Carotid Local Pulse Wave Velocity Measurement using Dual- Element Accelerometric Patch Probe
01 Jul 2018-Vol. 2018, pp 4571-4574
TL;DR: An accelerometric patch probe with two microelectromechanical accelerometer sensors for local pulse wave velocity (PWV) measurement from the carotid artery is demonstrated and the potential application of the developed dual-accelerometric system in non-invasive, continuous cuffless BP measurement techniques is illustrated.
Abstract: In this work, we demonstrate an accelerometric patch probe with two microelectromechanical accelerometer sensors for local pulse wave velocity (PWV) measurement from the carotid artery. Dual acceleration plethysmogram (APG) signals were acquired from a small section of the artery by keeping the sensors at 32 mm apart. A custom analog front-end circuit (inter-channel delay $< 0.15$ ms) was used for reliable signal acquisition. Simultaneously acquired dual APG signals were processed in real-time and local PWV was evaluated in a beat-by-beat manner. A transversal study on a cohort of 15 volunteers (4 males, 11 females, mean age = $25.6 \pm 1.92$ years) was conducted to validate the developed prototype system. During the study, carotid local PWV and brachial blood pressure (BP) parameters were recorded from both sitting and standing posture. The absolute values of measured carotid local PWV were in the range of 3 m/s – 4.2 m/s (beat-to-beat variation $=$ 2.61% – 13.07%). Measured local PWV values significantly correlated with brachial systolic BP ($\textbf{R}^{\mathbf {2}} =$ 0.87) and diastolic BP ($\textbf{R}_{\mathbf {\, }}^{\mathbf {2}} \quad =$ 0.79). Logarithmic functions provided the best monotonic model for carotid local PWV versus brachial BP parameters for the recorded data points. The developed population-specific mathematical models were then used for cuffless evaluation of BP parameters from carotid local PWV. The root-mean-square error in the estimated systolic and diastolic pressure was 7.53 mmHg and 6.0 mmHg respectively. Study results illustrate the potential application of the developed dual-accelerometric system in non-invasive, continuous cuffless BP measurement techniques.
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01 Jan 2021
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TL;DR: The great challenge is to explore the new instrumental solutions that allow the PWV assessment with fewer approximations for an accurately evaluation and relatively inexpensive techniques in order to be used in the clinical routine.
Abstract: The great incidence of cardiovascular (CV) diseases in the world spurs the search for new solutions to enable an early detection of pathological processes and provides more precise diagnosis based in multi-parameters assessment. The pulse wave velocity (PWV) is considered one of the most important clinical parameters for evaluate the CV risk, vascular adaptation, and therapeutic efficacy. Several studies were dedicated to find the relationship between PWV measurement and pathological status in different diseases, and proved the relevance of this parameter. The commercial devices dedicate to PWV estimation make a regional assessment (measured between two vessels), however a local measurement is more precise evaluation of artery condition, taking into account the differences in the structure of arteries. Moreover, the current devices present some limitations due to the contact nature. Emerging trends in CV monitoring are moving away from more invasive technologies to non-invasive and non-contact solutions. The great challenge is to explore the new instrumental solutions that allow the PWV assessment with fewer approximations for an accurately evaluation and relatively inexpensive techniques in order to be used in the clinical routine.
214 citations
"Carotid Local Pulse Wave Velocity M..." refers background or methods or result in this paper
...2 m/s, which is consistent with the previous studies [1]....
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...Pulse wave velocity (PWV) is defined as the velocity at which the blood pulse waves propagate along the arterial tree [1]....
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...Two-point method for local PWV evaluation utilizes simultaneously acquired blood pulse signals from two distinct sites (separated by a known distance) of a short arterial segment [1]....
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TL;DR: This study illustrates that the simple equation PWV = dQ/dA gives estimates correlated to the PWV of the reference method, however, improvements in the basic measurements seem necessary to increase the precision of the method.
148 citations
"Carotid Local Pulse Wave Velocity M..." refers methods in this paper
...Local PWV is then evaluated as the ratio of change in flow and change in cross-sectional area (Q-A method) during a cardiac cycle [4]....
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TL;DR: A novel photoplethysmograph probe employing dual photodiodes excited using a single infrared light source was developed for local pulse wave velocity (PWV) measurement and the potential use of the proposed system in cuffless blood pressure techniques was demonstrated.
