Final answer:
The Ankle-Brachial Index (ABI) is a noninvasive test for detecting Peripheral Arterial Disease (PAD) by comparing blood pressure measurements at the ankle and arm. In PAD, ankle blood pressure is usually lower than arm blood pressure, and plaques causing the condition contain cholesterol, calcium, and fibrous tissue.
Step-by-step explanation:
The test that is described in the question, which is used to measure blood pressure in the ankles and compare it with the blood pressure in the arms at rest and after exercise, is the Ankle-Brachial Index (ABI). It is a noninvasive test for patients with symptoms of Peripheral Arterial Disease (PAD). During the ABI test, blood pressure cuffs are placed on the patient's arm and ankle, and measurements are taken at rest and possibly after exercise to ascertain the severity of the blockage or constriction in the arteries.
Regarding peripheral artery disease, the blood pressure at the ankle is typically lower than the blood pressure at the upper arm. This is because PAD often results from atherosclerosis, which causes narrowing and blockages in the arteries, leading to decreased blood flow and pressure in the extremities, notably the ankles.
Three components of the plaque that can build up in arteries are cholesterol, calcium, and fibrous tissue. When this plaque accumulates in the arterial walls, it can lead to atherosclerosis, a primary underlying cause of PAD.