used, although there have not been any randomized studies to evaluate their effectiveness. The prognosis depends on the severity of neurologic deficit but is generally good in extracranial dissections. The recurrence rate is low.


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Surgery_Schwartz. been any randomized studies to evaluate their effectiveness. The prognosis depends on the severity of neurologic deficit but is generally good in extracranial dissections. The recurrence rate is low. Therapeutic interventions have been reserved for recurrent TIAs or strokes or failure of medical treatment. Endovascular options include intra-arterial stenting, coiling of associated pseudoaneurysms, or, more recently, deployment of covered stents.Figure 23-25. Carotid ultrasound reveals a patient with a carotid artery dissection in which carotid flow is separated in the true flow lumen (long arrow) from the false lumen (short arrow).Brunicardi_Ch23_p0897-p0980.indd 91727/02/19 4:14 PM 918SPECIFIC CONSIDERATIONSPART IIFigure 23-26. A. An anteroposterior angiogram of the neck revealing a carotid artery aneurysm. B. A lateral projection of the carotid artery aneurysm. C. Following endovascular placement, the carotid artery aneurysm is successfully excluded.Carotid Artery


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Surgery_Schwartz. revealing a carotid artery aneurysm. B. A lateral projection of the carotid artery aneurysm. C. Following endovascular placement, the carotid artery aneurysm is successfully excluded.Carotid Artery Aneurysms. Carotid artery aneurysms are rare, encountered in less than 1% of all carotid operations (Fig. 23-26). The true carotid artery aneurysm is generally due to atherosclerosis or medial degeneration. The carotid bulb is involved in most carotid aneurysms, and bilaterality is present in 12% of the patients. Patients typically present with a pul-satile neck mass. The available data suggest that, untreated, these aneurysms lead to neurologic symptoms from emboliza-tion. Thrombosis and rupture of the carotid aneurysm are rare. Pseudoaneurysms of the carotid artery can result from injury or infection. Mycotic aneurysms often involved syphilis in the past, but they are now more commonly associated with peri-tonsillar abscesses caused by Staphylococcus aureus infection. FMD and spontaneous


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Surgery_Schwartz. Mycotic aneurysms often involved syphilis in the past, but they are now more commonly associated with peri-tonsillar abscesses caused by Staphylococcus aureus infection. FMD and spontaneous dissection of the carotid artery can lead to A B CA BFigure 23-27. A. A carotid body tumor (arrow) located adjacent to the carotid bulb. B. Following periad-ventitial dissection, the carotid body tumor is removed.the formation of true aneurysms or pseudoaneurysms. Whereas conventional surgery has been the primary mode of treatment in the past, carotid aneurysms are currently being treated more commonly using endovascular approaches.38Carotid Body Tumor. The carotid body originates from the third branchial arch and from neuroectodermal-derived neural crest lineage. The normal carotid body is located in the adven-titia or periadventitial tissue at the bifurcation of the common carotid artery


Surgery_Schwartz

Surgery_Schwartz. branchial arch and from neuroectodermal-derived neural crest lineage. The normal carotid body is located in the adven-titia or periadventitial tissue at the bifurcation of the common carotid artery (Fig. 23-27). The gland is innervated by the glos-sopharyngeal nerve. Its blood supply is derived predominantly from the external carotid artery but can also come from the ver-tebral artery. Carotid body tumor is a rare lesion of the neuroen-docrine system. Other glands of neural crest origin are seen in Brunicardi_Ch23_p0897-p0980.indd 91827/02/19 4:14 PM 919ARTERIAL DISEASECHAPTER 23the neck, parapharyngeal spaces, mediastinum, retroperitoneum, and adrenal medulla. Tumors involving these structures have been referred to as paraganglioma, glomus tumor, or chemo-dectoma. Approximately 5% to 7% of carotid body tumors are malignant. Although chronic hypoxemia has been invoked as a stimulus for hyperplasia of carotid body, approximately 35% of carotid body tumors are hereditary.39 The risk


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Surgery_Schwartz. 7% of carotid body tumors are malignant. Although chronic hypoxemia has been invoked as a stimulus for hyperplasia of carotid body, approximately 35% of carotid body tumors are hereditary.39 The risk of malignancy is greatest in young patients with familial tumors.Symptoms related to the endocrine products of the carotid body tumor are rare. Patients usually present between the fifth and seventh decades of life with an asymptomatic lateral neck mass. The diagnosis of carotid body tumor requires confir-mation on imaging studies. Carotid duplex scan can localize the tumor to the carotid bifurcation, but CT or MRI is usually required to further delineate the relationship of the tumor to the adjacent structures. Classically, a carotid body tumor will widen the carotid bifurcation. The Shamblin classification describes the tumor extent: I, tumor is less than 5 cm and relatively free of vessel involvement; II, tumor is intimately involved but does not encase the vessel wall; and III, tumor


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Surgery_Schwartz. classification describes the tumor extent: I, tumor is less than 5 cm and relatively free of vessel involvement; II, tumor is intimately involved but does not encase the vessel wall; and III, tumor is intramural and encases the carotid vessels and adjacent nerves.40 With good-resolution CT and MRI, arteriography is usually not required. However, arteriography can provide an assessment of the vessel invasion and intracranial circulation and allows for preoperative embolization of the feeder vessels, which has been reported to reduce intraoperative blood loss. Surgical resection is the rec-ommended treatment for suspected carotid body tumor.Carotid Trauma. Blunt or penetrating trauma to the neck can cause injury to the carotid artery. Notwithstanding the massive bleeding from carotid artery transection, injury to the carotid artery can result in carotid dissection, thrombosis, or pseudoa-neurysm formation. Carotid duplex ultrasound can be useful to locate the site of injury in the


