The most appropriate management for this patient with an ischemic but viable extremity (severe acute limb ischemia) is urgent angiography to define the anatomic level of occlusion and assess appropriate treatment options, which may include surgical or percutaneous revascularization or thrombolytic therapy in selected patients. He has several risk factors for atherosclerotic peripheral arterial disease (PAD), and the claudication that he has experienced for the past year has progressed to severe resting limb pain. The limb is viable as indicated by the presence of pain, slow but present capillary refill, and the presence of Doppler vascular signals. Acute ischemia can be caused by remote embolization but may also result from in-situ thrombosis. Because of this, anticoagulation is crucial once a diagnosis of acute arterial occlusion has been made by history and physical examination. The next step in management is to further evaluate the limb ischemia and plan for treatment. Digital subtraction angiography provides the most helpful information and is the preferred imaging modality for acute limb ischemia; delaying angiography could lead to limb necrosis and loss of limb functioning.

Catheter-directed thrombolytic therapy may be an option in some patients with acute limb ischemia with a viable or marginally threatened limb as an alternative to a surgical approach, particularly if the duration of acute limb ischemia is less than 1 day. However, initiating thrombolytic therapy in this patient before further evaluation of the nature of the occlusion would not be appropriate.

For a nonviable extremity, surgical amputation without angiography is indicated because of the increased risk of tissue necrosis and infection. However, this patient's foot shows evidence of viability, making immediate amputation inappropriate.

Warfarin has not been shown to be an effective therapy for managing stable PAD, and although anticoagulation is indicated in managing acute limb ischemia pending further evaluation, initiation of long-term anticoagulation with warfarin in this patient with a viable but threatened limb without further intervention would not be appropriate.