Mark Butlin

Macquarie University · Macquarie Medical School, Faculty of Medicine, Health and Human Sciences

Amyloid β (Aβ) deposition is a hallmark of Alzheimer's disease (AD). Vascular modifications, including altered brain endothelial cell function and structural viability of the blood-brain barrier due to vascular pulsatility, are implicated in AD pathology. Pulsatility of phenomena in the cerebral vasculature are often not considered in in vitro mode...

Carotid-femoral pulse wave velocity (cfPWV) quantifies large artery stiffness, it is used in hemodynamic research and is considered a useful cardiovascular clinical marker. cfPWV is blood pressure (BP) dependent. Intrinsic heart rate (HR) dependency of cfPWV is unknown because increasing HR is commonly accompanied by increasing BP. This study aims...

Aortic stiffness, a predictive parameter in cardiovascular medicine, is blood pressure dependent and experimentally requires isobaric measurement for meaningful comparison. Vasoactive drug administration to change peripheral resistance and blood pressure allows such isobaric comparison but may alter large conduit artery wall tension, directly chang...

The purpose of this study was to determine the impact of age on regional aortic pulse wave velocity (aPWV). aPWV is an independent predictor of cardiovascular risk and increases exponentially with age. However, it is unclear whether such changes occur uniformly along the length of the aorta or vary by region. A total of 162 subjects, aged 18 to 77...

The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the b...

Purpose Anemia and red cell transfusion contribute to morbidity and mortality of surgery. The concept of patient blood management to mitigate preoperative anemia, optimize coagulation, conserve red cells intraoperatively and accept lower post-operative transfusion thresholds has recently gained widespread acceptance across a range of surgical disci...

Cardiorespiratory fitness has been shown to be correlated with cardiovascular complications and comparable to other conventional health parameters. Consequently, it can be a useful preventative and a practical first line of information for cardiovascular diseases, such as hypertension. Wearable devices have the capacity to provide a convenient asse...

Large artery stiffness is strongly correlated with cardiovascular outcomes. The stiffness of the artery can be measured non-invasively using carotid-femoral pulse wave velocity (cfPWV). Originally cfPWV assessment was performed by ECG-gated applanation tonometry at the carotid and femoral site. High quality applanation tonometry is a learned skill....

Purpose: Anemia and red cell transfusion contribute to morbidity and mortality of surgery. The concept of patient blood management to mitigate preoperative anemia, optimize coagulation, conserve red cells intraoperatively and accept lower post-operative transfusion thresholds has recently gained widespread acceptance across a range of surgical disc...

Purpose: Anemia and red cell transfusion contribute to morbidity and mortality of surgery. The concept of patient blood management to mitigate preoperative anemia, optimize coagulation, conserve red cells intraoperatively and accept lower post-operative transfusion thresholds has recently gained widespread acceptance across a range of surgical disc...

Objective: Hypertension is an increasingly prevalent global disease with an overwhelming burden on society and the healthcare system. Undiagnosed hypertension and poor adherence to monitoring have been highlighted in the literature to be a key factor in addressing this issue. Wearable devices are a potential solution to this problem through offeri...

Brain arteriovenous malformation (bAVM) resection imposes several post-operative clinical challenges including intracranial haemorrhage (ICH). Daily non-invasive monitoring of haemodynamic measurements may be useful in predicting post-operative ICH. This prospective study used transcranial colour duplex (TCCD) and central aortic pressure (CAP) meas...

Automated ‘oscillometric’ blood pressure (BP) measuring devices (BPMDs) were developed in the 1970s to replace manual auscultatory BP measurement by mercury sphygmomanometer. Automated BPMDs that have passed accuracy testing versus a reference auscultatory sphygmomanometer using a scientifically accepted validation protocol are recommended for clin...

The global health burden presented by hypertension is providing increased motivation for improved means of collection of blood pressure (BP) data. A growing area of research and commercial activity is the use of wearable devices to provide BP data using non-invasive cuffless techniques. The accelerated progress in recent years, particularly relatin...

Background. The association between arterial stiffness and cardiovascular risk in CKD and ESRD patients is well established. However, the relationship between renal function estimation and properties of large arteries is unclear due to the four different methods used to quantify glomerular filtration. This study investigated the relationship betwee...

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 opera...

Objective Aim of this study was to evaluate the associations of non-invasive central aortic and peripheral (brachial) blood pressure (BP) for Hypertension-mediated organ damage (HMOD) and atherosclerotic cardiovascular disease (ASCVD) risk. Methods We evaluated associations of HMOD with 24-h ambulatory blood pressure monitoring (ABPM) of central a...

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...

