PROPOSED SYNERGISTIC EFFECT OF CALCIUM-CHANNEL BLOCKERS WITH LIPID-LOWERING THERAPY IN RETARDING PROGRESSION OF CORONARY ATHEROSCLEROSIS

Lipid-lowering therapy now has undoubtedly proven to be an effective t herapeutic modality to retard the progression of coronary atherosclero sis, An additional approach for prevention of the progression of ather osclerosis is calcium channel blocker (CCB) treatment. Evidence indica ting that CCBs inhibit atherosclerosis is less unequivocal than the cl ear evidence for lipid-lowering therapy, Many investigations support t he view that a number of key processes in atherosclerosis may be influ enced by CCBs. From the ''negative'' and ''positive'' studies with CCB s performed in animals and humans we must conclude that apparently som e, but not all, types or stages of the atherosclerotic process are inh ibited by CCBs, To assess whether lipid-lowering therapy and CCB treat ment may have an additive or synergistic beneficial effect on human at herosclerosis, which is conceivable because their antiatherosclerotic properties differ, data fi om the angiographic Lipid-lowering trial RE GRESS (pravastatin vs. placebo) were reviewed. In REGRESS, patients in the pravastatin group had significantly less progression if cotreated with CCBs as compared with those with no CCB cotreatment, whereas in the placebo (no pravastatin) group no effect of CCB treatment was obse rved, With respect to angiographic new lesion formation, in the pravas tatin group there were 50% less patients with new angiographic lesions if cotreated with CCBs as compared with no CCB cotreatment, whereas i n the placebo (no pravastatin) group, again, no significant effect of CCB treatment was observed. No beneficial effects of CCB treatment on clinical events mere observed during the a-year study follow-up. In vi ew of the correlation between angiographic progression and subsequent clinical events as demonstrated in several large trials, it is not unr ealistic to also anticipate in this population, a beneficial effect on clinical events with longer follow-up. Although the REGRESS trial was not designed to evaluate combination therapy, the results suggest tha t addition of CCBs to HMG-CoA reductase inhibitor therapy (pravastatin ) acts synergistically in retarding the progression of established cor onary atherosclerosis, These results appear to warrant prospective ran domized trials to determine in a more definitive manner the merits of this combination in the prevention of progression of coronary atherosc lerosis. Currently a number of studies in these fields are being desig ned or are already underway.