Final answer:
The rationale behind assessing the ankle-brachial index in a patient with renal disease is to diagnose peripheral artery disease (PAD).
Step-by-step explanation:
The rationale behind assessing the ankle-brachial index in a patient with renal disease is to diagnose peripheral artery disease (PAD). Peripheral artery disease is a condition in which there is a build-up of plaque in the arteries, leading to reduced blood flow to the extremities.
The ankle-brachial index compares the blood pressure at the ankle to the blood pressure at the upper arm. In PAD, the blood pressure at the ankle is typically lower than the blood pressure at the upper arm.
By determining the ankle-brachial index, the nurse can assess the severity of peripheral artery disease and plan appropriate interventions for the patient.