The potential role of pre-operative cardiopulmonary exercise testing in endovascular aortic repair

Abstract

Introduction: Cardiopulmonary exercise testing (CPET) to assess maximal oxygen uptake (peak VO2) and oxygen uptake at the anaerobic threshold (AT) is of value in pre-operative risk stratification for abdominal aortic aneurysm (AAA) repair: an AT of 11ml.min.kg has been reported to correlate with healthcare utilisation and post-operative outcomes. Endovascular aortic repair (EVAR) is a minimally invasive technique associated with lower cardio-respiratory stress than open repair but the role of CPET is not yet established. We investigated the predictive value of CPET in EVAR outcomes. Method: Patient demographics, length of admission (LOA) and critical care requirements of all EVAR subjects who underwent preoperative CPET between July 2014 and September 2017 were compared using CPET data. Correlations between data sets were made using Spearman9s rank order correlation and the Mann Whitney U test. Results: 77 patients were included. Peak VO2, AT and Eq.CO2 did not predict LOA (r=-0.0997; p=0.3957, r=0.1409; p=0.3947; r=0.05575; p=0.6347, respectively) and classification of AT threshold to 11ml.min.kg did not influence the relationship with LOA (3 vs 2 days, p=0.1775). AT was no different in patients requiring post-operative critical care admission (12.3 vs 11.7ml.min.kg; p=0.08092, respectively). Conclusion: Our data suggest that AT does not predict LOA or critical care requirement following EVAR. The conventionally used AT threshold may be misleading as a marker of preoperative fitness by potentially excluding patients who are fit for EVAR. Furthermore our study may question the clinical usefulness of CPET in EVAR preoperative risk stratification.