Immediate Preoperative Transthoracic Echocardiography for the Prediction of Postoperative Atrial Fibrillation in High-Risk Cardiac Surgery

Abstract

The present study aimed to validate the utility of bedside cardiac ultrasound to identify patients for the risk of postoperative atrial fibrillation (POAF). A prospective cohort study of consecutive patients. Single-center tertiary referral center. After Institutional Review Board consent, 169 patients undergoing elective cardiac surgery were enrolled in the study. A preoperative transthoracic echocardiographic interrogation assessing diastolic function was performed. Measurements were assessed offline with experienced echocardiographers blinded to clinical outcomes. The primary outcome was POAF during the first 72 hours after surgery. A total of 169 patients completed the study, 44 of whom (26.0%) developed POAF, and 39 (25.2%) had diastolic dysfunction. Patients with POAF had a higher rate of postoperative heart failure, reintubation within 24 hours of surgery, and length of stay (p = 0.002, 0.01, and 0.0006, respectively). Predictors significant for POAF included increasing age, left atrial volume indexed to body surface area (LAVI), and diastolic dysfunction (p = 0.02, 0.0001, and 0.001, respectively). Multivariate spline regressions demonstrated a nonlinear correlation between increasing LAVI and risk of POAF. Left atrial volume can be assessed efficiently preoperatively to provide superior risk stratification over clinical factors and diastolic parameters alone for the prediction of POAF. Furthermore, the present study demonstrated that the cutoffs of chamber quantification currently used do not appropriately capture the increased risk of POAF. Thus, LAVI provides a simple measure to identify patients who are in need of targeted prophylaxis for POAF.