Surgery_Schwartz

Surgery_Schwartz. in an increase in pulmonary blood flow secondary to primarily left-to-right shunting through the defect. The direction of the intracardiac shunt is predomi-nantly determined by the compliance of the respective ventri-cles. In utero, the distensibility, or compliance, of the right and left ventricles is equal, but postnatally the left ventricle (LV) becomes less compliant than the right ventricle (RV). This shift occurs because the resistance of the downstream vascular beds changes after birth. The pulmonary vascular resistance falls with the infant’s first breath, decreasing RV pressure, whereas the systemic vascular resistance rises dramatically, increasing LV pressure. The increase in LV pressure promotes hypertrophy with a thicker muscle mass, which offers a greater resistance to diastolic filling than does the RV; thus, the majority of flow through the ASD occurs from left to right. The greater volume of blood returning to the right atrium causes volume overload in the RV, but


Surgery_Schwartz

Surgery_Schwartz. filling than does the RV; thus, the majority of flow through the ASD occurs from left to right. The greater volume of blood returning to the right atrium causes volume overload in the RV, but because of its lower muscle mass and low-resistance output, it easily distends to accommodate the increased volume.The long-term consequences of RV volume overload include hypertrophy with elevated RV end-diastolic pressure and a relative pulmonary stenosis across the pulmonary valve because it cannot accommodate the increased RV flow. Com-pliance gradually decreases as the right ventricular pressure approaches systemic pressure, and the size of the left-to-right shunt decreases. Patients at this stage have a balanced circula-tion and may deceptively appear less symptomatic.Key Points1 Congenital heart disease comprises a wide morphologic spec-trum. In general, lesions can be conceptualized as those that can be completely repaired, those that should be palliated, and those that can be either


Surgery_Schwartz

Surgery_Schwartz. heart disease comprises a wide morphologic spec-trum. In general, lesions can be conceptualized as those that can be completely repaired, those that should be palliated, and those that can be either repaired or palliated depending on particular patient and institutional characteristics.2 Percutaneous therapies for congenital heart disease are quickly becoming important adjuncts, and in some cases, alternatives, to standard surgical therapy. Important exam-ples include percutaneous closure of atrial and ventricular septal defects, the hybrid approach to hypoplastic left heart syndrome, radiofrequency perforation of the pulmonary valve, and percutaneous pulmonary valve placement. Further studies are necessary to establish criteria and current bench-marks for the safe integration of these novel approaches into the care of patients with congenital heart surgery.3 Patients with critical left ventricular outflow tract obstruc-tion, such as neonatal critical aortic stenosis, represent a


Surgery_Schwartz

Surgery_Schwartz. novel approaches into the care of patients with congenital heart surgery.3 Patients with critical left ventricular outflow tract obstruc-tion, such as neonatal critical aortic stenosis, represent a challenging population. It is critical that the correct decision (whether to pursue univentricular or biventricular repair) be made prior to the initial operation, as attrition when the incorrect decision is made is high. There are several pub-lished criteria (Congenital Heart Surgeons’ Society critical stenosis calculator) to help surgeons decide which strategy to pursue.4 Optimum strategy for repair of total anomalous pulmonary venous connection (TAPVC) remains a topic of some con-tention. Sutureless repair, formerly reserved for initial reste-nosis after conventional repair, has evolved in many centers to be the primary approach for high-risk patients. Defining whether sutureless repair should be considered in all patients with TAPVC will require further study.5 Vascular rings and


Surgery_Schwartz

Surgery_Schwartz. in many centers to be the primary approach for high-risk patients. Defining whether sutureless repair should be considered in all patients with TAPVC will require further study.5 Vascular rings and pulmonary artery slings often require multidisciplinary approaches for management. They can be associated with complete tracheal rings and tracheobronchomalacia.6 A recent prospective, randomized, multi-institutional trial sponsored by the National Institutes of Health, the Systemic Ventricle Reconstruction (SVR) trial, compared the out-comes of neonates with hypoplastic left heart syndrome hav-ing either a modified Blalock–Taussig shunt (MBTS) versus a right ventricle-to-pulmonary artery (RV-PA) shunt. The SVR trial demonstrated that transplantation-free survival 12 months after randomization was higher with the RV-PA shunt than with the MBTS. However, data collected over a mean follow-up period of 32 ± 11 months showed a nonsig-nificant difference in transplantation-free survival between


Surgery_Schwartz

Surgery_Schwartz. was higher with the RV-PA shunt than with the MBTS. However, data collected over a mean follow-up period of 32 ± 11 months showed a nonsig-nificant difference in transplantation-free survival between the two groups.7 Outcomes have improved substantially over time in congeni-tal heart surgery, and most complex lesions can be operated in early infancy. Neurologic protection, however, remains a key issue in the care of neonates undergoing surgery with cardiopulmonary bypass and deep hypothermic circulatory arrest. New monitoring devices and perioperative strategies are currently under investigation. Attention in the field has shifted from analyses of perioperative mortality, which for most lesions is under 10%, to longer-term outcomes, includ-ing quality of life and neurologic function.8 Pediatric mechanical circulatory support and heart transplan-tation is an upcoming and rapidly evolving component of congenital heart surgery. These are offering options for res-cue, palliation, and


Surgery_Schwartz

Surgery_Schwartz. mechanical circulatory support and heart transplan-tation is an upcoming and rapidly evolving component of congenital heart surgery. These are offering options for res-cue, palliation, and treatment of complex defects or children who were palliated and failing.9 Public reporting has become an integral part of this subspe-cialty. The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) remains the largest database in the world for congenital and pediatric heart surgery. Transparency in overall outcomes, mortality, and morbidity is allowing patients and their families an insight into the complexity of their diagnoses as well as the level of perfor-mance of different centers.Brunicardi_Ch20_p0751-p0800.indd 75222/02/19 2:54 PM 753CONGENITAL HEART DISEASECHAPTER 20ABCFigure 20-1. A. Echocardiogram of a patient with primum type artial septal defect (‘*’ points to the atrial septal defect). B. Echocardiogram of a large secundum type ASD (‘*’ points to the defect).


Surgery_Schwartz

Surgery_Schwartz. 20-1. A. Echocardiogram of a patient with primum type artial septal defect (‘*’ points to the atrial septal defect). B. Echocardiogram of a large secundum type ASD (‘*’ points to the defect). C. Intra-operative picture during repair of atrial septal defect. A large fenestrated atrial septum is seen. Bicaval venous cannulation has been performed and a right atriotomy provides exposure to the atrial septum.Patients with large ASDs gradually develop progressive pulmonary vascular changes as a result of chronic overcircu-lation. The increased pulmonary vascular resistance in these patients leads to an equalization of left and right ventricular pressures, and their ratio of pulmonary (Qp) to systemic flow (Qs), Qp to Qs, will approach 1.5 This does not mean, however, that there is no intracardiac shunting, only that the ratio between the left-to-right component and the right-to-left component is equal.The ability of the RV to recover normal function is related to the duration of chronic


Surgery_Schwartz

Surgery_Schwartz. shunting, only that the ratio between the left-to-right component and the right-to-left component is equal.The ability of the RV to recover normal function is related to the duration of chronic overload because those undergoing ASD closure before age 10 years have a better likelihood of achieving normal RV volumes and function in the postopera-tive period.6The physiology of sinus venosus ASDs is similar to that discussed earlier, except that these are frequently accompanied by anomalous pulmonary venous drainage. This often results in significant hemodynamic derangements that accelerate the clinical course of these infants.The same increase in symptoms is true for those with ostium primum defects because the associated mitral insuffi-ciency from the “cleft” mitral valve can lead to more atrial vol-ume load and increased atrial level shunting.Diagnosis. Patients with ASDs upon auscultation may reveal prominence of the first heart sound with fixed splitting of the second heart sound.


Surgery_Schwartz

Surgery_Schwartz. atrial vol-ume load and increased atrial level shunting.Diagnosis. Patients with ASDs upon auscultation may reveal prominence of the first heart sound with fixed splitting of the second heart sound. This results from the relatively fixed left-to-right shunt throughout all phases of the cardiac cycle. A diastolic flow murmur indicating increased flow across the tricuspid valve may be discerned, and frequently, an ejection flow mur-mur can be heard across the pulmonary valve. A right ventricu-lar heave and increased intensity of the pulmonary component of the second heart sound indicates pulmonary hypertension.Chest radiographs in the patient with an ASD demonstrate increased pulmonary vascularity, with prominent hilar mark-ings and cardiomegaly. The electrocardiogram shows right axis deviation with an incomplete bundle-branch block. When right bundle-branch block is associated with a leftward or superior axis, an AV canal defect should be strongly suspected.Diagnosis is clarified by


Surgery_Schwartz

Surgery_Schwartz. with an incomplete bundle-branch block. When right bundle-branch block is associated with a leftward or superior axis, an AV canal defect should be strongly suspected.Diagnosis is clarified by two-dimensional echocardiogra-phy (Fig. 20-1A,C), and use of color-flow mapping facilitates an understanding of the physiologic derangements created by the defects. Older children and adults with unrepaired ASDs may present with stroke or systemic embolism from paradoxical embolism or atrial arrhythmias from dilation of the right atrium.Echocardiography also enables the clinician to estimate the amount of intracardiac shunting, and it can demonstrate the degree of mitral regurgitation in patients with ostium primum defects. With the addition of an agitated saline injection (bubble study), it can also assist in the detection of sinus venosus defects.The advent of two-dimensional echocardiography with color-flow Doppler has largely superseded the use of cardiac catheterization because the ASD can


Surgery_Schwartz

Surgery_Schwartz. assist in the detection of sinus venosus defects.The advent of two-dimensional echocardiography with color-flow Doppler has largely superseded the use of cardiac catheterization because the ASD can be well defined by echo-cardiography alone. However, in cases where the right ventric-ular systolic pressure is elevated, or patient is older than age 40 years, catheterization can quantify the degree of pulmonary hypertension because those with a fixed pulmonary vascular resistance greater than 12 U/mL may be considered inoperable.7 Cardiac catheterization also can be useful in that it provides data that enable the calculation of Qp and Qs so that the magnitude of the intracardiac shunt can be determined. The ratio (Qp to Qs) can then be used to determine whether closure is indicated in equivocal cases, because a ratio of Qp to Qs greater than 1.5:1 Brunicardi_Ch20_p0751-p0800.indd 75322/02/19 2:54 PM 754SPECIFIC CONSIDERATIONSPART IIis generally accepted as the threshold for surgical


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Surgery_Schwartz. cases, because a ratio of Qp to Qs greater than 1.5:1 Brunicardi_Ch20_p0751-p0800.indd 75322/02/19 2:54 PM 754SPECIFIC CONSIDERATIONSPART IIis generally accepted as the threshold for surgical intervention. Finally, in patients older than age 40 years, cardiac catheteriza-tion can be important to evaluate for the presence of coronary artery disease.In general, ASDs are closed when patients are between 4 and 5 years of age. Children of this size can usually be oper-ated on without the use of blood transfusion and have excellent outcomes. Patients who are symptomatic may require repair earlier, even in infancy. Some surgeons advocate routine repair in infants and children especially in cases where prematurity-related lung disease may accelerate damage to the pulmonary vascular bed, though this philosophy may not be widespread. In a review by Reddy and colleagues, 116 neonates weighing less than 2500 g who underwent repair of simple and complex cardiac defects with the use of


Surgery_Schwartz

Surgery_Schwartz. though this philosophy may not be widespread. In a review by Reddy and colleagues, 116 neonates weighing less than 2500 g who underwent repair of simple and complex cardiac defects with the use of cardiopulmonary bypass were found to have no intracerebral hemorrhages, no long-term neu-rologic sequelae, and a low operative mortality rate (10%). These results correlated with the length of cardiopulmonary bypass and the complexity of repair.8 These investigators also found an 80% actuarial survival at 1 year and, more importantly, that growth following complete repair was equivalent to weight-matched neonates free from cardiac defects.8Treatment. Simple secundum type ASDs can frequently be repaired via a transcatheter technique, and assessment for trans-catheter closure with TTE assessment is generally indicated prior to consideration of a surgical repair. The most common surgical approach requires standard cardiopulmonary bypass (CPB) tech-nique through a midline sternotomy approach.


