Which of the following findings in a 66-year-old man is most indicative of peripheral arterial disease?

The most indicative finding of peripheral arterial disease (PAD) in a 66-year-old man is thinning skin on the ankles. This condition is a result of decreased blood flow due to narrowed or blocked arteries, which is characteristic of PAD. Reduced circulation leads to a lack of oxygen and nutrients that are crucial for maintaining skin integrity, resulting in thinning skin. This finding also reflects chronic changes associated with long-term arterial insufficiency, which can accelerate as a person ages, particularly in individuals with other risk factors like diabetes, smoking, or hypertension.

While other signs can suggest vascular issues, thinning skin specifically points to the chronic effects of poor circulation over time. Thickened, discolored skin around the ankles and painless ulcers can occur in various conditions, including venous insufficiency or neuropathy, but they are not as direct indicators of PAD. Pain in the feet after walking (claudication) is more characteristic of intermittent claudication than just peripheral arterial disease without any associated symptoms of critical ischemia. Thus, while those findings can be relevant in a comprehensive assessment, thinning skin on the ankles directly correlates with the hallmark effects of inadequate arterial blood supply.