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Acute lower extremity ischemia remains a common vascular disease with considerable associated morbidity, limb loss, and mortality. Both arterial embolism and thrombosis are recognized causes of acute limb ischemia. It is imperative that a distinction between the two be made preoperatively because this guides the appropriate approach to therapy.
Surgical embolectomy remains the treatment of choice in managing most cases of acute embolic limb ischemia because it offers more rapid restoration of blood flow in comparison to catheter-directed thrombolysis. Time often becomes critical when considering the near absence of well-developed arterial collaterals in acute arterial macroembolization, when compared to in-situ thrombosis of chronic vascular occlusive disease. Additionally, in settings of acute limb ischemia, embolectomy is highly protective against amputation and, potentially, mortality.
Catheter-based intervention, first introduced by Fogarty in 1963, simplified the surgical technique of embolectomy. Although the technical details have not evolved dramatically since that time, a number of additional catheter options and adjuncts have been developed to effectively manage residual thrombus and underlying chronic disease.
Patients who come to the hospital with acute limb ischemia require a thorough history and physical examination. Embolism should be suspected with a history of atherosclerotic or valvular heart disease, proximal arterial aneurysm, cardiac arrhythmia, and preceding trauma (iatrogenic or otherwise). Patients with embolic occlusion complain of acute symptom onset. They typically do not support a history of claudication or rest pain and have a normal contralateral pulse. The exception to this is the patient who comes to the hospital with aortic saddle embolism, paraplegia, and loss of bilateral femoral pulses. Symptom duration is important, and one should clinically categorize and document the ischemic limb as salvageable or not based on baseline motor, sensory, and Doppler examination. Physical examination should indicate the level of arterial occlusion, because signs of ischemia are often most pronounced one joint distal to the level of occlusion.
Upon arrival at the hospital, patients with acute limb ischemia should receive heparin to prevent thrombus propagation and maintain collateral patency, reducing the extent of ischemic injury. Additionally, the documented antiinflammatory effects of heparin protect some against ischemia-reperfusion injury. Appropriate and indicated medical resuscitation should be achieved if possible preoperatively (i.e., correcting any malignant arrhythmia, acidosis, or metabolic derangement). Noninvasive duplex imaging can efficiently aid in diagnosis and operative planning. Arteriography should be considered in patients with Rutherford class IIA disease, especially if the diagnosis of embolism is not certain.
Although femoral and brachial embolectomy may be performed with local anesthesia, distal exposures and certain adjunctive measures can require general anesthesia. Any invasive intraoperative monitoring (i.e., central venous catheterization, pulmonary artery catheterization, transesophageal echocardiogram) should be considered on a case-by-case basis as determined by medical comorbidities. Arterial line placement facilitates intraoperative surveillance of the activated clotting time and allows close blood pressure monitoring, which can become labile at the time of reperfusion.
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