What symptom is a reliable sign of arterial insufficiency in a 75-year-old female patient?

Calf pain with walking is a classic symptom of arterial insufficiency, specifically linked to a condition known as claudication. In older adults, reduced blood flow to the muscles, particularly in the lower limbs, often leads to pain during physical activity, such as walking. This pain is typically described as cramping or aching and occurs because the muscles require more oxygen than the compromised arterial supply can provide, especially during exertion.

This symptom can help differentiate arterial insufficiency from other conditions, as it is specifically related to the demand for increased blood flow during activities. Other factors, such as rest or slowing down, usually relieve the pain, further indicating its vascular origin.

In the context of the other options, lower extremity edema may present in different conditions, including venous insufficiency or heart failure, but does not directly indicate arterial insufficiency. Numbness in the lower extremities could relate to various problems, such as neuropathy or peripheral arterial disease, but it is not as specific an indicator as calf pain. Itching in the lower extremities may result from skin conditions or poor circulation but, again, is not a reliable sign of arterial insufficiency.