In a diabetic patient with tibial arterial calcification, how can the ankle/arm index be characterized?

In patients with diabetes who also have tibial arterial calcification, the ankle/arm index (AAI) can be characterized as potentially normal or falsely elevated. This is primarily due to the stiffness and calcification of the tibial arteries which can lead to elevated ankle pressures.

The AAI is a comparison of blood pressure in the ankle to that in the arm and is used to assess peripheral arterial disease (PAD). In instances where the arteries are calcified, as is often the case in diabetic patients, the Doppler waveform may not accurately reflect true hemodynamics because the calcified arteries do not compress easily, leading to misleadingly high ankle pressures. This can give a false impression of adequate blood flow, thus the index can appear normal or even elevated despite the presence of significant vascular disease.

Understanding this behavior of the AAI in the context of arterial calcification is crucial, as it can mislead clinicians in their assessment and management of patients with peripheral vascular concerns.