Surgery_Schwartz

Surgery_Schwartz. is generally indicated prior to consideration of a surgical repair. The most common surgical approach requires standard cardiopulmonary bypass (CPB) tech-nique through a midline sternotomy approach. The details of the repair itself are generally straightforward. An oblique atriotomy is made, the position of the coronary sinus and all systemic and pulmonary veins are determined, and the rim of the defect is completely visualized. Closure of an ostium secundum defect is accomplished either by primary repair or by insertion of a patch that is sutured to the rim of the defect. The decision of whether patch closure is necessary can be determined by the size and shape of the defect as well as by the quality of the edges.The type of repair used for sinus venosus ASDs associated with partial anomalous pulmonary venous connection is dictated by the location of the anomalous pulmonary vein. If the anoma-lous veins connect to the atria or to the superior vena cava cau-dal to where the cava is


Surgery_Schwartz

Surgery_Schwartz. pulmonary venous connection is dictated by the location of the anomalous pulmonary vein. If the anoma-lous veins connect to the atria or to the superior vena cava cau-dal to where the cava is crossed by the right pulmonary artery, the ASD can be repaired by inserting a patch, with redirection of the pulmonary veins behind the patch to the left atrium. Care must be taken with this approach to avoid obstruction of the pulmonary veins or the superior vena cava, although usually the superior vena cava is dilated and provides ample room for patch insertion. If the anomalous vein connects to the superior vena cava cranial to the right pulmonary artery, an alternative technique, the Warden procedure, may be necessary. In this operation, the superior vena cava is transected cranial to the connection of the anomalous vein (usually the right superior pulmonary vein). The caudal end of the transected cava is over-sewn. The cranial end of the transected cava is anastomosed to the auricle of the


Surgery_Schwartz

Surgery_Schwartz. of the anomalous vein (usually the right superior pulmonary vein). The caudal end of the transected cava is over-sewn. The cranial end of the transected cava is anastomosed to the auricle of the right atrium. Inside the atrium, a patch is used to redirect pulmonary venous blood flow to the left atrium. In contrast to the repair for a defect where the pulmonary veins enter the right atrium or the superior vena cava below the right pulmonary artery, the patch covers the superior vena caval right atrial junction so that blood from the anomalous pulmonary vein that enters the cava is directed to the left atrium. Blood returning from the upper body enters the right atrium via the anastomosis between the superior vena cava and the right atrial appendage.Results and Complications of Surgical ASD Closure. Tra-ditional operative strategies, such as pericardial or synthetic patch closure, have been well established, with a low complica-tion rate and a mortality rate of zero among patients


Surgery_Schwartz

Surgery_Schwartz. ASD Closure. Tra-ditional operative strategies, such as pericardial or synthetic patch closure, have been well established, with a low complica-tion rate and a mortality rate of zero among patients without pulmonary hypertension.9 The most frequently reported imme-diate complications include postpericardiotomy syndrome and atrial arrhythmias. Beyond immediate postoperative outcomes, long-term outcomes following surgical closure (up to 20 years) document the low mortality rates and durability of functional status benefit. Importantly, however, atrial arrhythmias, par-ticularly atrial fibrillation, are not completely mitigated by closure and can occur in 10% to 40% of patients, especially in older patients (>40 years) or those with preexisting arrhyth-mias.10 Kutty and colleagues11 followed 300 patients from their institution, 152 of whom had surgical closure. Late mortality at 10 years was 3%, and functional health status had declined in only 15 patients during follow-up. Recently,


Surgery_Schwartz

Surgery_Schwartz. 300 patients from their institution, 152 of whom had surgical closure. Late mortality at 10 years was 3%, and functional health status had declined in only 15 patients during follow-up. Recently, there have been an increasing number of reports regarding the results follow-ing surgical closure among elderly patients (>60 years of age), which demonstrate equivalent survival to younger patients, albeit with slightly higher complication rates.11-13 Hanninen and colleagues14 studied 68 patients between 68 and 86 years at their institution undergoing either surgical (n = 13) or device (n = 54) closure. Although the 23% incidence of major complications (including pneumothorax, heart failure, and pneumonia) was higher than that recently reported by Mascio et al15 using the Society of Thoracic Surgeons’ Congenital Database (20%) or a single-institution review by Hopkins et al16 (12%), there were no operative deaths among the elderly cohort. Moreover, after ASD closure, echocardiographic


Surgery_Schwartz

Surgery_Schwartz. Surgeons’ Congenital Database (20%) or a single-institution review by Hopkins et al16 (12%), there were no operative deaths among the elderly cohort. Moreover, after ASD closure, echocardiographic indices of right ventricular size and function were significantly improved from preoperative val-ues, and functional capacity as measured by standardized survey instruments was also significantly improved.New and Future Approaches to Traditional Surgical ASD Closure. Because of the uniformly excellent outcomes with traditional surgery, attention has shifted to improving the cos-metic result and minimizing hospital stay and convalescence. Multiple strategies have been described to achieve these aims, including the right submammary incision with anterior thora-cotomy, limited bilateral submammary incision with partial sternal split, and limited midline incision with partial sternal split. Some surgeons use either video-assisted thoracic surgery (VATS) in conjunction with the submammary and


Surgery_Schwartz

Surgery_Schwartz. incision with partial sternal split, and limited midline incision with partial sternal split. Some surgeons use either video-assisted thoracic surgery (VATS) in conjunction with the submammary and transxiphoid approaches to facilitate closure within a constricted operative field or totally endoscopic repair in selected patients.17-20 Use of robotics has also been reported in a small series of 12 adult patients by Argenziano and colleagues.18 The morbidity and mortality of all of these approaches are comparable to those of the traditional median sternotomy; however, each has technical drawbacks. Operative precision must be maintained with limited exposure in any minimally invasive technique. Extended CPB and aortic cross-clamp times, coupled with increased cost, may limit the utility of totally endoscopic or robotic-assisted ASD closure except at specific centers. Moreover, certain approaches have a specific patient population in whom they are most appli-cable. For example, the


Surgery_Schwartz

Surgery_Schwartz. of totally endoscopic or robotic-assisted ASD closure except at specific centers. Moreover, certain approaches have a specific patient population in whom they are most appli-cable. For example, the anterolateral thoracotomy should not be employed in prepubescent girls because it will interfere with breast development. Most totally endoscopic approaches are not feasible in very young patients because of the size of the tho-racoscopic ports. Despite these potential drawbacks, however, in carefully selected patients, minimally invasive techniques have demonstrated benefits. Luo and associates performed Brunicardi_Ch20_p0751-p0800.indd 75422/02/19 2:54 PM 755CONGENITAL HEART DISEASECHAPTER 20ABFigure 20-2. A. Picture of the Amplatzr device after open retrieval from the heart (dislodged during percutaenous catheter placement). B. Echocardiographic view of the septum after transcatheter closure of the atrial septal defect with an Amplatzar device.a prospective randomized study comparing


Surgery_Schwartz

Surgery_Schwartz. percutaenous catheter placement). B. Echocardiographic view of the septum after transcatheter closure of the atrial septal defect with an Amplatzar device.a prospective randomized study comparing ministernotomy (division of the upper sternum for aortic and pulmonary lesions and the lower sternum for septal lesions) to full sternotomy in 100 consecutive patients undergoing repair of septal lesions.19 The patients in the ministernotomy group had longer procedure times (by 15 to 20 minutes) but had less bleeding and shorter hospital stays. Consistent with these initiatives, conversion of “low-risk” patients undergoing minimally invasive ASD closure to an ambulatory population (discharge from hospital within 24 hours) has recently been described.21First performed in 1976, transcatheter closure of ASDs with the use of various occlusion devices is gaining widespread accep-tance.22 Certain types of ASDs, including patent foramen ovale, secundum defects, and some fenestrated secundum


Surgery_Schwartz

Surgery_Schwartz. closure of ASDs with the use of various occlusion devices is gaining widespread accep-tance.22 Certain types of ASDs, including patent foramen ovale, secundum defects, and some fenestrated secundum defects, are amenable to device closure, as long as particular ana-tomic criteria (e.g., an adequate superior and inferior rim for device seating and distance from the AV valve) are met. Since the introduction of percutaneous closure (Fig. 20-2A,B), there has been a dramatic rise in device closure prevalence to the point where device closure has supplanted surgical therapy as the domi-nant treatment modality for secundum ASD.23 A study from Karamlou et al23 found that ASD and patent foramen ovale clo-sures per capita increased dramatically from 1.08 per 100,000 population in 1988 to 2.59 per 100,000 population in 2005, an increase of 139%. When analyzed by closure type, surgical clo-sure increased by only 24% (from 0.86 per 100,000 population in 1988 to 1.07 per 100,000 in 2005), whereas


Surgery_Schwartz

Surgery_Schwartz. 100,000 population in 2005, an increase of 139%. When analyzed by closure type, surgical clo-sure increased by only 24% (from 0.86 per 100,000 population in 1988 to 1.07 per 100,000 in 2005), whereas transcatheter closure increased by 3475% (from 0.04 per 100,000 population in 1988 to 1.43 per 100,000 in 2005). Importantly, this study determined that the paradigm shift favoring transcatheter closure has occurred mainly due to increased prevalence of closure in adults over age 40 years rather than an increase in closure in infants or children.Despite the simplicity of ASD repair, there are a myriad of options for patients and physicians who care for patients with CHD. The patient population that might benefit from closure (whether device or surgical) is likely to increase, challenging current ideas and treatment algorithms that optimize outcomes.2Aortic StenosisAnatomy and Classification. The spectrum of aortic valve abnormality represents the most common form of CHD, with the great


