Preliminary results of the program on the surgical control of the hyperlipidemias (POSCH)

Abstract

The Program on the Surgical Control of the Hyperlipidemias (POSCH) is a randomized, prospective, secondary intervention trial examining the effects of lipid modification on overall mortality and the course of atherosclerotic cardiovascular disease in 838 survivors of a single myocardial infarction. Partial ileal bypass, a surgical procedure developed at the University of Minnesota and introduced in 1963, was selected as the intervention modality in POSCH. Complete, five-year lipid results are available currently in 660 POSCH participants, 330 surgical patients and 330 control patients treated with the Phase II American Heart Association diet. Total plasma cholesterol was 24.3 ± 0.9 percent lower (mean ± SEM) and low density lipoprotein (LDL) cholesterol was 38.7 ± 1.2 percent lower in the surgical group when compared with the diet-treated controls five years following operation. High density lipoprotein (HDL) cholesterol was 6.9 ± 1.8 percent higher in the surgical patients. In a subgroup of 185 control and 190 surgical patients undergoing apolipoprotein and HDL subfraction analysis, apolipoprotein B-100 was significantly lower and apolipoprotein A-I and HDL subfraction 2 were significantly higher in the operated patients in comparison with the controls. Partial ileal bypass has induced marked, sustained, favorable lipid modification. Based on morbidity and mortality assumptions derived from epidemiologic analyses, these lipid alterations should result in significant reductions in atherosclerotic cardiovascular disease morbidity and mortality when the final POSCH morbidity and mortality experience is examined at the conclusion of the trial in July, 1990.