Influence of age-specific lung function on survival after coronary bypass

Abstract

Background. Respiratory complications after successful coronary artery bypass grafting influence the immediate recovery of a patient; however, whether they influence the longevity of a patient is largely unknown. The aim of this study was to examine the effects of preoperative pulmonary risk factors in younger patients and older patients on outcome after coronary artery bypass grafting. Methods. A retrospective chart review was performed on 939 patients who underwent primary coronary artery bypass grafting between July 1987 and November 1996. For better comparison, they were arbitrarily divided by age into two groups: group 1, less than 70 years old (n = 710), and group 2, 70 years old or older (n = 229). The variables collected for each patient included history of chronic obstructive pulmonary disease, active smoking, forced expiratory volume, and ventilatory support for more than 48 hours. These variables were compared with postoperative length of stay in the intensive care unit, length of stay in the hospital, and the midterm survival up to 5 years. The data were analyzed by the use of univariate/multivariate log-rank tests and the method of Kaplan-Meier survival estimates. Results. The presence of chronic obstructive pulmonary disease was associated with increased length of stay in the intensive care unit and in the hospital for both groups. Preoperative forced expiratory volume in 1 second, significantly affected length of stay in the hospital only in the patients less than 70 years old ( p = 0.0001). Delayed extubation beyond 48 hours of ventilatory support resulted in prolonged length of stay in the intensive care unit and in the hospital for patients less than 70 years old ( p = 0.0001, p = 0.0001, respectively) and patients 70 years old or older ( p = 0.0001, p = 0.0001, respectively). The 5-year survival after coronary artery bypass grafting for both groups was significantly influenced by the level of preoperative forced expiratory volume in 1 second ( p = 0.0004, p = 0.0282, respectively). Conclusions. Patients with chronic obstructive pulmonary disease, irrespective of age, stay in the intensive care unit and in the hospital longer after coronary artery bypass grafting. In addition, preoperative forced expiratory volume in 1 second is a significant predictor of 5-year survival in the young and aged individuals undergoing coronary artery bypass grafting.