Beta blockade and intermittent claudication.

Abstract

The aim of the present study was to evaluate whether beta blockade presents a risk of intermittent claudication and how it affects the walking capacity and lower limb haemodynamics in patients with intermittent claudication. The study was divided into six parts: A case-control study with 55 pairs, cases with hypertension and intermittent claudication and controls with hypertension only, matched for age, sex, place of residence, and time of examination, all without coronary heart disease, which is a known confounding factor. An open controlled study on the effect of withdrawal of beta blockade on walking capacity of 28 patients with intermittent claudication. A placebo-controlled double-blind crossover study on the effect of antihypertensive treatment on the walking capacity of 14 patients with intermittent claudication. Three placebo-controlled double-blind crossover studies on the effect of propranolol, metoprolol, pindolol, labetalol, and/or methyldopa on calf blood flow in 34 hypertensive subjects without peripheral arterial disease and in altogether 21 patients with intermittent claudication. Walking capacity was measured on a treadmill. Calf blood flow was measured with strain gauge plethysmography by the venous occlusion technique. The case-control comparison showed that beta blockers were used as often by patients with intermittent claudication as by controls. Walking capacity increased during the first month of the open controlled study irrespective of whether the beta blockade was withdrawn or continued. There was no difference in this respect between the various types of beta blockers. Antihypertensive treatment with metoprolol or methyldopa did not affect walking capacity. Resting calf blood flow was unaffected by propranolol or metoprolol, regardless of the presence or absence of peripheral arterial disease, as well as by pindolol, labetalol, or methyldopa in patients with intermittent claudication. During reactive hyperaemia, propranolol and metoprolol reduced flow in patients without peripheral arterial disease. Propranolol also reduced hyperaemic blood flow in the limb with less or no symptoms in patients with intermittent claudication. None of the active drugs decreased the hyperaemic flow consistently in the limb with the stronger symptoms. In a comparison of haemodynamic effects between the drugs, calf blood flow at rest was higher after pindolol than after propranolol and hyperaemic flow of the better limb was higher after pindolol than after propranolol and labetalol.(ABSTRACT TRUNCATED AT 400 WORDS)