Program on Surgical Control of Hyperlipidemias (POSCH)

To determine whether a profound reduction in serum cholesterol level, induced and maintained by partial ileal bypass, would prevent a second heart attack among men and women who had one myocardial infarction and whose blood cholesterol could not be reduced sufficiently by diet. BACKGROUND: The correlative evidence linking elevated cholesterol to increased risk of cardiovascular disease is incontrovertible. Animal studies have shown that significant reductions in disease in humans may be forthcoming if blood lipids are reduced from elevated levels. Beginning in the 1960s, some patients had undergone a surgical bypass procedure for hyperlipidemia. Patients were selected for surgery after dietary management had been carried out for three years. The average serum cholesterol concentrations decreased markedly and the decrease was sustained. This grant-supported clinical trial attempted to determine the effect on cardiovascular morbidity and mortality of the partial ileal bypass in patients who had suffered a myocardial infarction within the previous 5 years and who had serum cholesterol over 220 mg deciliter (200 mg if LDL cholesterol was over l40 mg). DESIGN NARRATIVE: Randomized, non-blind, fixed sample study with a control group and an experimental group of equal size. The experimental group received a partial ileal bypass and diet therapy to reduce serum cholesterol and triglycerides. The control group was given conventional medical therapy exclusive of cholesterol-lowering drugs. The primary endpoint was death due to any cause. Secondary endpoints included death due to atherosclerosis and morbidity from recurrent myocardial infarction, unstable angina, cerebrovascular accident. Other secondary endpoints included coronary artery bypass surgery, percutaneous transluminal coronary angioplasty, cardiac transplantation, and peripheral vascular surgery. Beginning in January 1993, long-term morbidity and mortality follow-up are continuing through December 1997 under grant support (R01HL49522). Follow-up includes tracking morbidity and mortality by an annual telephone survey and review of patient records, including death and autopsy results. In addition, mortality and morbidity will be correlated with lipid changes and existing arteriographic results. The long-term course of control patients treated with the AHA Phase II Diet counseling will be assessed and the long-term side effects of partial ileal bypass will be evaluated.