ARTERIOSCLEROSIS OBLITERANS



Arteriosclerosis obliterans refers to athero­sclerotic narrowing of large and medium-sized ar­teries. It most commonly involves arteries sup­plying the lower extremities, mostly the superficial femoral artery, the aortoiliac area, and the popliteal artery. It is the leading cause of ob­structive peripheral arterial disease in patients after the age of 30 and more common in males and in diabetics. The process is often segmental, and there may be areas of normal or nearly normal vessel between areas of severe involvement. Symptoms may occur at rest but are usual with exertion and are due to decreased perfusion of the tissues distal to the obstruction.

Intermittent claudication is most common and is characterized by cramping, pain, and fatigue in muscles upon exercise, relieved promptly with rest. It often occurs in the calf muscles in patients with femoral artery disease, but the site of clau­dication may be higher, for example, in the low back, buttocks, or thigh in patients with more proximal arterial obstruction. Rest pain is a sign of severe vascular compromise; it usually has a stocking-like distribution and is often worse at night. The patient also may complain of coldness, numbness, and paresthesias. Diminished or ab­sent pulses help localize the obstruction. Bruits can often be heard over the aorta and iliac or fe­moral arteries. Signs of limb ischemia include coolness, pallor, cyanosis, shiny dry skin with ab­sence of hair, nail changes, and prolonged venous filling time when an elevated extremity becomes dependent. Localized ulcerations and gangrene may occur. Aortoiliac obstruction may produce a syndrome of intermittent claudication of the low back, buttocks, or thighs along with atrophy of the lower extremities, hypertension of the upper ex­tremities, and sometimes impotence (Leriche’s syndrome). The symptoms of claudication may re­main stable over a very long time period. Many of these patients eventually die from other com­plications of atherosclerosis. Obstruction at the origin of the subclavian artery can cause “subcla­vian steal,” i.e., reversal of flow in the ipsilateral vertebral artery with arm exertion.

The patient with intermittent claudication but normal appearance of his extremity should be treated without surgery. Exercise is advised (but to be discontinued once pain occurs) and may gradually increase the patient’s exercise duration. The patient should avoid tobacco and drugs that decrease peripheral blood flow (for example, beta blockers). The patients should protect their ex­tremities from cold temperature and trauma, and the skin should be cared for carefully with special attention to any apparently minor infections or ulcers. Toenail trimming must be done carefully. Surgery is indicated in patients with progressive claudication that interferes with their lifestyle or with the development of ischemic signs or symp­toms at rest. Doppler examination can localize and quantitate obstruction fairly reliably. Arteri­ography is necessary if surgical intervention is contemplated. Surgery usually involves a saphen­ous bypass graft across the area of stenosis. Per­cutaneous transluminal balloon angioplasty of discrete lesions is feasible and appears to be as­sociated with favorable long-term patency. Va­sodilating drugs have little or.no efficacy in the treatment of arteriosclerosis obliterans and may even decrease blood flow to ischemic areas. Am­putation of the affected limb may be necessary in patients in whom gangrene occurs.