Preservation of pleural integrity in patients undergoing coronary artery bypass grafting: effect on postoperative bleeding and respiratory function

Objective -The purpose of this study was to evaluate the influence of preserved integrity of pleura on postoperative bleeding and respiratory function in patients undergoing coronary artery bypass grafting (CABG). Methods and results - Seventy-two CABG patients who received pedunculated IMA graft without opening the pleura (group of intact pleura, group IP) between July 2002 and September 2004 were matched to 72 CABG patients who received pedunculated IMA graft with opened pleura (group of opened pleura, group OP).To match the patients with IP and unique patients with OP, logistic regression was used to develop a propensity score.The C statistic for this model was 0.79. Patients with IP were matched to unique patients with OP with an identical 5-digit propensity score. If this could not be done, we proceeded to a 4-, 3-, 2-, or 1-digit match. Patients characteristics were well matched. There were no differences in preoperative and peroperative variables between the groups. The incidence of postoperative pleural effusion and thoracentesis were significantly lower in group IP than group OP (pleural effusion in 15.2 versus 30.5%; p = 0.029, thoracentesis in 5.5 versus 18.5%; p = 0.036). Other pulmonary complications such as prolonged ventilation, reintubation, pneumothorax, atelectasis, diaphragmatic paralysis were similar in both groups. Patients with IP had significantly lower blood loss (520 versus 870 ml; p < 0.001) and whole blood unit transfusion (26.3 versus 41.6%, p = 0.036). Also, intensive care unit and hospital stay were similar in both groups. Conclusions - Meticulous internal mammary artery harvesting and preservation of the pleural integrity significantly reduces postoperative bleeding and pleural effusion.