Cardiopulmonary exercise testing for preoperative risk assessment before hepatic resection

Abstract

Background: Contemporary liver surgery practice must accurately assess operative risk in increasingly elderly populations with greater co‐morbidity. This study evaluated preoperative cardiopulmonary exercise testing (CPET) in high‐risk patients undergoing hepatic resection. Methods: In a prospective cohort referred for liver resection, patients aged over 65 years (or younger with co‐morbidity) were evaluated by preoperative CPET. Data were collected prospectively on functional status, postoperative complications and survival. Results: Two hundred and four patients were assessed for hepatic resection, of whom 108 had preoperative CPET. An anaerobic threshold (AT) of 9·9 ml O₂ per kg per min predicted in‐hospital death and subsequent survival. Below this value, AT was 100 per cent sensitive and 76 per cent specific for in‐hospital mortality, with a positive predictive value (PPV) of 19 per cent and a negative predictive value (NPV) of 100 per cent: no deaths occurred above the threshold. Age and respiratory efficiency in the elimination of carbon dioxide (V̇E/V̇CO₂) at AT were statistically significant predictors of postoperative complications. Receiver operating characteristic (ROC) curve analysis showed that a threshold of 34·5 for V̇E/V̇CO₂ at AT provided a specificity of 84 per cent and a sensitivity of 47 per cent, with a PPV of 76 (95 per cent confidence interval (c.i.) 58 to 88) per cent and a NPV of 60 (48 to 72) per cent for postoperative complications. Long‐term survival of those with an AT of less than 9·9 ml O₂ per kg per min was significantly worse than that of patients with a higher AT (hazard ratio for mortality 1·81, 95 per cent c.i. 1·04 to 3·17; P = 0·036). Conclusion: CPET provides a useful prognostic adjunct in the preoperative assessment of patients undergoing hepatic resection. Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.