Preoperative statins for prevention of atrial fibrillation following cardiac surgery

January 1, 2008 By Benjamin A. Olenchock, M.D. Ph.D. [mailto:bolenchock@partners.org]

Houston Atrial fibrillation is a common complication of cardiac surgery, causing significant morbidity and mortality. The role of inflammation in the pathogenesis of atrial fibrillation is a topic of much research interest. Statins have many beneficial effects on immune modulation and vascular function in addition to their lipid-lowering effects. The ARMYDA-3 study (Atorvastatin for Reduction of MYocardial Dysrhythmia After cardiac surgery), published last year in Circulation, demonstrated that preoperatively administration of 40 mg atorvastatin reduced the incidence of atrial fibrillation compared to placebo (35% versus 57%, p=0.003), corresponding to a 61% risk reduction (OR 0.39, CI 0.18 to 0.85, P=0.017). A large retrospective study published in the American Heart Journal challenges their findings.

Investigators analyzed data from 4044 patients who underwent heart surgery at St. Luke’s Episcopal Hospital / Texas Heart Institute. The only exclusion criteria was a history of atrial fibrillation. Most patients (66%) had isolated coronary artery bypass grafting (CABG), 25% had isolated valvular surgery, and 9% had valvular surgery and CABG. Just over half (52%) received statins preoperatively. There were many baseline differences between patients who received statins and those who did not. Patients who received statins were older, and more had hypertension, diabetes, unstable angina, prior heart attack or stroke, smoking history, dyslipidemia, and obesity. Fewer had clas III/IV heart failure. Cardiac medication use differed significantly as well, with more beta-blocker and ACE-inhibitor use among patients who received preoperative statins.

In the unadjusted analysis, there was no difference in incidence of postoperative atrial fibrillation between patients that received preoperative statin and those who did not (OR 1.13, CI 0.98 to 1.31). The subgroup analysis showed similar results for patients who had CABG, valvular surgery or both. The authors performed a multivariate analysis and determined a propensity score to account for selection bias. After adjustment, they again saw no effect of statins on risk of postoperative atrial fibrillation (OR 1.14, CI 0.92 to 1.41).

The results of this very large retrospective study are different than those of the ARMYDA-3 randomized controlled study. The authors point out concerns about the ARMYDA-3 data, including a very high rate of atrial fibrillation in the placebo arm (57% in ARMYDA-3 compared to 31% in this study). The retrospective trial design is a significant limitation to this study. Perhaps this new data should serve to encourage more research into the anti-inflammatory properties of statins and the role of inflammation in the pathogenesis of atrial fibrillation.

1. Salim S. Virani, Vijay Nambi, Mehdi Razavi, Vei-Vei Lee, MacArthur Elayda, James M. Wilson, Christie M. Ballantyne. Preoperative statin therapy is not associated with a decrease in the incidence of postoperative atrial fibrillation in patients undergoing cardiac surgery Am Heart J In Press Corrected Proof, Available online 10 December 2007 DOI: 10.1016/j.ahj.2007.10.027

2. 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 Oct 3;114(14):1455-61. Epub 2006 Sep 25. ''