Clinical profile of postoperative atrial fibrillation in cardiac surgery; Experience of a university center

Abstract

Introduction: atrial fibrillation is a frequent postoperative complication of cardiac surgery. Internationally, an incidence of 30% is registered, being its maximum peak between the second and third postoperative day, however, we do not have data in our center.
Method: a prospective cohort study was carried out, approved by the institutional ethics committee. It included patients over the age of 18 years, who received cardiac surgery between January 1 and December 31, 2018 at a university cardiovascular center. Those patients with AF at the time of surgery were excluded. Preoperative, operative, and postoperative variables were recorded. Continuous variables were presented as median and interquartile range, categorical variables in absolute value and relative frequencies. The incidence was calculated as the number of new cases / total population. Associations were evaluated with chi square and Mann Whitney test. Univariate and multivariate logistic regression was performed. A p <0.05 was considered significant.
Results: 104 patients were included. Median age of 66 years, 51% male. The incidence of postoperative atrial fibrillation was 29%, with a maximum between the second and third day, and a duration of less than 24 hours in 83% of cases. Recurrence during admission was 38%. Amiodarone was used for acute treatment of postoperative atrial fibrillation in 100% of cases, beta-blockers in 63%, digoxin 7%, and electrical cardioversion in 26%. All the patients were in sinus rhythm at discharge and one month after surgery. Variables with a significant association in univariate analysis for postoperative atrial fibrillation risk were age (OR 1.07, 95% CI: 1.01-1.12 p = 0.007) and chronic kidney disease (OR 3.75, 95% CI: 1.4-9.4 p = 0.005). A risk score of less than 14 in the Multicenter Risk Index (OR 0.18; 95% CI: 0.34-0.93 p = 0.04) and smoking were “protective” in the univariate analysis (OR 0.38; 95% CI: 0.14-0.98 p = 0.048). In the multivariate analysis, no variable reached statistical significance. A significant association was identified between postoperative atrial fibrillation and pulmonary edema (p <0.001), shock (p <0.04) and acute renal failure (p <0.01). Postoperative atrial fibrillation patients had a median of 5 aditional days of hospitalization (p <0.0003).
Conclusion: A high incidence of postoperative atrial fibrillation was found in the studied population. Factors associated with a higher risk of postoperative atrial fibrillation were identified, as well as an association with other serious complications in the postoperative period. The results highlight the importance of protocolizing the recognition of risk patients as well as their treatment.