Test Identification: Pedal Plantarflexion ABI Test
The test you are describing is the pedal plantarflexion ankle-brachial index (ABI) test, used to diagnose popliteal artery entrapment syndrome (PAES) and peripheral arterial disease (PAD).
Test Description and Positioning
- The patient lies supine (lying down) with the knee flexed at approximately 45 degrees 1.
- Active plantar flexion (pointing the foot downward) is then performed to provoke arterial compression or occlusion 1.
- This maneuver causes compression of the popliteal artery by abnormal musculotendinous structures, producing symptoms or demonstrable vascular changes 1.
Clinical Application
Primary Use in PAES Diagnosis
- The pedal plantarflexion test is specifically designed to identify dynamic arterial deviation and/or occlusion during active plantar flexion in patients with suspected popliteal artery entrapment syndrome 1.
- Real-time ultrasound duplex Doppler during plantar flexion allows visualization of flow dynamics and vessel caliber changes, making it paramount in diagnosing PAES 1.
- MR angiography can evaluate vascular abnormalities and dynamic changes in the popliteal artery during plantar flexion, though patients may struggle to maintain steady forced plantar flexion throughout lengthy MR sequences 1.
Alternative Use as Exercise ABI Test
- The American College of Cardiology/American Heart Association guidelines note that the pedal plantarflexion ABI test is a reasonable alternative to treadmill exercise testing when a treadmill is not available, as results correlate well with treadmill ABIs 1.
- This test is performed in patients with exertional non-joint-related leg symptoms and normal or borderline resting ABI (>0.90 and ≤1.40) to evaluate for PAD 1.
Important Clinical Distinction
This test should not be confused with the straight leg raise (SLR) test, which is performed with the patient supine and the leg raised with the knee extended to evaluate for lumbar radiculopathy and nerve root compression 2, 3, 4. The SLR test involves hip flexion without knee flexion and does not involve plantar flexion as the primary provocative maneuver.