Postoperative c-reactive protein resolution patterns in patients with and without postoperative atrial fibrillation after cardiac surgery

OBJECTIVES: Postoperative atrial fibrillation is common after cardiac surgery. Effective preventative measures are lacking, partly due to an incomplete understanding of its pathogenesis. Inflammation is a major contributor to postoperative atrial fibrillation development. This study aims to further characterize the association between systemic inflammation and postoperative atrial fibrillation. METHODS: A secondary analysis was conducted on a single-center cohort of patients undergoing cardiac surgery. The original study enrolled 405 cardiac surgery patients. After exclusion of patients with a history of persistent or permanent atrial fibrillation, patients undergoing heart transplantation and patients with incomplete interleukin measurements, 319 patients were included in the present analysis. Postoperative atrial fibrillation was identified through chart review and was defined as at least one AF episode lasting more than 30 seconds, as documented by telemetry or a 12-lead electrocardiogram during the patient's initial hospitalization. Perioperative levels of interleukins and C-reactive protein were measured. The decline in C-reactive protein levels between postoperative days 3 and 10 was modelled using a linear regression. The association with postoperative atrial fibrillation and other outcomes after cardiac surgery was assessed using logistic and Tobit regression models. RESULTS: Of the 319 patients included in the study, 51% developed postoperative atrial fibrillation, most commonly on postoperative days 2 and 3. Cardiopulmonary bypass and intraoperative ventilation time were significantly associated with an increased risk of postoperative atrial fibrillation. Patients with postoperative atrial fibrillation had longer intensive care unit stays and longer times to extubation. C-reactive protein levels peaked on postoperative day 3 and declined more slowly in postoperative atrial fibrillation patients. A slower C-reactive protein decline was independently associated with postoperative atrial fibrillation (Odds ratio: 1.71, p = 0.046), prolonged postoperative intensive care unit length of stay and time to extubation. Interleukin-10 levels were significantly higher in patients with postoperative atrial fibrillation (Mean ratio: 1.28, p < 0.001). CONCLUSIONS: Postoperative atrial fibrillation is a prevalent complication after cardiac surgery and correlates with a slower postoperative C-reactive protein decline. This study suggests that postoperative atrial fibrillation is associated with delayed resolution of postoperative inflammation.