Incidence and predictors of postoperative atrial fibrillation in kidney transplant recipients.

Background: Postoperative atrial fibrillation (POAF) is a complication of cardiothoracic and noncardiothoracic surgery. Kidney transplant recipients bear several known risk factors and may have a higher incidence of POAF. We retrospectively studied kidney and kidney/liver transplant recipients to estimate their POAF incidence and identify relevant risk factors. We also adapted a clinical score originally designed to predict thromboembolic risk in atrial fibrillation (AF; CHA2DS2-VASc) for assessing transplant patients.
Methods: We reviewed the clinical charts of kidney or kidney/liver transplant recipients from January 2005 to December 2008 at St. Orsola University Hospital Kidney Transplant Centre. Patients with and without POAF were compared on a number of clinical, laboratory, and instrumental data.
Results: The POAF incidence in kidney transplant recipients was 8.2%. Risk factors for POAF identified in univariate analyses included older recipient age, history of myocardial infarction, history of AF, liver/kidney transplantation, arterial stiffness, atherosclerotic plaques in the aorta or lower limbs, and diabetes mellitus. In a multivariate analysis, age, myocardial infarction history and combined liver/kidney transplantation were significant independent predictors of POAF. The modified CHA2DS2-VASc score proved to have a better predictive validity that the original CHA2DS2-VASc (area under the curve=0.71, 95% confidence interval=0.63-0.79 vs. area under the curve=0.62, 95% confidence interval=0.52-0.73, respectively).
Conclusion: AF is a notable complication of kidney, and particularly simultaneous liver/kidney, transplant surgery. Age, previous myocardial infarction, and simultaneous liver/kidney transplant independently predicted POAF. The modified CHA2DS2-VASc score could be useful to predict POAF risk in kidney transplant candidates.