Atrial fibrillation after cardiac surgery tied to increased thromboembolic stroke risk

Netherlands: A recent study reveals that postoperative atrial fibrillation (POAF) within 7 days following cardiac surgery is tied to a three-fold increased risk of thromboembolic stroke during hospital admission. The findings of the study, published in the Journal of Cardiothoracic and Vascular Anesthesia, therefore, suggests that speedy treatment of POAF may reduce early stroke risk after cardiac surgery.

Atrial fibrillation and atrial flutter are the most common cardiac arrhythmias in both the general population and preoperatively in cardiac surgery patients admitted to the ICU. In the ICU environment, the subclinical variant may have short episodes and few symptoms an can be missed. A a result, the condition may be underestimated and left untreated. POAF, preexisting or as a new-onset manifestation, occurs often after cardiac surgery. Its reported incidence is said to vary from 10%-to-50%, and is associated with a two-fold increase in long-term cardiovascular mortality and morbidity. 

Against the above background, Ramon Pierik, University of Groningen, Groningen, the Netherlands, and colleagues aimed to study the association between postoperative atrial fibrillation and thromboembolic stroke and to determine risk factors for thromboembolic stroke following cardiac surgery.

For this purpose, the researchers performed a secondary analysis from a randomized controlled trial (GRIP-COMPASS). The study included adult consecutive cardiac surgery patients admitted postoperatively to the intensive care unit. The patients with thromboembolic stroke were compared with those without thromboembolic stroke, and the difference in the incidence of POAF between these groups was assessed. Logistic regression analyses was used to calculate odds ratio (OR). For the occurrence of thromboembolic stroke during hospital admission, brain imaging was studied, and POAF monitoring was done for seven days. Stepwise backward regression analysis was performed to assess which characteristics were associated with occurrence of thromboembolic stroke.