Surgery_Schwartz

Surgery_Schwartz. ideas and treatment algorithms that optimize outcomes.2Aortic StenosisAnatomy and Classification. The spectrum of aortic valve abnormality represents the most common form of CHD, with the great majority of patients being asymptomatic until midlife. Obstruction of the left ventricular outflow tract (LVOT) occurs at multiple levels: subvalvular, valvular, and supravalvular (Fig. 20-3A-D). The critically stenotic aortic valve in the neo-nate or infant is commonly unicommissural or bicommissural, with thickened, dysmorphic, and myxomatous leaflet tissue and a reduced cross-sectional area at the valve level. Associ-ated left-sided lesions are often present. In a review of 32 cases from the Children’s Hospital in Boston, 59% had unicommis-sural valves, and 40% had bicommissural valves.24 Associated lesions were frequent, occurring in 88% of patients, most com-monly patent ductus arteriosus, mitral regurgitation, and hypo-plastic LV. Endocardial fibroelastosis (EFE) also is common among


Surgery_Schwartz

Surgery_Schwartz. lesions were frequent, occurring in 88% of patients, most com-monly patent ductus arteriosus, mitral regurgitation, and hypo-plastic LV. Endocardial fibroelastosis (EFE) also is common among infants with critical aortic stenosis (AS). In this condi-tion, the LV is usually prohibitively hypoplastic and noncom-pliant, rendering these patients poor candidates for recruitment of the LV into the systemic circulation with techniques that can be utilized in those with more normal sized LVs. In some neonates with critical AS, a dilated LV with poor diastolic com-pliance rather than a hypertrophied LV is encountered.24Neonates with critical AS are a challenging population because one must make a decision about the suitability of the left-sided structures to support a biventricular circulation. There are recent approaches that include techniques, such as aortic valvotomy coupled with EFE resection and mitral valve inter-vention, that are directed at LV rehabilitation. The advent of fetal


Surgery_Schwartz

Surgery_Schwartz. There are recent approaches that include techniques, such as aortic valvotomy coupled with EFE resection and mitral valve inter-vention, that are directed at LV rehabilitation. The advent of fetal valvotomy for critical AS may also increase the number of infants who are candidates for biventricular repair.Pathophysiology. The unique intracardiac and extracardiac shunts present in fetal life allow even neonates with critical AS to survive. In utero, left ventricular hypertrophy and ischemia cause left atrial hypertension, which reduces the right-to-left flow across the foramen ovale. In severe cases, a reversal of Brunicardi_Ch20_p0751-p0800.indd 75522/02/19 2:54 PM 756SPECIFIC CONSIDERATIONSPART IIFigure 20-3. A. Congenital aortic valve stenosis, en fosse echocardiographic view of the stenotic bicuspid aortic valve. Parasternal long axis view of the same valve with a gradient of 60 mm of Hg (‘*’ points to the valve). B. Parasternal long axis ecocardiographic view of a patient with


Surgery_Schwartz

Surgery_Schwartz. stenotic bicuspid aortic valve. Parasternal long axis view of the same valve with a gradient of 60 mm of Hg (‘*’ points to the valve). B. Parasternal long axis ecocardiographic view of a patient with discrete subaortic membrane (‘*’ points to the membrane). C. Parasternal long axis ecocardiographic view of a patient with diffuse tunnel like subvalvar aortic stenosis with membrane. Doppler revealed a gradient of 81 mm of hg (‘*’ represents the area of diffuse narrowing). D. Appearance of supravalvar aortic stenosis on an aortogram performed in the cardiac catheterization lab (‘*’ points to the stenosis). E. Appearance after four patch reconstruction of the same patient shown in Figure 20.3 d. (Re-formatted images obtained from a CT angiogram).ABCDEBrunicardi_Ch20_p0751-p0800.indd 75622/02/19 2:54 PM 757CONGENITAL HEART DISEASECHAPTER 20flow may occur, causing right ventricular volume loading. The RV then provides the entire systemic output via the patent duc-tus arteriosus


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Surgery_Schwartz. 75622/02/19 2:54 PM 757CONGENITAL HEART DISEASECHAPTER 20flow may occur, causing right ventricular volume loading. The RV then provides the entire systemic output via the patent duc-tus arteriosus (ductal-dependent systemic blood flow). Although cardiac output is maintained, the LV suffers continued damage as the intracavitary pressure precludes adequate coronary perfu-sion, resulting in LV infarction and subendocardial fibroelas-tosis. The presentation of the neonate with critical AS is then determined by the morphology of the LV and other left-sided heart structures, the degree of left ventricular dysfunction, and the completeness of the transition from a parallel circulation to an in-series circulation (i.e., on closure of the foramen ovale and the ductus arteriosus). Those infants with mild-to-moderate AS in whom LV function is preserved are asymptomatic at birth. The only abnormalities may be a systolic ejection murmur and electrocardiogram (ECG) evidence of left ventricular


Surgery_Schwartz

Surgery_Schwartz. with mild-to-moderate AS in whom LV function is preserved are asymptomatic at birth. The only abnormalities may be a systolic ejection murmur and electrocardiogram (ECG) evidence of left ventricular hypertro-phy. However, those neonates with severe AS and compromised LV function are unable to provide adequate cardiac output at birth and will present in circulatory collapse once the ductus closes, with dyspnea, tachypnea, irritability, narrowed pulse pressure, oliguria, and profound metabolic acidosis.24 If ductal patency is maintained, systemic perfusion will be provided by the RV via ductal flow, and cyanosis may be the only finding.Diagnosis. Neonates and infants with severe valvular AS may have a relatively nonspecific history of irritability and failure to thrive. Angina, if present, is usually manifested by episodic, inconsolable crying that coincides with feeding. As discussed previously, evidence of poor peripheral perfusion, such as extreme pallor, indicates severe LVOT


Surgery_Schwartz

Surgery_Schwartz. is usually manifested by episodic, inconsolable crying that coincides with feeding. As discussed previously, evidence of poor peripheral perfusion, such as extreme pallor, indicates severe LVOT obstruction. Differen-tial cyanosis is an uncommon finding, but it is present when enough antegrade flow occurs only to maintain normal upper body perfusion, while a large patent ductus arteriosus produces blue discoloration of the abdomen and legs.Physical findings include a systolic ejection murmur, although a quiet murmur may paradoxically indicate a more severe condition with reduced cardiac output. A systolic click correlates with a valvular etiology of obstruction. As LV dys-function progresses, evidence of congestive heart failure occurs.The chest radiograph is variable but may show dilatation of the aortic root, and the ECG often demonstrates LV hypertro-phy. Echocardiography with Doppler flow is extremely useful in establishing the diagnosis, as well as quantifying the transvalvular


Surgery_Schwartz

Surgery_Schwartz. of the aortic root, and the ECG often demonstrates LV hypertro-phy. Echocardiography with Doppler flow is extremely useful in establishing the diagnosis, as well as quantifying the transvalvular gradient. Furthermore, echocardiography can facilitate evaluation for the several associated defects that can be present in critical neonatal AS, including mitral stenosis, LV hypoplasia, LV endo-cardial fibroelastosis, subaortic stenosis, VSD, or coarctation. The presence of any or several of these defects has important impli-cations related to treatment options for these patients. Although cardiac catheterization is not routinely performed for diagnostic purposes, it can be invaluable as part of the treatment algorithm if the lesion is amenable to balloon valvotomy. Magnetic resonance imaging (MRI) is another very useful technique for assessing the adequacy of the left-sided structures and is increasingly utilized to determine candidacy for biventricular repairs.Treatment. As alluded to


Surgery_Schwartz

Surgery_Schwartz. (MRI) is another very useful technique for assessing the adequacy of the left-sided structures and is increasingly utilized to determine candidacy for biventricular repairs.Treatment. As alluded to previously, the first decision that must be made in the neonate with critical LVOT obstruction is whether the patient is a candidate for biventricular or univen-tricular repair. Central to this decision is assessment of the degree of hypoplasia of the LV and other left-sided structures. Alsoufi and colleagues25 have described a rational approach to the neonate with critical LVOT obstruction. The options vary depending on whether the infant follows a single or a 3biventricular pathway. The options for a single ventricle include the Norwood operation, a hybrid strategy (initial ductal stent and bilateral pulmonary artery bands followed by later completion of the Norwood operation) or heart transplantation. The options for a biventricular heart include balloon valvuloplasty, surgical


Surgery_Schwartz

Surgery_Schwartz. and bilateral pulmonary artery bands followed by later completion of the Norwood operation) or heart transplantation. The options for a biventricular heart include balloon valvuloplasty, surgical val-votomy, neonatal Ross operation, or a Yasui operation. Often valvotomy is accompanied by LV rehabilitation techniques, including EFE resection and mitral valve interventions. Fetal aortic valvotomy, which is now offered at specialized centers, is another promising strategy to decompress the LV in fetal life and potentially allow growth of the left-sided structures sufficient to permit a biventricular circulation. Regardless of whether the baby is triaged to a single or biventricular strategy, any infant with severe AS requires urgent intervention. Preoperative stabi-lization, however, has dramatically altered the clinical algorithm and outcomes for this patient population.25 The preoperative strategy begins with endotracheal intubation and inotropic sup-port. Prostaglandin infusion is


Surgery_Schwartz

Surgery_Schwartz. dramatically altered the clinical algorithm and outcomes for this patient population.25 The preoperative strategy begins with endotracheal intubation and inotropic sup-port. Prostaglandin infusion is initiated to maintain ductal patency, and confirmatory studies are performed prior to opera-tive intervention. Therapy is generally indicated in the presence of a transvalvular gradient of 50 mmHg with associated symp-toms including syncope, CHF, or angina, or if a gradient of 50 to 75 mmHg exists with concomitant ECG evidence of LV strain or ischemia. In the critically ill neonate, a gradient across the aortic valve may not be present because of poor LV function. However, the decision regarding treatment options must be based on a complete understanding of associated defects. For example, in the presence of a hypoplastic LV (left ventricular end-diastolic volume <20 mL/m2) or a markedly abnormal mitral valve, iso-lated aortic valvotomy should not be performed because studies have


