Response to Letters Regarding Article, “Randomized Trial of Atorvastatin for Reduction of Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery: Results of the ARMYDA-3 (Atorvastatin for Reduction of Myocardial Dysrhythmia After Cardiac Surgery) Study”
We thank Drs Padfield and Shroff for their interest in our paper.1 Although randomization is the best way to obtain homogenous groups of patients, this cannot produce identical characteristics, and the possibility of finding differences increases with the number of parameters included in the analysis. In the ARMYDA-3 trial, we assessed a total of 34 demographic/clinical features and 18 perioperative features and we did not find significant differences in any of them between the 2 arms of the study. We have performed a logistic regression analysis that included all 52 parameters (including mitral valve disease, left atrial enlargement, and treatment with β-blockers), which revealed that β-blocker therapy, atorvastatin and their combination were independently associated with risk reduction of atrial fibrillation after cardiac surgery. Although there was a nonsignificant higher prevalence of β-blocker therapy in the treatment arm of the study and more patients with valve disease in the placebo arm, there was also a higher prevalence of systemic hypertension and left ventricular hypertrophy, as well as a longer duration of cardiopulmonary bypass in the atorvastatin arm; all variables that are known to increase incidence of atrial fibrillation.2 This could thus counterbalance “inequalities that could account for a significant number of the 21 excess events,” perceived by Dr Padfield. As for the concerns of Dr Shroff, our multivariable analysis shows that the incremental benefit of statins in patients already receiving β-blockers amounts to a 90% risk reduction, as shown in Figure 4 of our study. Left atrial enlargement (defined as left atrial diameter >40 mm) was not a predictor of higher incidence of atrial fibrillation in our study.
Finally, we strongly agree with Dr Shroff that patients with established coronary artery disease should be treated with statins; however, this utilization of statins reflects the current practice patterns of the geographic area from which our university hospital draws its referrals.
Patti G, Chello M, Candura D, Pasceri V, D’Ambrosio A, Covino E, Di Sciascio G. A randomized trial of atorvastatin for reduction of post-operative atrial fibrillation in patients undergoing cardiac surgery. Results of the ARMYDA-3 (Atorvastatin for Reduction of MYocardial Dysrhythmia After cardiac surgery) study. Circulation. 2006; 114: 1455–1461.
Hogue CW Jr., Creswell LL, Gutterman DD, Fleisher LA; American College of Chest Physicians. Epidemiology, mechanisms, and risks: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery. Chest. 2005; 128 (2 Suppl): 9S–16S.