Surgery_Schwartz

Surgery_Schwartz. transection, injury to the carotid artery can result in carotid dissection, thrombosis, or pseudoa-neurysm formation. Carotid duplex ultrasound can be useful to locate the site of injury in the cervical segment of the carotid artery. Spiral CTA has become the modality of choice to detect extracranial carotid artery injury. Confirmation of carotid injury by contrast cerebral angiography remains the gold standard diagnostic test. Injuries to the cervical segment of the common and internal carotid arteries can be repaired surgically. Acute carotid artery thrombosis is usually treated medically with anti-coagulation if the patient is asymptomatic. Revascularization should be considered for patients presenting with ongoing cere-bral ischemia related to carotid artery thrombosis. Traumatic carotid artery dissection can cause cerebral ischemia due to thromboembolization, decreased flow, or thrombosis. Com-monly, the dissection involves the distal portion of the cervi-cal and petrous segment


Surgery_Schwartz

Surgery_Schwartz. artery dissection can cause cerebral ischemia due to thromboembolization, decreased flow, or thrombosis. Com-monly, the dissection involves the distal portion of the cervi-cal and petrous segment of the internal carotid artery. Medical management with antiplatelet or anticoagulation therapy is usu-ally adequate for uncomplicated traumatic carotid dissection. In patients with pseudoaneurysms of the carotid artery that are located in a segment that is out of surgical reach, the use of selective coil embolization of the pseudoaneurysm or exclu-sion of the pseudoaneurysm by a covered stent graft has been reported. Bare metal stent has been used with success in the treatment of traumatic carotid artery dissection.ABDOMINAL AORTIC ANEURYSMDespite more than 50,000 patients undergoing elective repair of abdominal aortic aneurysm (AAA) each year in the United States, approximately 15,000 patients die annually as a result of ruptured aneurysm, making it the 10th leading cause of death in men in


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Surgery_Schwartz. of abdominal aortic aneurysm (AAA) each year in the United States, approximately 15,000 patients die annually as a result of ruptured aneurysm, making it the 10th leading cause of death in men in this country.41 The incidence appears to be increasing, and this is due in part to improvements in diagnostic imaging and, more importantly, a growing elderly population. With early diagnosis and timely intervention, aneurysm rupture–related death is largely preventable. Conventional treatment of an AAA involves replacing the aneurysmal segment of the aorta with a prosthetic graft, with the operation performed through a large abdominal incision. Techniques for this open abdominal surgery have been refined, adapted, and extensively studied by vascular surgeons over the past four decades. Despite a well-documented low perioperative mortality rate of 2% to 3% in large academic institutions, the thought of undergoing an open abdominal aortic operation often provokes a sense of anxiety in many


Surgery_Schwartz

Surgery_Schwartz. a well-documented low perioperative mortality rate of 2% to 3% in large academic institutions, the thought of undergoing an open abdominal aortic operation often provokes a sense of anxiety in many patients due in part to the postoperative pain associated with the large abdominal incision as well as the long recovery time needed before the patient can return to normal physical activity.The most common location of aortic aneurysms is the infrarenal aorta. Endovascular stent graft placement represents a revolutionary and minimally invasive treatment for infrarenal AAAs that only requires 1 to 2 days of hospitalization, and the patient can return to normal physical activity within 1 week. The concept of using an endoluminal device in the management of vascular disease was first proposed by Dotter and colleagues, who successfully treated a patient with iliac occlusion using transluminal angioplasty in 1964.42 Nearly two decades later, Parodi and colleagues reported the first successful


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Surgery_Schwartz. Dotter and colleagues, who successfully treated a patient with iliac occlusion using transluminal angioplasty in 1964.42 Nearly two decades later, Parodi and colleagues reported the first successful endovascu-lar repair of AAA using a stent graft device.11 Since then, a variety of stent graft technologies have been developed to treat AAA. The rapid innovation of this new treatment modality has undoubtedly captured the attention of patients with aortic aneu-rysms as well as physicians who practice endovascular therapy. Physicians in general should be knowledgeable regarding avail-able treatment options of AAA in order to provide adequate evaluation and education to patients and their families. The pur-pose of this section is to outline the treatment options for AAAs, including conventional repair and endovascular approach. Advantages and potential complications of these treatments will also be addressed.Causes and Risk FactorsThe pathogenesis of aneurysmal disease of the aorta is


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Surgery_Schwartz. repair and endovascular approach. Advantages and potential complications of these treatments will also be addressed.Causes and Risk FactorsThe pathogenesis of aneurysmal disease of the aorta is complex and multifactorial. A degenerative process in the aortic wall is the most common cause of AAA development.43 Matrix metal-loproteinases (MMP), proteolytic enzymes, are found abun-dantly in the wall of AAA. Atherosclerotic disease, age, male sex, smoking history, family history, hypertension, coronary artery disease, and chronic obstructive pulmonary disease are associated with the development of AAA.44 Diabetes and black race have negative association with AAA. Other less common causes include inflammation, infection, and connective tissue disease. Inflammatory AAA accounts for 5% to 10% of all AAAs.43 In contrast to atherosclerotic AAA, the inflammatory variant is characterized pathologically by marked thickening of the aneurysm wall, fibrosis of the adjacent retroperitoneum, and rigid