Surgery_Schwartz

Surgery_Schwartz. in the presence of a hypoplastic LV (left ventricular end-diastolic volume <20 mL/m2) or a markedly abnormal mitral valve, iso-lated aortic valvotomy should not be performed because studies have demonstrated high mortality in this population following isolated valvotomy.26Patients who have an LV capable of providing systemic output are candidates for intervention to relieve AS, generally through balloon valvotomy. Occasionally, if catheter-based therapy is not an option, relief of valvular AS in infants and children can be accomplished with surgical valvotomy using standard techniques of CPB and direct exposure to the aortic valve. A transverse incision is made in the ascending aorta above the sinus of Valsalva, extending close to, but not into, the noncoronary sinus. Exposure is attained with placement of a retractor into the right coronary sinus. After inspection of the valve, the chosen commissure is incised to within 1 to 2 mm of the aortic wall (Fig. 20-4A,B).Balloon valvotomy


Surgery_Schwartz

Surgery_Schwartz. with placement of a retractor into the right coronary sinus. After inspection of the valve, the chosen commissure is incised to within 1 to 2 mm of the aortic wall (Fig. 20-4A,B).Balloon valvotomy performed in the catheterization lab is generally the procedure of choice for reduction of transvalvular gradients in symptomatic infants and children without signifi-cant aortic insufficiency. Balloon valvotomy provides relief of the valvular gradient and allows future surgical intervention (which is generally required in most patients when a larger prosthesis can be implanted) to be performed on an unscarred chest. An important issue when planning aortic valvotomy, whether percutaneously or via open surgical technique, is the risk of inducing hemodynamically significant aortic regurgita-tion. Induction of more than moderate aortic regurgitation is poorly tolerated in the infant with critical AS and may require an urgent procedure to replace or repair the aortic valve. Most often in these


Surgery_Schwartz

Surgery_Schwartz. Induction of more than moderate aortic regurgitation is poorly tolerated in the infant with critical AS and may require an urgent procedure to replace or repair the aortic valve. Most often in these patients, a Ross procedure represents the only real option as mechanical valve replacement in a neonate has exceptionally poor outcome.In general, catheter-based balloon valvotomy has supplanted open surgical valvotomy. The decision regarding Brunicardi_Ch20_p0751-p0800.indd 75722/02/19 2:54 PM 758SPECIFIC CONSIDERATIONSPART IIFigure 20-4. A. Intra-operative picture of a stenotic bicuspid aortic valve (as seen through an aortotomy). B. Intra-operative picture of the valve after a controlled valvotomy if performed. Note the forceps is across the opening of the aortic valve (‘*’ points to the valvotomy).the most appropriate method to use depends on several factors, including the available medical expertise, the patient’s overall status and hemodynamics, and the presence of associated


Surgery_Schwartz

Surgery_Schwartz. the valvotomy).the most appropriate method to use depends on several factors, including the available medical expertise, the patient’s overall status and hemodynamics, and the presence of associated cardiac defects requiring repair.25 Although evidence is emerging to the contrary, simple valvotomy, whether performed using percutaneous or open technique, is generally considered a palliative procedure. The goal is to relieve LVOT obstruction without producing clinically significant regurgitation, in order to allow sufficient annular growth for eventual aortic valve replacement. The reintervention rate is higher if balloon valvuloplasty is performed as the initial palliation (54%) compared to a surgical valvolomy (23%) as the latter is a more controlled division of the aortic commissure25 (Fig. 20-4C). The majority of infants who undergo aortic valvotomy will require further intervention on the aortic valve within 10 years following initial intervention.26Neonates with severely


Surgery_Schwartz

Surgery_Schwartz. (Fig. 20-4C). The majority of infants who undergo aortic valvotomy will require further intervention on the aortic valve within 10 years following initial intervention.26Neonates with severely hypoplastic LVs or significant LV endocardial fibroelastosis may not be candidates for biventricu-lar repair and are treated the same as infants with the hypoplas-tic left heart syndrome (HLHS), which is discussed later (see “Hypoplastic Left Heart Syndrome”).As mentioned previously, fetal intervention for the aortic valve has been described with the goal being to improve the growth of the left ventricle. The group at Boston Children’s Hospital have reported fairly favorable results in a small cohort.34Many surgeons previously avoided aortic valve replace-ment for AS in early childhood because the more commonly used mechanical valves would be outgrown and require replace-ment later and the obligatory anticoagulation for mechanical valves resulted in a substantial risk for complications. In


Surgery_Schwartz

Surgery_Schwartz. the more commonly used mechanical valves would be outgrown and require replace-ment later and the obligatory anticoagulation for mechanical valves resulted in a substantial risk for complications. In addi-tion, prosthetic valves have an incidence of bacterial endocardi-tis or perivalvular leak requiring reintervention.The use of allografts and the advent of the Ross procedure have largely obviated these issues and made early definitive cor-rection of critical AS a viable option.23,27,28 Donald Ross first described transposition of the pulmonary valve into the aortic position with allograft reconstruction of the pulmonary outflow tract in 1967.27 The result of this operation is a normal trileaf-let semilunar valve made of a patient’s native tissue with the potential for growth to adult size in the aortic position in place of the damaged aortic valve (Fig. 20-5). The Ross procedure has become a useful option for aortic valve replacement in children because it has improved durability and


Surgery_Schwartz

Surgery_Schwartz. in the aortic position in place of the damaged aortic valve (Fig. 20-5). The Ross procedure has become a useful option for aortic valve replacement in children because it has improved durability and can be performed with acceptable morbidity and mortality rates. The placement of a pulmonary conduit, which does not grow and becomes calci-fied and stenotic over time, does obligate the patient to rein-tervention (either surgically or using transcatheter techniques) to replace the RV-to-pulmonary artery conduit. Karamlou and colleagues29 have reviewed the outcomes and associated risk factors for aortic valve replacement in 160 children from the Hospital for Sick Children in Toronto. They found that younger age, lower operative weight, concomitant performance of aortic root replacement or reconstruction, and use of prosthesis type other than a pulmonary autograft were significant predictors of death, whereas the use of a bioprosthetic or allograft valve type and earlier year of operation


Surgery_Schwartz

Surgery_Schwartz. and use of prosthesis type other than a pulmonary autograft were significant predictors of death, whereas the use of a bioprosthetic or allograft valve type and earlier year of operation were identified as significant risk factors for repeated aortic valve replacement. Autograft use was associated with a blunted progression of the peak prosthetic valve gradient and a rapid decrease in the left ventricular end-diastolic dimension. In agreement with these findings, Lupinetti and Jones28 compared allograft aortic valve replacement with the Ross procedure and found a more significant transvalvular gradient reduction and regression of left ventricular hypertro-phy in those patients who underwent the Ross procedure. In some cases, the pulmonary valve may not be usable because of associated defects or congenital absence. These children are not candidates for the Ross procedure and can be treated with cryopreserved allografts (cadaveric human aortic valves) or prosthetic aortic valve


Surgery_Schwartz

Surgery_Schwartz. defects or congenital absence. These children are not candidates for the Ross procedure and can be treated with cryopreserved allografts (cadaveric human aortic valves) or prosthetic aortic valve replacement. At times, there may be a size discrepancy between the right ventricular outflow tract (RVOT) and the LVOT, especially in cases of severe critical AS in infancy. For these cases, the pulmonary autograft is placed in a manner that also provides enlargement of the aortic annulus (Ross/Konno).Subvalvular AS occurs beneath the aortic valve and may be classified as discrete or tunnel-like (diffuse). A thin, ABBrunicardi_Ch20_p0751-p0800.indd 75822/02/19 2:54 PM 759CONGENITAL HEART DISEASECHAPTER 20fibromuscular diaphragm immediately proximal to the aortic valve characterizes discrete subaortic stenosis. This diaphragm typically extends for 180o or more in a crescentic or circular fash-ion, often attaching to the mitral valve as well as the interven-tricular septum. The aortic valve


Surgery_Schwartz

Surgery_Schwartz. stenosis. This diaphragm typically extends for 180o or more in a crescentic or circular fash-ion, often attaching to the mitral valve as well as the interven-tricular septum. The aortic valve itself is usually normal in this condition, although the turbulence imparted by the subvalvular stenosis may affect leaflet morphology and valve competence.Diffuse subvalvular AS results in a long, tunnel-like obstruction that may extend to the left ventricular apex. In some individuals, there may be difficulty in distinguishing between hypertrophic cardiomyopathy and diffuse subaortic steno-sis. Operation for subvalvular AS is indicated with a gradient exceeding 30 mmHg, in the presence of aortic valve insuffi-ciency, or when symptoms indicating LVOT obstruction are present.30 Given that repair of isolated discrete subaortic ste-nosis can be done with low rates of morbidity and mortality, some surgeons advocate repair in all cases of discrete AS to avoid progression of the stenosis and the


Surgery_Schwartz

Surgery_Schwartz. of isolated discrete subaortic ste-nosis can be done with low rates of morbidity and mortality, some surgeons advocate repair in all cases of discrete AS to avoid progression of the stenosis and the development of aortic insufficiency, although more recent data demonstrate that sub-aortic resection should be delayed until the LV gradient exceeds 30 mmHg because most children with an initial LV gradient less than 30 mmHg have quiescent disease.31 Diffuse AS is a more complex lesion and often requires aortoventriculoplasty. Results are generally excellent, with operative mortality less than 5%.32Supravalvular AS occurs more rarely and also can be clas-sified into a discrete type, which produces an hourglass defor-mity of the aorta, and a diffuse form that can involve the entire arch and brachiocephalic arteries. The aortic valve leaflets are usually normal, but in some cases, the leaflets may adhere to the supravalvular stenosis, thereby narrowing the sinuses of Valsalva in diastole


Surgery_Schwartz

Surgery_Schwartz. brachiocephalic arteries. The aortic valve leaflets are usually normal, but in some cases, the leaflets may adhere to the supravalvular stenosis, thereby narrowing the sinuses of Valsalva in diastole and restricting coronary artery perfusion. In addition, accelerated intimal hyperplastic changes in the coronary arteries can be demonstrated in these patients because the proximal position of the coronary arteries subjects them to abnormally high perfusion pressures.The signs and symptoms of supravalvular AS are similar to other forms of LVOT obstruction. An asymptomatic murmur is the presenting manifestation in approximately half of these patients. Syncope, poor exercise tolerance, and angina may all occur with nearly equal frequency. Supravalvar AS is associated with Williams’ syndrome, a constellation of elfin facies, mental retardation, and hypercalcemia.33 Following routine evaluation, cardiac catheterization should be performed in order to delin-eate coronary anatomy, as well as to


