Technical Validation of ARTSENS–An Image Free Device for Evaluation of Vascular Stiffness
12 May 2015-IEEE Journal of Translational Engineering in Health and Medicine (IEEE)-Vol. 3, pp 1900213-1900213
TL;DR: The feasibility of the novel ARTSENS device in performing accurate in vivo measurements of arterial stiffness is verified, a device for image free, noninvasive, automated evaluation of vascular stiffness amenable for field use.
Abstract: Vascular stiffness is an indicator of cardiovascular health, with carotid artery stiffness having established correlation to coronary heart disease and utility in cardiovascular diagnosis and screening. State of art equipment for stiffness evaluation are expensive, require expertise to operate and not amenable for field deployment. In this context, we developed ARTerial Stiffness Evaluation for Noninvasive Screening (ARTSENS), a device for image free, noninvasive, automated evaluation of vascular stiffness amenable for field use. ARTSENS has a frugal hardware design, utilizing a single ultrasound transducer to interrogate the carotid artery, integrated with robust algorithms that extract arterial dimensions and compute clinically accepted measures of arterial stiffness. The ability of ARTSENS to measure vascular stiffness in vivo was validated by performing measurements on 125 subjects. The accuracy of results was verified with the state-of-the-art ultrasound imaging-based echo-tracking system. The relation between arterial stiffness measurements performed in sitting posture for ARTSENS measurement and sitting/supine postures for imaging system was also investigated to examine feasibility of performing ARTSENS measurements in the sitting posture for field deployment. This paper verified the feasibility of the novel ARTSENS device in performing accurate in vivo measurements of arterial stiffness. As a portable device that performs automated measurement of carotid artery stiffness with minimal operator input, ARTSENS has strong potential for use in large-scale screening.
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TL;DR: This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization.
Abstract: Local pulse wave velocity (PWV) is evolving as one of the important determinants of arterial hemodynamics, localized vessel stiffening associated with several pathologies, and a host of other cardiovascular events. Although PWV was introduced over a century ago, only in recent decades, due to various technological advancements, has emphasis been directed toward its measurement from a single arterial section or from piecewise segments of a target arterial section. This emerging worldwide trend in the exploration of instrumental solutions for local PWV measurement has produced several invasive and noninvasive methods. As of yet, however, a univocal opinion on the ideal measurement method has not emerged. Neither have there been extensive comparative studies on the accuracy of the available methods. Recognizing this reality, makes apparent the need to establish guideline-recommended standards for the measurement methods and reference values, without which clinical application cannot be pursued. This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization. Further, a summary of the advancements in measuring modalities and clinical applications is provided. Additionally, a detailed discussion on the minimally explored concept of incremental local PWV is presented along with suggestions of future research questions.
88 citations
Cites methods from "Technical Validation of ARTSENS–An ..."
...timates arterial dynamics by processing A-scan frames [255], [256]....
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...The ARTSENS technology [255] was used here for diameter and arterial wall thickness measurements, and the pressure was derived from the measured diameter based on an empirically deduced exponential relationship....
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TL;DR: The feasibility of calibration-free, cuffless BP measurement at an arterial site of interest was demonstrated with a level of acceptable accuracy and the potential utility of the proposed method and system in hypertension screening and local evaluation of arterial stiffness indices was demonstrated.
Abstract: Objective: We propose a calibration-free method and system for cuffless blood pressure (BP) measurement from superficial arteries. A prototype device with bi-modal probe arrangement was designed and developed to estimate carotid BP – an indicator of central aortic pressure. Methods: Mathematical models relating BP parameters of an arterial segment to its dimensions and local pulse wave velocity (PWV) are introduced. A bi-modal probe utilizing ultrasound and photoplethysmograph sensors was developed and used to measure diameter values and local PWV from the carotid artery. Carotid BP was estimated using the measured physiological parameters without any subject- or population-specific calibration procedures. The proposed cuffless BP estimation method and system were tested for accuracy, usability, and for potential utility in hypertension screening, on a total of 83 subjects. Results: The prototype device demonstrated its capability of detecting beat-by-beat arterial dimensions and local PWV simultaneously. Carotid diastolic BP (DBP) and systolic BP (SBP) were estimated over multiple cardiac cycles in real-time. The absolute error in carotid DBP was Conclusion: The feasibility of calibration-free, cuffless BP measurement at an arterial site of interest was demonstrated with a level of acceptable accuracy. The study also demonstrated the potential utility of the proposed method and system in hypertension screening and local evaluation of arterial stiffness indices. Significance: Novel approach for calibration-free cuffless BP estimation; a potential tool for local BP measurement and hypertension screening.
