Finger photoplethysmogram pulse amplitude changes induced by flow-mediated dilation

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Vascular Physiology

Background:

• Endothelial dysfunction is a key indicator of cardiovascular risk.
• Flow-mediated dilation (FMD) assessed via Doppler ultrasound is the standard method for evaluating endothelial function.
• Ultrasound is operator-dependent and requires specialized equipment.

Purpose of the Study:

• To compare the efficacy of finger photoplethysmogram pulse amplitude (PPG-AC) with Doppler ultrasound for assessing endothelial function.
• To evaluate PPG-AC as a rapid, non-invasive, and low-cost alternative to ultrasound for vascular function assessment.

Main Methods:

• High-resolution B-mode ultrasound of the brachial artery (BA) was performed before and after upper arm occlusion in 31 healthy and 52 at-risk subjects.
• Concurrent finger PPG signals were recorded from both index fingers.
• PPG-AC changes were compared with BA diameter changes (FMD) measured by ultrasound.

Main Results:

• Finger PPG-AC demonstrated a similar response pattern to brachial artery dilation following occlusion release.
• The peak PPG-AC was achieved significantly faster than peak FMD in both healthy and at-risk groups (P < 0.001).
• PPG-AC showed a comparable trend to FMD, indicating its utility in reflecting vascular changes.

Conclusions:

• Finger PPG-AC is a promising, rapid, and non-invasive technique for assessing peripheral vascular function.
• This method offers a low-cost, less operator-dependent alternative to traditional ultrasound-based FMD measurements.
• PPG-AC can be utilized for quick screening of vascular health and endothelial function.