Surgery_Schwartz

Surgery_Schwartz. of elfin facies, mental retardation, and hypercalcemia.33 Following routine evaluation, cardiac catheterization should be performed in order to delin-eate coronary anatomy, as well as to delineate the degree of obstruction. A gradient of 50 mmHg or greater is an indication for operation. However, the clinician must be cognizant of any coexistent lesions, most commonly pulmonic stenosis, which may add complexity to the repair.The localized form of supravalvular AS can be treated by creating an inverted Y-shaped aortotomy across the area of ste-nosis, straddling the right coronary artery. The obstructing shelf is then excised, and a pantaloon-shaped patch (Doty technique) or individual sinus patch enlargement (Brom technique) is used (Fig. 20-3E).The diffuse form of supravalvular stenosis is more vari-able (Fig. 20-6), and the particular operative approach must be tailored to each specific patient’s anatomy. In general, either an aortic endarterectomy with patch augmentation can be


Surgery_Schwartz

Surgery_Schwartz. is more vari-able (Fig. 20-6), and the particular operative approach must be tailored to each specific patient’s anatomy. In general, either an aortic endarterectomy with patch augmentation can be per-formed or if the narrowing extends past the aorta arch, a pros-thetic graft can be placed between the ascending and descending aorta. Operative results for discrete supravalvular AS are gen-erally good, with a hospital mortality of less than 1% and an actuarial survival rate exceeding 90% at 20 years.35 In contrast, however, the diffuse form is more hazardous to repair and car-ried a mortality of 15% in a recent series.35,36Patent Ductus ArteriosusAnatomy. The ductus arteriosus is derived from the sixth aor-tic arch and normally extends from the main or left pulmonary artery to the upper descending thoracic aorta, distal to the left subclavian artery. In the normal fetal cardiovascular system, ductal flow is considerable (approximately 60% of the com-bined ventricular output) and is


Surgery_Schwartz

Surgery_Schwartz. descending thoracic aorta, distal to the left subclavian artery. In the normal fetal cardiovascular system, ductal flow is considerable (approximately 60% of the com-bined ventricular output) and is directed exclusively from the pulmonary artery to the aorta. In infancy, the length of the duc-tus may vary from 2 to 8 mm, with a diameter of 4 to 12 mm.Locally produced and circulating prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2) induce active relaxation of the duc-tal musculature, maintaining maximal patency during the fetal period.38 At birth, increased pulmonary blood flow metabo-lizes these prostaglandin products, and absence of the placenta removes an important source of them, resulting in a marked decrease in these ductal-relaxing substances. In addition, release of histamines, catecholamines, bradykinin, and acetylcholine all promote ductal contraction. Despite all of these complex Figure 20-5. Appearance of the stenotic aortic valve during aortography performed in the


Surgery_Schwartz

Surgery_Schwartz. catecholamines, bradykinin, and acetylcholine all promote ductal contraction. Despite all of these complex Figure 20-5. Appearance of the stenotic aortic valve during aortography performed in the cardiac catheterization lab. (left). Balloon valvuloplasty being performed. (right). The ‘*’ points to the the “waist” created by the stenotic valve during dilation. (Used with permission from Kelly Rosso MD.)Brunicardi_Ch20_p0751-p0800.indd 75922/02/19 2:54 PM 760SPECIFIC CONSIDERATIONSPART IIFigure 20-6. Reformatted image obtained after CT angiography of a child with diffuse supravalvar aortic stenosis (‘*’ points to the transverse aortic arch).interactions, the rising oxygen tension in the fetal blood is the main stimulus causing smooth muscle contraction and ductal closure within 10 to 15 hours postnatally.39 Anatomic closure by fibrosis produces the ligamentum arteriosum connecting the pulmonary artery to the aorta.Delayed closure of the ductus is termed prolonged patency, whereas


Surgery_Schwartz

Surgery_Schwartz. 15 hours postnatally.39 Anatomic closure by fibrosis produces the ligamentum arteriosum connecting the pulmonary artery to the aorta.Delayed closure of the ductus is termed prolonged patency, whereas failure of closure causes persistent patency, which may occur as an isolated lesion or in association with more complex congenital heart defects. In many of these infants with more complex congenital heart defects, either pulmonary or systemic perfusion may depend on ductal flow, and these infants may decompensate if exogenous PGE is not administered to maintain ductal patency.Natural History. The incidence of patent ductus arteriosus (PDA) is approximately 1 in every 2000 births; however, it increases dramatically with increasing prematurity.39 In some series, PDAs have been noted in 75% of infants of 28 to 30 weeks gestation. Persistent patency occurs more commonly in females, with a 2:1 ratio.40PDA is not a benign entity, although prolonged survival has been reported. The estimated


Surgery_Schwartz

Surgery_Schwartz. of infants of 28 to 30 weeks gestation. Persistent patency occurs more commonly in females, with a 2:1 ratio.40PDA is not a benign entity, although prolonged survival has been reported. The estimated death rate for infants with iso-lated, untreated PDA is approximately 30%.41 The leading cause of death is congestive heart failure, with respiratory infection as a secondary cause. Endocarditis is more likely to occur with a small ductus and is rarely fatal if aggressive antibiotic therapy is initiated early.Clinical Manifestations and Diagnosis. After birth, in an otherwise normal cardiovascular system, a PDA results in a left-to-right shunt that depends on both the size of the ductal lumen and its total length. As the pulmonary vascular resistance falls 8 to 10 weeks postnatally, the shunt will increase, and its flow will ultimately be determined by the relative resistances of the pulmonary and systemic circulations.The hemodynamic consequences of an unrestrictive duc-tal shunt are


Surgery_Schwartz

Surgery_Schwartz. will increase, and its flow will ultimately be determined by the relative resistances of the pulmonary and systemic circulations.The hemodynamic consequences of an unrestrictive duc-tal shunt are left ventricular volume overload with increased left atrial and pulmonary artery pressures and right ventricular strain from the augmented afterload. These changes result in increased sympathetic discharge, tachycardia, tachypnea, and ventricular hypertrophy. The diastolic shunt results in lower aortic diastolic pressure and increases the potential for myo-cardial ischemia and underperfusion of other systemic organs, while the increased pulmonary flow leads to increased work of breathing and decreased gas exchange. Unrestrictive ductal flow may lead to pulmonary hypertension within the first year of life. These changes will be significantly attenuated if the size of the ductus is only moderate, and they will be completely absent if the ductus is small.Physical examination of the afflicted


Surgery_Schwartz

Surgery_Schwartz. of life. These changes will be significantly attenuated if the size of the ductus is only moderate, and they will be completely absent if the ductus is small.Physical examination of the afflicted infant will reveal evi-dence of a hyperdynamic circulation with a widened pulse pres-sure and a hyperactive precordium. Auscultation demonstrates a systolic or continuous murmur, often termed a machinery mur-mur. Cyanosis is not present in uncomplicated isolated PDA.The chest radiograph may reveal increased pulmonary vascularity or cardiomegaly, and the ECG may show LV strain, left atrial enlargement, and possibly RV hypertrophy. Echocar-diogram with color mapping reliably demonstrates the patency of the ductus as well as estimates the shunt size. Cardiac cath-eterization is necessary only when pulmonary hypertension is suspected.Therapy. The presence of a persistent PDA is sufficient indica-tion for closure because of the increased mortality and risk of endocarditis.40 In older patients with


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Surgery_Schwartz. hypertension is suspected.Therapy. The presence of a persistent PDA is sufficient indica-tion for closure because of the increased mortality and risk of endocarditis.40 In older patients with pulmonary hypertension, closure may not improve symptoms and is associated with much higher mortality.In premature infants, aggressive intervention with indometh-acin or ibuprofen to achieve early closure of the PDA is beneficial unless contraindications such as necrotizing enterocolitis or renal insufficiency are present.41 Term infants, however, are gener-ally unresponsive to pharmacologic therapy with indomethacin, so mechanical closure must be undertaken once the diagnosis is established. This can be accomplished either surgically (Fig. 20-7) or with catheter-based therapy.15,42,43 Currently, transluminal placement of various occlusive devices, such as the Rashkind double-umbrella device or embolization with Gianturco coils, is in widespread use.42 However, there are a number of


Surgery_Schwartz

Surgery_Schwartz. transluminal placement of various occlusive devices, such as the Rashkind double-umbrella device or embolization with Gianturco coils, is in widespread use.42 However, there are a number of complications inherent with the use of percutaneous devices, such as thromboem-bolism, endocarditis, incomplete occlusion, vascular injury, and hemorrhage secondary to perforation.43 In addition, these tech-niques may not be applicable in very young infants because the peripheral vessels do not provide adequate access for the delivery devices. Attempts are being made to develop such devices for pre-mature infants with early successful results in study populations.44Surgical closure can be achieved via either open or video-assisted approaches. The open approach employs a muscle-sparing posterior lateral thoracotomy in the third or fourth intercostal space on the side of the aorta (generally the left). The lung is then retracted anteriorly. In the neonate, the PDA is singly ligated with a surgical


Surgery_Schwartz

Surgery_Schwartz. thoracotomy in the third or fourth intercostal space on the side of the aorta (generally the left). The lung is then retracted anteriorly. In the neonate, the PDA is singly ligated with a surgical clip or permanent suture. Care must be taken to avoid the recurrent laryngeal nerve, which courses around the PDA. The PDA can also be ligated via a median sternotomy; however, this approach is generally reserved for patients who have additional cardiac or great vessel lesions requiring repair. Occasionally, a short, broad ductus, in which the dimension of Brunicardi_Ch20_p0751-p0800.indd 76022/02/19 2:54 PM 761CONGENITAL HEART DISEASECHAPTER 20its width approaches that of its length, will be encountered. In this case, division between vascular clamps with oversewing of both ends is advisable (Fig. 20-8). In extreme cases, the use of CPB to decompress the large ductus during ligation is an option.Video-assisted thoracoscopic occlusion, using metal clips, also has been described, although


Surgery_Schwartz

Surgery_Schwartz. (Fig. 20-8). In extreme cases, the use of CPB to decompress the large ductus during ligation is an option.Video-assisted thoracoscopic occlusion, using metal clips, also has been described, although it offers few advantages over the standard surgical approach. Preterm newborns and children may do well with a surgical technique, while older patients (older than age 5 years) and those with smaller ducts (<3 mm) do well with coil occlusion. In fact, Moore and colleagues recently concluded from their series that coil occlusion is the procedure Figure 20-7. Chest x-ray before and after PDA ligation showing the dramatic improvement in the lung fields after ligation (arrow points to the clip used for PDA ligation).Figure 20-8. Surgical PDA ligation. A clip has been applied to occlude the ductus arteriosus. Note the relationship of the recurrent laryngeal nerve to the ductus arteriosus. (Used with permission from Kelly Rosso MD.)of choice for ducts smaller than 4 mm.45 Complete closure rates