60 citations
Cites background or methods or result from "Technical Validation of ARTSENS–An ..."
...for vascular screening [19], [20]) are essential to investigate the ability of the proposed system to detect subtle changes in arterial stiffness that occur due to various cardiac conditions as well as...
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...Obtained stiffness measures were comparable to similar estimates reported in previous studies [19], [40]....
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...arterial walls by analyzing the inherent out of phase motion of the wall echoes (as the artery contracts and relaxes during each cardiac cycle) using sliding window covariance-based method [19], [30]....
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...The negative correlation between the proximal and distal wall movement was checked using wall motion negative correlation check (WMNCC) algorithm to ensure that both the walls were in opposite motion [18], [19]....
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TL;DR: This review aims to explain the biomechanical factors that are responsible for the formation and development of IH and their relationship with compliance mismatch and address the current methods used to measure compliance both in vitro and in vivo.
Abstract: Despite much effort, synthetic small diameter vascular grafts still face limited success due to vascular wall thickening known as intimal hyperplasia (IH). Compliance mismatch between graft and native vessels has been proposed to be one of a key mechanical factors of synthetic vascular grafts that could contribute to the formation of IH. While many methods have been developed to determine compliance both in vivo and in vitro, the effects of compliance mismatch still remain uncertain. This review aims to explain the biomechanical factors that are responsible for the formation and development of IH and their relationship with compliance mismatch. Furthermore, this review will address the current methods used to measure compliance both in vitro and in vivo. Lastly, current limitations in understanding the connection between the compliance of vascular grafts and the role it plays in the development and progression of IH will be discussed.
35 citations
TL;DR: The study results revealed the sensitivity of ARTSENS® Pen to detect changes in arterial stiffness with age, and the easy-to-use technology and the automated algorithms of the ARtsENS Pen make it suitable for cardiovascular risk assessment in resource-constrained settings.
Abstract: OBJECTIVE The conventional medical imaging modalities used for arterial stiffness measurement are non-scalable and unviable for field-level vascular screening. The need for an affordable, easy-to-operate automated non-invasive technologies remains unmet. To address this need, we present a portable image-free ultrasound device-ARTSENS® Pen, that uses a single-element ultrasound transducer for carotid stiffness evaluation. APPROACH The performance of the device was clinically validated on a cohort of 523 subjects. A clinical-grade B-mode ultrasound imaging system (ALOKA eTracking) was used as the reference. Carotid stiffness measurements were taken using the ARTSENS® Pen in sitting posture emulating field scenarios. MAIN RESULTS A statistically significant correlation (r > 0.80, p < 0.0001) with a non-significant bias was observed between the measurements obtained from the two devices. The ARTSENS® Pen device could perform highly repeatable measurements (with variation smaller than 10%) on a relatively larger percentage of the population when compared to the ALOKA system. The study results also revealed the sensitivity of ARTSENS® Pen to detect changes in arterial stiffness with age. SIGNIFICANCE The easy-to-use technology and the automated algorithms of the ARTSENS® Pen make it suitable for cardiovascular risk assessment in resource-constrained settings.
33 citations
TL;DR: The association of carotid stiffness with age, gender, hypertension/diabetes, smoking, and clustering of risk factors was studied and the trend persisted even after excluding hypertensives and subjects with diabetes.
