Clinical & Experimental Cardiology
Open Access

Abstract

Postoperative Atrial Fibrillation is Associated with Higher Euroscore, but not with Hospital Mortality after Coronary Artery Bypass Graft Surgery

Carol Chen-Scarabelli, Tiziano Scarabelli, Giuseppe Petrilli, Louis Saravolatz, Alessandro Mazzucco and Giuseppe Faggian

Background: Postoperative atrial fibrillation (POAF) is the most common arrhythmia after coronary artery bypass surgery (CABG) and is associated with an increased morbidity. Recently, it has been suggested that POAF is also associated with increased postoperative mortality.
Aim: To investigate whether POAF after isolated CABG was associated with a higher EuroSCORE, indicating greater in-hospital mortality risk.
Methods: We reviewed data from our prospective cardiac surgery database of all patients (n=2791) undergoing isolated CABG from January 2003 through December 2006 at a large university medical center. The Mann-Whitney test was used to test for differences in continuous variables between the POAF and non-POAF groups, while the Chi-square test was used for categorical variables. Cox proportional-hazards regression analysis was used to identify independent predictors of in-hospital mortality.
Results: The mean age was 68 ± 9.1yrs, and mean EuroSCORE was 6.91 ± 3.18. The overall incidence of POAF was 32.3%. The POAF group was older (70.5 ± 7.8 vs. 66.8 ± 9.5yrs non-POAF: p<0.0001), but there was no significant difference in ejection fraction (EF) between the two groups (p=0.13). There was a significant difference in the mean EuroSCORE (POAF, 7.6 ± 3.2 vs non-POAF, 6.6 ± 3.1, p<0.0001), indicating that the POAF group was at greater risk for postoperative mortality. Although, there was a significant association between EuroSCORE and POAF (p<0.0001), there was no significant difference in hospital mortality between the POAF and non-POAF groups. The overall hospital mortality was 1.9%, with no difference between the two groups (p=0.91). Furthermore, POAF was not predictive of hospital mortality after CABG.
Conclusion: POAF is associated with a higher EuroSCORE, but it is neither associated with, nor predictive of increased hospital mortality after CABG