By Lisa Ellis
InteliHealth News Service

Heart patients need to watch their triglycerides, not just their cholesterol , if they want to prevent strokes, a study from Israel concludes.

The study was conducted among 1,100 people with coronary heart disease. It found that participants with high triglycerides, a form of blood fat, were more likely to suffer the most common form of stroke than patients with normal triglycerides.

Participants with high triglycerides had a 27 percent higher risk of ischemic strokes and transient ischemic attacks , or TIAs, than participants with normal triglyceride levels. People with high levels of high-density lipoprotein (HDL), so-called good cholesterol, were less likely to have strokes than those with lower HDL.

The study is published in the Dec. 11, 2001, issue of Circulation, a journal of the American Heart Association.

About 80 percent of strokes are ischemic. This type of stroke occurs when a vessel in the brain is blocked by a blood clot or a thickening of the vessel walls. A transient ischemic attack — sometimes called a "mini-stroke" — is a temporary blockage. TIA symptoms disappear within 24 hours.

The study results do not apply to hemorrhagic stroke, caused by bleeding from a damaged vessel.

Heart disease patients "often have problems as well with the arteries that go to their brains," notes Louis Caplan, M.D., director of the Stroke and Cerebrovascular Disorders Clinic at Beth Israel Deaconess Medical Center in Boston.

He says the study's results are not surprising. However, the results provide another reason for people with coronary heart disease to control triglycerides and not just cholesterol.

"People who have abnormal cholesterol frequently also have high triglycerides," says Dr. Caplan. "Before, most people had thought that they just go together and that it's hard to separate them.

"Here it's saying there's an additional risk. I think people suspected it anyway. This also confirms that the high-density cholesterol, HDL, is very important."

Dr. Caplan, former chairman of the Stroke Council of the American Heart Association, is a professor of neurology at Harvard Medical School.

Triglycerides are used by the body to store and transport fat. Less than 150 milligrams per deciliter of blood is considered normal and more than 200 is high, according to standards released in 2001 by a U.S. government advisory panel. Levels in between are labeled "borderline-high."

Many patients in the Israeli study had high levels of total cholesterol and low-density lipoprotein (LDL), or "bad cholesterol." But the researchers found that having high triglycerides further increased the risk of stroke.

David Tanne, M.D., and colleagues at Chaim Sheba Medical Center in Tel-Hashomer, Israel, conducted the new study along with researchers at two other Israeli medical centers.

Few studies have examined the relationship between specific blood fats, particularly triglycerides, and stroke, the authors write in the Circulation article. Nevertheless, they write, some studies have shown that using drugs to reduce various blood fats lowers the risk of stroke. Other studies indicate that people with high triglycerides have a higher risk of developing coronary heart disease.

Most members of the public realize that having a high triglyceride level is unhealthy, and many people with coronary heart disease — the group in the Israeli study — already are treated for high triglycerides, Dr. Caplan says.

This study therefore is not likely to have a strong impact on patient care, he says. Some medicines for lowering cholesterol also will reduce triglycerides, and this study provides a further reason to treat both, he says.

Such treatment is especially important for patients with a family history of coronary heart disease or stroke. "If you have a family history of vascular disease," Dr. Caplan says, "you ought to know what your cholesterol and triglycerides are and then take measures to modify then."