Comparison of the prognostic accuracy of scoring systems, cardiopulmonary exercise testing, and plasma biomarkers: a single-centre observational pilot study.

BACKGROUND: Current approaches to risk assessment before major surgery have important limitations. The aim of this pilot study was to compare predictive accuracy of preoperative scoring systems, plasma biomarkers, and cardiopulmonary exercise testing (CPET) for complications after major non-cardiac surgery.
METHODS: Single-centre, observational study of patients aged ≥40 yr undergoing major elective non-cardiac surgery. Before surgery, risk scores were calculated and blood samples collected for measurement of plasma biomarkers. Patients underwent CPET for measurement of anaerobic threshold (AT) and peak oxygen consumption ( peak). After surgery, patients were followed for 28 days to evaluate complications and major adverse cardiac events (MACE). Data are presented as area under the receiver operating characteristic curve (AUROC) with 95% confidence intervals.
RESULTS: A total of 100 patients were recruited between April 2009 and October 2010; 17 of whom did not proceed to surgery. CPET variables suggested good predictive accuracy for MACE [AT: AUROC 0.83 (0.69-0.96); peak AUROC 0.81 (0.69-0.96)] and poor predictive accuracy for all complications [AT: AUROC 0.64 (0.52-0.77); peak AUROC 0.64 (0.52-0.77)]. There was a trend towards predictive accuracy of the plasma biomarkers B-type natriuretic peptide and estimated glomerular filtration rate (calculated from serum creatinine) for MACE but not all complications. C-reactive protein, ASA score, and revised cardiac risk index had little or no predictive value.
CONCLUSIONS: These pilot data suggest that CPET and plasma biomarkers may improve risk assessment before surgery. Only large clinical studies can confirm this observation and define the optimal use of these tests in clinical practice.