PROGRAM ON THE SURGICAL CONTROL OF THE HYPERLIPIDEMIAS - 1994 REPORT

The Program on the Surgical Control of the Hyperlipidemias (POSCH), a randomized clinical trial, tested the hypothesis that cholesterol modi fication induced by partial ileal bypass would favorably affect mortal ity and morbidity due to coronary heart disease (CHD). The study popul ation consisted of 838 patients (417 in the control group and 421 in t he surgery group) in four clinical centers, both men (90.7%) and women with an average age of 51 years who had survived a first myocardial i nfarction. The lipid changes in POSCH have been the most marked in any atherosclerosis intervention trial utilizing a single mode of interve ntion in addition to diet therapy. At 5 years, the surgery group, comp ared with the control group, had a 23.3 +/- 1.0% (mean +/- SE) lower t otal plasma cholesterol level (p < 0.0001), a 37.7 +/- 1.2% lower low- density lipoprotein cholesterol level (p < 0.0001), and a 4.3 +/- 1.8% higher high-density lipoprotein cholesterol level (p = 0.02). For the combined end point of CHD mortality and confirmed nonfatal myocardial infarction, there was a 35.0% reduction in the surgery group (p < 0.0 01). Coronary artery bypass grafting was reduced in the surgery group by 62.0% (p < 0.0001) and percutaneous transluminal coronary angioplas ty was reduced by 55.0% (p < 0.01). A comparison of baseline coronary arteriograms with those obtained at 3, 5, 7, and, 10 years consistentl y showed less atherosclerosis disease progression (p < 0.001) and grea ter atherosclerosis disease regression at 5 and 7 years (p < 0.01)in t he surgery group. At formal trial completion in July 1990, the overall mortality in the surgery subgroup with an ejection fraction of 50% or greater was 36.1% lower (p = 0.02). During subsequent follow-up, tren ds toward statistical significance for differences in both CHD and in overall mortality have become evident. The POSCH results provide stron g support for beneficial clinical and arteriographic reduction of athe rosclerosis progression after lipid modification by partial ileal bypa ss.