Cardioselective Beta Blockers Safe in COPD
By Will Boggs MD
NEW YORK (Reuters Health) May 11 - Cardioselective beta blockers are generally safe in moderate to severe chronic obstructive pulmonary disease (COPD), according to researchers from Canada.
"Beta blockers are likely underused in COPD patients," Dr. Steeve Provencher from Université Laval, Québec, Canada told Reuters Health in an email. "Stable COPD should no longer be considered as a contraindication for beta blockers when there is a clear indication for them."
To address the concern that beta blockers might worsen respiratory function in patients with COPD, Dr. Provencher and colleagues conducted a crossover trial of bisoprolol vs placebo in 27 patients with moderate to severe COPD. They were particularly interested in the effect of the cardioselective beta blocker on dynamic hyperinflation.
Forced expiratory volume in one second (FEV1) is a marker of COPD severity, Dr. Provencher explained in his email. "However," he added, "dynamic hyperinflation is an important parameter in COPD as 1) it is more sensitive to changes in bronchial obstruction and 2) more closely related to patients' symptoms."
As reported online April 10 in the American Journal of Cardiology, inspiratory capacity decreased during exercise to a greater extent after patients had been taking bisoprolol for 14 days than when they took a placebo (by 0.50 vs 0.41 L; p=0.01).
Bisoprolol did not affect rest lung volumes, expiratory flows, and other parameters related to dynamic hyperinflation. It was, however, associated with lower oxygen consumption, heart rate, and blood pressure and higher oxygen pulse at peak isotime, compared to placebo, but there were no differences in respiratory exchange ratio, minute ventilation, or Borg scale.
Cycle endurance test duration did not differ significantly between bisoprolol and placebo.
Individual changes in endurance time correlated with changes in inspiratory capacity with bisoprolol, the researchers note, "suggesting that subtle changes in dynamic airway function may influence exercise capacity in some patients."
"Ideally," Dr. Provencher said, "a large placebo-controlled trial should be planned to assess the long-term effect of beta-blockers on death and other significant outcomes in COPD patients with cardiovascular disorders/risk factors. However, getting funds for such a trial would not be easy."
SOURCE: http://bit.ly/JjCvN0
Am J Cardiol 2012.
NEW YORK (Reuters Health) May 11 - Cardioselective beta blockers are generally safe in moderate to severe chronic obstructive pulmonary disease (COPD), according to researchers from Canada.
"Beta blockers are likely underused in COPD patients," Dr. Steeve Provencher from Université Laval, Québec, Canada told Reuters Health in an email. "Stable COPD should no longer be considered as a contraindication for beta blockers when there is a clear indication for them."
To address the concern that beta blockers might worsen respiratory function in patients with COPD, Dr. Provencher and colleagues conducted a crossover trial of bisoprolol vs placebo in 27 patients with moderate to severe COPD. They were particularly interested in the effect of the cardioselective beta blocker on dynamic hyperinflation.
Forced expiratory volume in one second (FEV1) is a marker of COPD severity, Dr. Provencher explained in his email. "However," he added, "dynamic hyperinflation is an important parameter in COPD as 1) it is more sensitive to changes in bronchial obstruction and 2) more closely related to patients' symptoms."
As reported online April 10 in the American Journal of Cardiology, inspiratory capacity decreased during exercise to a greater extent after patients had been taking bisoprolol for 14 days than when they took a placebo (by 0.50 vs 0.41 L; p=0.01).
Bisoprolol did not affect rest lung volumes, expiratory flows, and other parameters related to dynamic hyperinflation. It was, however, associated with lower oxygen consumption, heart rate, and blood pressure and higher oxygen pulse at peak isotime, compared to placebo, but there were no differences in respiratory exchange ratio, minute ventilation, or Borg scale.
Cycle endurance test duration did not differ significantly between bisoprolol and placebo.
Individual changes in endurance time correlated with changes in inspiratory capacity with bisoprolol, the researchers note, "suggesting that subtle changes in dynamic airway function may influence exercise capacity in some patients."
"Ideally," Dr. Provencher said, "a large placebo-controlled trial should be planned to assess the long-term effect of beta-blockers on death and other significant outcomes in COPD patients with cardiovascular disorders/risk factors. However, getting funds for such a trial would not be easy."
SOURCE: http://bit.ly/JjCvN0
Am J Cardiol 2012.