Evaluation of patients with peripheral vascular disease

Approximately 10% of people age >55 years have asymptomatic peripheral atherosclerotic disease (PAD), 5% have intermittent claudication (IC, the cardinal symptom), and 1% critical leg ischemia (rest pain or gangrene). In patients with IC, worsening occurs in approximately 16%, bypass surgery is required in approximately 7%, and amputation in approximately 4%. Disease progresses more frequently in diabetics and in tobacco smokers. Patients with PAD suffer increased cardiovascular morbidity related mainly to coronary artery disease with a mortality rate of approximately 30% after 5 years. Compared to patients without PAD, the relative risk of coronary death is approximately 6.6, overall cardiovascular mortality 5.9, and all-cause mortality 3.1. Pain at rest or ischemic gangrene indicates severe, often multilevel arterial occlusive disease and calls for aggressive management, which usually includes angiography and revascularization by percutaneous angioplasty or surgery. Critical limb ischemia results in some 150,000 amputations annually in the U.S., with perioperative mortality rates of 5-10% for below-knee and up to 50% for above-knee amputation because of comorbidities. Physical findings include trophic signs of ischemia, vascular bruits and peripheral pulse deficits. Ischemic ulcers usually involve the tips of the toes or the heel of the foot, and are typically painful on elevation and most bothersome at night. Ancillary diagnostic modalities begin with the ankle/arm systolic pressure index (ABI); a value <0.90 indicates PAD with significant prognostic implications. More precise assessment in the noninvasive vascular laboratory may involve a combination of segmental limb pressure measurements and pulse volume waveform recording, which is over 90% accurate for predicting the level and extent of PAD. Exercise testing enhances the value of these observations. Magnetic resonance imaging methods are emerging to characterize the arterial wall and atherosclerotic lesions. The diagnosis of PAD does not generally require invasive techniques, and most patients with IC do not need contrast angiography. Angiography is indicated for mapping of the extent and location of arterial pathology prior to revascularization.