In the National Heart, Lung and Blood Institute Type II Coronary Intervention Study, patients with
Type II hyperlipoproteinemia and
coronary artery disease (CAD) were placed on a low-fat, low-
cholesterol diet and then were randomly allocated to receive either 6 g
cholestyramine four times daily or placebo. This double-blind study evaluated the effects of
cholestyramine on the progression of CAD as assessed by angiography. Diet alone reduced the
low-density lipoprotein cholesterol 6% in both groups. After randomization,
low-density lipoprotein cholesterol decreased another 5% in the placebo group and 26% in the
cholestyramine-treated group. Coronary angiography was performed in 116 patients before and after 5 years of treatment. CAD progressed in 49% (28 of 57) of the placebo-treated patients vs 32% (19 of 59) of the
cholestyramine-treated patients (p less than .05). When only definite progression was considered, 35% (20 of 57) of the placebo-treated patients vs 25% (15 of 59) of the
cholestyramine-treated patients exhibited definite progression; the difference was not statistically significant. However, when this analysis was performed with adjustment for baseline inequalities of risk factors, effect of treatment was more pronounced. Of lesions causing 50% or greater
stenosis at baseline, 33% of placebo-treated and 12% of
cholestyramine-treated patients manifested lesion progression (p less than .05). Similar analyses with other end points (percent of baseline lesions that progressed, lesions that progressed to occlusion, lesions that regressed, size of lesion change, and all cardiovascular end points) all favored the
cholestyramine-treated group, but were not statistically significant. Thus, although the sample size does not allow a definitive conclusion to be drawn, this study suggests that
cholestyramine treatment retards the rate of progression of CAD in patients with
Type II hyperlipoproteinemia.