Letter by Padfield et al 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”
To the Editor:
We read with interest the results of the ARMYDA-3 trial.1 The putative antiarrhythmic properties of statins and their utility in the perioperative period warrant investigation. Patti et al report an effective and easily implemented strategy to significantly reduce the incidence of atrial fibrillation after cardiac surgery through the use of preoperative atorvastatin. However, there was a greater use of β-blockers in the treatment group. Though this is not significant in the formal statistical sense (P=0.08), it is notably higher (72% versus 60%). The authors do refer to the established role of β-blockade in the reduction of postoperative atrial fibrillation,2 and include it in their multivariate analysis. However, they do not highlight this as a potential confounder in their discussion. We consider this to be of particular relevance given the size of the study population (n=200). Additionally, there is a nonsignificant excess of patients undergoing valve surgery in the placebo group (25% versus 16%), which compared with non-valvular surgery confers a greater likelihood of postoperative atrial fibrillation.3 It is not clear whether this excess in valve surgery has been taken into account by the multivariate analysis. Together, these inequalities could account for a significant number of the 21 excess events.
Perioperative statin use has been associated with favorable postoperative outcome in both cardiovascular and noncardiovascular conditions, and has particular advantage in combination with β-blocker therapy.4 However, elucidating the impact of statin therapy on a specific clinical end point would require a larger study population in order to generate a robust conclusion. The lack of mechanistic data relating to statins as antiarrhythmics amplifies this necessity. The excess of β-blockade and valvular surgery in the placebo group are plausible explanations for the observed treatment effect and suggest the need for larger studies.
Patti G, Chello M, Candura D, Pasceri V, D’Ambrosio A, Covino E, Di Sciascio G. 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. Circulation. 2006; 114: 1455–1461.
Siebert J, Anisimowicz L, Lango R, Rogowski J, Pawlaczyk R, Brzezinski M, Beta S, Narkiewicz M. Atrial fibrillation after coronary artery bypass grafting: does the type of procedure influence the early postoperative incidence? Eur J Cardiothorac Surg. 2001; 19: 455–459.
Kertai MD, Boersma E, Westerhout CM, Klein J, Van Urk H, Bax JJ, Roelandt JR, Poldermans D. A combination of statins and beta-blockers is independently associated with a reduction in the incidence of perioperative mortality and nonfatal myocardial infarction in patients undergoing abdominal aortic aneurysm surgery. Eur J Vasc Endovasc Surg. 2004; 28: 343–352.