JACC: ACE inhibitors may independently predict worse outcomes after CABG
Pre-operative therapy with angiotensin-converting enzyme (ACE) inhibitors is associated with an increased risk of mortality, use of inotropic support, post-operative renal dysfunction and new onset of post-operative atrial fibrillation, based on research reported online Aug. 12 in the Journal of the American College of Cardiology.

This study sought to evaluate the effect of pre-operative ACE inhibitor therapy on early clinical outcomes after CABG, according to Antonio Miceli, MD, from the Bristol Heart Institute, University of Bristol in England, and colleagues. They noted that therapy with ACE inhibitors previously has shown to reduce the rate of mortality and prevent cardiovascular events in patients with coronary artery disease; however, the pre-operative use in patients undergoing CABG is “still controversial.”

The researchers undertook a retrospective, observational, cohort study of prospectively collected data on 10,023 consecutive patients undergoing isolated CABG between April 1996 and May 2008. Of these, 3,052 patients receiving pre-operative ACE inhibitors were matched to a control group by propensity score analysis.

Miceli and colleagues found that the overall rate of mortality was 1 percent. Pre-operative ACE inhibitor therapy was associated with a doubling in the risk of death (1.3 vs. 0.7 percent). They also noted a significant difference between the ACE inhibitor and control group in the risk of post-operative renal dysfunction (7.1 vs. 5.4 percent), atrial fibrillation (25 vs. 20 percent) and increased use of inotropic support (45.9 vs. 41.1 percent).

In a multivariate analysis, the investigators found that pre-operative ACE inhibitor treatment was an independent predictor of mortality, post-operative renal dysfunction, use of inotropic drugs and atrial fibrillation.

In 2004, Devbhandari et al published the result of a U.K. national survey to address the issue whether it is beneficial or not to discontinue ACE inhibitors before cardiac surgery. They found that 35 percent of respondents said that ACE inhibitors should be withheld before surgery, and 63 percent said that their use leads to vasodilation, resulting in increased use of fluids, inotropes and vasoconstrictors. Despite these findings, 65 percent of U.K. surgeons did not think that ACE inhibitors should be withheld before surgery.

Miceli and colleagues said that ACE inhibitor therapy may increase adverse events during the first three months and does not improve clinical outcome up to three years after surgery. However, they also added that there “seems to be increasing evidence to suggest that ACE inhibitors have the potential to prevent post-operative atrial fibrillation, possibly because of its ability to decrease left atrial stretching secondary to afterload reduction and atrial remodeling.”