Z. J. Carr, Yale University, School of Medicine, New Haven, CT, USA.
J. Charchaflieh, A. Brenes-Bastos, H. He, H. M. Lin, A. Jankelovits, et al.

BJA Open 2025 Vol. 14 Pages 100407

BACKGROUND: Early postoperative complication risk prediction would enhance perioperative surveillance and resource allocation. Reports have described brief submaximal cardiopulmonary exercise testing (CPET) for the routine assessment of cardiopulmonary disease. Compared with conventional CPET, it can be performed in 6 min and is used to predict peak CPET measurements. We aimed to determine whether submaximal CPET-derived measures outperform structured surveys in early postoperative complication detection.
METHODS: An institutional review board-approved, single-centre, open-label, clinical device trial was conducted. A total of 101 participants undergoing noncardiac surgery, aged >60 yr, with revised cardiac risk index </=2, self-reported metabolic equivalents >4 (METs in ml O(2) kg(-1) min(-1); self-endorsed reliably climbing two flights of stairs), were enrolled. Participants completed a subjective METs assessment, Duke Activity Status Index, and submaximal CPET that derived peak oxygen uptake (VO(2), ml O(2)kg(-1) min(-1)), METs, and gas exchange-derived pulmonary capacitance (GXCAP, in ml O(2) beat(-1) kPa(-1)). Elastic net regularisation machine learning identified feature importance among study measures for the primary endpoint (Postoperative Morbidity Survey [POMS] >/=1), secondary endpoints (cardiac, pulmonary and renal domains of the POMS [POMS-CPR >/=1]), and length of stay. Adjusted multivariable regression models were used to identify significance.
RESULTS: Of 101 participants, 53 (52.4%) had POMS >/=1. GXCAP to peak VO(2) slope (GXCAP-VO(2)) was associated with POMS >/=1 (OR(adj) 0.94; 95% CI 0.89-0.99; P=0.011) and increasing length of stay (OR(adj) 0.98; 95% CI 0.96-0.99; P=0.01). GXCAP-VO(2) slope (OR(adj) 0.93; 95% CI 0.88-0.99; P=0.015) was associated with POMS-CPR >/=1.
CONCLUSIONS: Compared with structured surveys (subjective METs or Duke Activity Status Index) or conventional peak CPET values (VO(2) or METs), a novel measure, GXCAP-VO(2) slope, offered superior early postoperative complication discrimination in low-morbidity subjects. These preliminary findings support GXCAP-VO(2) slope as a compelling investigational target for early postoperative complication risk, supporting the use of CPET to enhance early postoperative complication prediction. CLINICAL TRIAL REGISTRATION: NCT05743673.