Buttock Claudication and Normal ABI
A 67-year-old man presents to the clinic complaining of cramping buttock pain after walking a few blocks. The pain is relieved after several minutes of rest. He also complains of being unable to achieve a firm erection for the last 6 months, despite having increased libido. His past medical history includes hypertension, diabetes and dyslipidemia, which have been treated appropriately. He smokes 2 packs/day for the last 40 years. His vital signs are normal, except for a slightly increased blood pressure. On physical examination, his abdomen is normal. He has normal pulses throughout. Both of his lower limbs and feet are well perfused and warm. No pain is elicited during passive movement of his legs relative to his hips. His resting ankle-branchial index (ABI) is 1.0 and it does not change after exercise. Neurological examination is normal.
Which of the following is the most likely diagnosis?