Stroke risk and anticoagulation in the setting of post-cardiac surgery atrial fibrillation: a systematic review of the literature

Postoperative atrial fibrillation (POAF) affects up to 50% of patients undergoing cardiac surgery. It remains unclear to what extent POAF increases the stroke risk and whether anticoagulation is warranted in this setting. The primary objective of this review was to conduct a systematic review of the evidence for a correlation between POAF and stroke. Further, we sought to evaluate the published evidence on anticoagulation in the setting of POAF to prevent stroke. To this end, we performed a comprehensive literature search to identify studies on POAF in patients undergoing cardiac surgery with stroke as an outcome. To date, eight meta-analyses providing pooled estimates of the stroke risk associated with POAF in patients undergoing cardiac surgery have been published. The reported pooled odds ratios range from 1.36 to 4.09 for unadjusted estimates. Additionally, five studies were identified that evaluated the impact of anticoagulation on stroke in the setting of POAF. Of these, three supported the use of anticoagulants, and two studies were inconclusive. This systematic review did not find strong supporting evidence that POAF is causally related to stroke, despite a strong correlation with comorbidities and all-cause mortality in the literature. Available evidence to date suggests an elevated risk of bleeding with no clear reduction in stroke or other thromboembolic events when anticoagulation is initiated in the setting of POAF. An upcoming randomized clinical trial by the Cardiothoracic Surgery Network group will hopefully provide clarification on the recommendations for anticoagulation in the setting of POAF after cardiac surgery.