Acute Limb Ischemia

Abstract

Acute limb ischemia (ALI) is one of the most challenging conditions in vascular surgery and carries a high risk of amputation and mortality when treatment is delayed. Limb ischemia occurs when there is abrupt interruption of blood supply to an extremity because of either embolic or in situ thrombotic arterial or bypass graft occlusion. The goals of management include limb salvage, minimization of morbidity, and prevention of death. However, given that no objective markers of limb viability are currently available, the initial determination of whether a limb is likely to be viable must be made on clinical grounds. An early clinical evaluation is crucial for the diagnosis and identification of the underlying etiology of the ALI. As ALI is a clinical diagnosis, this review describes all aspects of the clinical evaluation as essential: patient history, staging of limb ischemia, and investigative studies. Atheromatous embolization is also discussed in depth. The characteristic signs of ALI may be summarized as the “six p’s”: pulselessness, pain, pallor, poikilothermia, paresthesia, and paralysis. Pain is the most common symptom in an ischemic limb and progresses along with the ischemia. As ischemia continues to progress, severe pain can be replaced by anesthesia of the limb, which can confound the examiner. Thus, pain should be documented with regard to severity, localization, and progression. ALI therapies covered are heparin therapy, thrombolytic therapy, thrombectomy, and surgical embolectomy and revascularization. The pathophysiology of limb ischemia is related to the progression of tissue infarction and irreversible cell death. Compared with other organs and tissues (e.g., the brain and the heart), the extremities are relatively resistant to ischemia. However, the various tissue types of which an extremity is composed have different metabolic rates. This review has 2 figures, 6 tables, and 165 references.