Abstract: Objective: We investigate the field feasibility of carotid stiffness measurement using ARTSENS® Touch and report the first community-level data from India. Method: In an analytical cross-sectional survey among 1074 adults, we measured specific stiffness index ( $\beta $ ), pressure-strain elastic modulus ( $\text{E}_{\text {p}}$ ), arterial compliance (AC), and one-point pulse wave velocity (PWV $_{\beta }$ ) from the left common carotid artery. Data for established risk factors (waist circumference, blood pressure, plasma glucose, triglycerides, and HDL-C) were also collected. The association of carotid stiffness with age, gender, hypertension/diabetes, smoking, and clustering of risk factors was studied. Results: Measurements were repeatable with a relative difference (RD) between consecutive readings of $\sim 80$ % of arterial diameter values. The average RDs for $\beta $ , $\text{E}_{\text {p}}$ , AC, and PWV $_{\beta }$ , were 20.51%, 22.31%, 25.10%, and 14.13%, respectively. Typical range for stiffness indices among females and males were $\beta $ : 8.12 ± 3.59 vs 6.51 ± 2.78, $\text{E}_{\text {p}}$ : 113.24 ± 56.12 kPa vs 92.33 ± 40.65 kPa, PWV $_{\beta }$ : 6.32 ± 1.38 ms−1 vs 5.81 ± 1.16 ms−1, and AC: 0.54 ± 0.36 mm2 kPa−1 vs 0.72 ± 0.38 mm2 kPa−1. Mean $\beta $ , $\text{E}_{\text {p}}$ , and PWV $_{\beta }$ increased (and mean AC decreased) across decades of age; the trend persisted even after excluding hypertensives and subjects with diabetes. The odds ratio of presence of multiple risk factors for $\text{E}_{\text {p}} \ge93.71$ kPa and/or PWV $_{\beta } \ge6.56$ ms−1 was ≥ 2.12 or above in males. In females, it was just above 2.00 for $\text{E}_{\text {p}} \ge91.21$ kPa and/or PWV $_{\beta } \ge5.10$ ms−1 and increased to ≥ 3.33 for $\text{E}_{\text {p}} \ge143.50$ kPa and ≥ 3.25 for PWV $_{\beta } \ge7.31$ ms−1. Conclusion: The study demonstrated the feasibility of carotid stiffness measurement in a community setting. A positive association between the risk factors and carotid artery stiffness provides evidence for the device’s use in resource-constrained settings. Clinical Impact: The device paves the way for epidemiological and clinical studies that are essential for establishing population-level nomograms for wide-spread use of carotid stiffness in clinical practice and field screening of ‘at-risk’ subjects.
25 citations
Cites background from "Technical Validation of ARTSENS–An ..."
...set of automated algorithms identify and continuously track echoes originating from the walls and perform an online evaluation of the arterial lumen diameter and distension waveforms [14], [15], [17]....
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...These continuous echoes are displayed in real-time to provide a visual (video-graphic) effect, which helps the operator precisely orienting the probe along the diameter of the artery by ensuring out-of-phase moving echoes from both the proximal and distal walls [14]....
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TL;DR: In this paper, the authors summarized the proceedings of several meetings of the European Network for Non-invasive Investigation of Large Arteries and aimed at providing an updated and practical overview of the most relevant methodological aspects and clinical applications in this area.
Abstract: In recent years, great emphasis has been placed on the role of arterial stiffness in the development of cardiovascular diseases. Indeed, the assessment of arterial stiffness is increasingly used in the clinical assessment of patients. Although several papers have previously addressed the methodological issues concerning the various indices of arterial stiffness currently available, and their clinical applications, clinicians and researchers still report difficulties in selecting the most appropriate methodology for their specific use. This paper summarizes the proceedings of several meetings of the European Network for Non-invasive Investigation of Large Arteries and is aimed at providing an updated and practical overview of the most relevant methodological aspects and clinical applications in this area.
4,410 citations
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TL;DR: This population-based study shows that arterial stiffness is strongly associated with atherosclerosis at various sites in the vascular tree.
Abstract: Background and Purpose—Studies of the association between arterial stiffness and atherosclerosis are contradictory. We studied stiffness of the aorta and the common carotid artery in relation to se...
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"Technical Validation of ARTSENS–An ..." refers background in this paper
...Carotid artery stiffness has been demonstrated to have strong association with increased intima-media thickness and even with severity of plaques in aorta [8]....
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TL;DR: The effects of current and future cardiovascular drugs on arterial stiffness are discussed, as is the relationship between arterial elasticity and endothelial function.
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813 citations