Coronary Artery Bypass Grafting in Patients With COPD: Discussion


1 May 2014

Several studies have examined the preoperative factors that impact on the postoperative outcome of patients with COPD undergoing cardiac surgery. Braun et al, for example, found significant ventila-tion-perfusion abnormalities that persisted beyond 2 weeks postoperatively and recommended preoperative pulmonary function studies with ABGs and spirometry in smokers scheduled for elective coronary revascularization. Cain and coworkers, however, believed that routine quantitation of clinically apparent pulmonary dysfunction was of little value in predicting postoperative morbidity. Instead, clinical assessment was a more rational basis for therapy. Their study, however, did show a correlation between preoperative arterial hypercapnia (Pco2>50 mm Hg) and the development of major postoperative problems. In a study by Grover and colleagues, the presence of COPD preoperatively increased the operative mortality by 1.5 times. Furthermore, the operative mortality correlated with the FEV1 of 3.8% for FEVX >1.25 L/s vs 11.7% for FEV1 <1.25 L/s. In our study, there was a twofold increase in hospital mortality for COPD patients compared with non-COPD patients. Since we did not measure FEVi routinely preoperatively, we cannot confirm the findings of Grover et al. We did, however, observe a significant difference in outcome for steroid-dependent COPD patients and older COPD patients. antibiotics amoxicillin
To our knowledge, there are no other studies demonstrating the difference in mortality between steroid-dependent and nonsteroid-dependent COPD patients. The effects of advanced age, however, are documented. As demonstrated by Ghattas, postoperative decreases in pulmonary function were more profound in older patients and patients with previous lung disease, such that patients with underlying lung disease may not be able to tolerate further reduction in lung volumes and would be susceptible to more complications. Cosgrove et al, in a review of the trends in surgical mortality following CABG, found that cardiac causes of death decreased and were replaced by other system failure. The respiratory system was no exception. In a similar report by Naunheim and others, there has been a trend in operating on more patients with serious associated medical diseases. In 1975, there were no patients with COPD in the first 100 consecutive CABG patients, compared with 9 patients in 1985. As a consequence of this trend, there were marked increases in morbidity and mortality, including prolonged (>48 h) ventilator dependence. At our institution, we have observed a similar trend. Prolonged ventilator dependence was observed in 5.2% of COPD patients compared with 2.8% of non-COPD patients. Thus, we would agree with Jackson, who argues for prevention of postoperative complications in COPD patient beginning in the preoperative period with discontinuation of smoking before surgery and vigorous pulmonary toilet prior to operation. While the time frame for these maneuvers is subject to debate, we would argue that it is worthwhile in the older and sicker patient with COPD whose mortality is significantly higher than his or her younger and healthier counterpart.

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