The effect of beta-blockade on objectively measured physical fitness in patients with abdominal aortic aneurysms - a blinded interventional study

West, M.A., Parry, M., Asher, R., Key, A., Walker, P., Loughney, L., Pintus, S., Duffy, N., Jack, S. and Torella, F. (2017) The effect of beta-blockade on objectively measured physical fitness in patients with abdominal aortic aneurysms - a blinded interventional study. British Journal of Anaesthesia, 114 (6), 878–885. (doi:10.1093/bja/aev026).

Abstract

Background: perioperative beta-blockade is widely used, especially before vascular surgery; however, its impact on exerciseperformance assessed using cardiopulmonary exercise testing (CPET) in this group is unknown. We hypothesized that betablocker therapy would significantly improve CPET-derived physical fitness in this group.

Methods: we recruited patients with abdominal aortic aneurysms (AAA) of <5.5 cm under surveillance. All patients underwentCPET on and off beta-blockers. Patients routinely prescribed beta-blockers underwent a first CPET on medication. Beta-blockerswere stopped for one week before a second CPET. Patients not routinely taking beta-blockers underwent the first CPET offtreatment, then performed a second CPET after commencement of bisoprolol for at least 48 h. Oxygen uptake (V_ O2 ) at estimatedlactate threshold (θ^L) and V_ O2 at peak were primary outcome variables. A linear mixed-effects model was fitted to investigate anydifference in adjusted CPET variables on and off beta-blockers.

Results: forty-eight patients completed the study. No difference was observed in V_ O2 at θ^L and V_ O2 at peak; however, asignificant decrease in V_ E=V_ CO2 at θ^L and peak, an increase in workload at θ^L, O2 pulse and heart rate both at θ^L and peak wasfound with beta-blockers. Patients taking beta-blockers routinely (chronic group) had worse exercise performance (lower V_ O2 ).

Conclusions: beta blockade has a significant impact on CPET-derived exercise performance, albeit without changing V_ O2 at θ^Land V_ O2 at peak. This supports performance of preoperative CPET on or off beta-blockers depending on local perioperativepractice.Clinical trial registration: NCT 02106286

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Contributors

Author: M.A. West

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