The effect of an exercise prescription on fitness of patients with abdominal aortic aneurysms

Patients undergoing aortic surgery are at increased risk of cardiorespiratory complications. Initiatives to improve outcome have focused predominantly on medical optimisation and endovascular surgery. Despite evidence that exercise can improve fitness in older patients [1], fitness initiatives have received limited attention pre-operatively. Anaerobic threshold derived from cardiopulmonary exercise testing (CPX) is a well documented measure of fitness before major surgery. Our aim was to determine if a short, supervised exercise programme could improve the anaerobic threshold in subjects with abdominal aortic aneurysm. With Research Ethics Committee approval we conducted a prospective, randomised pilot study in subjects with an abdominal aortic aneurysm under surveillance (diameter < 5.5 cm). Following sample size calculation, 30 subjects (allowing for 20% attrition rate) were randomly allocated either an exercise programme (n = 20) or no programme (n = 10). All subjects had a baseline anaerobic threshold measured (AT1, week 0). Those in the exercise group were required to complete a 6-week prescribed, supervised, in-hospital programme, attending twice a week for a 40-min bicycle based exercise session, graded so that patients achieved a level of 12–14 using Borg's Scale of Rate of Perceived Exertion. All subjects had their anaerobic threshold reassessed at weeks 5 (AT2) and 7 (AT3). The primary end-point was improvement in fitness between weeks 0 and 7 (AT3–AT1). Subjects' characteristics were similar for both groups. Twenty-five patients completed the study. No significant difference in fitness was found (Table 1). There was one serious adverse event in the exercise group. We found no significant improvement in fitness with the exercise prescription. This may be because the volume of exercise (intensity × duration × frequency) was insufficient or less beneficial than ‘interval training’ in this population, or because this elderly, high-risk group is very difficult to train to higher levels of fitness overall. This study was funded by The Association of Anaesthetists of Great Britain and Ireland.