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Surgery_Schwartz. all AAAs.43 In contrast to atherosclerotic AAA, the inflammatory variant is characterized pathologically by marked thickening of the aneurysm wall, fibrosis of the adjacent retroperitoneum, and rigid adherence of the adjacent structures to the anterior aneurysm wall. Male sex and smoking are even stronger risk factors in inflammatory AAA.45 Smoking cessation is the first step of medical therapy, followed by surgical repair. Infectious or mycotic AAA is rare but is associated with high mortality. Patients with connective tissue disorders such as Marfan’s syn-drome and Ehlers-Danlos syndrome tend to have more exten-sive and larger aneurysms at a younger age.43Brunicardi_Ch23_p0897-p0980.indd 91927/02/19 4:14 PM 920SPECIFIC CONSIDERATIONSPART IITable 23-8Annualized risk of rupture of abdominal aortic aneurysm (AAA) based on sizeDESCRIPTIONDIAMETER OF AORTA (CM)ESTIMATED ANNUAL RISK OF RUPTURE (%)ESTIMATED 5-YEAR RISK OF RUPTURE (%)aNormal aorta2–300 (unless AAA develops)Small


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Surgery_Schwartz. of abdominal aortic aneurysm (AAA) based on sizeDESCRIPTIONDIAMETER OF AORTA (CM)ESTIMATED ANNUAL RISK OF RUPTURE (%)ESTIMATED 5-YEAR RISK OF RUPTURE (%)aNormal aorta2–300 (unless AAA develops)Small AAA4–515–10Moderate AAA5–62–530–40Large AAA6–73–10>50Very large AAA>7>10Approaching 100aThe estimated 5-year risk is more than five times the estimated annual risk because over that 5 years, the AAA, if left untreated, will continue to grow in size.Natural History of Aortic AneurysmThe natural history of an AAA is to expand and rupture. AAA exhibits a “staccato” pattern of growth, where periods of relative quiescence may alternate with expansion. Therefore, although an individual pattern of growth cannot be predicted, average aggregate growth is approximately 3 to 4 mm/year. There is some evidence to suggest that larger aneurysms may expand faster than smaller aneurysms, but there is significant overlap between the ranges of growth rates at each strata of size.Rupture risk appears to be


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Surgery_Schwartz. to suggest that larger aneurysms may expand faster than smaller aneurysms, but there is significant overlap between the ranges of growth rates at each strata of size.Rupture risk appears to be directly related to aneurysm size as predicted by Laplace’s Law. Although more sophisti-cated methods of assessing rupture risk based on finite element analysis of wall stress are under active investigation, maximum transverse diameter remains the standard method of risk assess-ment for aneurysm rupture. In the past, AAA rupture risk has been overestimated. More recently, two landmark studies have served to better define the natural history of AAA.46,47 Based on best available evidence, the annualized risk of rupture is given in Table 23-8. The rupture risk is quite low below 5.5 cm and begins to rise exponentially thereafter. This size can serve as an appropriate threshold for recommending elective repair provided one’s surgical mortality is below 5%. For each size strata, however, women appear


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Surgery_Schwartz. exponentially thereafter. This size can serve as an appropriate threshold for recommending elective repair provided one’s surgical mortality is below 5%. For each size strata, however, women appear to be at higher risk for rup-ture than men, and a lower threshold of 4.5 to 5.0 cm may be reasonable in good-risk patients. Although data are less compel-ling, a pattern of rapid expansion of >0.5 cm within 6 months can be considered a relative indication for elective repair. Aneu-rysms that fall below these indications may safely be followed with CT or ultrasound at 6-month intervals, with long-term out-comes equivalent to earlier surgical repair. Interestingly, in the Aneurysm Detection and Management (ADAM) study, 80% of all AAAs that were followed in this manner eventually came to repair within 5 years.48Unless symptomatic or ruptured, AAA repair is a pro-phylactic repair. The rationale for recommending repair is predicated on the assumption that the risk of aneurysm rupture exceeds the


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Surgery_Schwartz. 5 years.48Unless symptomatic or ruptured, AAA repair is a pro-phylactic repair. The rationale for recommending repair is predicated on the assumption that the risk of aneurysm rupture exceeds the combined risk of death from all other causes such as cardiopulmonary disease and cancer. On the other hand, our limitation in predicting timing and cause of death is underscored by the observation that over 25% of patients who were deemed unfit for surgical repair because of their comorbidities died from rupture of their aneurysms within 5 years.Clinical ManifestationsMost AAAs are asymptomatic and are usually found inciden-tally during workup for chronic back pain or kidney stones. Physical examination is neither sensitive nor specific except 2in thin patients. Large aneurysms may be missed in the obese, while normal aortic pulsations may be mistaken for an aneurysm in thin individuals. Rarely patients present with back pain and/or abdominal pain with a tender pulsatile mass. Patients with


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Surgery_Schwartz. the obese, while normal aortic pulsations may be mistaken for an aneurysm in thin individuals. Rarely patients present with back pain and/or abdominal pain with a tender pulsatile mass. Patients with these symptoms must be treated as a rupture until proven otherwise. If the patient is hemodynamically stable and the aneurysm is intact on a CT scan, the patient is admitted for blood pressure control with intravenous antihypertensive agents and undergoes repair usually within 12 to 24 hours or at least during the same hospitalization. In contrast, patients who are hemodynamically unstable with a history of acute back pain and/or syncope and a known unrepaired AAA or a pulsatile abdominal mass should be immediately taken to the operating room with a presumed diagnosis of a ruptured AAA.Overall mortality of AAA rupture is 71% to 77%, which includes all out-of-hospital and in-hospital deaths, as compared with 2% to 6% for elective open surgical repair.49 Nearly half of all patients with


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Surgery_Schwartz. mortality of AAA rupture is 71% to 77%, which includes all out-of-hospital and in-hospital deaths, as compared with 2% to 6% for elective open surgical repair.49 Nearly half of all patients with ruptured AAA will die before reaching the hospital. For the remainder, surgical mortality is 45% to 50% and has not substantially changed in the last 30 years.50Relevant AnatomyAn AAA is defined as a pathologic focal dilation of the aorta that is greater than 30 mm or 1.5 times the adjacent diameter of the normal aorta (Fig. 23-28). Male aortas tend to be larger than female aortas, and there is generalized growth of the aortic diameter with each decade of life. Ninety percent of AAAs are infrarenal in location and have a fusiform morphology. There is a higher predilection for juxtarenal and suprarenal AAAs in women compared with men. Concomitant common iliac and/or hypogastric artery aneurysms can be found in 20% to 25% of patients. Although the etiology of most aortic aneurysms is