Surgery_Schwartz

Surgery_Schwartz. arteriosus. Note the relationship of the recurrent laryngeal nerve to the ductus arteriosus. (Used with permission from Kelly Rosso MD.)of choice for ducts smaller than 4 mm.45 Complete closure rates using catheter-based techniques have steadily improved.Outcomes. In premature infants, the surgical mortality is very low, although the overall hospital death rate is significant as a consequence of other complications of prematurity. In older infants and children, mortality is less than 1%. Bleeding, chylo-thorax, vocal cord paralysis, and the need for reoperation occur infrequently. With the advent of muscle-sparing thoracotomy, the risk of subsequent arm dysfunction or breast abnormalities is virtually eliminated.46Aortic CoarctationAnatomy. Coarctation of the aorta (COA) is defined as a lumi-nal narrowing in the aorta that causes an obstruction to blood flow. This narrowing is most commonly located distal to the left subclavian artery. The embryologic origin of COA is a sub-ject of


Surgery_Schwartz

Surgery_Schwartz. lumi-nal narrowing in the aorta that causes an obstruction to blood flow. This narrowing is most commonly located distal to the left subclavian artery. The embryologic origin of COA is a sub-ject of some controversy. One theory holds that the obstructing shelf, which is largely composed of tissue found within the duc-tus, forms as the ductus involutes.47 The other theory holds that a diminished aortic isthmus develops secondary to decreased aortic flow in infants with enhanced ductal circulation.Extensive collateral circulation develops, predominantly involving the intercostals and mammary arteries as a direct result of aortic flow obstruction. This translates into the well-known finding of “rib-notching” on chest radiograph, as well as a prominent pulsation underneath the ribs.Other associated anomalies, such as ventricular septal defect, PDA, and ASD, may be seen with COA, but the most common is that of a bicuspid aortic valve, which can be demon-strated in 25% to 42% of


Surgery_Schwartz

Surgery_Schwartz. associated anomalies, such as ventricular septal defect, PDA, and ASD, may be seen with COA, but the most common is that of a bicuspid aortic valve, which can be demon-strated in 25% to 42% of cases.48Pathophysiology. Infants with COA develop symptoms con-sistent with left ventricular outflow obstruction, including pulmo-nary overcirculation and, later, biventricular failure. In addition, proximal systemic hypertension develops as a result of mechanical obstruction to ventricular ejection, as well as hypoperfusion-induced activation of the renin-angiotensin-aldosterone system. PAAoBrunicardi_Ch20_p0751-p0800.indd 76122/02/19 2:54 PM 762SPECIFIC CONSIDERATIONSPART IIFigure 20-9. Reformatted images obtained from CT angiography of a baby showing a descrete coarctation of the aorta (‘*’ points to the coarctation).ABFigure 20-10. A. Reformatted images obtained from a CT angio-gram of a child with discrete coarctation of the aorta (‘*’ points to the coarctation). B. Aortogram performed


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Surgery_Schwartz. to the coarctation).ABFigure 20-10. A. Reformatted images obtained from a CT angio-gram of a child with discrete coarctation of the aorta (‘*’ points to the coarctation). B. Aortogram performed in the cardiac catheteriza-tion lab after stenting the coarctation (‘*’ points to the stent).Interestingly, hypertension is often persistent after surgical correction despite complete amelioration of the mechanical obstruction and pressure gradient.49 It has been shown that early surgical correction may prevent the development of long-term hypertension, which undoubtedly contributes to many of the adverse sequelae of COA, including the development of circle of Willis aneurysms, aortic dissection and rupture, and an increased incidence of coronary arteriopathy with resulting myocardial infarction.50Diagnosis. COA is likely to become symptomatic either in the newborn period if other anomalies are present or in the late ado-lescent period with the onset of left ventricular failure.Physical


Surgery_Schwartz

Surgery_Schwartz. is likely to become symptomatic either in the newborn period if other anomalies are present or in the late ado-lescent period with the onset of left ventricular failure.Physical examination will demonstrate a hyperdynamic precordium with a harsh murmur localized to the left chest and back. Femoral pulses will be dramatically decreased when com-pared to upper extremity pulses, and differential cyanosis may be apparent until ductal closure.Echocardiography will reliably demonstrate the narrowed aortic segment, as well as define the pressure gradient across the stenotic segment. In addition, detailed information regarding other associated anomalies can be gleaned. Aortography (Fig. 20-9) is reserved for those cases in which the echocardiographic findings are equivocal. Cross-sectional imaging with computed tomogra-phy (CT) scan or MRI is also increasing to facilitate definition of arch anatomy (i.e., transverse arch hypoplasia), assess intracardiac volumes, and associated


Surgery_Schwartz

Surgery_Schwartz. imaging with computed tomogra-phy (CT) scan or MRI is also increasing to facilitate definition of arch anatomy (i.e., transverse arch hypoplasia), assess intracardiac volumes, and associated defects.Therapy. The routine management of hemodynamically sig-nificant COA in all age groups has traditionally been surgical. Transcatheter repairs (Fig. 20-10) are used with increasing frequency in older patients and those with recoarctation fol-lowing surgical repair. Balloon dilatation of native coarctation in neonates generally is avoided because of the high recoarc-tation rate. However, in infants who present with severely depressed LV function and a closed ductus arteriosus, initial decompression with balloon dilation of the COA followed by later surgical intervention may be useful. The most common surgical techniques in current use are resection with end-to-end anastomosis or extended end-to-end anastomosis, taking care to remove all residual ductal tissue.51,52 Extended end-to-end


Surgery_Schwartz

Surgery_Schwartz. most common surgical techniques in current use are resection with end-to-end anastomosis or extended end-to-end anastomosis, taking care to remove all residual ductal tissue.51,52 Extended end-to-end anastomosis (Fig. 20-11) may also allow the surgeon to treat transverse arch hypoplasia, which is commonly encoun-tered in infants with aortic coarctation.53,54 The subclavian flap Brunicardi_Ch20_p0751-p0800.indd 76222/02/19 2:55 PM 763CONGENITAL HEART DISEASECHAPTER 20aortoplasty is another repair, although it is used less frequently in the modern era because of the risk of late aneurysm formation and possible underdevelopment of the left upper extremity isch-emia.52 In this method, the left subclavian artery is transected and brought down over the coarcted segment as a vascular-ized patch. The main benefit of these techniques is that they do not involve the use of prosthetic materials, and evidence sug-gests that extended end-to-end anastomosis may promote arch growth, especially


Surgery_Schwartz

Surgery_Schwartz. The main benefit of these techniques is that they do not involve the use of prosthetic materials, and evidence sug-gests that extended end-to-end anastomosis may promote arch growth, especially in infants with the smallest initial aortic arch diameters.53Despite the benefits, however, extended end-to-end anas-tomosis may not be feasible when there is a long segment of coarctation or in the presence of previous surgery because suf-ficient mobilization of the aorta above and below the lesion may not be possible. In this instance, prosthetic materials, such as a patch aortoplasty, in which a prosthetic patch is used to enlarge the coarcted segment, or an interposition tube graft must be employed. One of the most important decisions in infants and neonates with COA and some degree of transverse arch hypoplasia is whether the lesion should be approached with a sternotomy or a thoracotomy. Cross-sectional imaging with CT scan can be extremely helpful in assessing the adequacy of the


Surgery_Schwartz

Surgery_Schwartz. arch hypoplasia is whether the lesion should be approached with a sternotomy or a thoracotomy. Cross-sectional imaging with CT scan can be extremely helpful in assessing the adequacy of the transverse arch and any associated abnormalities with branching that may complicate repair from the side.The most common complications after COA repair are late restenosis (Fig. 20-12) and aneurysm formation at the repair site.55-57 Aneurysm formation is particularly common after patch aortoplasty when using Dacron material. In a large series of 891 patients, aneurysms occurred in 5.4% of the total, with 89% occurring in the group who received Dacron-patch aortoplasty and only 8% occurring in those who received resection with primary end-to-end anastomosis.55 A further complication, although uncommon, is lower-body paralysis resulting from ischemic spinal cord injury during the repair. This dreaded outcome complicates 0.5% of all surgical repairs, but its incidence can be lessened with the use of


Surgery_Schwartz

Surgery_Schwartz. is lower-body paralysis resulting from ischemic spinal cord injury during the repair. This dreaded outcome complicates 0.5% of all surgical repairs, but its incidence can be lessened with the use of some form of distal perfusion, preferably left heart bypass with the use of femoral arterial or distal thoracic aorta for arterial inflow and Figure 20-11. Appearance of the aorta after resection of the seg-ment of coarctation and reconstruction with an extended end-to-end anastomosis. (Used with permission from Kelly Rosso MD.)Figure 20-12. Reformatted images obtained from a CT angiogram after recurrent coarctation repaired by an extra anatomic bypass (‘*’ points to the bypass graft).the femoral vein or left atrium for venous return.51 These tech-niques are generally reserved for older patients with complex coarctations that may need prolonged aortic cross clamp times for repair, often in the setting of large collateral vessels and/or previous surgery.58Hypertension is also well


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Surgery_Schwartz. patients with complex coarctations that may need prolonged aortic cross clamp times for repair, often in the setting of large collateral vessels and/or previous surgery.58Hypertension is also well recognized following repair of COA. Bouchart and colleagues reported that in a cohort of 35 hypertensive adults (mean age, 28 years) undergoing repair, despite a satisfactory anatomic outcome, only 23 patients were normotensive at a mean follow-up period of 165 months.56 Like-wise, Bhat and associates reported that in a series of 84 patients (mean age at repair, 29 years), 31% remained hypertensive at a mean follow-up of 5 years following surgery.57Although operative repair is still the gold standard, treat-ment of COA by catheter-based intervention has become more widespread for older children and adults. Both balloon dilata-tion and primary stent implantation have been used successfully. The most extensive study of the results of balloon angioplasty reported on 970 procedures: 422 native


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Surgery_Schwartz. and adults. Both balloon dilata-tion and primary stent implantation have been used successfully. The most extensive study of the results of balloon angioplasty reported on 970 procedures: 422 native and 548 recurrent COAs. Mean gradient reduction was 74% ± 24% for native and 70% ± 31% for recurrent COA.59 This demonstrated that catheter-based therapy could produce equally effective results both in recurrent and in primary COA, a finding with far-reaching implications in the new paradigm of multidisciplinary treatment algorithms for CHD. In the Valvuloplasty and Angioplasty of Congeni-tal Anomalies (VACA) report, higher preangioplasty gradient, earlier procedure date, older patient age, and the presence of recurrent COA were independent risk factors for suboptimal procedural outcome.5The gradient after balloon dilatation in most series is gen-erally acceptable. However, there is a significant minority of patients (0%–26%) for whom the procedural outcome is sub-optimal, with a


