Validity of estimated aortic pulse wave velocity measured during the 6-minute walk test to predict anaerobic fitness before major non-cardiac surgery.

Abstract

Background: This study aimed to assess the efficacy of estimated preoperative aortic pulse wave velocity (AoPWV) to discriminate between low and high 6 min walk test (6MWT) distance in patients awaiting major non-cardiac surgery.

Methods: Prospective observational study in 133 patients undergoing non cardiac surgery. AoPWV and the distance walked during a 6MWT were assessed. Receiver operating characteristic (ROC) curve analysis was used to determine two different AoPWV cut-points for predicting a distance of 427 metres in the 6MWT. We also calculated lower and upper AoPWV cut-points (probability ≥ 0.75) for predicting a distance of < 427 metres, ≥ 427 metres, and also 563 metres in the 6MWT.

Results: The ROC curve analysis for the < 427 metre distance revealed an area under the curve (AUC) of 0.68 (95% confidence interval 0.56-0.79) and an AUC of 0.72 (95% confidence interval 0.61-0.83) for > 563 metres. Patients with AoPWV > 10.97 m/s should be considered high risk, while those with < 9.42 m/s can be considered low risk.

Conclusions: AoPWV is a simple, non-invasive, useful clinical tool for identifying and stratifying patients awaiting major non-cardiac surgery. In situations of clinical uncertainty, additional measures should be taken to assess the risk.