Christopher Clemens Mayer

AIT Austrian Institute of Technology | ait · Center for Health & Bioresources

Background: Vascular age (VA) is independent and chronological age for assessing cardiovascular disease (CVD) risk. However, tools for the implementation of VA are currently lacking. We aimed to develop a questionnaire to assess the current knowledge gaps related to VA and barriers to its implementation in routine practice. Methods: Using a step...

Prevention of cardiovascular disease (CVD) remains one of the largest public health challenges of our time. Identifying individuals at increased cardiovascular risk at an asymptomatic, subclinical stage is of paramount importance for minimizing disease progression as well as the substantial health and economic burden associated with overt CVD. Vasc...

Prescribing the ultrafiltration in hemodialysis patients remains challenging and might benefit from the information on absolute blood volume, estimated by intradialytic dialysate bolus administration. Here, we aimed at determining the relationship between absolute blood volume, normalized for body mass (specific blood volume, Vs), and ultrafiltrati...

Background The Covid-19 pandemic necessitated a decrease in non-Covid-19 related diagnostic and therapeutic procedures in many countries. We explored the impact on tertiary hypertension care. Methods We conducted an electronic survey regarding 6 key procedures in hypertension care within the Excellence Center network of the European Society of Hyp...

Cardiovascular disease (CVD) has long been deemed a disease of old men. However, in 2019 CVD accounted for 35% of all deaths in women and, therefore, remains the leading cause of death in both men and women. There is increasing evidence to show that risk factors, pathophysiology and health outcomes related to CVD differ in women compared with men,...

Objective: The Covid-19 pandemic necessitated a decrease in non-Covid-19 related diagnostic and therapeutic procedures in many countries. We explored the impact on hypertension care in the Excellence Center (EC) network of the European Society of Hypertension. Design and method: We conducted an electronic survey regarding 6 key procedures in hyp...

Objective: Despite current evidence demonstrating the important role of Vascular ageing (VA) in cardiovascular risk assessment, its awareness and mostly implementation in everyday practice still lags significantly. To effectively assess the need for future target strategies for health providers, a qualitative questionnaire was developed. The aim o...

Background: Renal denervation (RDN) lowers blood pressure (BP), but BP response is variable in individual patients. We investigated whether measures of pulsatile hemodynamics, obtained during 24-hour ambulatory BP monitoring, predict BP drop following RDN. Methods: From the randomized, sham-controlled SPYRAL HTN-OFF MED Pivotal trial, we perform...

Attractor reconstruction is a new way to quantify the morphology of a cardiovascular waveform by plotting all data points in the three-dimensional phase space, generating a trajectory of overlapping loops. The aim of this study is to show the feasibility of an automatic approach to quantify pulse wave attractors from a device-guided breathing study...

Background Assistive technologies have the potential to facilitate everyday life of people with dementia and their families. Close collaboration with affected people and interdisciplinary research are essential to understand and address the needs of prospective users. In this study, we present the results of the evaluation of such an assistive syst...

Medical devices are subject to strict regulatory and approval processes to enter the market and to be used by operators and patients. These are needed to guarantee the users’ safety. The different activities of these processes have important implications for all involved stakeholders and for the whole lifecycle of a medical device. The aim of this...

Background Absolute blood volume (ABV) is a critical component of fluid status, which may inform target weight prescriptions and hemodynamic vulnerability of dialysis patients. Here, we utilized the changes in relative blood volume (RBV), monitored by ultrasound (BVM) upon intradialytic 240 mL dialysate fluid bolus-infusion 1 h after hemodialysis s...

Background: Older age is a substantial risk factor for serious illness from COVID-19. Moreover, isolation and quarantine are more likely to cause physical, mental and social deprivation in older age. Information and Communication Tools are means to prevent such consequences. Objective: This study aimed therefore to investigate the impact of the...

Purpose: Assistive technologies have the potential for supporting people with memory complaints in their daily life. User-centered interaction design research helps developers to create systems that are suitable for users. The aim of this work is to describe the methodology and the results of the usability test for the first Memento prototype invo...

