The Effect of beta-blockade on objectively measured physical fitness in patients with abdominal aortic aneurysms–A blinded interventional study.

West MA; Parry M; Asher R; Key A; Walker P;
Loughney L; Pintus S; Duffy N; Jack S; Torella F

British Journal Of Anaesthesia [Br J Anaesth], ISSN: 1471-6771, 2015 Jun; Vol. 114 (6),
pp. 878-85; Publisher: Oxford University Press; PMID: 25716221;

Background: Perioperative beta-blockade is widely used, especially
before vascular surgery; however, its impact on exercise performance
assessed using cardiopulmonary exercise testing (CPET) in this group is
unknown. We hypothesized that beta-blocker 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 underwent CPET on and off
beta-blockers. Patients routinely prescribed beta-blockers underwent a
first CPET on medication. Beta-blockers were stopped for one week
before a second CPET. Patients not routinely taking beta-blockers
underwent the first CPET off treatment, then performed a second CPET
after commencement of bisoprolol for at least 48 h. Oxygen uptake
(.VO2) at estimated lactate threshold and .VO2 at peak were primary
outcome variables. A linear mixed-effects model was fitted to
investigate any difference in adjusted CPET variables on and off
beta-blockers.Results: Forty-eight patients completed the study. No
difference was observed in .VO2 at estimated lactate threshold and .VO2
at peak; however, a significant decrease in .VE/.VCO2 at estimated
lactate threshold and peak, an increase in workload at estimated
lactate threshold., O2 pulse and heart rate both at estimated lactate
threshold and peak was found with beta-blockers. Patients taking
beta-blockers routinely (chronic group) had worse exercise performance
(lower .VO2 ).

Conclusions: Beta blockade has a significant impact on
CPET-derived exercise performance, albeit without changing .VO2 at
estimated lactate threshold and.VO2 at peak. This supports performance
of preoperative CPET on or off beta-blockers depending on local
perioperative practice.Clinical Trial Registration: NCT 02106286.