Thursday, January 19, 2006

Preventing heart attacks

This article was contributed to The Star (Malaysia) and published on the 1st of January 2006. It was cotributed on behalf of the Federation of Private Medical Practitioners Associations Malaysia. Please note our standard disclaimer.

EARLIER in this series, I wrote extensively on coronary artery disease. Just to recap, coronary artery disease (CAD) is a disease of cholesterol accumulation in the walls of the arteries of the heart. CAD often results in heart attacks, sudden cardiac death and heart failure.

As explained in an earlier article, a heart attack occurs when the plaque, rich in cholesterol, ruptures, with resulting blood clot formation and occlusion of artery lumen, preventing life-giving blood from reaching functioning heart muscles.

Sudden cardiac death (SCD) is diagnosed when a person collapses and dies within 24 hours of the onset of symptoms. In 90% of the time when someone drops dead, autopsy will show severe cholesterol accumulation in his heart arteries, with erosion and embolisation of the cholesterol material from the plaque. In this instance, the loss of heart muscle is minimal, but the area with inadequate blood flow happens to be sensitive and vulnerable to irregular heartbeats. This sudden occurrence of irregular heartbeats sometimes causes the heart to fibrillate and stop, resulting in sudden cardiac death.

Can these cardiac catastrophies be prevented?

The obvious answer is yes, but the tough part is how? At present, there is no magic pill that one can take to prevent a heart attack. The solution is there, but it’s not simple. It is best to view it as:

1. What can the patient do?
2. What can the doctor do?

What can the patient do?

The first point is to minimise your risk. Unlike typhoid or malaria, CAD has no known single cause. The cause of CAD is probably multi-factorial. The major CAD risk factors include hypertension, cigarette smoking, blood lipid abnormalities and diabetes.

It must be noted that these CAD risk factors are, in many ways, lifestyle related. An unhealthy lifestyle promotes hypertension, high cholesterol and diabetes. It is therefore obvious that a healthy lifestyle reduces the risk of CAD and therefore of heart attacks.

This fact is very well borne out by medical studies. Healthy cardiac lifestyle includes eating a diet low in salt (no added salt or sauce), calories (enough to balance the calories usage for the day) and fats (about 300 gms of cholesterol/day), smoking cessation and regular exercise (15km of brisk walking per week in divided portions). For those of us who are target oriented, you may wish to know that our aim is to achieve a waistline of 34 inches, and a BMI (body mass index) of 23-24.

Coming back to food, it is heartening to note that McDonalds has recently announced its plan to label all their food so that the consumer can know and be responsible for what they eat.

The second thing that we can do as lay people is to go for check-ups. It is prudent that all males above 40 years old and all females above 50 years old go for a full (fasting) screening blood test, ECG and if possible a stress ECG, to establish their respective cardiac status. These tests are reliable and fairly cheap. The more expensive and sophisticated, much touted tests should be done with medical advice. It is hoped that with this strategy, potential CAD patients or even asymptomatic CADs can be detected early, and treated, to avoid heart attacks.

What can the doctor do?

The medical approach is to risk profile a person. Obviously not all of us have the same risk for a heart attack. The people more at risk of a heart attack are males above 40 years, and females above 50 years, those with high blood pressure, those with high cholesterol, those with diabetes, and those who smoke.

People with a family history of heart disease, for example, two or more members in the family with heart attacks, or who have undergone angioplasty, or bypass surgery, are also at risk. The more risk factors a person has, the higher the risk of CAD and therefore of heart attacks.

Decreasing the number of risk factors lessens the risk of heart attacks. It is true that not all who have CAD will suffer a heart attack. Medical science is truly perplexed by patients who have severe three vessel CAD but who live till a ripe old age and die from natural causes.

On the other hand, we have all heard of healthy males with no apparent disease who die from heart attacks.

The difficult question is, what makes a stable cholesterol blockage become unstable, therefore triggering a heart attack? Why are some blockages vulnerable to rupture, causing heart attacks, while others are not vulnerable, remaining stable and event-free for the moment, only to be vulnerable at another time?

What triggers a heart attack in patients with cholesterol plaques?

It is clear that vulnerable plaques are those with a lot of fat (cholesterol crystals) in them. The problem is we cannot see these arteries by the bedside. The fats in the artery wall can only be visualised during an angiogram procedure.

The next best thing is to try and identify those patients with the potential for fats in their artery wall, and then try and identify, among these patients, those prone to cardiac events (the high risk patients).

Using this strategy, we have been broadly successful. Certain types of patients are very prone to cardiac events, for example, those with diabetes, those with poorly controlled hypertension, those with certain infections or inflammation, those with “stress” and those on certain drugs.

Certain blood tests can help to warn us of an impending heart attack, like the hs-CRP (highly sensitive-C reactive protein), and also the Lp-PLA2. High levels of these substances in the blood may warn us that that patient may be at risk of some cardiac event in the near future. Treatment with the proper drugs may lower the level of these substances and lessen the risk of cardiac events significantly. At the moment, that seems the best that we can do.

In conclusion

So, how do we prevent heart attacks? The basic steps are:

1. Identifying those at risk of CAD.

2. Identifying those at risk of a major adverse cardiac events, for example, diabetics, especially those who are poorly controlled, those with poorly controlled hypertension, those who have certain infections or inflammation, those under tremendous stress, and those on certain drugs.

3. Identify those with high levels of hs-CRP or Lp-PLA2.

4. Immediate medical advice to lower all the above-mentioned risks, with strict lifestyle modification and drugs.

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