What is the expected change in ABI for abnormal patients after exercise?

In patients with abnormal ankle-brachial index (ABI) results, especially those indicative of peripheral artery disease (PAD), it is expected that the ABI will actually decrease after exercise. This is primarily due to the increased demand for blood flow by the muscles during physical activity, which leads to a further reduction in the already compromised blood supply through narrowed or blocked arteries.

When a patient with PAD exercises, the muscles require more oxygen and, consequently, more blood flow. If the peripheral arteries are severely narrowed, they cannot adequately supply the blood, resulting in claudication, which often manifests as pain or cramping in the legs. As a result, when measuring ABI immediately after exercise, the ankle pressures may not be able to compensate for the increased demand, leading to a decrease in the ABI value compared to the resting measurement. This contrast highlights the severity of arterial insufficiency and the responsiveness of the ABI test in identifying compromised vascular function under stress.

In contrast, an increase in ABI might be expected in healthy individuals or those without significant vascular obstruction, as their arteries can typically accommodate increased blood flow. A stable ABI might be considered in those with mild conditions or where no significant vascular issues exist. Lastly, fluctuations in ABI do not typically provide a reliable