Beta blockers for peripheral arterial disease
Abstract
Background
Beta (ß) blockers are indicated for use in coronary artery disease (CAD). However, optimal therapy for people with CAD accompanied by intermittent claudication has been controversial due to the presumed peripheral haemodynamic consequences of beta blockers, leading to worsening symptoms of intermittent claudication.
Objectives
To quantify the potential harm of beta blockers on maximum walking distance, claudication distance, calf blood flow, calf vascular resistance, and skin temperature when used in patients with peripheral arterial disease (PAD).
Search methods
The Cochrane Peripheral Vascular Diseases (PVD) Group searched for publications describing randomised controlled trials (RCTs) of beta blockers in PAD in their Trials Register (last searched 6 May 2008) and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library 2008, Issue 2). We handsearched relevant journals and conference proceedings.
Selection criteria
Randomised controlled trials evaluating the role of both selective (ß1) and non‐selective (ß1 and ß2) beta blockers compared with placebo. We excluded trials comparing different types of beta blockers.
Data collection and analysis
Primary outcome measures were claudication distance in metres, and the time to claudication in minutes, and maximum walking distance in metres and minutes (as assessed by treadmill).
Secondary outcome measures were calf blood flow (ml/100 ml/min), calf vascular resistance, and skin temperature (ºC).
Main results
We included six RCTs fulfilling the above criteria, with a total of 119 patients. The beta blockers studied were atenolol, propranolol, pindolol, and metoprolol. None of the trials showed a statistically significant worsening effect of beta blockers on either the primary or secondary outcomes. There were no reports of any adverse events with the beta blockers studied.
Authors' conclusions
There is currently no evidence that beta blockers adversely affect walking distance in people with intermittent claudication. However, due to the lack of large published trials beta blockers should be used with caution if clinically indicated.
PICOs
Plain language summary
Beta blockers for peripheral arterial disease
Intermittent claudication is the most common symptom of atherosclerotic peripheral arterial disease and results from decreased blood flow to the legs during exercise. Beta blockers are a large group of drugs that have been shown to decrease deaths in people with high blood pressure and coronary artery disease and are used to treat a number of disorders. They reduce heart activity but can also inhibit relaxation of smooth muscle in blood vessels, bronchi, and the gastrointestinal and genitourinary tracts.
The non‐selective beta blockers propranolol, timolol and pindolol are effective at all beta‐adrenergic sites in the body whereas some beta blockers are selective for the heart, such as atenolol and metoprolol.
Optimal therapy for people with either coronary artery disease or hypertension and intermittent claudication is controversial. This is because of the presumed peripheral blood flow consequences of beta blockers, leading to worsening of symptoms.
There is currently no evidence from randomised controlled trials that beta blockers adversely affect walking distance in people with intermittent claudication and beta blockers should be used with caution if clinically indicated. The review authors identified six randomised controlled trials that involved a total of only 119 people with mild to moderate peripheral arterial disease. The beta blockers studied were propranolol, pindolol, atenolol and metoprolol. None of the trials showed a clear worsening effect of beta blockers on time to claudication, claudication and maximal walking distances measured on a treadmill, calf blood flow, calf vascular resistance and skin temperature when compared with placebo. The trials did not report any adverse events or issues regarding taking the medication with the beta blockers studied.
Most of the trials were over 10 years old, reported on between 1980 and 1991. All were small and of poor quality. The drugs were administered for a short period of time (10 days to two months) and most of the outcome measures were reported in single studies. Additional drugs, calcium channel blockers and combined alpha and beta blockers, were also given in some of the trials.
