There are good data suggesting that ACE inhibitors (ACE-I) are important in patients post STEMI (ST-segment elevated myocardial infarction) and are recommended therapy. However, no data are available on the role of angiotensin receptor blockers (ARBs), which are typically used for other ACE-I indications in the 15-20% of patients intolerant of ACE-I. A prospective Korean cohort study was just published in BMJ looking at their post STEMI treatment, assessing the outcomes of 6698 patients from 53 hospitals, all of whom had primary percutaneous coronary interventions (PCI) and LV ejection fractions >40%, of whom 1185 (17.7%) were given ARBs, 4564 (68.1%) given ACE-I and 949 (14.2%) neither.
Median followup of 371 days. This study involved propensity scoring, a technique used in nonrandomized trials to mathematically compensate for covariates that could have influenced treatment allocation (in this case, adjusting for differences in clinical, angiographic and procedural characteristics of the groups).
Results:
–In comparing the groups: those on ARBs (vs ACE-I) were older, had higher creatinine levels, had more LAD artery lesions in the area of infarct, though had lower prevalence of smoking. those in the “neither” group tended to have a higher risk profile at the time of the PCI
–Cardiac death or myocardial infarction occurred in 21 patients on ARBs (1.8%), 77 patients on ACE-I (1.7%), but in 33 on neither (3.5%).
–By propensity matching (1175 pairs), no significant difference between ARBs and ACE-I, with those endpoints in 1.8% in ARB group and 2.0% in ACE-Igroup. Propensity matching (803 pairs) between the ARB group and the neither group found the ARB group had 1.7% and the neither group 3.1%, a significant difference (p=0.03)
So, not a randomized controlled trial, but a large trial doing mathematical modeling to try to compensate for underlying potential differences in patients assigned to one of the 3 groups (ARB vs ACE-I vs neither), finding essentially no difference in the hard outcomes of cardiac death or MI between ABR or ACE-I, and that either was much better than neither. There were unanswered questions in this registry cohort, such as the relatively short followup time of 1 year, the dose of meds taken, why patients were assigned to the different groups, and ultimately the numbers of events was pretty small, limiting the statistical power. But, overall this study validates what probably most of us were doing anyway: try an ACE-I, using ARBs with patients who are ACE-intolerant.
Geoff