INTRODUCTION AND DEFINITIONS

According to the 2007 Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II), acute limb ischemia is defined as a sudden decrease in limb perfusion that causes a potential threat to limb viability (manifested by ischemic rest pain, ischemic ulcers, and/or gangrene) in patients who present within two weeks of the acute event [1]. Patients with similar manifestations who present later than two weeks are considered to have chronic limb ischemia.

The management of acute arterial occlusion remains a challenge for vascular specialists. Surgical thromboembolectomy and bypass grafting were the mainstays of therapy for many years [2]. Subsequently, thrombolytic therapy and percutaneous transluminal angioplasty (PTA) have become treatment options for selected patients.

Despite these advances, the morbidity, mortality, and limb loss rates from acute lower extremity ischemia remain high. Thus, regardless of the treatment modality used, early diagnosis and rapid initiation of therapy are essential in order to salvage the ischemic extremity.

The major causes and management approaches to acute limb ischemia will be reviewed here. Issues related to chronic limb ischemia (ie, similar manifestations in patients who present more than two weeks after symptom onset) are discussed separately. (See "Clinical manifestations and evaluation of chronic critical limb ischemia" and "Treatment of chronic lower extremity critical limb ischemia".)

ETIOLOGY

Acute arterial occlusion can be the result of an embolus dislodged from a distant source, acute thrombosis of a previously patent artery or graft, or direct trauma to an artery. Common etiologies for each of these mechanisms are presented in the table (table 1).