Background: Previous investigations suggested thiazolidinediones (TZDs) have the ability to suppress inflammation. Since the pathophysiology of atrial fibrillation (AF) after cardiothoracic surgery (CTS) likely involves an inflammatory mechanism, we sought to determine whether preoperative use of TZDs could further reduce the incidence of post-CTS AF in a population treated with beta-blockers and prophylactic amiodarone.
Methods: All diabetic patients over the age of 50 years, not in atrial arrhythmia prior to surgery, who underwent CTS from the Atrial Fibrillation Suppression Trials I, II and III (AFIST I, II and III) were evaluated in this nested case-control study. Patient demographics, surgical characteristics, medication utilization and the incidence of post-CTS AF (AF > 5 minutes duration) were collected as part of AFIST I, II and III. Multivariate logistic regression was used to calculate adjusted odds ratios with 95% confidence intervals (CIs).
Results: One hundred and eighty-four diabetic patients were enrolled in the three trials. Overall, the study population averaged 66.9 +/- 7.3 years of age, 71.7% were male, 7.1% underwent valve surgery, 4.9% had prior AF, 17.9% had heart failure and 84.2% and 41.8% received postoperative beta-blockade and prophylactic amiodarone, respectively. Forty patients (21.7%) received a preoperative TZD and 144 (78.3%) did not. In total, 66 patients (35.9%) developed post-CTS AF. Upon multivariate logistic regression, the preoperative use of TZDs was found to be associated with a 20% non-statistically significant reduction in post-CTS AF (adjusted odds ratio; 0.80, 95% CI 0.32-1.99; p = 0.63).
Limitations: Patients were not randomized to receive TZDs or not. We may not have had adequate power to evaluate our post-CTS AF endpoint.
Conclusions: In a diabetic population treated perioperatively with beta-blocker and amiodarone, adjunctive TZD use was associated with a non-statistically significant reduction in a patient's odds of developing post-CTS AF. Further research is needed to determine whether TZDs, in fact, do not have anti-fibrillatory effects or whether our study was underpowered to detect a statistically significant benefit with TZDs.