Validation of Noninvasive Derivation of the Central Aortic Pressure Waveform from Fingertip Photoplethysmography Using a Novel Selective Transfer Function Method.

Introduction: Central aortic pressure waveform analyses can provide clinically relevant information beyond conventional brachial blood pressure (BP) assessment. This waveform can be reproduced noninvasively through application of a generalized transfer function (GTF) on a peripheral waveform, as conventionally performed by applanation tonometry. Photoplethysmography (PPG) is an alternate approach; however, differences in measurement site and modality demand the use of a transfer function (TF) specific for those differences.

Myocardial oxygen supply and demand imbalance predicts mortality in older nursing home residents: The PARTAGE study.

Background: A mismatch between myocardial oxygen supply and demand is the most common cause of ischemic myocardial injury in older persons. The subendocardial viability ratio (SEVR) can usefully estimate the degree of myocardial perfusion relative to left-ventricular workload. The aim of the present study was to evaluate the ability of SEVR to predict long-term mortality in the older population.

Bilateral cuff-induced lower limb post-ischemia hyperemia as a method for acute reduction in blood pressure for cuffless blood pressure device testing.

Objective: Development and testing of cuffless blood pressure (BP) devices requires methods to increase and decrease BP. This is also required by cuffless BP validation standards. Pharmacological interventions, whilst successful, are not always feasible for all subpopulations or research settings.

Comparison of effects of peripheral vasculature on tonometric radial pulse and cuff-based brachial pulse waveform as used in estimation of central aortic pressures.

Objective: Aortic pressure estimation requires reliable peripheral pulse waveform acquisition. The peripheral waveform can change with local vascular effects that can be independent of aortic pressure. This study quantifies the effects of peripheral vasculature changes on radial and brachial waveforms.

From peripheral finger-derived pulse waveforms to aortic pressure waveform features: an application of a generalized transfer function.

Objective: Aortic (central) pressure features are associated with cardiovascular complications and can be algorithmically derived from non-invasive peripheral arterial waveforms. This has conventionally been performed with a pressure waveform (i.e.

Interaction of large artery stiffness and baroreceptor function explored through multiple measurement techniques - a pilot study.

Baroreceptors, sensors that play a role in controlling arterial blood pressure (BP), are mechanical stretch receptors located in the aortic arch and carotid sinuses. Factors affecting the degree of stretch in the vessel wall with BP, such as increased arterial stiffness, may compromise baroreceptor sensitivity (BRS) to BP changes. Yet, evidence of this is scattered, as both baroreceptor sensitivity (BRS) and arterial stiffness are calculated variables with multiple methodological approaches.

Personalized aortic pressure waveform estimation from brachial pressure waveform using an adaptive transfer function.

Background And Objective: The aortic pressure waveform (APW) provides reliable information for the diagnosis of cardiovascular disease. APW is often measured using a generalized transfer function (GTF) applied to the peripheral pressure waveform acquired noninvasively, to avoid the significant risks of invasive APW acquisition. However, the GTF ignores various physiological conditions, which affects the accuracy of the estimated APW.

Expert Consensus on the Clinical Use of Pulse Wave Velocity in Asia.

Arterial stiffness is a progressive aging process that predicts cardiovascular disease. Pulse wave velocity (PWV) has emerged as a noninvasive, valid, and reliable measure of arterial stiffness and an independent risk predictor for adverse outcomes. However, up to now, PWV measurement has mostly been used as a tool for risk prediction and has not been widely used in clinical practice.

The Microsoft Research Aurora Project: Important Findings on Cuffless Blood Pressure Measurement.

Conventional blood pressure (BP) measurement devices based on an inflatable cuff only provide a narrow view of the continuous BP profile. Cuffless BP measuring technologies could permit numerous BP readings throughout daily life and thereby considerably improve the assessment and management of hypertension. Several wearable cuffless BP devices based on pulse wave analysis (applied to a photoplethysmography or tonometry waveform) with or without use of pulse arrival time are now available on the market.

Cuffless Blood Pressure Measurement.

Cuffless blood pressure (BP) measurement has become a popular field due to clinical need and technological opportunity. However, no method has been broadly accepted hitherto. The objective of this review is to accelerate progress in the development and application of cuffless BP measurement methods.

Association between Brachial-Ankle Pulse Wave Velocity as a Marker of Arterial Stiffness and Body Mass Index in a Chinese Population.

Objectives: Arterial stiffness is widely accepted as an important predictor of cardiovascular disease (CVD) development. While obesity is generally associated with increased CVD risk, there is evidence that overweight patients with existing CVD may have better clinical outcomes than their lean counterparts. Our study sought to observe any potential association between brachial−ankle pulse wave velocity (BAPWV), a marker of arterial stiffness related to CVD risk, and Body Mass Index (BMI), a crude and widely used measure of obesity.

Estimation of cardiac stroke volume from radial pulse waveform by artificial neural network.

Background And Objectives: Stroke volume (SV) and cardiac output (CO) are the key indicators for the evaluation of cardiac function and hemodynamic status during the perioperative period, which are very important in the detection and treatment of cardiovascular diseases. Traditional CO and SV measurement methods have problems such as complex operation, low precision and poor generalization ability.

Methods: In this paper, a method for estimating stroke volume based on cascade artificial neural network (ANN) and time domain features of radial pulse waveform (SV) was proposed.

