Diet, Drugs Slow Heart-Felt 'Insults.' (Research on Whether Controlling Cholesterol Can Regulate Existing Atherosclerotic Lesions)
Edwards, Diane D., Science News
Diet, drugs slow heart-felt 'insults'
Another piece of the cholesterol puzzlefell into place last week with the announcement that cholesterol-reducing drugs and decreased dietary fat together not only significantly lower blood cholesterol, but also slow the spread of fatty buildup in blood vessels. Based on a study of patients who had had coronary bypass surgery, the findings are expected to alter the standard treatment of patients after heart surgery. But they also raise questions about which of several groups considered at increased risk for heart disease -- including asymptomatic individuals with moderate to high cholesterol levels --1 should follow the time-consuming and potentially expensive therapy regimen as a preventive measure.
Although elevated cholesterol levelshave been tied to increased risk of heart disease for several years, the latest study is one of the first to lower blood cholesterol in patients who have had previous coronary bypass surgery. During a briefing at the National Heart, Lung, and Blood Institute (NHLBI) in Bethesda, Md., institute director Claude Lenfant said this "very important" study, conducted at the University of southern California (USC) in Los Angeles, also is the first designed to det ermine whether controlling cholesterol can regulate existing atherosclerotic lesions.
Called the Cholesterol-Lowering AtherosclerosisStudy, the two-year test included 162men -- nonsmokers and ex-smokers aged 40 to 59 years -- who at the beginning of the study had blood cholesterol levels ranging from relatively low (185 milligrams per deciliter) to high (350 mg/dl) levels. Placed on similar low-cholesterol diets, half received a placebo, while the remainder were given a combination of colestipol hydrochloride and niacin.
In the drug-treated group, there was a26 percent reduction in total cholesterol, a 43 percent reduction in low-density lipoprotein (LDL) cholesterol and a 37 percent increase in high-density lipoprotein (HDL) cholesterol. HDL cholesterol, the "good" kind, helps block the adverse effects of LDL cholesterol.
In contrast, parallel changes in theplacebo group varied between 2 percent and 5 percent, said USC researcher David H. Blankenhorn at last week's briefing. Because of their history of heart disease, the men had been following a variety of low-cholesterol diets prior to beginning the study.
By injecting special dyes, the researchersalso studied the size of atherosclerotic lesions in both native and "foreign" blood vessels, the latter added during bypass surgery to replace damaged vessels. Lesion changes, described in the June 19 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION (JAMA), showed either stabilization or shrinkage of lesions in the drug-treated group. According to Blankenhorn, actual regression of the lesions "as judged by perceptible improvement" occurred in 16. …