Additional spirometry criteria predict postoperative complications after coronary artery bypass grafting (CABG) independently of concomitant chronic obstructive pulmonary disease. When is off‑pump CABG more beneficial?

INTRODUCTION Concomitant chronic obstructive pulmonary disease (COPD) is associated with an increased rate of post‑coronary artery bypass grafting (CABG) complications. The ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) <70%, proposed by the Global Initiative for Chronic Obstructive Lung Disease as a criterion for the diagnosis of COPD, is criticized for not considering physiological, age‑related changes in lung function.
OBJECTIVES The aim of the study was to evaluate which of the additional spirometric parameters, adjusted for age and the distribution of values in the population, represent the best predictors of post‑CABG complications and to identify patients who are more likely to benefit from off‑pump cardiac bypass (OPCAB) than from CABG. 
PATIENTS AND METHODS In the retrospective cohort study, data from a total of 3617 CABG or OPCAB patients were recorded. Patients with COPD, diagnosed prior to admission, were classified according to the spirometry results: group 1 with FEV1/FVC <70%, group 2 with FEV1/FVC below the mean normal value adjusted to age, group 3 with FEV1/FVC below the lower limit of normal (LLN), group 4 with FEV1 <LLN. The control group comprised subjects with no history of COPD. The occurrence of post‑CABG complications was analyzed using the χ2 and Mann‑Whitney U tests.
RESULTS FEV1 below LLN predicted a higher incidence of reoperation, readmission to intensive care unit (ICU), sternal wound infection, pulmonary complications, and pulmonary edema after surgery (p <0.05). CABG patients with FEV1 below LLN stayed in the ICU significantly longer than OPCAB patients, and tended to require prolonged mechanical ventilation and more time from operation to discharge.
CONCLUSIONS FEV1 <LLN is the best prognostic marker for post‑CABG complications independently of concomitant COPD. Patients with FEV1 <LLN have better outcomes after OPCAB compared with those post-CABG.