Chronic obstructive pulmonary disease severity influences outcomes after off-pump coronary artery bypass

To analyze the impact and severity of chronic obstructive pulmonary disease (COPD) on pulmonary function and postoperative clinical outcome based on the Global Initiative for Obstructive Lung Disease criteria in patients undergoing off-pump coronary artery bypass grafting (CABG).

Patients were allocated into 3 groups according to presence and severity of COPD: no or mild COPD (n = 144); moderate COPD (n = 77); and severe COPD (n = 30). Spirometry values were obtained preoperatively and on postoperative days (PODs) 2 and 5. The incidences of pneumonia and reintubation, time of mechanical ventilation, and length of postoperative hospital stay were recorded.

Significant impairment in pulmonary function was observed in all groups on PODs 2 and 5 (P < .001). However, postoperative pulmonary dysfunction was significantly higher in the moderate and severe COPD groups compared with the no or mild COPD group (P < .05). On multivariable analysis, severe COPD was associated with an elevated risk for composite outcomes (odds ratio, 1.37; 95% confidence interval, 1.20-1.57; P < .001). A preoperative forced expiratory volume in 1 second (FEV₁) <50% of the predicted value was associated with poor outcome. A significant negative correlation was found between FEV₁ at POD 5 and postoperative length of stay (r = -0.5; P < .001).

More severe COPD was associated with greater impairment in pulmonary function and worse clinical outcomes after off-pump CABG surgery. A preoperative FEV₁ <50% of predicted value appears to be an important predictor of postoperative complications.