OAP – Optical Arterial Pressure – Vascular Academy

OAP – Optical Arterial Pressure

Description

Optical Arterial Pressure is a measurement method to determine systolic blood pressure in either finger or toes. The Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease (TASC) recommends the determination of the systolic toe pressure for diagnosis of CLI (critical limb ischemia). It is also valuable in assessment of severe peripheral artery disease, particularly in patients with diabetes where measurement of ankle pressure and ABI is often unreliable (because of local stiffening of the arterial wall).

Measurement Principle

To record the necessary pressure values, toe cuffs are used for occluding the toe cuffs and optical PPG sensors for pulse wave recording are applied distally to the cuffs. The cuffs are then inflated to compress the toe arteries, thus flattening the PPG signal (arterial occlusion) and released continuously afterwards, until the first pulse wave oscillations can be recorded, which is then determined as the systolic toe pressure. The measurement procedure used to determine systolic finger pressure is identical.

A normal toe pressure is about 30 mmHg less than the ankle pressure. A systolic toe pressure of less than 30 to 50 mmHg suggests chronic limb ischemia, according to the recommendations of the TASC group.

Medical Applications

Patients with high (>1.4) or unclear ABI
Suspicion of digital arterial occlusions
Suspicion of Raynaud’s Syndrome or TOS (Thoracic Outlet Syndrome)
Patients at increased risk of Lower Extremity Peripheral Artery Disease (PAD):
- Aged ≥ 65 years
- Diabetes, Smoking, Hyperlipidemia, Hypertension, and other risk factors for atherosclerosis
- Family history of PAD or other known forms of atherosclerosis
Monitoring of vascular status pre- and post-intervention

Main Parameters

Parameter	Unit	Description
Toe Pressure	mmHg	Systolic toe pressure of less than 30 to 50 mmHg suggests chronic limb ischemia.
Finger Pressure	mmHg	Used to assess digital artery diseases, such as Raynaud’s Syndrome. There are no recommended reference values for pathologic measurements.
Skin Temperature	°C	Skin temperature on toes/fingers recorded by the probes on the optical sensors. Side differences of more the 3 °C should be observed.

Test Examples

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Table of Contents

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