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Surgery_Schwartz. and suprarenal AAAs in women compared with men. Concomitant common iliac and/or hypogastric artery aneurysms can be found in 20% to 25% of patients. Although the etiology of most aortic aneurysms is ath-erosclerotic, clinically significant peripheral occlusive disease is unusual and present in less than 10% of all cases.Although extravascular anatomy is important for open surgical repair of AAA, intravascular anatomy and aortoiliac morphology are important for endovascular repair. Pertinent anatomic dimensions include the diameter of the proximal non-dilated infrarenal aortic neck, which can range from 18 to 30 mm; common iliac artery, which can range from 8 to 16 mm; and external iliac arteries, which can range from 6 to 10 mm. Mor-phologically, the aortic neck can manifest complex angulation above and below the renal arteries due to combination of elon-gation and anterolateral displacement by the posterior bulge of the aneurysmal aorta. Furthermore, the shape of the proxi-mal neck


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Surgery_Schwartz. above and below the renal arteries due to combination of elon-gation and anterolateral displacement by the posterior bulge of the aneurysmal aorta. Furthermore, the shape of the proxi-mal neck is rarely tubular, but often is conical, reverse coni-cal, or barrel-shaped. Distally, the iliac arteries can have severe Brunicardi_Ch23_p0897-p0980.indd 92027/02/19 4:14 PM 921ARTERIAL DISEASECHAPTER 23Figure 23-28. An operative view of an infrarenal aortic aneurysm.tortuosity with multiple compound turns. Although significant from hemodynamic standpoint, severe iliac calcifications com-bined with extreme tortuosity can pose a formidable challenge during endovascular repair.Diagnostic EvaluationPreoperative evaluation should include routine history and physical exam with particular attention to (a) any symptoms referable to the aneurysm, which may impact the timing of repair; (b) history of pelvic surgery or radiation, in the event retroperitoneal exposure is required or interruption of


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Surgery_Schwartz. to (a) any symptoms referable to the aneurysm, which may impact the timing of repair; (b) history of pelvic surgery or radiation, in the event retroperitoneal exposure is required or interruption of hypogas-tric circulation is planned; (c) claudication suggestive of sig-nificant iliac occlusive disease; (d) lower extremity bypass or other femoral reconstructive procedures; and (e) chronic renal insufficiency or contrast allergy.Cross-sectional imaging is required for definitive evalu-ation of AAA. Although ultrasound is safe, widely available, relatively accurate, and inexpensive and thus the screening modality of choice, CT scan remains the gold standard for deter-mination of anatomic eligibility for endovascular repair. Size of AAA may differ up to 1 cm between CT and ultrasound, and during longitudinal follow-up, comparisons should be made between identical modalities. With modern multirow detector scanners, a timed-bolus intravenous contrast-enhanced, 2.5to 3.0-mm slice spiral CT


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Surgery_Schwartz. longitudinal follow-up, comparisons should be made between identical modalities. With modern multirow detector scanners, a timed-bolus intravenous contrast-enhanced, 2.5to 3.0-mm slice spiral CT of the chest, abdomen, and pelvis can be performed in less than 30 seconds with a single breath hold. Extremely high-resolution images are obtained with submilli-meter spatial resolution (Fig. 23-29). Proper window level and width (brightness and contrast) are important for discrimination among aortic wall, calcific plaque, thrombus, and lumen. The only major drawback to CT is the risk of contrast nephropathy in diabetics and in patients with renal insufficiency.The spiral technique further affords the ability for three-dimensional reconstruction. Three-dimensional reconstructions Figure 23-29. High resolution of image displaying an aortic aneu-rysm (arrow) can be achieved with multidetector computed tomog-raphy angiography.can yield important morphologic information that is critical to


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Surgery_Schwartz. resolution of image displaying an aortic aneu-rysm (arrow) can be achieved with multidetector computed tomog-raphy angiography.can yield important morphologic information that is critical to endovascular therapy. Using third-party software, these images can be viewed and manipulated on one’s desktop computer, and so-called “center-line” (transverse slices perpendicular to the central flow lumen of the aorta) diameter and length measure-ments obtained. Conventional angiography has a minimal role in the current management of AAA. Angiography is invasive with an increased risk of complications. Indications for angiog-raphy are isolated to concomitant iliac occlusive disease (pres-ent in <10% of patients with AAA) and unusual renovascular anatomy.Surgical Repair of Abdominal Aortic AneurysmGeneral anesthesia is necessary when performing a conventional open AAA repair. While a retroperitoneal incision is a well-accepted surgical approach, a midline transabdominal incision remains the more


Surgery_Schwartz

Surgery_Schwartz. anesthesia is necessary when performing a conventional open AAA repair. While a retroperitoneal incision is a well-accepted surgical approach, a midline transabdominal incision remains the more common approach for open aortic aneurysm operation. Since the abdominal incision can lead to significant pain and discomfort, an epidural catheter can be placed prior to the operation for postoperative analgesic infusion to provide pain control. Once the abdominal cavity is opened, the small intestines and transverse colon are retracted to expose the ret-roperitoneum overlying the AAA. The retroperitoneum is next divided, followed by isolation of both proximal and distal seg-ments of the AAA. Intravenous heparin (100 IU/kg) is given followed by clamping of the proximal and distal segments of the aneurysm. The aneurysm sac is open next, and a prosthetic graft is used to reconstruct the aorta. If the aneurysm only involves the abdominal aorta, a tube graft can be used to replace the aorta (Fig.