Elasticity of arteries is a fundamental structural property that is a major determinant of the relationship of the pulsatile components of arterial blood pressure and flow. The basic periodic nature of cardiac contraction enables the oscillatory phenomena of blood pressure and flow to be represented in the frequency domain by decomposing time-varyi...

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...

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...

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 fr...

Objective Nonalcoholic fatty fiver disease (NAFLD) is a metabolic liver injury closely related to insulin resistance. Fatty liver index (FLI) can be used as a surrogate marker and is a validated index for NAFLD. This study aimed to explore the relationship between FLI and arterial stiffness in a Chinese population. Methods From December 2017 to Ma...

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 pr...

It is well known that non-invasive blood pressure measurements significantly underestimate true systolic blood pressure (SBP), and overestimate diastolic blood pressure (DBP). The aetiology for these errors has not yet been fully established. This study aimed to investigate the accuracy of Korotkoff sounds for detection of SBP and DBP points as use...

The clinical work of GPs and physiotherapists frequently involves the assessment of patient pain. In this study, we aimed to determine the correlation of patient- and clinician-assessment of severity of pain through quantitative analysis of patient- and clinician-assessed pain scores collected at metropolitan general practice and physiotherapy clin...

Objectives: Carotid-femoral pulse wave velocity (cfPWV) approximates aortic stiffness and is a predictor of cardiovascular events. Despite the literature highlighting the clinical relevance of cfPWV, there is minimal integration of this parameter in clinical assessments. An underlying reason may stem from potential measurement errors. This paper in...

Background: Resection of a brain arteriovenous malformation (bAVM) can impose several post-operative challenges including post- operative haemorrhage (POH) [1]. The mechanism of such complications remains controversial although deliberately inducing hypotension has proven successful for POH prevention [2]. Daily non-invasive monitoring for patients...

Purpose: Studies support beneficial effects of isoflavones, but antidiabetic effects of these agents remains unconfirmed [1,2]. This pilot study investigates isoflavones and Inonotus obliquus (chaga) extract effects on diabetes. Methods: Diabetes was induced (streptozotocin 65 mg/kg, nicotinamide 110 mg/kg) in 9 male Wistar rats (12 weeks old). 9 a...

Central Systolic Blood Pressure (cSBP) and Central Augmentation Index (cAIx) have been independently associated with cardiovascular risk in adults, and can be estimated using a generalized peripheral-to-central transfer function. We hypothesize that transfer function accuracy and precision will be influenced by degree of growth and change in body h...

Background: In adults, central systolic blood pressure (cSBP) and augmentation index (cAIx) are independently associated with cardiovascular (CV) events and mortality. As CV disease begins in early life, there is increasing interest in central hemodynamic indices in children. We aimed to assess the accuracy of current techniques against invasive i...

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...

To investigate the association of noninvasive indices of arterial stiffness with chronic kidney disease (CKD) in patients with primary hypertension, 547 (mean age 60 years, 63% males) hypertensive hospital inpatients were recruited, comprising 337 hypertensives without CKD and 210 hypertensives with CKD. Noninvasive arterial stiffness indices were...

Video-based photoplethysmography (vPPG) enables remote and contactless detection of the peripheral pulse of blood flow. This provides a potential mean to extract heart rate (HR) and pulse transit time (PTT) for the purpose of remote health monitoring. The accuracy of average HR and PTT extracted from a two-minute vPPG recording has been investigate...

The arterial wall is a composite material of elastin, collagen, and extracellular matrix with acutely modifiable material properties through the action of smooth muscle cells. Therefore, arterial stiffness is a complex parameter that changes not only with long-term remodeling of the wall constituents but also with acute contraction or relaxation of...

Carotid-femoral pulse wave velocity is associated with arterial stiffness in major elastic arteries, and predicts future cardiovascular events. However, little is known about carotid-femoral pulse wave velocity as a marker of vascular health in children. Semi-automated cuff-based devices for assessing pulse wave velocity are increasingly popular, a...

Significance Spontaneous arousals from sleep are associated with tachycardia and blood pressure responses excessive to physiological need. The prevailing view is that stereotyped autonomic activity is generated by feedforward inputs from cortical and subcortical systems implicated in the arousal, akin to autonomic activation with emotional behavior...

Objective: The changing living patterns in China are accompanied by an increase in prevalence of cardiovascular disease for which obesity is a significant factor. This study investigated the association between obesity phenotypes and risk of cardiovascular disease in a Chinese cohort. Methods: A sample of 10,826 community-dwelling individuals aged...

Purpose: The retinal vasculature provides unique in vivo access to the microcirculation and presents the possibility of measuring small artery (retinal) stiffness using pulse wave velocity (PWV). This study investigates whether retinal artery PWV (rPWV) has a blood pressure (BP) dependency. Methods: Fundus videos from eight Sprague-Dawley rats aged...

