Usefulness of the mean platelet volume for predicting new-onset atrial fibrillation after isolated coronary artery bypass grafting.

Postoperative atrial fibrillation (AF) is a common complication of coronary artery bypass grafting (CABG). The mean platelet volume (MPV) is an important marker of platelet activity and is associated with cardiovascular risk factors. We investigated whether the MPV is associated with the development of AF after CABG. This study included 208 patients undergoing elective isolated CABG. We evaluated the standard preoperative 12-lead electrocardiograph (ECG) recorded at a paper speed of 25 mm/s obtained for each patient from our hospital records before surgery. All study patients underwent standard CABG requiring cardiopulmonary bypass without concurrent valvular surgery. Forty-three patients were excluded. After CABG, all patients were monitored by telemetry and 12-lead ECGs. AF was defined using the established Society of Thoracic Surgeons definition. Postoperative AF occurred in 38 (22%) patients. The hemoglobin and platelet and leukocyte counts were similar in the groups with and without AF. However, the MPV and neutrophil/lymphocyte ratio were significantly higher in the AF group (8.9 [1.4] vs. 7.9 [1.2], p < 0.001 and 3.2 ± 1.9 vs. 2.6 ± 1.2, p = 0.005, respectively). In addition, the C-reactive protein (CRP) levels were significantly higher in the AF group (8.9 [19.6] vs. 5.3 [8.7], p = 0.025). Multivariate logistic regression analysis showed that MPV and CRP were independent predictors of postoperative AF (odds ratio [OR] 2.564, 95% confidence interval [CI] 1.326-4.958, p = 0.005; OR 1.055, 95% CI 1.000-1.114, p = 0.050, respectively). Our results show that increased platelet activity is associated with the development of AF after CABG.