The new trials: AIRE, ISIS-4, and GISSI-3. Is the dossier on ACE inhibitors and myocardial infarction now complete?

Recent studies have strengthened the arguments for the use of angiotensin-converting enzyme (ACE) inhibitors in the early postinfarct period. Those with clinically detectable heart failure, and hence at highest risk, will benefit most, as shown in the AIRE study, but those at lower risk with left ventricular dysfunction still have some benefit, theoretically through ventricular remodeling. In patients in the very early stages of acute myocardial infarction, three trials have shown discordant results. In CONSENSUS-II, intravenous enalaprilat followed by oral enalapril gave no benefit, rather causing excess hypotension and a possible increase in mortality. In ISIS-4 and GISSI-3, mortality improved by 0.46% and 0.8%, respectively, with risk reductions of 9% and 11%. Added transdermal nitrate in GISSI-3 gave a total reduction of 17%. In view of the risk of hypotension (20% in ISIS-4, compared with placebo 10%), very early ACE inhibition will probably only be used for selected patients. Logically, one target group would be those seen 7-24 hours after the onset of symptoms, particularly 7-12 hours, at which time captopril alone gave a reduction of 14.5% in risk. These mortality differences compare favorably with those recently found when comparing tPA and streptokinase in the GUSTO study.