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M141 Impact Of Beta-blockade On Exercise Capacity And Dynamic Hyperinflation In People With And Without Copd Awaiting Vascular Surgery
  1. A Key,
  2. M Parry,
  3. M West,
  4. S Jack,
  5. F Torella,
  6. N Duffy,
  7. PP Walker
  1. University Hospital Aintree, Liverpool, UK

Abstract

Beta-blockers have a key role in the management of heart failure but have been under-utilised in people with COPD due to fear of bronchoconstriction and its impact on symptoms and function. Beta-blockers are also used peri-operatively in people undergoing vascular surgery due to improved cardiac function though this practice is contentious due to a risk of post-operative complications, particularly stroke. As part of a study looking at the impact of beta-blockade in people under abdominal aortic aneurysm surveillance we examined the impact of beta-blockade on CPET variables and dynamic hyperinflation at peak exercise

55 subjects were recruited though only 46 completed incremental CPET off and on beta-blockers. Mean age was 70 (6) years and 42 (91%) were male. IHD or heart failure was diagnosed in 13 people and COPD diagnosed in 7. However, 24/46 (52%) had post-bronchodilator airflow obstruction consistent with COPD (10 mild, 10 moderate and 4 severe). 18 were routinely prescribed beta-blockers (mainly bisoprolol). Those taking beta-blockers stopped treatment for the second CPET and other subjects commenced weight-adjusted bisoprolol before the second CPET.

The 25 COPD subjects had a mean FEV1 of 2.14 (0.62) L, FEV1 predicted 76 (20)% and FEV1/FVC 0.54 (0.11). The main results are shown in the table. Compared with the subjects without COPD at peak exercise the COPD subjects had slightly lower VO2, work and ventilatory equivalents but these did not differ significantly. When beta-blocked both COPD and non-COPD subjects had a lower heart rate (p < 0.001) and consequently oxygen pulse (p < 0.001) but there was a minimal effect on other variables. The COPD patients showed a greater fall in IC (p = 0.02) but the addition of a beta-blocker did not have any additional effect. The 7 subjects already diagnosed with COPD did not differ from the whole COPD group.

In an unselected clinic population with arterial vascular disease a majority of people had, mostly undiagnosed, COPD albeit predominantly mild to moderate. Continuation or commencement of beta-blockers had little effect on level of peak exercise or degree of dynamic hyperinflation. This supports the use of beta-blockers in this COPD population, both in a peri-operative setting and for a cardiac indication.

Abstract M141 Table 1

Change in peak CPET variables and inspiratory capacity at isotime with and without beta-blockade in 46 subjects with and without COPD

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