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Surgery_Schwartz. The aneurysm sac is open next, and a prosthetic graft is used to reconstruct the aorta. If the aneurysm only involves the abdominal aorta, a tube graft can be used to replace the aorta (Fig. 23-30). If the aneurysm extends distally to the iliac arter-ies, a prosthetic bifurcated graft is used for either an aorto-bi-iliac or aorto-bi-femoral bypass reconstruction (Fig. 23-31). The overlying aneurysm sac and the retroperitoneum are closed to cover the prosthetic bypass graft to minimize potential bowel contact to the graft. Small and large intestines are returned to the abdominal cavity followed by the closure of the abdominal fascia and skin.Brunicardi_Ch23_p0897-p0980.indd 92127/02/19 4:14 PM 922SPECIFIC CONSIDERATIONSPART IIABFigure 23-30. A. Schematic depiction of an aortic tube graft used to repair an aortic aneurysm. B. Intraoperative image of an aortic tube graft reconstruction.Advantages and Risks of Open Abdominal Aortic Aneu-rysm Repair. The main advantage of a


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Surgery_Schwartz. tube graft used to repair an aortic aneurysm. B. Intraoperative image of an aortic tube graft reconstruction.Advantages and Risks of Open Abdominal Aortic Aneu-rysm Repair. The main advantage of a conventional open repair is that the AAA is permanently eliminated because it is entirely replaced by a prosthetic aortic graft. The risk of aneurysm recurrence or delayed rupture no longer exists. As a result, long-term imaging surveillance is not needed with these patients. In contrast, the long-term efficacy of endovascular repair remains unclear. Consequently, long-term imaging sur-veillance is critical to ensure that the aortic aneurysm remains properly sealed by the stent graft. Other potential advantages of open repair include direct assessment of the circulatory integrity of the colon. If signs of colonic ischemia become evident after aortic bypass grafting, a concomitant mesenteric artery bypass can be performed to revascularize the colonic circulation. In addition, open repair


Surgery_Schwartz

Surgery_Schwartz. If signs of colonic ischemia become evident after aortic bypass grafting, a concomitant mesenteric artery bypass can be performed to revascularize the colonic circulation. In addition, open repair permits the surgeons to explore for other abdominal pathologies, such as gastrointestinal tumors, liver mass, or cholelithiasis.As for the risks associated with open repair, cardiac com-plications, in the form of either myocardial infarction or arrhyth-mias, remain the most common morbidity, with an incidence between 2% and 6%.51 Another significant complication is renal failure or transient renal insufficiency as a result of peri-operative hypotension, atheromatous embolization, inadvertent injury to the ureter, preoperative contrast-induced nephropathy, or suprarenal aortic clamping. Although the incidence of renal failure is less than 2% in elective aneurysm repair, it can occur in more than 20% of patients after repair of a ruptured AAA.49Ischemic colitis is a devastating potential


Surgery_Schwartz

Surgery_Schwartz. the incidence of renal failure is less than 2% in elective aneurysm repair, it can occur in more than 20% of patients after repair of a ruptured AAA.49Ischemic colitis is a devastating potential complication after open repair. The likelihood of such a complication is highest in those who had a prior colon resection and undergo repair of a ruptured AAA, due to the loss of collateral blood supply to the rectosigmoid colon. It is estimated that 5% of patients who undergo elective aneurysm repair will develop partial-thickness ischemic colitis but without significant clini-cal sequelae.52 However, if the partial-thickness ischemia pro-gresses to full-thickness gangrene and peritonitis, mortality can be as high as 90%.52The incidence of prosthetic graft infection ranges between 1% and 4% after open repair.53 It is more common in those who undergo repair of a ruptured AAA. If the prosthetic graft is not fully covered by the aneurysm sac or retroperitoneum, intestinal adhesion with


Surgery_Schwartz

Surgery_Schwartz. 4% after open repair.53 It is more common in those who undergo repair of a ruptured AAA. If the prosthetic graft is not fully covered by the aneurysm sac or retroperitoneum, intestinal adhesion with subsequent bowel erosion may occur, resulting in an aortoenteric fistula. The predominant sign of such a com-plication is massive hematemesis, and it typically occurs years after the operation. Despite these potential complications, how-ever, the majority of patients who undergo successful elective open repair have an uneventful recovery.Endovascular Repair of Abdominal Aortic AneurysmOver a decade has passed since the first report of human implan-tation of a homemade stent graft for endovascular repair of an AAA by Parodi in 1991.11 Several prospective clinical trials across different devices and analysis of large Medicare adminis-trative databases and meta-analyses of published literature have consistently demonstrated significantly decreased operative time, blood loss, hospital length


Surgery_Schwartz

Surgery_Schwartz. and analysis of large Medicare adminis-trative databases and meta-analyses of published literature have consistently demonstrated significantly decreased operative time, blood loss, hospital length of stay, and overall periopera-tive morbidity and mortality of endovascular repair compared Brunicardi_Ch23_p0897-p0980.indd 92227/02/19 4:14 PM 923ARTERIAL DISEASECHAPTER 23Figure 23-31. Intraoperative view of a bifurcated graft used to repair an aortic aneurysm.with open surgical repair. For patients who are at increased risk for surgery because of age or comorbidity, endovascular repair is a superior minimally invasive alternative.The principle of endovascular repair of AAA involves the implantation of an aortic stent graft that is fixed proximally and distally to nonaneurysmal aortoiliac segment and thereby endoluminally excluding the aneurysm from the aortic circu-lation (Fig. 23-32). Unlike open surgical repair, the aneurysm BAFigure 23-32. A. An aortogram dem-onstrating a large