Surgery_Schwartz

Surgery_Schwartz. gradient after balloon dilatation in most series is gen-erally acceptable. However, there is a significant minority of patients (0%–26%) for whom the procedural outcome is sub-optimal, with a postprocedure gradient of 20 mmHg or greater. These patients may be ideal candidates for primary stent place-ment. Deaths from the procedure also are infrequent (<1% of cases), and the main major complication is aneurysm formation, PAAoBrunicardi_Ch20_p0751-p0800.indd 76322/02/19 2:55 PM 764SPECIFIC CONSIDERATIONSPART IIwhich occurs in 7% of patients.51 With stent implantation, many authors have demonstrated improved resolution of stenosis compared with balloon dilatation alone, yet the long-term com-plications on vessel wall compliance remain largely unknown because only mid-term data are widely available.In summary, children younger than age 6 months with native COA should be treated with surgical repair, while those requiring intervention at later ages may be ideal candidates for balloon


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Surgery_Schwartz. available.In summary, children younger than age 6 months with native COA should be treated with surgical repair, while those requiring intervention at later ages may be ideal candidates for balloon dilatation or primary stent implantation.51 Additionally, catheter-based therapy should be employed for those cases of restenosis following either surgical or primary endovascular management.Truncus ArteriosusAnatomy. Truncus arteriosus is a rare anomaly, compris-ing between 1% and 2% of all live born cases of CHD.60 It is characterized by a single great artery that arises from the heart, overrides the ventricular septum, and supplies the pulmonary, systemic, and coronary circulations.The two major classification systems are those of Collett and Edwards, described in 1949, and Van Praagh, described in 1965 (Fig. 20-13).61,62 The Collett and Edwards classification focuses mainly on the origin of the pulmonary arteries from the common arterial trunk, whereas the Van Praagh system is based on


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Surgery_Schwartz. in 1965 (Fig. 20-13).61,62 The Collett and Edwards classification focuses mainly on the origin of the pulmonary arteries from the common arterial trunk, whereas the Van Praagh system is based on the presence or absence of a VSD, the degree of formation of the aorticopulmonary septum, and the status of the aortic arch.During embryonic life, the truncus arteriosus normally begins to separate and spiral into a distinguishable anterior pul-monary artery and posterior aorta. Persistent truncus, therefore, represents an arrest in embryologic development at this stage.63 Other implicated events include twisting of the dividing trun-cus because of ventricular looping, subinfundibular atresia, and abnormal location of the semilunar valve anlages.64The neural crest may also play a crucial role in the normal formation of the great vessels, as experimental studies in chick embryos have shown that ablation of the neural crest results in persistent truncus arteriosus.65 The neural crest also


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Surgery_Schwartz. in the normal formation of the great vessels, as experimental studies in chick embryos have shown that ablation of the neural crest results in persistent truncus arteriosus.65 The neural crest also develops into the pharyngeal pouches that give rise to the thymus and parathyroids, which likely explains the prevalent association of truncus arteriosus and DiGeorge’s syndrome.66The annulus of the truncal valve usually straddles the ventricular septum in a “balanced” fashion; however, it is not unusual for it to be positioned predominantly over the RV, which increases the potential for LVOT obstruction following surgical repair. In the great majority of cases, the leaflets are thickened and deformed, which leads to valvular insufficiency. There are usually three leaflets (60%), but occasionally a bicus-pid (5%) or even a quadricuspid valve (25%) is present.61In truncus arteriosus, the pulmonary trunk bifurcates, with the left and right pulmonary arteries forming posteriorly and to the


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Surgery_Schwartz. a bicus-pid (5%) or even a quadricuspid valve (25%) is present.61In truncus arteriosus, the pulmonary trunk bifurcates, with the left and right pulmonary arteries forming posteriorly and to the left in most cases. The caliber of the pulmonary arterial branches is usually normal, with stenosis or diffuse hypoplasia occurring in rare instances.The coronary arteries may be normal; however, anomalies are not unusual and occur in 50% of cases.67 Many of these are relatively minor, although two variations are of particular importance because they have implications in the conduct of operative repair. The first is that the left coronary ostium may arise high in the sinus of Valsalva or even from the truncal tis-sue at the margin of the pulmonary artery tissue. This coronary artery can be injured during repair when the pulmonary arteries are removed from the trunk or when the resulting truncal defect is closed. The second is that the right coronary artery can give rise to an important


Surgery_Schwartz

Surgery_Schwartz. injured during repair when the pulmonary arteries are removed from the trunk or when the resulting truncal defect is closed. The second is that the right coronary artery can give rise to an important accessory anterior descending artery, which often passes across the RV in the exact location where the right ventriculotomy is commonly performed during repair.68Physiology and Diagnosis. The main pathophysiologic con-sequences of truncus arteriosus are (a) the obligatory mixing of systemic and pulmonary venous blood at the level of the ven-tricular septal defect (VSD) and truncal valve, which leads to arterial saturations near 85% and (b) the presence of a nonre-strictive left-to-right shunt, which occurs during both systole and diastole, the volume of which is determined by the relative resistances of the pulmonary and systemic circulations. Addi-tionally, truncal valve stenosis or regurgitation, the presence of important LVOT obstruction, and stenosis of pulmonary artery branches can


Surgery_Schwartz

Surgery_Schwartz. of the pulmonary and systemic circulations. Addi-tionally, truncal valve stenosis or regurgitation, the presence of important LVOT obstruction, and stenosis of pulmonary artery branches can further contribute to both pressure and volume-loading of the ventricles. The presence of these lesions often results in severe heart failure and cardiovascular instability early in life. Pulmonary vascular resistance may develop as early as 6 months of age, leading to poor results with late surgical correction.Patients with truncus arteriosus usually present in the neo-natal period, with signs and symptoms of congestive heart fail-ure and mild to moderate cyanosis. A pansystolic murmur may be noted at the left sternal border, and occasionally a diastolic murmur may be heard in the presence of truncal regurgitation.Chest radiography will be consistent with pulmonary over-circulation, and a right aortic arch can be appreciated 35% of the time. The thymus is prominent by its absence if associated


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Surgery_Schwartz. regurgitation.Chest radiography will be consistent with pulmonary over-circulation, and a right aortic arch can be appreciated 35% of the time. The thymus is prominent by its absence if associated with DiGeorge syndrome (Fig. 20-14). The ECG is usually non-specific, demonstrating normal sinus rhythm with biventricular hypertrophy.Echocardiography with Doppler color-flow or pulsed Doppler is diagnostic and usually provides sufficient informa-tion to determine the type of truncus arteriosus, the origin of the Figure 20-13. Collett & Edwards classification for Truncus arteriosus. (Used with permission from Kelly Rosso MD.)RPARPARPAType 1Type 2Type 3LPALPALPABrunicardi_Ch20_p0751-p0800.indd 76422/02/19 2:55 PM 765CONGENITAL HEART DISEASECHAPTER 20coronary arteries and their proximity to the pulmonary trunk, the character of the truncal valves, and the extent of truncal insuffi-ciency (Fig. 20-15). CT scan helps define the pulmonary arteries and the coronary anatomy (Fig. 20-16).


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Surgery_Schwartz. to the pulmonary trunk, the character of the truncal valves, and the extent of truncal insuffi-ciency (Fig. 20-15). CT scan helps define the pulmonary arteries and the coronary anatomy (Fig. 20-16). Cardiac catheterization can be helpful in cases where pulmonary hypertension is sus-pected or to further delineate coronary artery anomalies prior to repair.The presence of truncus is an indication for surgery. Repair should be undertaken in the neonatal period or as soon as the diagnosis is established.Repair. Truncus arteriosus was first managed with pulmonary artery banding as described by Armer and colleagues in 1961.69 However, this technique led to only marginal improvements in 1-year survival rates because ventricular failure inevitably occurred. In 1967, however, complete repair was accomplished by McGoon and his associates based on the experimental work of Rastelli, who introduced the idea that an extracardiac valved conduit could be used to restore ventricular-to-pulmonary artery


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Surgery_Schwartz. by McGoon and his associates based on the experimental work of Rastelli, who introduced the idea that an extracardiac valved conduit could be used to restore ventricular-to-pulmonary artery continuity.70 Over the next 20 years, improved survival rates led to uniform adoption of complete repair even in the youngest and smallest infants.71Surgical correction entails the use of CPB. Repair is completed by separation of the pulmonary arteries from the aorta, closure of the aortic defect (occasionally with a patch) to minimize coronary flow complications, placement of a valved cryopreserved allograft or jugular venous valved conduit (Con-tegra) to reconstruct the RVOT, and VSD closure. Important branch pulmonary arterial stenosis should be repaired at the time of complete repair and can usually be accomplished with longitudinal allograft patch arterioplasty. Severe truncal valve insufficiency occasionally requires truncal valve repair or even replacement, which can be accomplished with a


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Surgery_Schwartz. be accomplished with longitudinal allograft patch arterioplasty. Severe truncal valve insufficiency occasionally requires truncal valve repair or even replacement, which can be accomplished with a cryopreserved allograft.72Results. The results of complete repair of truncus have steadily improved. Ebert reported a 91% survival rate in his series of 77 patients who were younger than 6 months of age; later reports by others confirmed these findings and demonstrated that excel-lent results could be achieved in even smaller infants with com-plex-associated defects.71Newer extracardiac conduits also have been developed and used with success, which has widened the repertoire of the modern congenital heart surgeon and improved outcomes.72,73 Severe truncal regurgitation, interrupted aortic arch, coexistent coronary anomalies, chromosomal or genetic anomalies, and age younger than 100 days are risk factors associated with peri-operative death and poor outcome.Total Anomalous Pulmonary Venous


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Surgery_Schwartz. coexistent coronary anomalies, chromosomal or genetic anomalies, and age younger than 100 days are risk factors associated with peri-operative death and poor outcome.Total Anomalous Pulmonary Venous ConnectionTotal anomalous pulmonary venous connection (TAPVC) occurs in 1% to 2% of all cardiac malformations and is char-acterized by abnormal drainage of the pulmonary veins into the right heart, whether through connections into the right atrium or into its tributaries.74 Accordingly, the only mechanism by which oxygenated blood can return to the left heart is through an ASD, which is almost uniformly present with TAPVC.Figure 20-14. Chest x-ray of a baby with DiGeorge syndrome and truncus arteriosus. Note the absence of the thymic shadow in the superior mediastinum (‘*’).Figure 20-15. Echo appearance of a baby with Truncus Ateriosus. The ‘*’ represents the VSD, and the arrow points to the truncal valve.Figure 20-16. CT scan of a baby with Truncus Arteriosus Type 2. The ‘*’ mark the RPA


