The effect of carvedilol in patients with impaired left ventricular systolic function following an acute myocardial infarction. How do the treatment effects on total mortality and recurrent myocardial infarction in CAPRICORN compare with previous beta-blocker trials?

In previous beta-blocker trials, post-myocardial infarction (MI) patients were essentially treated with a beta-blocker or placebo. In the CAPRICORN trial, patients were selected on the basis of a left ventricular (LV) ejection fraction (EF) <40% following the index MI and randomised to carvedilol or placebo, in addition to modern secondary prophylaxis with ACE inhibitors, aspirin and statins. In 1959 patients with a mean LVEF of 33%, treatment with carvedilol over a mean follow-up period of 15 months reduced total mortality from 15.3% with placebo to 11.9% with carvedilol [relative risk reduction (RRR) =23%, absolute risk reduction (ARR) =3.4%]. The incidence of recurrent MI was reduced from 5.8 to 2.3% (RRR 41%, ARR 2.3%). The number needed to treat (NNT) to prevent one death was 28 for the entire study period and 43 for 1 year of treatment. The results of the CAPRICORN trial are compared with three previous beta-blocker post-MI trials: the Gothenburg metoprolol trial (GMT), the Norwegian timolol trial (NTT) and the beta-blocker heart attack trial (BHAT). The RRRs for total mortality were 36% in the GMT and NTT, and 27% in BHAT. The respective NNTs for total mortality were 32, 18 and 38. NNT for 1 year of treatment was 25 in NTT and 80 in BHAT. The RRR for recurrent MIs were 28% in NTT and 16% in BHAT. The reduction of mortality and recurrent MIs in CAPRICORN is within the range of previous post-MI beta-blocker studies. In post-MI patients with LVEF<40%, add-on treatment with a beta-blocker should be given >48 h after initiation with an angiotensin-converting enzyme inhibitor (ACEI) and then with a slow dose escalation as applied in CAPRICORN.