A 77-year-old male is evaluated for a 4-week history of progressive left foot pain that occurs at rest. He also has calf muscle pain that worsens when he ambulates. The ankle-brachial index (ABI) is 0.62 on the right and unobtainable on the left. Which of the following is the most likely diagnosis based on these findings?
a) Peripheral artery disease (PAD)
b) Acute arterial thrombosis
c) Acute compartment syndrome
d) Chronic venous insufficiency
