Dealing with new risk factors for heart disease

Dr Aashish Contractor

A few weeks back, Sunil Shah had a massive heart attack at 6 am on a Monday morning. He underwent a bypass surgery within three days of the attack. At present he is recovering, but is in a depression and is perplexed as to how a 'healthy' person like him could have a heart attack.

Sunil Shah is a 40-year-old trader. He is a pure vegetarian, does not smoke or drink, walks daily for an hour and is a teetotaler. He does not have diabetes or high blood pressure and his cholesterol was 'borderline high'. Shah did not have the well-established risk factors of smoking, diabetes, blood pressure and high cholesterol.

After doing detailed investigations, it was found that he had a high omocysteine level and a high Lipoprotein (a) level. These proteins have been discovered in the past few years and are known as 'new' risk factors for heart disease.

In studies conducted on Indians living in England and North America, it has been observed that they have high levels of both these conditions and are therefore more prone to heart disease. It is therefore even more important to keep one's risk factors in control.

Homocysteine

Homocysteine is a common amino acid (one of the building blocks that make up proteins) found in the blood. High levels of homocysteine are related to the early development of heart disease. High homocysteine is associated with low levels of vitamin B6, B12 and folic acid and renal disease.

Levels of the amino acid are related partly to a genetic mechanism and diet. The good news is that diet, especially one high in folic acid and B vitamins, favorably affects the levels of homocysteine.

How does homocysteine increase heart disease risk?

Doctors believe that homocysteine may contribute to the buildup of fatty substances in the arteries, increase the stickiness of blood platelets (clotting), and make blood vessels less flexible, less able to widen to permit increased blood flow.

When does one need to have homocysteine level checked?

Currently, there is no universal recommendation for checking homocysteine in everyone. The test is still relatively expensive and isn't widely available. However, testing for homocysteine is useful in people with other risk factors for heart disease or those who have a personal or family history of cardiovascular disease, but do not have any of the standard risk factors. The normal blood level of homocysteine is 5-15 micromoles per liter.

Can high homocysteine levels be prevented?

High-risk patients with high homocysteine levels should increase their intake of B-vitamins (folic acid, vitamins B-12 and B-6). These vitamins can be found in a wide variety of fruits, green, leafy vegetables, and grain products. Doctors do not know for sure if lowering homocysteine levels will lower heart disease risk. More studies are in progress.

Lipoprotein (a)

Lipoprotein Lp(a) is a major and independent genetic risk factor for atherosclerosis and cardiovascular disease. Lipoprotein (a), is a variant of "bad" LDL attached to an extra protein particle.

How does Lipoprotein (a) increase heart disease risk?

Unlike LDL cholesterol, Lp(a) does not appear to promote fatty buildup in the arteries. Instead, its damage may come from preventing the breakup of clots.

When does one need to have Lipoprotein (a) level checked?

Like in the case of homocysteine, there is no universal recommendation for checking lipoprotein (a) in everyone. Testing is useful in those who have a high cholesterol and a strong family history of heart disease, or those who have had heart disease at an early age.The normal blood level of lipoprotein (a) is less than 30 mg/dl.

Can high Lipoprotein (a) levels be prevented?

Lp (a) is largely an inherited risk factor and cannot be prevented. However, if the Lp (a) is high, then it is extremely important to keep your LDL cholesterol as low as possible, to reduce your risk for heart disease. At present, only niacin, and estrogen replacement (for ladies) has been shown to reduce Lp (a) levels.

The writer is head of department of cardiac prevention and rehabilitation at the Asian Heart Institute, Mumbai.