Rose GA; Davies RG; Appadurai IR; Lewis WG; Cho JS; Lewis MH; Williams IM; Bailey DM;
Experimental Physiology [Exp Physiol] 2018 Sep 26. Date of Electronic Publication: 2018 Sep 26.
New Findings: What is the central question of this study? To what extent cardiorespiratory fitness (CRF) is impaired in patients with abdominal aortic aneurysmal (AAA) disease and corresponding implications for postoperative survival requires further investigation. What is the main finding and its importance? Cardiorespiratory fitness is impaired in patients with AAA disease. Patients with peak oxygen uptake < 13.1 mL O2 .kg-1 .min-1 and ventilatory equivalent for carbon dioxide at anaerobic threshold ≥ 34 are associated with increased risk of post-operative mortality at 2 years. These findings demonstrate that CRF can predict mid-term postoperative survival in AAA patients which may help direct care provision.
Abstract: Preoperative cardiopulmonary exercise testing (PCPET) is a standard assessment used for the assessment of cardiorespiratory fitness (CRF) and risk stratification. However, to what extent CRF is impaired in patients undergoing surgical repair of abdominal aortic aneurysm (AAA) disease and corresponding implications for postoperative outcome requires further investigation. We measured CRF during an incremental exercise test to exhaustion using online respiratory gas analysis in patients with AAA disease (n = 124, aged 72 ± 7 years) and healthy sedentary controls (n = 104, aged 70 ± 7 years). Postoperative survival was examined for association with CRF and threshold values calculated for independent predictors of mortality. Patients who underwent PCPET prior to surgical repair had lower CRF [age-adjusted mean difference of 12.5 mL O2 .kg-1 .min-1 for peak oxygen uptake (V̇O2 peak), P < 0.001 vs. controls]. Following multivariable analysis, both V̇O2 peak and the ventilatory equivalent for carbon dioxide at anaerobic threshold (V̇E /V̇CO2 -AT) were independent predictors of mid-term postoperative survival (2 years). Hazard ratios of 5.27 (95% confidence interval (CI) 1.62 to 17.14, P = 0.006) and 3.26 (95% CI 1.00 – 10.59, P = 0.049) were observed for V̇O2 peak < 13.1 mL O2 .kg-1 .min-1 and V̇E /V̇CO2 -AT ≥ 34 respectively. Thus, CRF is lower in patients with AAA and those with a V̇O2 peak < 13.1 mL O2 .kg-1 .min-1 and V̇E /V̇CO2 -AT ≥ 34 are associated with a markedly increased risk of post-operative mortality. Collectively, our findings demonstrate that CRF can predict mid-term postoperative survival in AAA patients which may help direct care provision.