Editor's Choice – The Abdominal Aortic Aneurysm Get Fit Trial: A Randomised Controlled Trial of Exercise to Improve Fitness in Patients with Abdominal Aortic Aneurysm

Abstract

Ruptured abdominal aortic aneurysm (AAA) carries a mortality rate of up to 80%. Elective repair prevents rupture, but peri-operative mortality remains at 2% - 3%. This mortality rate and long term survival rate are associated with impaired peak oxygen uptake (peak VO2), oxygen uptake at anaerobic threshold (AT) and ventilatory equivalent for CO2 (VECO2) at AT on cardiopulmonary exercise testing (CPET). Improving fitness to optimise these variables could improve peri-operative and long term survival, but the required exercise training suitable for patients with AAA has yet to be established. This randomised controlled trial aimed to evaluate the effectiveness of 24 week, patient directed, community based exercise on CPET measured fitness in AAA surveillance patients. This was a prospective randomised controlled trial in a tertiary UK vascular centre conducted using CONSORT guidelines. Patients on AAA surveillance (n= 56) were randomly assigned to either (1) a 24 week community exercise programme (CEP) with choice of gym or home exercises, or (2) standard clinical care including advice on weight loss and exercise. The primary outcome was change in peak VO2 at 24 weeks, with secondary outcomes including AT, VECO2, cardiovascular biomarkers (lipid profile, pro-B-type natriuretic peptide, and high sensitivity C reactive protein, body mass index, and HRQoL. Follow up was at eight, 16, 24, and 36 weeks to evaluate duration of benefit. All analyses were performed on an intention to treat basis. CEP patients (n= 28) achieved mean (95% confidence interval [CI]) improvements from baseline in peak VO2 of 1.5 (95% CI 0.5 - 2.5), 2.1 (95% CI 1.1 - 3.2), 2.3 (95% CI 1.2 - 3.3), and 2.2 (95% CI 1.1, 3.3) mL/kg/min at 8, 16, 24, and 36 weeks, respectively. These changes in CEP patients were significantly greater than those seen in control patients at 16 (p= .002), 24 (p= .031), and 36 weeks (p < .001). There were also significant improvements in AT, triglyceride levels, and HRQoL in CEP patients. This CEP significantly improved those CPET parameters associated with impaired peri-operative and long term survival in patients following AAA repair. These improvements were maintained at 12 weeks following the end of the programme.