Antithrombotic Therapy in Peripheral Arterial Occlusive Disease: Acute Extremity Arterial Insufficiency
Nontraumatic acute occlusion may be embolic or thrombotic. Arterial embolism is a common cause of acute arterial occlusion, and, in approximately 85% of cases, the emboli arise from a cardiac source. Cardiac causes include atrial fibrillation associated with valvular heart disease or mural thrombi in an infarcted left ventricle. Noncardiac causes of emboli include arterial aneurysms; atherosclerotic plaques, especially when ulcerated; recent vascular surgery; paradoxic emboli from venous thrombi in the lower extremities; and, rarely, arteritis or vascular trauma. Approximately two thirds of noncerebral emboli enter vessels of the lower extremity, and 50% of these obstruct the iliofemoral arterial segment; the remainder involve the popliteal and tibial vessels. The upper-extrem-ity and renal/visceral vessels each receive approximately 15% of emboli.
Thrombotic occlusions of arteries are usually associated with advanced atherosclerosis, and arteries often have preexisting and developed collateral blood supply. For this reason, final occlusion may not be a dramatic event and is sometimes silent; it is not an emergent process in most patients. Arterial occlusions most frequently involve the lower extremities. In the upper extremities, arterial occlusions are better tolerated because of rich collateral blood supply, and gangrene or ischemic rest pain is rare in the absence of distal embolization. Some patients with stable intermittent claudication will suddenly develop ischemic rest pain and have barely detectable Doppler arterial signals at the ankle. Allergy relief More info Many vascular surgeons fully heparin -ize these patients to prevent occlusion of marginal collateral beds and to prevent tissue necrosis while performing a thorough work-up for semielective vascular reconstruction. It is unknown whether heparin improves outcome in this circumstance.
Introduction of the Fogarty balloon catheter in 1963 dramatically altered the management of peripheral emboli. It reduced mortality from this disorder by nearly 50% and decreased the incidence of amputation by approximately 35%. In nearly all patients, prompt removal of emboli is indicated unless the patient is moribund, the involved extremity is gangrenous, or evidence of ischemia is advanced when the patient is first seen. With this approach, mortality is approximately 15%, and death is usually due to underlying cardiopulmonary disorders; limb salvage, even in elderly patients, ranges from 62 to 96%. Mortality is higher in patients with embolism than in patients with acute arterial thrombosis because severe cardiac disease is more common.