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Surgery_Schwartz. segment and thereby endoluminally excluding the aneurysm from the aortic circu-lation (Fig. 23-32). Unlike open surgical repair, the aneurysm BAFigure 23-32. A. An aortogram dem-onstrating a large infrarenal abdominal aortic aneurysm. B. Following endovas-cular stent graft implantation, the aortic aneurysm is successfully excluded.sac is not resected, which is subjected for potential aneurysm expansion or even rupture. Importantly, aortic branches, such as lumbar arteries or the inferior mesenteric artery (IMA), are occluded, which can lead to persistent aneurysm pressurization and aneurysm expansion. Currently, there are more than fifteen different endovascular devices approved for clinical use for infrarenal aortic aneurysm implantation throughout the world. Despite some differences in physical appearance, mechanical properties, and endograft materials, these endovascular devices will be discussed collectively for this chapter. Most of these devices are modular devices consisting of


Surgery_Schwartz

Surgery_Schwartz. appearance, mechanical properties, and endograft materials, these endovascular devices will be discussed collectively for this chapter. Most of these devices are modular devices consisting of a primary device or main body and one or two iliac limbs that insert into the main body to complete the repair. Depending on the device, there are varying degrees of flexibility in the choice of iliac limbs that can be matched to the main body, which can impact the customiz-ability for a particular anatomy.A severe limitation of the endovascular repair devices is the need for adequate proximal neck to achieve a durable seal-ing zone. Several techniques have been proposed to overcome this limitation. These include fenestrated or branched endografts and the “chimney,” “snorkel,” and “periscope” techniques. The fenestrated stent grafts rely on precise alignment between the fen-estration and the corresponding visceral artery.12,54 Multiple clinical trials using customized fenestrated stent graft for


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Surgery_Schwartz. The fenestrated stent grafts rely on precise alignment between the fen-estration and the corresponding visceral artery.12,54 Multiple clinical trials using customized fenestrated stent graft for the treatment of short-necked and juxtarenal aortic aneurysm repair have shown promising shortand mid-term results.54,55 How-ever, fenestrated stent graft generally requires device customiza-tion which is accessible only to high volume tertiary institutions, and not widely available to all hospital facilities. Alternatively, some centers have reported good results with intraoperative surgeon-modified endograft to create fenestrations for the treat-ment of complex aortic aneurysms in high-risk patients.56 Fur-ther development of the fenestrated techniques also opens the way for endovascular treatment of suprarenal and thoracoab-dominal aneurysm.57 The review of literature showed that open surgery remains a safe and effective treatment option for good-risk patients with juxtarenal aortic


Surgery_Schwartz

Surgery_Schwartz. treatment of suprarenal and thoracoab-dominal aneurysm.57 The review of literature showed that open surgery remains a safe and effective treatment option for good-risk patients with juxtarenal aortic aneurysm.58 Fenestrated endovascular repair is associated with low mortality and com-pares favorably with open surgery in terms of morbidity, espe-cially renal function impairment and cardiac complications.59Brunicardi_Ch23_p0897-p0980.indd 92327/02/19 4:14 PM 924SPECIFIC CONSIDERATIONSPART IIPatient Selection for Endovascular Aortic Aneurysm Repair. Anatomic eligibility for endovascular repair is mainly based on three areas: the proximal aortic neck, common iliac arteries, and external iliac and common femoral arteries, which relate to the proximal and distal landing zones or fixation sites and the access vessels, respectively. The requirements for the proximal aortic neck are a diameter of 18 to 28 mm and a mini-mum length of 15 mm (Table 23-9). Usually, multiple measure-ments of


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Surgery_Schwartz. sites and the access vessels, respectively. The requirements for the proximal aortic neck are a diameter of 18 to 28 mm and a mini-mum length of 15 mm (Table 23-9). Usually, multiple measure-ments of the diameter are taken along the length of the neck to assess its shape. All diameter measurements are mid-wall to mid-wall of the vessel. Secondary considerations include mural calcifications (<50% circumference), luminal thrombus (<50% circumference), and angulation (<45°). Presence of a significant amount of any one of these secondary features in combination with a relatively short proximal neck may compromise success-ful shortand long-term fixation of the stent graft and exclusion of the aneurysm. The usual distal landing zone is the common iliac artery. The external iliac artery may serve as an alternate site when the ipsilateral common iliac artery is aneurysmal or ectatic. The treatable diameters of common iliac arteries range from 8 to 20 mm, and there should be at least 20 mm of


Surgery_Schwartz

Surgery_Schwartz. as an alternate site when the ipsilateral common iliac artery is aneurysmal or ectatic. The treatable diameters of common iliac arteries range from 8 to 20 mm, and there should be at least 20 mm of patent artery of uniform diameter to allow adequate fixation. Finally, at least one of two common femoral and external iliac arteries must be at least 7 mm in diameter in order to safely introduce the main delivery sheath. Slightly smaller iliac diameters may be tolerated depending on the specific device and in the absence of severe tortuosity and calcific disease. Difficult access is one of the main causes of increased procedural time and intraopera-tive complications. Using these criteria, approximately 60% of all AAAs are anatomic candidates for endovascular repair.The next step in the preoperative planning is device selec-tion. Typically, the proximal diameter of the main device is oversized by 10% to 20% of the nominal diameter of the aor-tic neck. Distally, the iliac limbs are


