Metabolic Profiling of Patients Undergoing Elective Aortic Aneurysm Repair Surgery: Correlation with Anaerobic Threshold

Abstract

The anaerobic threshold (AT) measured by the cardiopulmonary exercise (CPX) test is becoming an established means of identifying patients at high risk of developing cardiac complications perioperatively. The aim of the present study was to investigate the relationship between AT and the plasma metabolic profile of patients undergoing aortic aneurysm repair surgery to see if an alternative or adjunct to the CPX test could be devised. Plasma was obtained from 15 male patients classified (through preoperative CPX tests) as having high (≥11.0 mL kg−1 min−1) or low (<11.0 mL kg−1 min−1) AT before and 1, 2, 24, 48, and 72 hours after elective open aortic aneurysm surgery. Samples were analysed using 1H-NMR spectroscopy coupled with multivariate statistical analysis. Principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA) distinguished between low- and high-AT patients postoperatively, with high AT patients being more tightly clustered. High AT patients had higher plasma lipid and lower 3-hydroxybutyrate and acetoacetate levels than low AT patients post-operatively. Similar differences were identified preoperatively. 1H-NMR metabolic profiling of plasma has identified molecules whose concentration correlates with AT scores. These may prove a useful biomarker in conjunction with AT in predicting response to major surgical procedures.