Beat-to-beat and spectral analyses of the noninvasive radial pulse and laser-Doppler signals in patients with hypertension

Article type: Research Article

Authors: Liu, Ju-Chi^{a; b; c; 1} | Hsu, Yi-Ping^{b; 1} | Zhu, Jia-Cheng^d | Hao, Wen-Rui^{a; b; 2} | Yang, Tsung-Yeh^{a; b; 2} | Sung, Li-Chun^{a; b; c; 3} | Kao, Pai-Feng^{a; b; c; 3} | Hwang, Jaulang^{e; *} | Hsiu, Hsin^{d; f; *}

Affiliations: [a] Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan | [b] Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan | [c] Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan | [d] Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan | [e] Department of Biochemistry and Molecular Cell Biology, School of Medicine, Taipei Medical University, Taipei, Taiwan | [f] Biomedical Engineering Research Center, National Defense Medical Center, Taipei, Taiwan

Correspondence: [*] Corresponding author: Hsin Hsiu, PhD and Jaulang Hwang, PhD., No.43, Section 4, Keelung Road, Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan. Tel.: +1 886 22730 3730; Fax: +1 886 2 2730 3733; E-mail: hhsiu@mail.ntust.edu.tw.

Note: [1] These authors contributed equally to this work as first authors.

Note: [2] Wen-Rui Hao and Tsung-Yeh Yang: equal contribution as 4th author.

Note: [3] Li-Chun Sung and Pai-Feng Kao: equal contribution as 6th author.

Abstract: This study performed beat-to-beat and spectral analyses of 20-minute skin-surface laser-Doppler-flowmetry (LDF) and radial blood-pressure-waveform (BPW) signals in order to compare the blood-flow perfusion condition and regulatory mechanisms between essential-hypertension (EHT) patients and aged-matched control subjects. Beat-to-beat LDF analyses yielded the pulse width (PW), AC-to-DC ratio (AD), and their corresponding variability indices (coefficients of variation [CVs]). The relative energy contributions (RECs) of five characteristic frequency peaks (defined as FR1–FR5) were also calculated. Spectral BPW analysis obtained the amplitude proportion (Cn) and phase angle (Pn) of each harmonic component n. PW, AD, AD_CV, and REC of FR2 were significantly smaller in the EHT group than in the control group. Regarding BPW indices, C1, C2, C4, and C5 were significantly larger and P2–P8 were significantly smaller in EHT patients than in controls. The present results indicate that BPW and LDF indices can be used to evaluate the blood-flow perfusion efficiency and microcirculatory regulatory activities in EHT. Sex differences were found, with the effects being more prominent in female patients. These findings may be partly attributable to impairment of endothelial and neural regulatory functions. The present findings might aid the development of new noninvasive methods for reducing the risk of EHT-induced damage.

Keywords: Essential hypertension, laser Doppler, beat-to-beat, spectral analysis, pulse

DOI: 10.3233/CH-201056

Journal: Clinical Hemorheology and Microcirculation, vol. 79, no. 3, pp. 365-379, 2021