Surgery_Schwartz

Surgery_Schwartz. preoperative planning is device selec-tion. Typically, the proximal diameter of the main device is oversized by 10% to 20% of the nominal diameter of the aor-tic neck. Distally, the iliac limbs are oversized by 1 to 4 mm depending on the individual device’s instructions for use. The biggest challenge to proper device selection remains determin-ing the optimal length from the renal arteries to the hypogastric arteries. Despite availability of sophisticated three-dimensional reconstructions, the exact path that a device will take from the proximal aortic neck to the distal iliac arteries is difficult to pre-dict. It is dependent on a host of factors related to the mechanical properties of the stent graft and the morphology of the aortoiliac flow lumen. “Plumb-line” measurements of axial CT images can be quite inaccurate, typically grossly underestimating the Table 23-9Ideal characteristics of an aneurysm for endovascular abdominal aortic aneurysm repairNeck length (mm)>15Neck diameter


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Surgery_Schwartz. images can be quite inaccurate, typically grossly underestimating the Table 23-9Ideal characteristics of an aneurysm for endovascular abdominal aortic aneurysm repairNeck length (mm)>15Neck diameter (mm)>18, <32Aortic Neck angle (degrees)<60Neck mural calcification (% circumference)<50Neck luminal thrombus (% circumference)<50Common iliac artery diameter (mm)Between 8 and 20Common iliac artery length (mm)>20External iliac artery diameter (mm)>7length, whereas center-line measurements usually overestimate the length. Angiographic measurements using a marker catheter are invasive, require contrast and radiation exposure, and are also inaccurate because they fail to account for the stiffness of the stent graft. The consequences of not choosing the correct length of the device include inadvertent coverage of the hypo-gastric artery if too long and the need for additional devices if too short.Advantages and Risks of Endovascular Repair. The obvi-ous advantage of an endovascular AAA


Surgery_Schwartz

Surgery_Schwartz. inadvertent coverage of the hypo-gastric artery if too long and the need for additional devices if too short.Advantages and Risks of Endovascular Repair. The obvi-ous advantage of an endovascular AAA repair is its minimally invasive nature. Typically, patients who undergo this procedure stay in the hospital for only 1 to 3 days, in contrast to the 5to 10-day stay required after conventional open surgical repair. In our institution, patients who have had an endovascular repair are routinely transferred to a general vascular ward from the post-anesthesia recovery unit, avoiding admission to a more costly intensive care unit.Because an abdominal incision is not necessary in endo-vascular repair, the procedure is particularly beneficial in patients with severe pulmonary disease, such as chronic obstruc-tive pulmonary disease or emphysema. Patients can sustain ade-quate breathing in the postoperative period, avoiding respiratory complications or prolonged mechanical ventilation. Because


Surgery_Schwartz

Surgery_Schwartz. obstruc-tive pulmonary disease or emphysema. Patients can sustain ade-quate breathing in the postoperative period, avoiding respiratory complications or prolonged mechanical ventilation. Because the abdominal cavity has not been entered, the risk of gastro-intestinal complications, such as ileus, ventral hernia, or bowel obstruction due to intestinal adhesion, is also greatly reduced. Moreover, regional or epidural anesthesia can be used, avoid-ing the risks associated with general anesthesia in patients with severe cardiopulmonary dysfunction.Despite its many advantages, endovascular repair does have potential complications. Since the stent graft device is attached endoluminally within the abdominal aorta, an endoleak due to incomplete stent graft exclusion of the aneurysm can occur. With this type of leak, blood flow persists outside the lumen of the endoluminal graft but within an aneurysm sac. A meta-analysis of 1118 patients who underwent successful endo-vascular repair found an


Surgery_Schwartz

Surgery_Schwartz. this type of leak, blood flow persists outside the lumen of the endoluminal graft but within an aneurysm sac. A meta-analysis of 1118 patients who underwent successful endo-vascular repair found an endoleak incidence of 24%.60 Although a small endoleak usually poses little clinical significance because it will typically become thrombosed spontaneously, a large or persistent endoleak may lead to continuous aneurysm perfusion and ultimately to aneurysm rupture. The rupture rate following an endovascular AAA repair has been reported to be less than 0.8%.61Stent graft iliac limb dysfunction resulting in thrombosis has been reported following endovascular repair. One possible cause is aneurysm remodeling, resulting in a shortening in the aortic length, which can cause the stent graft to kink. Alterna-tively, progression of an underlying iliac atherosclerotic lesion may cause compression of the iliac limb and ultimately result in graft-limb occlusion. Treatment options include thrombolysis


Surgery_Schwartz

Surgery_Schwartz. Alterna-tively, progression of an underlying iliac atherosclerotic lesion may cause compression of the iliac limb and ultimately result in graft-limb occlusion. Treatment options include thrombolysis or graft thrombectomy to determine the underlying cause and possibly additional stent graft placement. Renal artery occlusion may occur due to improper stent graft positioning or migration.62 Graft limb separation or dislocation has also been reported.62In patients with AAA and concurrent iliac artery aneu-rysms who undergo preoperative coil embolization of the inter-nal iliac artery, 20% to 45% experience symptoms of pelvic ischemia.63 These symptoms may include buttock claudication, impotence, gluteal skin sloughing, and colonic ischemia. Other complications pertaining to endovascular repair relate to the access site and include groin hematoma and wound infection. Brunicardi_Ch23_p0897-p0980.indd 92427/02/19 4:14 PM 925ARTERIAL DISEASECHAPTER 23Occasionally, the stent graft device


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Surgery_Schwartz. relate to the access site and include groin hematoma and wound infection. Brunicardi_Ch23_p0897-p0980.indd 92427/02/19 4:14 PM 925ARTERIAL DISEASECHAPTER 23Occasionally, the stent graft device can malfunction by either failing to deploy or dislodging during the deployment proce-dure. If the device cannot be salvaged or rescued endoluminally, open surgical repair of the aneurysm may be necessary.Technical Considerations of Endovascular Aortic Aneu-rysm Repair. Although endovascular AAA repair may be performed in any venue with appropriate digital fluoroscopic imaging capability, due to the need for absolute sterility and aseptic technique, it is most safely performed in a surgical suite. The patient is prepped and draped just as in open AAA repair. Patients with renal insufficiency should be started on periopera-tive oral N-acetylcysteine (Mucomyst) and sodium bicarbonate infusion to reduce the risk of contrast nephropathy. A variety of anesthetic options may be used. Regional


