Prevention of brain attacks

The Charter Bureau

As a cardiologist, I commonly encounter patients and other lay people who confuse heart attacks (myocardial infarctions) for brain attacks (strokes). While it is true that these diseases affect different organs (the former involving the heart and the latter the brain) with very different symptoms and treatments, these conditions are remarkably similar and interrelated when it comes to their root causes.

This article will thus focus on how the average Filipino can use these similarities to help prevent both brain and heart attacks, from the viewpoint of a cardiologist.

Most strokes and heart attacks occur due to problems with the blood vessels that supply the heart and brain. These vessels may develop a blockage (due to a process called atherosclerosis), or particularly in the brain, may rupture (due to high blood pressure).

Statistically, patients with blockages of the blood vessels supplying the heart muscle (called coronary artery disease or CAD) have a 50 percent risk of developing a brain attack (stroke), and conversely, stroke patients have a 30 percent risk of developing CAD.

Thus, both conditions may co-exist in the same patient, and when a patient presents with blood vessel problems in the heart, it may be prudent to check for similar problems in the brain, and vice-versa.

It is also important to note that it is the heart’s pumping action that provides blood supply to the brain, and thus, heart failure may reduce this blood supply and cause a stroke, particularly in the setting of previously unnoticed blockages in the brain’s blood vessels.

Strokes and heart attacks share not only underlying structural causes but also common environmental and health triggers, called risk factors. These include cigarette smoking, obesity, diabetes, high cholesterol levels and high blood pressure.

Smoking increases the risk of developing diabetes, itself a known risk for blood vessel damage. Smoking directly injures the lining of blood vessels (called the endothelium) allowing fatty substances to penetrate, accumulate, and eventually block these vessels (called atherosclerosis).

High levels of blood fat and cholesterol (called hyperlipidemia) will, of course, accelerate this process of blood vessel blockage. In fact, recent studies have shown that hyperlipidemia is so important a risk factor that currently, many physicians prescribe the so-called statins (a class of cholesterol-lowering drugs) even to patients with high-normal cholesterol and in certain cases, even patients with normal cholesterol levels may benefit.

Obesity results in excess heart pumping action, heart muscle thickening, progressing to heart enlargement and eventually heart failure. Likewise, obesity by itself is also a diabetes risk, which again results in blood vessel damage.

High blood pressure not only damages blood vessels (thus accelerating atherosclerosis), but also results in the heart muscle thickening called left ventricular hypertrophy, with the same dire consequences. Thus, it is logical for both doctor and patient to address all of these risk factors to prevent both strokes and heart attacks.

Certain types of heart conditions may increase the risk of stroke. These include heart failure and irregular heartbeats. Heart failure may predispose vulnerable patients toward the development of a stroke. Irregular heartbeats may result in the formation of blood clots within the heart chambers.

Should such a clot be a dislodged and travel to the brain’s blood vessels, a stroke will result. Heart specialists and patients with heart disease should therefore be conscious of the possible consequences of heart conditions toward the brain and other vital organs.

In a recently published scientific study involving 6,105 patients with a previous history of either major or minor strokes, treatment over a four-year-period based on the blood pressure-lowering drug perindopril (Coversyl) decreased the chances of a recurrent disabling or fatal stroke and non-fatal heart attack by 38 percent.

Furthermore, the chances of a recurrent stroke due to bleeding inside the brain (cerebral hemorrhage) was reduced by 50 percent. There was no other study in the past which showed similar outcomes.

Based on this study, the drug perindopril may be the better choice compared to other blood pressure-lowering agents, in the field of stroke prevention.

For stroke victims, preventing a repeat stroke is certainly welcome news and it is no longer impossible in this day and age with a therapeutic lifestyle change (TLC) and proper medications.

(The author is professor emeritus at the University of the Philippines College of Medicine, an academician of the National Academy of Science and Technology, and a member of the scientific advisory board of Charter, a non-stock, non-profit research foundation which promotes lifestyle changes in the prevention of common medical problems.)