Arteriolar Elasticity Measurement in the Fingertip Based on Photoplethysmographic Volume-Oscillometry: A New Approach to the Assessment of Vasomotor Functions in the Microvasculature

Ken-Ichi Yamakoshi; Peter Rolfe; Takehiro Yamakoshi

doi:10.1007/s13239-025-00772-3

Arteriolar Elasticity Measurement in the Fingertip Based on Photoplethysmographic Volume-Oscillometry: A New Approach to the Assessment of Vasomotor Functions in the Microvasculature

Cardiovasc Eng Technol. 2025 Jan 17. doi: 10.1007/s13239-025-00772-3. Online ahead of print.

Authors

Ken-Ichi Yamakoshi^{1

2

3}, Peter Rolfe^{4

5}, Takehiro Yamakoshi^{6

7}

Affiliations

¹ Department of Orthopedic Surgery, Showa University School of Medicine, Shinagawa, Tokyo, 142-8555, Japan.
² College of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan.
³ Department of Research and Development, Nonprofit Organization of Research Institute of Life Benefit, Sapporo, Hokkaido, 005-0006, Japan.
⁴ Department of Automatic Measurement and Control, Harbin Institute of Technology, No. 92 West Dazhi Street, Nan Gang District, Harbin, Heilongjiang Province, 150001, China.
⁵ Science and Technology, Oxford BioHorizons, 12 Park View Road, Berkhamsted, UK.
⁶ Department of Research and Development, Nonprofit Organization of Research Institute of Life Benefit, Sapporo, Hokkaido, 005-0006, Japan. takehiroy@me.com.
⁷ Institute of Liberal Arts and Science, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan. takehiroy@me.com.

PMID: 39825176
DOI: 10.1007/s13239-025-00772-3

Abstract

Purpose: Dysfunction of vasomotor reactions due to arteriolar smooth muscle causes serious adverse events, such as loss of hemodynamic coherence. This in turn can increase risks of cardiovascular-related diseases. A noninvasive and quantitative evaluation of microvascular disorder is therefore very important for early diagnosis and treatment. This paper describes a new approach to the assessment of vasomotor functions using the arteriolar elasticity measurement technique in the fingertip.

Methods: A recently developed device, modified to detect a photoplethysmogram with green light (gPPG) in arteriolar regions, allowed the measurement of arteriolar blood pressure (BP_ca.) and gPPG from a left index fingertip placed on an occlusive cuff of the device. Arteriolar stiffness and distensibility were analyzed as effective elasticity indices, as a function of arteriolar distending pressure derived by volume-oscillometry. Cold pressor tests to induce vasoconstriction were carried out whether appropriate elasticity changes could be obtained.

Results: Experiments using 6 healthy subjects were successfully made to obtain arteriolar elastic properties before and while immersing a right hand in cold water. The index-values of stiffness and distensibility showed, respectively, a considerable increase and decrease, clearly demonstrating the appropriate elasticity changes with vasoconstrictive reactions.

Conclusion: Although a further study using many subjects is needed, the results so far suggest that this method could easily provide important features to acquire quantitatively arteriolar elasticity together with BP_ca. and to assess vasomotor functions in the microvasculature. This convenient method appears useful for clinical practices and health management and promising also for screening cardiovascular-related diseases. (242/250 words).

Keywords: Arteriolar elasticity; Green light photoplethymography; Microvasculature; Noninvasive evaluation; Vasomotor function; Volume-oscillometry.