Trial design, statins, atrial fibrillation, and prevention: Four horsemen of the apocalypse

To the Editor,

We have read with great interest the article entitled “Efficiency of postoperative statin treatment for preventing new onset postoperative atrial fibrillation in patients undergoing isolated coronary artery bypass grafting: a prospective randomized study” published in the June 2014 issue of The Anatolian Journal of Cardiology by Aydın et al. (1). This article was about the effect of postoperative statin treatment on new onset postoperative atrial fibrillation (POAF) in patients undergoing isolated coronary artery bypass grafting (CABG). The study consisted of 60 consecutive patients who were divided into two groups: those undergoing postoperative statin treatment (n=30) and those not undergoing it (n=30). They concluded that atorvastatin treatment (40 mg), when started in the early postoperative period after isolated CABG, reduces the incidence of new-onset POAF.

AF is the most common cardiac arrhythmia after cardiac surgery, which generally occurs in 20%-40% of patients (2). POAF may be multifactorial and involves an interaction between surgical trauma, preexisting atrial pathology, activation of the inflammatory response and increased adrenergic tone (3).

POAF generally occurs between days 2 and 4 after surgery, with a peak incidence on the second day (3). Several randomized controlled trials support the use of longer duration statin therapy preoperatively to reduce the incidence and risk of developing AF after elective cardiac surgery (4). In contrast, the authors of the present study (1) preferred to start atorvastatin treatment in the early postoperative period (average of 6 h after the operation). Inflammation has a major role in the pathogenesis of POAF, and the occurrence of anti-inflammatory effects of statins requires approximately 30 days after their initiation (5). In the present study (1), the time between surgery and AF development is similar in both groups. Therefore, a major point of discussion is after how many days or hours after should postoperative statin therapy be started or should be expected to obtain the beneficial effects of statins in a relatively short time interval. More importantly, most patients are often unable to take oral medications shortly after surgery, and there is no intravenous formula for statins.

In cardiac surgery, manipulation of the pericardium is strongly associated with the development of POAF. Hence, it would be very useful if Aydın et al. (1) information about the occurrence of acute postoperative pericarditis and the development of AF in both groups.

In conclusion, larger randomized studies are required to confirm the possible beneficial effects of statins on AF when administrated postoperatively.