False Normalization of Ankle Brachial Index: A Case of Lower Extremity Peripheral Arterial Disease with Normal Ankle-Brachial Index

Abstract

Screening for lower extremity peripheral arterial disease (PAD) is essential in assessing a patient’s risk of cerebrovascular disorders. The ankle-brachial index (ABI) is widely used as a screening tool for PAD, but it can produce falsely normalized results due to factors like artery calcification and collateral vessels. We report a patient with normal ABI but confirmed lower extremity PAD through ultrasound and computed tomography (CT). This case shows the limitation of ABI for PAD diagnosis. Additional tests, such as CT or ultrasound, should be considered when PAD is suspected, even if the ABI is normal.