Postoperative Atrial Fibrillation and Long-Term Risk of Stroke in Patients Undergoing Liver Transplantation

Background and Purpose: Postoperative atrial fibrillation (POAF) is the commonest cardiovascular complication following liver transplantation (LT). This study sought to assess a possible association of POAF with subsequent thromboembolic events in patients undergoing LT. Methods: A retrospective cohort study of consecutive adults undergoing LT between 2010 and 2018 was undertaken. Patients were classified as POAF if atrial fibrillation (AF) was documented within 30 days of LT without a prior history of AF. Cases of ischemic stroke or systemic embolism were adjudicated by a panel of 2 independent physicians. Results: Among the 461 patients included, POAF occurred in 47 (10.2%) a median of 3 days following transplantation. Independent predictors of POAF included advancing age, postoperative sepsis and left atrial enlargement. Over a median follow-up of 4.9 (interquartile range, 2.9-7.2) years, 21 cases of stroke and systemic embolism occurred. Rates of thromboembolic events were significantly higher in patients with POAF (17.0% versus 3.1%; P<0.001). After adjustment, POAF remained a strong independent predictor of thromboembolic events (hazard ratio, 8.36 [95% CI, 2.34-29.79]). Increasing CHA(2)DS(2)VASc score was also an independent predictor of thromboembolic events (hazard ratio, 1.58 [95% CI, 1.02-2.46]). A model using POAF and a CHA(2)DS(2)VASc score >= 2 alone yielded a C statistic of 0.77, with appropriate calibration for the prediction of thromboembolic events. However, POAF was not an independent predictor of long-term mortality. Conclusions: POAF following LT is associated with an 8-fold increased risk of thromboembolic events and the use of the CHA(2)DS(2)VASc score may facilitate risk stratification of these patients. Prospective studies are warranted to assess whether the use of oral anticoagulants can reduce the risk of thromboembolism following LT.