[Drug therapy prevention of coronary sclerosis]

Primary preventive drug treatment of coronary artery disease (CAD) has gained importance in recent years as more efficient lipid lowering drugs and substances with new mechanisms become available, e.g. calcium entry blockers and antioxidants. For lipid lowering drugs, the exact mechanism of action is still not clear; the results of quantitated coronary angiography (QCA) revealing a small but significant increase in luminal size in stenotic areas can be explained both by stabilization of endothelial function (increased EDRF production)--as demonstrated in animal studies--leading to a decrease in basal tone, and by a decrease in plaque volume (so far not evidenced by QCA in man). Calcium entry blockers and antioxidants inhibit the formation of new atherosclerotic lesions, mainly by improving cholesterol excretion from vascular smooth muscle cells and macrophages into the extracellular space, and by suppression of proliferation and differentiation of vascular smooth muscle cells. The ensuing reduction of cardiac events is not yet proven for calcium entry blockers and also needs further confirmation for lipid lowering drugs; the difficulty of studies looking for clinical endpoints (myocardial infarction on sudden coronary death, unstable angina) lies in the very slow anatomical progression of CAD as demonstrated by QCA, demanding large numbers of patients and long intervals to demonstrate statistical significance.