Cardio-pulmonary Exercise Testing (CPET) assesses aerobic fitness by measuring a range of physiological parameters at rest and at different intensity of exercise. These parameters have been shown to be predictive of postoperative morbidity and mortality in non-cardiac surgery. Revised Cardiac Risk Index (RCRI) is a comorbidity-based score used to estimate the risk of cardiovascular complications following major surgery. All these tools are used to objectively assess fitness for surgery in patients with aortic aneurysms. Frailty is a multi-domain syndrome characterised by reduced ability to cope with physiological stressors. Sarcopenia is a predominantly age-related loss of muscle strength and mass linked to frailty. Both are associated with worse outcomes after surgery. Frailty and sarcopenia can be measured reproducibly using very basic, inexpensive methods. We demonstrated that frailty, but not sarcopenia or myopenia, is independently associated with one-year mortality in patients with aortic aneurysms irrespective of management strategy (operative v. non-operative). The aim of this study was to explore potential associations between CPET parameters and frailty, sarcopenia and RCRI in patients with aortic aneurysms.

All consecutive patients with aortic aneurysms seen in the specialist aortic clinic between Jul 2019 and Apr 2020 were assessed objectively for preventative, corrective surgery. All patients underwent objective assessment including CPET and pulmonary function tests (PFT). All had RCRI calculated and used for risk stratification in decision-making process. Frailty (Rockwood Clinical Frailty Scale), cognitive status (Abbreviated Mental Test), and quality of life (EQ-5D-5L) were assessed by Vascular Specialist Nurses as part of routine clinical practice. Patients were screened for sarcopenia using SARC-F questionnaire; core muscle mass was measured on CT angiograms. The outcome was association of frailty, sarcopenia, and radiological myopenia with CPET/PFT parameters (Peak VO2, VO2 at anaerobic threshold, Peak heart rate, VE/VECO2 slope, FVC and FEV1) and RCRI score.

We assessed 84 patients (median age 75 [72,82], 85% male; median aneurysm diameter 6cm [5.8,7.0]; 22% infrarenal, 46% juxtarenal and 32% thoracoabdominal aneurysms). Following objective assessment seventeen patients were deemed not fit for surgery; 41% of these were frail compared with 14% out of those who were deemed fit. Forty-eight patients underwent surgery (57%), 17(20%) did not, and 2(2%) declined despite being deemed fit. Eleven patients (13%) died within one year of assessment. Neither comorbid status nor CPET/PFT parameters were independently associated with one-year mortality. However, Peak VO2 demonstrated a positive trend (OR 0.65, 95%CI 0.42-1.01, p=0.056). Amongst CPET parameters only VE/VECO2 was significantly associated with frailty (OR 1.13, 95%CI 1.01-1.27, p=0.035). None of the routinely analysed CPET/PFT parameters were independently associated with sarcopenia score (SARC-F), radiological myopenia or RCRI. However, VE/VECO2 demonstrated a trend for association with myopenia (OR 1.09, 95%CI 0.99-1.19, p=0.064).

Absence of independently significant associations between CPET parameters and sarcopenia and myopenia may suggest that they measure different aspects of physiological reserve. However, frailty may complement routine assessment of physiological fitness and support decision making in patients with aortic aneurysms.