Objective: Large artery stiffening leads to an increase in cardiovascular risk and organ damage of the kidneys, brain or the heart. Biomarkers that allow for early detection of this phenomenon are a point of interest in research, with pulse-wave velocity (PWV) having been proven useful in predicting and monitoring arterial stiffness. We previously introduced a laser doppler vibrometry (LDV) prototype which can measure carotid-femoral PWV (cfPWV). In this work, we assesss the feasibility of using the same device to infer heart-carotid pulse-transit time (hcPTT) as a first step towards measuring heart-carotid PWV (hcPWV). The advantage of hcPWV over cfPWV is that the ascending aorta, which is the most distensible segment of the aorta contributing most to total arterial compliance, is included in the arterial pathway.

Approach: Signals were simultaneously acquired from a location on the chest (near either the base or the apex of the heart) and the right carotid artery for 100 patients (45% female). Fiducial points on the heart waveforms are associated with opening and closure (second heart sound; S2) of the aortic valve, which can be combined with, respectively, the foot and dicrotic notch of the carotid waveform to retrieve hcPTT. Considering two distinct heart-signal measurement sites, four hcPTT estimations are evaluated in about 94% of all measurements.

Main results: Correlations between these and known predictors of arterial stiffness i.e. age, blood pressure and cfPTT via applanation tonometry indicated that combining S2 from a heart- measurement site located at the base of the heart, with the carotid dicrotic notch yields hcPTT providing convincing correlations with known determinants of arterial stiffness (ρ = 0.377 with age).

Significance: We conclude that LDV may provide a corollary biomarker of arterial stiffness, encompassing the ascending aorta.

Keywords: Arterial Stiffness; Biosignal Processing; Heart-Carotid Pulse Transit Time; InSiDe Horizon 2020; Laser Doppler Vibrometry; Sphygmocor.

Creative Commons Attribution license.

目标: 大动脉硬化会导致心血管风险增加和肾脏、大脑或心脏等器官的损伤。能够早期检测这一现象的生物标志物是研究中的一个重点，脉搏波速度（PWV）已被证明在预测和监测动脉僵硬度方面非常有用。我们之前介绍了一种激光多普勒测振仪 (LDV) 原型，它可以测量颈-股 PWV (cfPWV)。在此项工作中，我们评估了使用同一设备推断心-颈脉冲传递时间（hcPTT）的可行性，这是迈向测量心-颈 PWV（hcPWV）的第一步。hcPWV 相比 cfPWV 的优势在于它包括升主动脉，这是最具弹性的主动脉段，对总体动脉顺应性贡献最大。

方法: 从100名患者（女性占45%）的胸部位置（心脏基部或尖端附近）和右侧颈动脉同时采集信号。心电波形上的地标点与主动脉瓣开启和关闭（第二心音；S2）相关联，可以分别结合颈动脉波形中的足点和二支点来获取 hcPTT。考虑到两个不同的心脏信号测量位置，大约94%的所有测量中评估了四种hcPTT估计方法。

主要结果: 这些与已知的动脉僵硬度预测因子（即年龄、血压和通过压平多普勒检测到的cfPTT）之间的相关性表明，结合位于心脏基部的心脏测量位置处的S2信号以及颈动脉二支点，可以获取提供令人信服的相关性的hcPTT结果（与年龄的ρ值为0.377）。

意义: 我们得出结论，LDV 可能会提供一种包括升主动脉在内的动脉僵硬度的伴随生物标志物。

关键词: 动脉硬化；生物信号处理；心-颈脉冲传递时间；InSiDe 欧盟地平线2020；激光多普勒测振仪；Sphygmocor。