Surgery_Schwartz

Surgery_Schwartz. should be started on periopera-tive oral N-acetylcysteine (Mucomyst) and sodium bicarbonate infusion to reduce the risk of contrast nephropathy. A variety of anesthetic options may be used. Regional anesthesia may be appropriate for patients with pulmonary disease. There are reports of success with local anesthetics alone, as the incisions are typically smaller than a typical open inguinal hernia repair.64Groin access for endovascular aortic aneurysm repair can be achieved by either surgical cutdown for femoral artery expo-sure or percutaneous approach using “preclose” technique with the Perclose suture-mediated vascular closure device (Abbott Perclose, Redwood City, CA). Review of reported series on this percutaneous technique suggest a technical success rate of 95% for medium-size sheaths ranging from 12 to 16 French, and 87% success for 18to 24-French sizes.65 Once femoral artery access is obtained followed by introducer sheath placement, initial soft-tipped starter guidewires are


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Surgery_Schwartz. ranging from 12 to 16 French, and 87% success for 18to 24-French sizes.65 Once femoral artery access is obtained followed by introducer sheath placement, initial soft-tipped starter guidewires are exchanged for stiff guidewires that are advanced to the thoracic arch. Intravenous heparin at 80 IU/kg are administered, and the activated clotting time is maintained at 200 to 250 seconds. These guidewires provide the necessary support for the subsequent introduction of the large-diameter delivery catheters and devices. In the absence of special anatomic considerations, the primary device is inserted through the right side and the contralateral iliac limb is inserted through the left side. After administration of heparin, the deliv-ery catheter or the introducer sheath is advanced to the L1-L2 vertebral space, which typically marks the location of the renal arteries. An angiographic catheter is advanced from the contra-lateral femoral artery to the same level.A road-mapping aortogram is


Surgery_Schwartz

Surgery_Schwartz. vertebral space, which typically marks the location of the renal arteries. An angiographic catheter is advanced from the contra-lateral femoral artery to the same level.A road-mapping aortogram is obtained to localize the renal arteries. The primary device is rotated to the desired ori-entation and deployed immediate below the lowest renal artery (Fig. 23-33). The angiographic catheter is replaced with a direc-tional catheter and an angled guidewire, and the opening for the contralateral limb on the main device is cannulated. Intrastent passage of the guidewire is confirmed, and the angled guidewire is replaced with a stiff guidewire. The contralateral iliac limb is inserted into the docking opening of the primary device and deployed. A completion angiogram is performed looking for patency of the renal and hypogastric arteries, the device limbs, proximal and distal fixation, and endoleak. Adjunctive interven-tions including additional devices, balloons, and bare stents are performed


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Surgery_Schwartz. of the renal and hypogastric arteries, the device limbs, proximal and distal fixation, and endoleak. Adjunctive interven-tions including additional devices, balloons, and bare stents are performed as needed. The procedure is concluded with routine repairs of the femoral arteries and closure of the groin incisions. The patients recover in the recovery room for 2 to 4 hours and admitted to the general care floor. Although in the past, patients were admitted to the intensive care unit, this is rarely needed. Most patients can be started on a regular diet that evening and discharged the next morning.Surveillance Following Endovascular Aortic Aneurysm Repair. Life-long follow-up is essential to the long-term ADCBFigure 23-33. A. During an endovascular aortic aneurysm repair, the main endograft device is inserted through a femoral artery approach. B. The device is deployed in the aorta just below the renal arteries. C. A contralateral iliac endograft device is inserted through a


Surgery_Schwartz

Surgery_Schwartz. endograft device is inserted through a femoral artery approach. B. The device is deployed in the aorta just below the renal arteries. C. A contralateral iliac endograft device is inserted through a contralateral gate opening, which is next deployed. D. Completion of deployment of the endograft device should fully exclude an aortic aneurysm while preserving flow of the renal and hypogastric arteries.success after endovascular AAA repair. Indeed, one may go so far as to say that absence of appropriate follow-up is tantamount to not having had a repair at all. A triple-phase (noncontrast, contrast, and delayed) spiral CT scan and a four-view (antero-posterior, lateral, and two obliques) abdominal X-ray should be obtained within the first month. Subsequent imaging can be obtained at 6-month intervals in the first 1 to 2 years and yearly thereafter. After the first 6 months, patients who cannot travel easily may obtain their studies locally and submit them for review. The CT scan is for


Surgery_Schwartz

Surgery_Schwartz. intervals in the first 1 to 2 years and yearly thereafter. After the first 6 months, patients who cannot travel easily may obtain their studies locally and submit them for review. The CT scan is for detection of endoleaks, subtle proxi-mal migrations, and changes in aneurysm size. The abdominal X-ray gives a “birds-eye” view of the overall morphology of the stent graft. Subtle changes in conformation of the iliac limbs relative to each other and/or the spine can provide early signs of impending component separation or loss of fixation. Further, stent fractures and/or suture breaks that can compromise long-term device integrity can sometimes only be detected on a plain film and not on a CT scan.Results From Clinical Studies Comparing Endovascular Versus Open RepairThe primary success rate after endovascular repair of AAA has been reported to be as high as 95%.41 The less invasive nature Brunicardi_Ch23_p0897-p0980.indd 92527/02/19 4:14 PM 926SPECIFIC CONSIDERATIONSPART IIof this