Purpose: The retina provides a non-invasive window to monitor microvascular circulation. Carotid-femoral Pulse Wave Velocity (cfPWV) is an indicator of large artery stiffness and is associated with systemic cardiovascular diseases. This study investigates whether Retinal artery PWV (rPWV) reflects cfPWV changes in an elderly cohort. Methods: A tota...

Menopausal transition acceleratesan age‐associated decreasein vascular function and a decline in aerobic fitness. The purpose of this study was to examine the effect of 8weeksof interval sprinting cycle ergometer exerciseon arterial stiffness, basal forearm blood flow, and aerobic fitnessof postmenopausal women.Sixtyoverweight postmenopausal women...

Background: Inter-arm differences in brachial systolic Blood Pressure (BP) are associated with increased cardiovascular risk. It is unclear whether anatomical factors contribute to brachial Interarm Blood Pressure (IABP) differences or whether brachial IABP differences translate to differences in derived central aortic BP. This study aimed to ascer...

A new wearable sensor using millimetre-wave radar and electromagnetic technology provides 64 signals reflected from one radar sinusoidal signal beamed around the radial artery. It is non-invasive, can be non-contact, and is potentially simpler in acquiring the radial pulse then tonometry. This study assesses whether selection of a signal from the r...

Background: Arterial stiffness is a significant cardiovascular risk factor. Carotid-femoral pulse wave velocity (cfPWV) is the standard for measuring arterial stiffness, but indices such as central augmentation index (cAIx) and carotid artery elasticity (cE[p]) also correlate to arterial stiffness. Early-life determinants of arterial stiffening are...

Background: Central aortic pressure waveforms can be modelled non-invasively in adults using general transfer functions. These techniques have been applied to, but not formally validated in paediatric populations. We recently developed and validated two age-appropriate paediatric transfer functions and sought to determine their effectiveness in chi...

Background: Arterial stiffness (e.g., as measured by carotid-femoral pulse wave velocity (cfPWV)) changes acutely with blood pressure (BP). High cfPWV at high BP could be due to structural arterial changes or acute BP effects. Various parameters have been proposed as BP-independent parameters of arterial stiffness. These rely on assumptions to simp...

Background: Cardio-ankle vascular index (CAVI) has long been considered a measure of arterial stiffness independent of short-term changes in blood pressure (BP) [1]. Recently and theoretically, CAVI was found to be partially affected by actual BP, thus, a novel BP-corrected index, CAVI0, was proposed to diminish these effects [2,3]. Direct, repeate...

[This corrects the article DOI: 10.7759/cureus.6181.].

Pulse wave velocity (PWV) is a reliable measurement of arterial stiffness. Our study assesses the association between body mass index (BMI) and brachial-ankle PWV (baPWV) in a healthy cohort and seeks to explain possible mechanisms associated with the obesity paradox.A cross-sectional study was conducted in 578 normal individuals. The mean age was...

Vitamin D deficiency may increase arterial stiffness, a sub-clinical symptom of Target Organ Damage (TOD). This study aimed to investigate the associations between total serum vitamin D level and arterial stiffness assessed by brachial-ankle Pulse Wave Velocity (baPWV) and atherosclerosis assessed by Ankle-Brachial Index (ABI) in a Chinese communit...

Given the rarity of arteriovenous malformations of the brain (bAVMs) with concomitant obstructive hydrocephalus, few papers have commented on the resultant hydrodynamic perturbations. To date, no study has specifically investigated the effect of ventricular shunting on intracranial venous parameters as measured by transcranial color duplex ultrasou...

Recently, the 2017 ACC/AHA released new hypertension guidelines and proposed a redefinition of hypertension from 140/90 to 130/80 mm Hg. This study assesses the impact of the lower threshold for hypertension diagnosis on the association of hypertension with target organ damage (TOD). Health checks were conducted in a community‐dwelling population i...

Obesity is generally considered an undesirable risk factor for cardiovascular disease; however, obese subjects with heart failure paradoxically can have better outcomes than their lean counterparts. This study aimed to investigate this characteristic in an elderly Chinese population. Elderly participants (N = 414, age 77 ± 11 years, 211 males) were...

Studying dynamic characteristics of retinal vessels, as opposed to static measures, may provide additional insight into pathophysiological changes associated with local and systemic abnormalities such as glaucoma and hypertension. Various approaches have been developed to derive static biomarkers from retinal still images, but not many for dynamic...

Physiological monitoring broadly encompasses the measurement of a biological signal over time and referencing this against the expected value of the parameter in order to make a decision about what action, if any, needs to be taken to bring that biological parameter back to a normal range. This could be weight or waist and hip circumference measure...

An Investigation of the repeatability of the BP/PWV relationship using a postural-induced change in BP.