Increased preoperative white blood cell count predicts postoperative atrial fibrillation after coronary artery bypass surgery.

OBJECTIVE

To better understand the relationship between humoral and cellular markers of inflammation and postoperative atrial fibrillation (AF).

DESIGN

A prospective and descriptive study.

SETTING

Academic institution.

PARTICIPANTS

Sixty adult patients > or = 60 years of age presenting for elective coronary artery bypass surgery with cardiopulmonary bypass (CPB).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

With institutional review board approval, serial measurements for high sensitivity C-reactive protein (CRP) and white blood cell count (WBC) were performed before the induction of anesthesia, on arrival in the intensive care unit, and on the mornings of postoperative days 1 and 2. Continuous telemetry and daily 12-lead electrocardiographs were used to confirm new-onset AF. AF occurred in 17 of 60 (28%; 95% confidence interval, 17%-41%) patients. A history of preoperative myocardial infarction was more frequent among patients who developed AF (p = 0.049). Patients with or without AF did not differ in CRP values at any of the 4 study time points (p = 0.61 to p = 0.81). Preoperative WBC values were higher for patients who developed AF, and, according to stepwise logistic regression, it was the sole independent predictor of postoperative AF (odds ratio = 6.7; 95% confidence interval, 1.6-29.0; p = 0.01). A 2-fold higher preoperative WBC was associated with a nearly 7-fold higher risk of developing AF, and WBC >7 x 10(9)/L was associated with a nearly 4-fold higher risk of AF (odds ratio = 3.8, p = 0.03).

CONCLUSION

In this cohort of patients undergoing CABG surgery, preoperative leukocytosis was a significant predictor of AF independent of CRP.