Clinical research: complications of bypass surgery
Postoperative atrial fibrillation and mortality after coronary artery bypass surgery

https://doi.org/10.1016/j.jacc.2003.11.023Get rights and content
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Abstract

Objectives

We sought to determine if the occurrence of postoperative atrial fibrillation (AF) affects early or late mortality following coronary artery bypass surgery (CABG).

Background

Atrial fibrillation is the most common arrhythmia seen following CABG.

Methods

The Texas Heart Institute Cardiovascular Research Database was used to identify all patients that developed AF after isolated initial CABG from January 1993 to December 1999 (n = 994). This population was compared with patients who underwent CABG during the same period but did not develop AF (n = 5,481). In-hospital end points were adjusted using logistic regression models to account for baseline differences. Long-term survival was evaluated using a retrospective cohort design, where Cox proportional hazards methods were used to adjust for baseline differences, and with case-matched populations (n = 390, 195 per arm).

Results

Atrial fibrillation was diagnosed in 16% of the population. Postoperative AF was associated with greater in-hospital mortality (odds ratio [OR] 1.7, p = 0.0001), more strokes (OR 2.02, p = 0.001), prolonged hospital stays (14 vs. 10 days, p < 0.0001), and a reduced incidence of myocardial infarction (OR 0.62, p = 0.01). At four to five years, survival was worse in patients who developed postoperative AF (74% vs. 87%, p < 0.0001 in the retrospective cohort; 80% vs. 93%, p = 0.003 in the case-matched population). On multivariate analysis, postoperative AF was an independent predictor of long-term mortality (adjusted OR 1.5, p < 0.001 in the retrospective cohort; OR 3.4, p = 0.0018 in the case-matched population).

Conclusions

The occurrence of AF following CABG identifies a subset of patients who have a reduced survival probability following CABG. The impact of various strategies, such as antiarrhythmics and warfarin, aimed at reducing AF and its complications deserves further study.

Abbreviations

AF
atrial fibrillation
CABG
coronary artery bypass graft surgery
CAD
coronary artery disease
CHF
congestive heart failure
CI
confidence intervals
COPD
chronic obstructive pulmonary disease
CPK
creatine phosphokinase
CVD
cerebrovascular disease
IMA
internal mammary artery
LOS
length of stay
MI
myocardial infarction
OR
odds ratio
PVD
peripheral vascular disease
THI
Texas Heart Institute
TIA
transient ischemic attack

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