Peripheral arterial disease (PAD) is a highly prevalent medical condition. Patients with PAD are usually diagnosed on the basis of the ankle-brachial index. The ankle-brachial index is the ratio of ankle pressure to arm pressure based on measurement of blood pressures in the arms and legs using a Doppler device. The need for dedicated equipment and trained personnel, along with the time required to perform the test, have been identified as barriers to widespread implementation of ankle-brachial index screening. The use of automated oscillometric devices for blood pressure measurement and determination of the ankle-brachial index has been applied with variable success. It will be beneficial to investigate a reliable oscillometric-based procedure that can accurately measure leg pressures for the ankle-brachial index across the entire spectrum of PAD severity.

The purpose of this study is to determine the optimal oscillometric-based technique for estimation of Doppler-derived systolic arm and ankle blood pressures for calculation of the ankle-brachial index in patients with and without PAD.

Subjects with suspected arterial disease in the non-invasive lab will be enrolled. Arm, ankle, and toe pressure measurements will be made in the supine position using Doppler, oscillometric methods, and photoplethysmographic sensor. Arm and ankle pressures from a subset of subjects will be obtained in both seated and supine positions. The ankle-brachial index and toe-brachial index will be calculated.

Inclusion Criteria:

• Patient at least 50 years of age
• Ambulatory outpatient
• Referred to non-invasive Vascular Laboratory for evaluation of suspected arterial disease.

Exclusion Criteria:

• Unable to give informed consent
• Unable to lie supine for at least 15 minutes

Patients presenting to Cleveland Clinic's non-invasive vascular lab