A 72-year-old man with hypertension and hyperlipidemia presents with sudden onset of severe pain in the left leg, pallor, pulselessness, and coldness. On examination, the left foot is mottled and cyanotic; femoral pulse is absent on the left. Right femoral pulse is palpable. He denies recent trauma. Doppler ultrasound shows no flow in the left superficial femoral artery. What is the most likely diagnosis?