Abstract: Objective: A novel photoplethysmograph probe employing dual photodiodes excited using a single infrared light source was developed for local pulse wave velocity (PWV) measurement. The potential use of the proposed system in cuffless blood pressure (BP) techniques was demonstrated. Approach: Initial validation measurements were performed on a phantom using a reference method. Further, an in vivo study was carried out in 35 volunteers (age = 28 ± 4.5 years). The carotid local PWV, carotid to finger pulse transit time (PTTR) and pulse arrival time at the carotid artery (PATC) were simultaneously measured. Beat-by-beat variation of the local PWV due to BP changes was studied during post-exercise relaxation. The cuffless BP estimation accuracy of local PWV, PATC, and PTTR was investigated based on inter- and intra-subject models with best-case calibration. Main results: The accuracy of the proposed system, hardware inter-channel delay (<0.1 ms), repeatability (beat-to-beat variation = 4.15%–11.38%) and reproducibility of measurement (r = 0.96) were examined. For the phantom experiment, the measured PWV values did not differ by more than 0.74 m s−1 compared to the reference PWV. Better correlation was observed between brachial BP parameters versus local PWV (r = 0.74–0.78) compared to PTTR (|r| = 0.62–0.67) and PATC (|r| = 0.52–0.68). Cuffless BP estimation using local PWV was better than PTTR and PATC with population-specific models. More accurate estimates of arterial BP levels were achieved using local PWV via subject-specific models (root-mean-square error ≤2.61 mmHg). Significance: A reliable system for cuffless BP measurement and local estimation of arterial wall properties.
53 citations
"Carotid Local Pulse Wave Velocity M..." refers background or methods in this paper
...The signal-to-noise ratio (signals above 25 Hz was considered as noise) of the acquired signals was approximately 32 dB with peak-to-peak signal amplitude in the range of 20 mVPP – 35 mVPP, this was sufficient for local PWV evaluation [3]....
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...Therefore, DC subtraction circuits implemented using a JFET-input operational amplifier LF347 (Texas Instruments) were used to remove the DC components [3]....
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...It has been demonstrated that the local PWV obtained from superficial arteries can be potentially used to realize clinical diagnostic and wearable devices for cuffless evaluation of arterial blood pressure (BP) parameters [3]....
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TL;DR: In this paper, the authors presented a new protocol for local pulse wave velocity (PWV) measurement using dynamic MR sequences, which have a high temporal resolution (TR < 6 ms).
Abstract: The current study presents a new protocol for local pulse wave velocity (PWV) measurement using dynamic MR sequences, which have a high temporal resolution (TR < 6 ms). MR images were obtained at two positions along the common carotid artery, separated by a distance of 5 cm. In each phase of a MR series, carotid region was automatically extracted and then its area distension waveform could be obtained. Sixteen volunteers with no symptoms of cardiovascular diseases were studied. For local PWV estimation, three delay estimation principles were tested and produced the following values: intersecting tangents method (M1): 4.72 ± 1.40 m/s, second derivative method (M2): 4.94 ± 1.68 m/s and cross-correlation method (M3): 5.03 ± 1.17 m/s. The cross-correlation method showed a relative high reliability as its least standard deviation.
9 citations
"Carotid Local Pulse Wave Velocity M..." refers background in this paper
...PWV measurement made on a small arterial segment (local PWV) is a surrogate indicator for local evaluation of vascular conditions and provides the information regarding the elastic properties of the arterial walls [2]....
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01 May 2017
TL;DR: In-vivo validation study promising the potential use of the developed accelerometer probe for cuffless evaluation of BP parameters and heartrate as a confounder of local PWV assessment was obtained.
Abstract: The velocity of propagation of arterial blood pulse signals obtained from a smaller arterial section referred as local pulse wave velocity (PWV) is an index of cardiovascular events of a particular artery. In this work, we introduce a novel design of accelerometer probe for local PWV measurement from the carotid artery. The proposed probe was developed using highly sensitive dual MEMS accelerometers. The probe design with tiny dual element sensors was capable of simultaneously acquiring acceleration signals generated due to arterial wall displacement towards the skin surface. Measurements were performed from carotid artery over a smaller arterial section of length 24 mm. The ability of the probe to acquire continuous arterial waveforms and cycle-to-cycle local PWV measurement was verified by conducting an in-vivo test in multiple subjects (11 volunteers aged between 20 – 60 years) under controlled settings. Reliable as well as repeatable signals (maximum beat-to-beat variation was less than 13%) and carotid PWV measurement with high reproducibility was obtained. A correlation examination of the local PWV with heartrate and BP was conducted during the same study. A statistically significant correlation was observed with the correlation coefficient greater than 0.78 for BP parameters and 0.66 for heartrate. In-vivo validation study promising the potential use of the developed accelerometer probe for cuffless evaluation of BP parameters and heartrate as a confounder of local PWV assessment was obtained.
6 citations
"Carotid Local Pulse Wave Velocity M..." refers methods in this paper
...The overall performance of dual-element accelerometric patch probe was superior to our initial prototype design [5]....
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...An initial prototype system of the proposed technique was reported in [5]....
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