Coronary surgery in patients with preexisting chronic atrial fibrillation: early and midterm clinical outcome

Abstract

Background: The purpose of this study was to investigate the effect of preexisting atrial fibrillation on early and midterm clinical outcome in patients undergoing coronary surgery.

Methods: All elective patients undergoing coronary artery bypass grafting surgery between April 1996 and September 2002 were investigated. Patients were grouped according to their preoperative cardiac rhythm: sinus rhythm (SR) or preexisting atrial fibrillation (AF). In-hospital clinical outcomes and 5-year patient survival and cardiac-related event-free survival were compared using regression methods to adjust for differences between the groups. In all, 5,092 patients were identified, 175 (3.4%) with a history of preexisting AF. These patients were older (median, 64 versus 68 years) and had higher Parsonnet scores (median, 4 versus 8) than the SR group. Previous myocardial infarction, cerebrovascular accident, hypertension, diabetes mellitus, renal impairment, peripheral vascular disease, ejection fraction less than 50%, previous surgery, congestive heart failure, and use of angiotensin-converting enzyme inhibitors were also more common in the AF group.

Results: There were 60 in-hospital deaths (1.2%), with no difference between the two groups (odds ratio 1.02, 95% CI: 0.35 to 2.94). Atrial fibrillation patients were more likely to need intraoperative inotropes (p = 0.044), postoperative intra-aortic balloon pump (p = 0.038), and were less likely to be discharged within 6 days (p = 0.017). The risk of death in the 5 years after surgery was higher in the AF group (relative risk 1.49, 95% CI: 1.06 to 2.08, p = 0.020). In the AF group, 109 (62.2%) patients were cardioverted spontaneously by surgery, but only 69 (39.4%) remained in SR until discharge. Longer-term rhythm follow-up data were available for 48 of these 69 patients, and only 36 remained in SR at a median follow-up of 1,483 days (interquartile range, 1,120 to 2,209). Spontaneous conversion to SR after surgery did not confer a midterm survival benefit (p = 0.91).

Conclusions: Preexisting AF in patients undergoing coronary artery bypass graft surgery is not associated with increased in-hospital mortality and major morbidity; however, it is a risk factor for reduced 5-year survival. Spontaneous cardioversion to SR during surgery is transient in the majority of patients and is not associated with midterm survival benefit.