Medical Therapy in Peripheral Artery Disease

T he epidemiology of peripheral artery disease (PAD) is well described and related to age and, in particular, the risk factors of diabetes mellitus and smoking.Recent data from the National Health and Nutrition Examination Survey found a 5.9% prevalence in subjects Ն40 years of age resulting in an estimated prevalence of 7.2 million affected individuals in the United States. 1 These subjects have a significant increased risk of all-cause mortality because of the underlying atherosclerotic disease process and general undertreatment of PAD risk factors. 2 There is a wide spectrum of clinical manifestations for PAD: (1) the completely asymptomatic patient found to have PAD from a screening ankle-brachial index (ABI), (2) atypical leg symptoms associated with an exercise limitation, (3) classic intermittent claudication, and (4) ischemic pain and ulceration in the lower extremity from chronic limb ischemia.However, despite the level and degree of limb symptoms, even asymptomatic persons with PAD have a greatly reduced functional capacity.This suggests that occlusive disease in the lower extremity is associated with reduced exercise capacity and functional status regardless of the symptomatic state.As noted above, symptomatic and asymptomatic PAD is associated with an increased risk for morbidity and mortality, and for impairment of quality of life, as well.A prospective cohort in subjects Ͼ65 years of age found a similar high ischemic risk in symptomatic and asymptomatic adults with PAD. 3 Pooled data from 11 studies in 6 countries found that PAD, defined by a an ABI of Ͻ0.90 was associated with an increased risk of subsequent all-cause mortality (relative risk 1.60), cardiovascular mortality (relative risk 1.96), coronary heart disease (relative risk 1.45), and stroke (relative risk 1.35) after adjustment for age, sex, conventional cardiovascular risk factors, and prevalent cardiovascular disease.4 The treatment of PAD has evolved over the past decade to include a broad approach, focusing on the reduction of adverse cardiovascular events, improving symptoms in claudication, and preventing tissue loss in critical limb ischemia.5 Because quality of life is severely limited in these subjects, great emphasis is placed on ameliorating symptoms and reducing the risk of PAD progression.