Peak power output testing: novel method for preoperative assessment of exercise capacity

Abstract

Background: Assessment of exercise capacity is an important component of risk assessment before major surgery. Cardiopulmonary exercise testing (CPET) provides comprehensive assessment but is resource-intensive, limiting widespread adoption. Measurement of a patient's peak power output (PPO) using a simplified test on a cycle ergometer has the potential to identify patients likely to have abnormal CPET findings and to be at increased perioperative risk. The aim of this study was to investigate the potential for PPO to identify those with abnormal CPET and to determine whether PPO predicted the risk of adverse postoperative outcomes.

Methods: In a retrospective analysis of a single-centre cohort, the ability of PPO to predict a high-risk CPET result in patients undergoing major cancer surgery was analysed. The assessment was validated in patients undergoing major abdominal surgery from a UK national multicentre cohort. The association between PPO and adverse postoperative outcomes to traditional CPET-derived variables were compared.

Results: In 2262 patients from a single centre, PPO was an excellent discriminator of high-risk CPET, with an area under the receiver operating characteristic curve (AUROC) of 0.901 (95 per cent c.i. 0.888 to 0.913). In the national cohort of 2742 patients, there was excellent discrimination, with an AUROC of 0.856 (0.842 to 0.871). A PPO cut-off of 1.5 W/kg may be appropriate for use in screening, with a sensitivity of 90 per cent in both cohorts. PPO and traditional CPET-derived predictors demonstrated similar discrimination of major postoperative complications and death. The association between PPO and major postoperative complications persisted on multivariable analysis.

Conclusion: These results suggest a role for the PPO test in preoperative screening and risk stratification for major surgery. Prospective evaluation is recommended.