Cardiac Rehabilitation Protects Against the Expansion of Abdominal Aortic Aneurysm

BACKGROUND: Virtually no reports on the effects of exercise in patients with a small abdominal aortic aneurysm (AAA) exist. METHODS AND RESULTS: We conducted a retrospective cohort study on 1515 patients with a small AAA before surgery at 2 high‐volume hospitals in Tokyo, Japan, from April 2004 to September 2015. A carefully modified cardiac rehabilitation program without excessive blood pressure elevation during exercise was prescribed to 50 patients with an AAA. Using propensity score matching, mortality and clinical outcomes, including AAA expansion rate, were compared between 2 groups: rehabilitation group and nonrehabilitation group. The background characteristics of the rehabilitation group (n=49) and the nonrehabilitation group (n=163) were almost identical. The risk for AAA repair was much lower in the rehabilitation group after matching (before matching: hazard ratio, 0.43; 95% confidence interval, 0.25–0.72; P=0.001; and after matching: hazard ratio, 0.19; 95% confidence interval, 0.07–0.50; P<0.001). AAA expansion rate was slower in the rehabilitation group (before matching: rehabilitation versus nonrehabilitation group, 2.3±3.7 versus 3.8±3.4 mm/y [P=0.008]; after matching: rehabilitation versus nonrehabilitation group, 2.1±3.0 versus 4.5±4.0 mm/y [P<0.001]). Elevation of blood pressure during exercise was positively correlated with AAA expansion rate after the rehabilitation program (r=0.569, P<0.001). CONCLUSIONS: Cardiac rehabilitation protects against the expansion of small AAAs and mitigates the risk associated with AAA repair, possibly because of the decreased elevation of blood pressure during exercise. CLINICAL TRIAL REGISTRATION: URL: upload.umin.ac.jp. Unique identifier: UMIN000028237.