The Pulse of Progress: James S.T. Yao, MD, PhD's Breakthrough Ankle-Brachial Index and Biography.

Affecting over 230 million people worldwide, peripheral artery disease (PAD) is a chronic disease that can lead to significant functional deficits, amputation, and death. Early detection of PAD is critical as risk factor modification and medical management can slow disease progression. It was not until the mid-twentieth century that arterial reconstruction surgery was developed for PAD but even then there was no tool to objectively and reliably assess postoperative success. At the beginning of his career, James S.T. Yao, M.D., Ph.D., published groundbreaking work on the ankle-brachial index (ABI) as a reliable diagnostic tool that would change the field of vascular surgery forever. In 1969, Yao pioneered the ABI, which objectively assessed the presence and severity of PAD by comparing a patient's ankle and brachial systolic blood pressures. His landmark paper revealed that the ABIs of patients with PAD correlated with clinical severity, and patients with successful revascularization experienced an increase in ABI. These measurements were effective and accessible, requiring minimal equipment and training to perform. Over 50 years later, the ABI is still recognized as the leading diagnostic tool for PAD by current American Heart Association, American College of Cardiology, and Center for Disease Control guidelines.