Ann Thorac Surg 2007;84:1164-1165
© 2007 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
Invited commentary
Lawrence L. Creswell, MD
Division of Cardiothoracic Surgery, University of Mississippi Medical Center, 2500 N. State St, Jackson, MS 39216
(Email: lcreswell{at}surgery.umsmed.edu).
Mariscalco and colleagues [1] report on the beneficial effect of preoperative administration of statin medications in reducing atrial fibrillation (AF) after coronary artery bypass grafting (CABG). This effect was preserved in a multivariate analysis that considered other pertinent preoperative and intraoperative variables.
The mechanisms responsible for postoperative AF are not completely understood, but may include ischemia, anatomic changes in the atrium, transient electrophysiologic and hemodynamic changes perioperatively, and inflammation, among others. These arrhythmias likely occur in patients at risk (eg, anatomical substrate) because of a perioperative trigger. The motivation for the current study is the possibility that perioperative inflammation is related to the development of postoperative AF.
In cardiac surgery, statins have recently received attention with the observation that pretreatment with atorvastatin reduced cytokine release and neutrophil adhesion in patients undergoing CABG with cardiopulmonary bypass. Two previous nonrandomized studies of preoperative statin therapy in patients undergoing CABG have shown that the incidence and duration of postoperative AF were reduced. Most recently, a randomized trial of preoperatively used atorvastatin showed a significant reduction in postoperative AF in the treated group. Interestingly, the benefit of atorvastatin was not enjoyed by patients with left atrial enlargement or those who were undergoing heart valve surgery.
The current report involves a relatively small number of patients and it is impossible to know if the study and control groups are similar except for the use of statins [1]. Nonetheless, this study adds to the accumulating evidence that statins may be a useful strategy for helping to prevent postoperative AF.
We must keep in mind the entire body of evidence related to the prevention of postoperative AF [2]. We know that postoperative AF is related to preoperative variables, including patient age and type of operation. We also know that mild rather than moderate degrees of hypothermia may be protective. Accumulating evidence suggests that off-pump CABG may be associated with a lower incidence of postoperative AF than conventional CABG. We also know that pharmacologic interventions such as beta-blockers or amiodarone used both preoperatively and postoperatively may reduce the incidence of postoperative AF. An "institutional" approach should be tailored to the patient population and resources of a given institution.
How should we clinically use the emerging information regarding statin medications and postoperative AF? There are several beneficial effects of statins apart from any role in preventing postoperative AF; therefore, statins may be indicated for other reasons for many of our patients. The randomized data show a benefit for 1 week of preoperative oral therapy, but this is not always possible in ordinary practice. One might reasonably administer these agents to patients as soon as is practical before the operation and then continue them postoperatively. This approach is an example of a low-risk, low-cost intervention that may provide incremental benefit.
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References
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- Mariscalco G, Lorusso R, Klersy C, et al. Observational study on the beneficial effect of preoperative statins in reducing atrial fibrillation after coronary surgery Ann Thorac Surg 2007;84:1158-1165.[Abstract/Free Full Text]
- McKeown PP, Gutterman D. American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery Chest 2005;128(Suppl):1S-5S.[Medline]