NEW YORK (Reuters Health) – Hospital outcomes in patients with an acute coronary syndrome are no different whether they were previously taking an angiotensin-converting enzyme inhibitor or not, according to the findings of a Canadian study reported in the American Journal of Cardiology online November 14.
“In contrast to benefits reported with the early use of an ACE inhibitor after an MI, a favorable association between chronic ACE inhibitor use and clinical events with an ACS was not demonstrated even after adjusting for multiple important demographic, clinical, and therapeutic variables,” conclude Dr. Andrew T. Yan, with the University of Toronto, Ontario, and colleagues.
In the introduction to their paper, the authors note that it is unclear whether prior use of ACE inhibitors affects the course of ACS. To investigate, they analyzed data in three large registries on 13,632 Canadian patients with ACS.
Overall, 4,308 of these patients (31.6%) received an ACE inhibitor before being hospitalized with ACS. Those taking an ACE inhibitor were more likely to have diabetes than those not on an ACE inhibitor (40.6% vs 21,2%), to have had a prior MI (51.8% vs 23.3%), and to have heart failure (18.0% vs 6.9%), the team found.
When these factors and other confounders were accounted for in multivariate analysis, there was no significant association between prior ACE inhibitor use and mortality (adjusted odds ratio 1.15; p=0.27), in-hospital recurrent MI (aOR 0.99; p=0.91) or the composite of the two (aOR 1.01; p=0.94), the report indicates.
“Although one can hypothesize that ACE inhibitor-associated hypotension may account for our findings, this is less likely because our findings persisted after adjusting for systolic blood pressure and Killip class at time of presentation,” Dr. Yan and colleagues comment.
A more likely explanation, they suggest, is that patients on ACE inhibitor therapy represent a high-risk group that tends to develop ACS despite optimal treatment. “This selection bias may have persisted despite adjustments in our multivariable model, and as such we did not observe a favorable association between chronic ACE inhibitor use and clinical outcomes after an ACS,” the authors conclude.
Am J Cardiol 2011.
