PREDICTING COMPLICATIONS AFTER PULMONARY RESECTION - PREOPERATIVE EXERCISE TESTING VS A MULTIFACTORIAL CARDIOPULMONARY RISK INDEX

Recent studies have used preoperative cardiopulmonary exercise testing to improve risk assessment of pulmonary resection for lung cancer. Th ese studies have demonstrated inconsistent correlation between peak ox ygen uptake (VO2) and postoperative complications but have not systema tically examined other methods of risk stratification. We analyzed the findings in 42 patients who had cardiopulmonary exercise testing prio r to lung cancer resection. Preoperative clinical data combining pulmo nary factors (obesity, productive cough, wheezing, tobacco use, ratio of the forced expiratory volume in 1 s over the forced vital capacity [FEV1/FVC] <70 percent, and PaCO2 >45 mm Hg), and an established cardi ac risk index were used to generate a cardiopulmonary risk index (CPRI ). When analyzed using the risk index, the incidence of postoperative complications increased with higher CPRI scores. Those with a CPRI of 4 or greater were 22 times more likely to develop a complication, comp ared to a CPRI of less than 4 (p<0.0001). We found that patients with a peak VO2 less than 500 ml/m2/min (body surface area) were 6 times mo re likely to experience a cardiopulmonary complication (p<0.05). With multiple logistic regression analysis, peak VO2 was not an independent predictor of postoperative complications. Analysis also demonstrated that a CPRI of 4 or greater was associated with significant reductions in peak VO2. We conclude that both the peak VO2 during cardiopulmonar y exercise testing and a multifactorial CPRI are highly predictive of complications after lung resection. Adding the peak VO2 did not enhanc e the risk estimation generated by the CPRI. The association between p ostoperative complications and peak VO2 may be explained by the correl ation between identifiable cardiopulmonary disease (CPRI) and reduced oxygen uptake with exercise.