Beta Blockers May Increase Risk during Surgery

A new study suggests that patients on β-blockers face heightened risks of heart complications during non-cardiac surgeries.

Researchers at the University of Copenhagen (KU; Denmark), Rigshopitalet University Hospital (Copenhagen, Denmark) and other institutions conducted a study to determine the risk of major adverse cardiovascular events (MACEs) associated with long-term therapy for uncomplicated hypertension in patients who underwent noncardiac surgery between 2005 and 2011. In all, 14,644 patients who received β-blockers and 40,676 patients who received other antihypertensive drugs—such as thiazides, calcium antagonists, or renin-angiotensin system [RAS] inhibitors—were included in the study.

The main outcomes and measures included 30-day risk of MACEs (i.e., cardiovascular death, nonfatal ischemic stroke, nonfatal myocardial infarction (MI), and all-cause mortality). Overall, 1.3% of the patients treated with β-blockers suffered a MACE, compared with 0.8% of patients not treated with β-blockers. β-blocker use was also associated with increased risks of MACE in two-drug combinations with RAS inhibitors, calcium antagonists, and thiazides, compared to the reference combination of RAS inhibitors and thiazides; results were similar for all-cause mortality.

The researchers also found that the risk of MACE associated with β-blocker use seemed especially pronounced for patients 70 years and older and for patients undergoing acute surgery, when compared to younger patients, women, and patients undergoing elective surgery, respectively. The researchers stressed that the findings were pertinent only for people with uncomplicated high blood pressure and not those with heart problems. The study was published early online on October 5, 2015, in JAMA Internal Medicine.

“Surgery is a big stress, and the body needs to accommodate that; β-blockers put on a lid on the heart's response,” said lead author Mads Jorgensen, MD, of the University of Copenhagen. “This observation may suggest that perioperative management of patients with hypertension should receive specific attention in clinical practice and future guidelines, but additional randomized clinical trials on this question may be warranted.”

β-blockers are used for the management of cardiac arrhythmias, protecting the heart from a second MI after a first heart attack (secondary prevention), and hypertension. They block the action of the endogenous catecholamines epinephrine and norepinephrine, in particular on adrenergic beta receptors located on cells of the heart muscles, airways, arteries, and other tissues that are part of the sympathetic nervous system. They also interfere with the binding to the receptor of other stress hormones, mediating the fight-or-flight response.

Related Links:
University of Copenhagen
Rigshopitalet University Hospital