Coronary Exercise Hyperemia Is Impaired in Patients with Peripheral Arterial Disease

Abstract

Peripheral arterial disease (PAD) is an atherosclerotic vascular disease that affects over 200 million people worldwide. The hallmark of PAD is ischemic leg pain and this condition is also associated with an augmented blood pressure response to exercise, impaired vascular function, and high risk of myocardial infarction and cardiovascular mortality. In this study, we tested the hypothesis that coronary exercise hyperemia is impaired in PAD. Twelve patients with PAD and no overt coronary disease (65±2years, 7 men) and 15 healthy control subjects (64±2years, 9 men) performed supine plantar flexion exercise (30 contractions/min, increasing workload). A subset of subjects (n=7 PAD, n=8 healthy) also performed isometric handgrip exercise (40% of maximum voluntary contraction to fatigue). Coronary blood velocity in the left anterior descending artery was measured by transthoracic Doppler echocardiography; blood pressure and heart rate were monitored continuously. Coronary blood velocity responses to 4min of plantar flexion exercise (PAD: Δ2.4±1.2, healthy: Δ6.0±1.6cm/sec, P=0.039) and isometric handgrip exercise (PAD: Δ8.3±4.2, healthy: Δ16.9±3.6, P=0.033) were attenuated in PAD patients. These data indicate that coronary exercise hyperemia is impaired in PAD, which may predispose these patients to myocardial ischemia.