Chronic obstructive pulmonary disease (COPD) has been linked to increased early morbidity and mortality following coronary artery bypass grafting (CABG). We sought to determine the impact of COPD on long-term survival after CABG.
We studied 3760 consecutive patients who underwent CABG between 1992 and 2002. Patients without COPD were compared with those who had COPD preoperatively. Long-term survival data (mean follow-up 5.2 years) were obtained from the National Death Index. Groups were compared by Cox proportional hazard models and Kaplan-Meier survival plots. The propensity for COPD was determined by logistic regression analysis and each patient with COPD was then matched with 3 patients without COPD.
There were 550 patients (14.6%) who had COPD preoperatively. Multivariate logistic regression analysis found that patients with COPD were older and had higher EuroSCORE, more urgent operations, lower ejection fraction and higher percentages of unstable angina, transmural infarction, peripheral vascular disease, congestive heart failure, immune deficiency, smoking and left ventricular hypertrophy. After adjustment for all pre-, intra- and post-operative factors the adjusted hazard ratio of long-term mortality for patients with COPD was 1.31 (95% confidence interval 1.10-1.57; P=0.003) and if deaths during the first year excluded the adjusted hazard ratio was 1.29 (95% confidence interval 1.04-1.60; P=0.022). Four-hundred and forty-two patients with COPD were matched with 1326 patients without COPD using propensity scores identical to within 1%. Early outcome of matched groups is shown in tableVariableWithout COPD (n=1326)With COPD (n=442)P valueEuroSCORE7.6±3.77.6±3.30.935Length of stay (days)11.6±11.813.0±13.2<0.00130-day mortality, n (%)50 (3.8)22 (5.0)0.268In-hospital mortality, n (%)45 (3.4)18 (4.1)0.553Intraoperative stroke, n (%)39 (2.9)12 (2.7)0.871Stroke over 24 hours, n (%)14 (1.1)2 (0.5)0.385Postoperative myocardial infarction, n (%)10 (0.8)2 (0.5)0.741Deep sternal wound infection, n (%)14 (1.1)5 (1.1)0.999Bleeding/reoperation, n (%)26 (2.0)7 (1.6)0.690Gastrointestinal complications, n (%)22 (1.7)12 (2.7)0.165Renal failure/dialysis, n (%)16 (1.2)3 (0.7)0.435Sepsis/endocarditis, n (%)17 (1.3)3 (0.7)0.437Respiratory failure, n (%)72 (5.4)28 (6.3)0.476and Kaplan-Meier curves are shown in figure. Freedom from all-cause mortality at 5 years after CABG was 79.0±1.2% in patients without COPD versus 71.3±2.3% in patients with COPD (P=0.0022).
Patients with COPD showed similar early morbidity and mortality when compared with patients without COPD. However, COPD is a continuing detrimental risk factor for long-term survival following CABG.
The effect of COPD following CABG on patient survival extends far beyond the 30-day and in-hospital mortality time periods. These data suggest the need for a more frequent follow-up among patients with COPD.
I.K. Toumpoulis, None.