Abstract 4102: Preoperative Angiotensin Blocking Drug Therapy Does Not Reduce Atrial Fibrillation After Cardiac Surgery
Introduction: Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery. Angiotensin blocking drug therapy (ABDT) with Angiotensin converting enzyme (ACE) inhibitors and Angiotensin II receptor blockers (ARBs) has been shown to have anti-arrhythmic effects in animal models. However, data from small observational studies of ABDT use in patients undergoing cardiac surgery had discordant results and did not sufficiently adjust for selection bias. Therefore, we performed the largest study to date examining the association between preoperative use of ABDT and postoperative atrial fibrillation.
Methods and Results: A consecutive series of 10,552 patients underwent coronary artery bypass graft (CABG) surgery with or without valvular surgery at Cleveland Clinic between 1997 through 2002. Of these 4,795 (45%) patients were on ABDT within 30 days prior to surgery and 3,633 (34%) patients developed POAF prior to discharge. Without adjusting for patient co-morbidities, ABDT had an Odds Ratio (OR) of 1.13 (95% Confidence Interval (CI) 1.05–1.25, p<0.01). A propensity score matched sample was developed, adjusting for 68 potential confounders. In the 6874 matched patients, who had a well balanced co-morbidity profile, ABDT was not associated with POAF (OR 1.03, CI 0.93–1.12, p=0.67). A subsequent propensity score matched analysis of 3227 patients, who underwent isolated valvular surgery in the same timeframe, also demonstrated ineffectiveness of preoperative ABDT (OR 0.91, CI 0.74 –1.09, p=0.33), irrespective of valve location. Stratified analysis by linear propensity score quintiles and propensity-adjusted logistic multivariable regression analysis of all patients in the CABG and the valvular surgery cohort confirmed these findings.
Conclusions: In this large observational study preoperative use of ACE inhibitors or ARBs did not reduce postoperative occurrence of atrial fibrillation in patients undergoing cardiac surgery. Although withdrawal from ABDT prior to surgery is common practice and could account for this result, we cannot recommend such therapy for primary prophylaxis without larger randomized controlled trials.