Incidence, predictors, and outcome for post-operative atrial fibrillation in Indian patients undergoing off-pump coronary artery bypass grafting-a prospective observational study.

PURPOSE

Indian patients who undergo surgical revascularization are relatively younger than their Western counterparts and are predominantly revascularized using off-pump coronary artery bypass grafting (OPCAB) technique. They may therefore be at a reduced risk of developing post-operative atrial fibrillation (POAF). The aim of this study was to assess the incidence of POAF, measure its impact on outcomes, and identify the predictors for POAF in the Indian patients undergoing OPCAB. Besides, the ability of European System for Cardiac Operative Risk Evaluation (EuroSCORE) and Society of Thoracic Surgeons (STS) scores in predicting POAF was also assessed.

METHODS

In this prospective observational study, all patients undergoing isolated OPCAB in a single institution over a 12-month period were included. Patients undergoing re-operative surgery, emergency procedure, concomitant surgery, or those with history of previously diagnosed or treated atrial fibrillation were excluded. Logistic regression was performed to identify the predictors of POAF. The receiver operating characteristic (ROC) curve was used to determine the ability of EuroSCORE and STS scores to assess risk of developing POAF.

RESULTS

We recruited 1108 patients in the study of which 88 (7.94%) patients developed POAF. Age (OR = 1.082,  < 0.001, 95%CI: 1.050-1.114), unstable angina (OR = 16.32,  = 0.036, 95%CI: 1.2-221.4), presence of diabetes mellitus (OR 1.781,  = 0.025, 95%CI: 1.074-2.955), left atrial size (OR 2.506,  = 0.001, 95%CI: 1.478-4.251), and presence of chronic renal failure (OR 8.7,  = 0.001, 95%CI: 2.4-31.53) were significant predictors of POAF. Both the EuroSCORE ( = 0.035) and the STS score ( = 0.001) were significantly higher in patients developing POAF. The area under the ROC curve for the EuroSCORE II was 0.62 and for the STS score was 0.64 suggesting satisfactory and similar discriminatory power of both the scores to predict POAF in these patients. POAF was associated with significantly increased adverse outcomes like stroke and prolonged hospital stay.

CONCLUSIONS

In our study, the incidence of POAF was much lower (7.94%) than that reported previously. POAF significantly increased adverse outcomes and length of hospital stay. Both EuroSCORE II and STS scores had similar discriminating power in predicting POAF.