Anticoagulation management of postoperative atrial fibrillation after cardiac surgery: A systematic review

BACKGROUND: Postoperative atrial fibrillation (POAF) often complicates cardiac surgery and is associated with increased mortality and risk of thromboembolism. However, the optimal oral anticoagulation (OAC) strategy is uncertain. We performed a systematic review to examine the OAC practice patterns and efficacy in these circumstances. METHODS: MEDLINE and EMBASE were searched from 2000 to 2019 using the search terms cardiac surgical procedures, cardiac surgery, postoperative complications, atrial fibrillation, atrial flutter, and terms for anticoagulants. Collected data included anticoagulation patterns (time of initiation, type, and duration) and outcomes (stroke, bleeding, and mortality). RESULTS: From 763 records, 4 prospective and 13 retrospective studies were included totaling 44,908 patients with 8929 (19.9%) who developed POAF. Anticoagulation rates ranged from 4% to 43% (mean 21% overall). Sixteen studies used warfarin, 3 nonvitamin K OAC (NOAC), and 2 both. Four studies reported the use of bridging unfractionated or low-molecular-weight heparin. Concomitant antiplatelet therapy was reported in half the studies, ranging from 80% to 99%. OAC use was associated with lower risk of thromboembolic events in two retrospective studies (including a national Danish cohort with 2108 patients with POAF). Patients discharged on warfarin experienced reduced mortality in a large, single center, retrospective analysis, but no association was observed in the Danish cohort. CONCLUSION: There is wide practice variation in the uptake, timing of initiation, duration, and choice of OAC for POAF following cardiac surgery. The evidence is largely retrospective and insufficient to assess the efficacy of different OAC strategies. Further studies are warranted to guide clinical practice.