The prevalence and impact of orthostatic intolerance in young women across the hypermobility spectrum.

Orthostatic intolerance (OI) is frequently reported in young women with generalized hypermobility spectrum disorder (G-HSD) and hypermobile EDS (hEDS). However, it remains currently unclear whether OI is a comorbidity or fundamental part of the pathophysiology of G-HSD or hEDS. This study investigated the prevalence and impact of OI in young women across the hypermobility spectrum.

An investigation of the individualized, two-point calibration method for cuffless blood pressure estimation using pulse arrival time: an historical perspective using the Casio BP-100 digital watch.

Background: The use of wearable cuffless blood pressure (BP) devices is becoming commercially prevalent with little published validation information. Most devices rely, at least in part, on the relationship between pulse arrival time (PAT) and BP, a theoretical fundamental relationship that was first commercially exploited in 1993 with the release of the Casio BP-100 digital watch.

Objective: This study explored the PAT method of BP estimation in a commercial device where it first began, the Casio BP-100 (Model No.

Blood pressure-independent neurogenic effect on conductance and resistance vessels: a consideration for cuffless blood pressure measurement?

Background: Pulse transit time (PTT) and pulse arrival time (PAT) are promising measures for cuffless arterial blood pressure (BP) estimation given the intrinsic arterial stiffness-BP relationship. However, arterial stiffness (and PTT) is altered by autonomically-driven smooth muscle tension changes, potentially independent of BP. This would limit PTT or PAT as accurate BP correlates, more so in resistance vessels than conductance arteries.

Contactless video-based photoplethysmography technique comparison investigating pulse transit time estimation of arterial blood pressure.

Background: Non-contact measurement of physiological vital signs, such as blood pressure (BP), by video-based photoplethysmography (vPPG) is a potential means for remote health monitoring. However, the signal-to-noise ratio of cardiovascular signals within the vPPG is very low.

Objective: This study investigates the potential of BP estimation from vPPG.

Evaluation of the Accuracy of Cuffless Blood Pressure Measurement Devices: Challenges and Proposals.

Several novel cuffless wearable devices and smartphone applications claiming that they can measure blood pressure (BP) are appearing on the market. These technologies are very attractive and promising, with increasing interest among health care professionals for their potential use. Moreover, they are becoming popular among patients with hypertension and healthy people.

Comparison Between Invasive and Noninvasive Methods to Estimate Subendocardial Oxygen Supply and Demand Imbalance.

Background Estimation of the balance between subendocardial oxygen supply and demand could be a useful parameter to assess the risk of myocardial ischemia. Evaluation of the subendocardial viability ratio (SEVR, also known as Buckberg index) by invasive recording of left ventricular and aortic pressure curves represents a valid method to estimate the degree of myocardial perfusion relative to left ventricular workload. However, routine clinical use of this parameter requires its noninvasive estimation and the demonstration of its reliability.

Female Gender Is Associated with Higher Susceptibility of Weight Induced Arterial Stiffening and Rise in Blood Pressure.

Arterial stiffness is an important predictor of cardiovascular events, independent of traditional risk factors. Stiffening of arteries, though an adaptive process to hemodynamic load, results in substantial increase in the pulsatile hemodynamic forces that detrimentally affects the microcirculation perfusing the vital organs such as the brain, heart and kidneys. Studies have proposed that arterial stiffness precedes and may contribute to the development of hypertension in individuals with obesity.

Relationship between heart rate and central aortic blood pressure: implications for assessment and treatment of isolated systolic hypertension in the young.

Isolated systolic hypertension in the young (ISHY) remains a challenging problem, partly due to the differences in central aortic pressure observed in studies investigating ISHY. The fundamental relationship between heart rate and central aortic pressure, and more precisely, the relationship between heart rate and amplification of central aortic pressure in the periphery, underpins the assessment and, as a consequence, the treatment of ISHY. Physiology warrants that an increase in heart rate would lead to increased amplification of the pressure pulse between the aorta and the brachial artery.

Heart rate and blood pressure dependence of aortic distensibility in rats: comparison of measured and calculated pulse wave velocity.

Objectives: When assessing arterial stiffness, heart rate (HR) and blood pressure (BP) are potential confounders. It appears that the HR/BP dependences of pulse wave velocity (PWV) and distensibility are different, even though both assess arterial stiffness. This study aims to compare aortic PWV as measured using pulse transit time (PWVTT) and as calculated from distensibility (PWVdist) at the same measurement site and propose a solution to the disparity in dependences of PWVTT and PWVdist.

Age-Specific Acute Changes in Carotid-Femoral Pulse Wave Velocity With Head-up Tilt.

Background: Aortic stiffness as measured by carotid-femoral pulse wave velocity (cfPWV) is known to depend on blood pressure (BP), and this dependency may change with age. Therefore, the hydrostatic BP gradient resulting from a change in body posture may elicit a cfPWV change that is age-dependent. We aimed to analyze the relationship between BP gradient-induced by head-up body tilting-and related changes in cfPWV in individuals of varying age.

Reply to Comments: Using the Cardio-Ankle Vascular Index (CAVI) or the Mathematical Correction Form (CAVI) in Clinical Practice.

We read with great interest Alizargar et al [...