[Do beta-blockers prevent coronary events in hypertensive patients?]

Abstract

Beta-blockers have been considered for decades as effective agents in preventing coronary events in hypertensive patients. Actually, the scrutiny of the available data arises some doubts over the real value of this pharmacological class. In primary prevention, the clinical benefits of beta-blockers are poorly documented: the studies conducted against placebo (MRC, IPPPSH...) did not show any significant differences regarding the rate of coronary events (except within non smokers); moreover, the beneficial effect of propranolol in preventing sudden deaths and silent myocardial infarctions has been reported byjust one retrospective analysis. Likewise in HAPPHY study, the comparison with diuretics did not emphasize a clear superiority of one of both classes; the better effect of metoprolol regarding overall mortality and fatal coronary events was shown in the pecular subset MAPHY, only. Furthermore, in elderly people, HEP, MRC OA and STOP studies did not find any significant effect of beta-blockers in preventing coronary events, as compared with placebo. However, SHEP study, which involved patients older than 60 years with isolated systolic hypertension receiving first a diuretic, then a beta-blocker(atenolol) in 1/4 of the cases, demonstrated a significant reduction versus placebo both in strokes and in coronary events. Finally, in UKPDS, CAPP, LIFE and CONVINCE studies, atenolol turned out to have a similar efficacy as captopril, losartan and verapamil, in preventing ischemic heart disease. Among the numerous published meta-analyses, that of Psaty pointed out the absence of a primary cardioprotective effect by beta-blockers; more recently, that of Carlberg, emphasized atenolol given alone as the first-line drug to fail in significantly reducing coronary events and strokes. In secondary prevention, some more convincing data may be found in the literature, regarding post myocardial infarction patients (meta-analyses of Staessen, 1982, Yusuf, 1985 and Soriano, 1997), as well as those with stable angina (BIP study in diabetics) or silent ischemia (ASIST study: significant reduction in number and duration of ischemic events by atenolol). Moreover, INVEST study recently showed atenolol and verapamil to have an equivalent efficacy in the hypertensive patients with stable coronary artery disease. Last, hypertension should be reminded as resulting in many cases of heart failure, a pathology where beta-blockers have clearly demonstrated their beneficial effects.