Sudden in Surgery — 68yo Man | Vascular Surgery | SMLE Q#5911

A 68-year-old man with a 10-year smoking history and intermittent left calf claudication after walking 200 m presents with sudden, severe left leg pain for 3 hours that began at rest and rapidly worsened. He was recently diagnosed with atrial fibrillation and is not on anticoagulation. The left leg is pale, cold, and very tender below the knee with decreased foot sensation and weakness of ankle dorsiflexion. Femoral pulse is present, but popliteal and pedal pulses are absent; capillary refill is markedly delayed. No skin blistering or gangrene is present. In the ED, IV unfractionated heparin is started. What is the most appropriate next step in management?