Level 1: Likely reliable evidence
A recent Cochrane review evaluated the efficacy of various antihypertensive drugs given within 24 hours of acute MI (Cochrane Database Syst Rev. 2009 Oct 7;:CD006743). Compared with either placebo or no intervention, nitrates and angiotensin-converting enzyme (ACE) inhibitors were each associated with reductions in short-term all-cause mortality. In an analysis of 82,624 patients from six trials, nitrates reduced the risk of death during the first two days (risk ratio [RR] 0.81, 95% confidence interval [CI] 0.74-0.89). Assuming a baseline two-day mortality of 2.3%, the number needed to treat (NNT) would be 168-396. Risk reduction after 10 days was similar. ACE inhibitors showed a trend toward reduced mortality at two days, and they significantly reduced 10-day mortality (RR 0.93, 95% CI 0.87-0.98) in an analysis of 12 trials with 84,456 patients. For ACE inhibitors, the NNT was 146-944 (assuming 5.3% baseline 10-day mortality). Neither beta blockers nor calcium channel blockers given during the first 24 hours were found to reduce all-cause mortality at two, 10, or 30 days follow-up.