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Surgery_Schwartz. appearance of a baby with Truncus Ateriosus. The ‘*’ represents the VSD, and the arrow points to the truncal valve.Figure 20-16. CT scan of a baby with Truncus Arteriosus Type 2. The ‘*’ mark the RPA and the LPA. Note the stenosis at the origin of the LPA.Brunicardi_Ch20_p0751-p0800.indd 76522/02/19 2:55 PM 766SPECIFIC CONSIDERATIONSPART IIUnique to this lesion is the absence of a definitive form of palliation. Thus, TAPVC with concomitant obstruction (Fig. 20-17) represents one of the only true surgical emergen-cies across the entire spectrum of congenital heart surgery.Anatomy and Embryology. The lungs develop from an out-pouching of the foregut, and their venous plexus arises as part of the splanchnic venous system. TAPVC arises when the pul-monary vein evagination from the posterior surface of the left atrium fails to fuse with the pulmonary venous plexus surround-ing the lung buds. In place of the usual connection to the left atrium, at least one connection of the pulmonary


Surgery_Schwartz

Surgery_Schwartz. surface of the left atrium fails to fuse with the pulmonary venous plexus surround-ing the lung buds. In place of the usual connection to the left atrium, at least one connection of the pulmonary plexus to the splanchnic plexus persists. Accordingly, the pulmonary veins drain to the heart through a systemic vein.Darling and colleagues classified TAPVC (Fig. 20-18) according to the site or level of connection of the pulmonary veins to the systemic venous system75: type I (45%), anomalous connection at the supracardiac level; type II (25%), anomalous connection at the cardiac level; type III (25%), anomalous con-nection at the infracardiac level; and type IV (5%), anomalous connection at multiple levels.76 Within each category, further subdivisions can be implemented, depending on whether pul-monary venous obstruction exists. Obstruction to pulmonary venous drainage is a powerful predictor of adverse natural out-come and occurs most frequently with the infracardiac type, especially when


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Surgery_Schwartz. venous obstruction exists. Obstruction to pulmonary venous drainage is a powerful predictor of adverse natural out-come and occurs most frequently with the infracardiac type, especially when the pattern of infracardiac connection prevents the ductus venosus from bypassing the liver.77Pathophysiology and Diagnosis. Because both pulmonary and systemic venous blood returns to the right atrium in all forms of TAPVC, a right-to-left intracardiac shunt must be present in order for the afflicted infant to survive. This invariably occurs via a nonrestrictive patent foramen ovale. Because of this obliga-tory mixing, cyanosis is usually present, and its degree depends on the ratio of pulmonary to systemic blood flow. Decreased Figure 20-17. Infracardiac type of TAPVR. Note the stenosis (‘*’) of the descending vertical vein as it drains into the portal system.Figure 20-18. The various types of TAPVC as described by Darling and colleagues. (Used with permission from Nicholas Clarke MD.)pulmonary


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Surgery_Schwartz. descending vertical vein as it drains into the portal system.Figure 20-18. The various types of TAPVC as described by Darling and colleagues. (Used with permission from Nicholas Clarke MD.)pulmonary blood flow is a consequence of pulmonary venous obstruction, the presence of which is unlikely if the right ven-tricular pressure is less than 85% of systemic pressure.78The child with TAPVC may present with severe cyanosis and respiratory distress, necessitating urgent surgical interven-tion if a severe degree of pulmonary venous obstruction is pres-ent. However, in cases where there is no obstructive component, the clinical picture is usually one of pulmonary overcircula-tion, hepatomegaly, tachycardia, and tachypnea with feeding. In a child with serious obstruction, arterial blood gas analysis reveals severe hypoxemia (partial pressure of oxygen [Po2] < 20 mmHg), with metabolic acidosis.79Chest radiography (Fig. 20-19) will show normal heart size with generalized pulmonary edema.


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Surgery_Schwartz. analysis reveals severe hypoxemia (partial pressure of oxygen [Po2] < 20 mmHg), with metabolic acidosis.79Chest radiography (Fig. 20-19) will show normal heart size with generalized pulmonary edema. Two-dimensional echocardiography is very useful in establishing the diagnosis and also can assess ventricular septal position, which may be leftward secondary to small left ventricular volumes, as well as estimate the right ventricular pressure based on the height of the tricuspid regurgitant jet. Echocardiography can usually identify the pulmonary venous connections (types I to IV), and it is rarely necessary to perform other diagnostic tests.Cardiac catheterization is not recommended in these patients because the osmotic load from the intravenous contrast can exacerbate the degree of pulmonary edema.80 When cardiac catheterization is performed, equalization of oxygen saturations in all four heart chambers is a hallmark finding in this disease because the mixed blood returned to the right


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Surgery_Schwartz. edema.80 When cardiac catheterization is performed, equalization of oxygen saturations in all four heart chambers is a hallmark finding in this disease because the mixed blood returned to the right atrium gets dis-tributed throughout the heart.Therapy. Operative correction of TAPVC requires anastomo-sis of the common pulmonary venous channel to the left atrium, obliteration of the anomalous venous connection, and closure of the ASD.79,81IIIAIVCIVCSVCLPVLARARPVIVCRVLVRARVDVVVPVLVLASVCCPVIVCIIBIIISVCVVLPVCPVSVCRPRALARVLVCPVLALVRARVBrunicardi_Ch20_p0751-p0800.indd 76622/02/19 2:55 PM 767CONGENITAL HEART DISEASECHAPTER 20All types of TAPVC are approached through a median ster-notomy, and many surgeons use deep hypothermic circulatory arrest in order to achieve an accurate and widely patent anastomo-sis. The technique for supracardiac TAPVC includes early division of the vertical vein, retraction of the aorta and the superior vena cava laterally to expose the posterior aspect of the


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Surgery_Schwartz. anastomo-sis. The technique for supracardiac TAPVC includes early division of the vertical vein, retraction of the aorta and the superior vena cava laterally to expose the posterior aspect of the left atrium and the pulmonary venous confluence, and a side-to-side anastomosis between a long, horizontal biatrial incision and a longitudinal inci-sion within the pulmonary venous confluence. The ASD can then be closed with an autologous pericardial or synthetic patch.In patients with TAPVC to the coronary sinus without obstruction, a simple unroofing of the coronary sinus can be performed through a single right atriotomy with concomitant closure of the ASD. If pulmonary venous obstruction is pres-ent, the repair should include generous resection of roof of the coronary sinus.79Repair of infracardiac TAPVC entails ligation of the verti-cal vein at the diaphragm, followed by construction of a proximal, patulous longitudinal venotomy. This repair is usually performed by “rolling” the heart


Surgery_Schwartz

Surgery_Schwartz. TAPVC entails ligation of the verti-cal vein at the diaphragm, followed by construction of a proximal, patulous longitudinal venotomy. This repair is usually performed by “rolling” the heart toward the left, thus exposing the left atrium where it usually overlies the descending vertical vein.As originally described by Lacour-Gayet and colleagues at the Marie-Lannelongue Hospital, Paris, and Coles and col-leagues at The Hospital for Sick Children, Toronto, the suture-less technique was developed for patients with anastomotic stenosis occurring after TAPVC repair.80,81 After determining that favorable outcomes were possible using this technique, it is currently used in selected patients upon initial presentation of TAPVC.81 Incisions are made in the venous confluence. Based on the surgeon’s discretion, the incisions are extended into both upper and lower pulmonary veins separately if judged to be important for an unobstructed pathway. An atriopericardial anastomosis is created using the


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Surgery_Schwartz. discretion, the incisions are extended into both upper and lower pulmonary veins separately if judged to be important for an unobstructed pathway. An atriopericardial anastomosis is created using the pericardium adjacent to where the pulmonary veins enter the pericardium (Fig. 20-20). This anastomosis avoids direct contact with the incision site in the wall of the pulmonary veins and allows the free egress of blood from the lungs to the left atrium.The perioperative care of these infants is crucial because episodes of pulmonary hypertension can occur within the first 48 hours, which contribute significantly to mortality following repair. Muscle relaxants and narcotics should be administered during this period to maintain a constant state of anesthesia. Arterial partial pressure of carbon dioxide (Pco2) should be maintained at 30 mmHg with use of a volume ventilator, and the fraction of inspired oxygen (Fio2) should be increased to keep the pulmonary arterial pressure at less than


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Surgery_Schwartz. dioxide (Pco2) should be maintained at 30 mmHg with use of a volume ventilator, and the fraction of inspired oxygen (Fio2) should be increased to keep the pulmonary arterial pressure at less than two-thirds of the systemic pressure.Results. Results of TAPVC in infancy have markedly improved in recent years, with an operative mortality of 5% or less in some series.79-82 This improvement is probably multifac-torial, mainly as a consequence of early noninvasive diagnosis and aggressive perioperative management. The routine use of echocardiography; improvements in myocardial protection with specific attention to the RV; creation of a large, tension-free anastomosis with maximal use of the venous confluence and atrial tissue; use of a sutureless technique in selected cases; and prevention of pulmonary hypertensive events have likely played a major role in reducing operative mortality. The importance of risk factors for early mortality, such as venous obstruction at presentation, urgency of


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Surgery_Schwartz. hypertensive events have likely played a major role in reducing operative mortality. The importance of risk factors for early mortality, such as venous obstruction at presentation, urgency of operative repair, and infradiaphrag-matic anatomic type, has been debated.81,83Bando and colleagues84 made the controversial statement that both preoperative pulmonary venous obstruction and ana-tomic type had been neutralized as potential risk factors beyond calendar year 1991. Hyde et al82 similarly reported that connec-tion type was not related to outcome. However, a large single-institution report of 377 children with TAPVC by the author from the Hospital for Sick Children in Toronto85 found that, although outcomes had improved over time, patient anatomic factors were still important determinants of both survival and the need for subsequent reoperation. Risk factors for postrepair death were earlier operation year, younger age at repair, cardiac connection type, and postoperative pulmonary


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Surgery_Schwartz. of both survival and the need for subsequent reoperation. Risk factors for postrepair death were earlier operation year, younger age at repair, cardiac connection type, and postoperative pulmonary venous obstruc-tion. Risk-adjusted estimated 1-year survival for a patient repaired at birth with unfavorable morphology in 2006 was 37% (95% confidence interval [CI], 8%–80%) compared with 96% (95% CI, 91%–99%) for a patient with favorable morphology repaired at age 1 year. Freedom from reoperation was 82% ± 6% 4Figure 20-19. Chest x-ray of a newborn with obstructed infracar-diac type of TAPVR rescued by ECMO. Note the ECMO cannulas in the right neck (‘*’).InfracardiacTAPVCConventionalRepairSuturelessRepairFigure 20-20. Differences between conventional repair of total anomalous pulmonary venous connection (TAPVC) and sutureless repair of TAPVC. In the sutureless techniques, there are no sutures placed in the fragile veins themselves. Rather, the pericardial flaps are used to create a “well”