Background: Ambulatory-BP-monitoring (ABPM) is recommended for hypertension diagnosis and management in hemodialysis patients due to its strong association with outcomes. Intradialytic and scheduled interdialytic BP recordings show agreement with ambulatory BP. This study assesses in parallel the association of pre-dialysis, intradialytic, schedul...

Measurements of arterial stiffness and pulsatile hemodynamics undoubtedly led to enormous progress in our understanding of cardiovascular physiology, aging, and development of diseases. Until very recently, these measurements were confined primarily to research laboratories and hospitals and less to the doctor's office. In contrast, we know from th...

Neuropeptide Y (NPY) is a 36-amino-acid peptide member of a family also including peptide YY and pancreatic polypeptide, which are all ligands to Gi/Go coupled receptors. NPY regulates several fundamental biologic functions including appetite/satiety, sex and reproduction, learning and memory, cardiovascular and renal function and immune functions....

The photoplethysmogram (PPG) signal is widely measured by clinical and consumer devices, and it is emerging as a potential tool for assessing vascular age. The shape and timing of the PPG pulse wave are both influenced by normal vascular ageing, changes in arterial stiffness and blood pressure, and atherosclerosis. This review summarises research i...

New findings: What is the central question of this study? First, we validated easy-to-use oscillometric left ventricular ejection time (LVET) against echocardiographic LVET. Second, we investigated progression of left ventricular ejection time index (LVETI), pre-ejection period index (PEPI), total electromechanical systole index (QS2I) and PEP/LVE...

Kidney function has two important elements: glomerular filtration and tubular function (secretion and reabsorption). A persistent decrease in glomerular filtration rate (GFR), with or without proteinuria, is diagnostic of chronic kidney disease (CKD). While glomerular injury or disease is a major cause of CKD and usually associated with proteinuria...

Central (aortic) systolic blood pressure (cSBP) is the pressure seen by the heart, the brain, and the kidneys. If properly measured, cSBP is closer associated with hypertension-mediated organ damage and prognosis, as compared with brachial SBP (bSBP). We investigated 24-hour profiles of bSBP and cSBP, measured simultaneously using Mobilograph devic...

Kidney dysfunction can profoundly influence many organ systems, and recent evidence suggests a potential role for increased albuminuria in the development of mild cognitive impairment (MCI) or dementia. Epidemiological studies conducted in different populations have demonstrated that the presence of increased albuminuria is associated with a higher...

Neuropeptide Y (NPY) is a 36-amino-acid peptide member of a family also including peptide YY and pancreatic polypeptide which are all ligands to Gi/Go coupled receptors. NPY regulates several fundamental biologic functions including appetite/satiety, sex and reproduction, learning and memory, cardiovascular and renal function and the immune functio...

Background: Atrial fibrillation (AF) is common in hemodialysis patients and contributes to increased mortality. We aimed to examine heart rate variability triangular index (HRVI) in hemodialysis patients with AF as it has recently been reported to predict mortality in AF patients without kidney disease. Methods: A total of 88 patients on hemodialys...

Neurocognitive disorders are frequent among chronic kidney disease (CKD) patients. Identifying and characterizing cognitive impairment (CI) can help to assess the ability of adherence to CKD risk reduction strategy, identify potentially reversible causes of cognitive decline, modify pharmacotherapy, educate the patient and caregiver and provide app...

Chronic kidney disease (CKD) perturbs the crosstalk with others organs, with the interaction between the kidneys and the heart having been studied most intensively. However, a growing body of data indicates that there is an association between kidney dysfunction and disorders of the central nervous system. In epidemiological studies, CKD is associa...

Metabolic acidosis, defined as a plasma or serum bicarbonate concentration <22 mmol/L, is a frequent consequence of chronic kidney disease (CKD) and occurs in ~10–30% of patients with advanced stages of CKD. Likewise, in patients with a kidney transplant, prevalence rates of metabolic acidosis range from 20% to 50%. CKD has recently been associated...

Vascular ageing biomarkers have been found to be predictive of cardiovascular risk independently of classical risk factors, yet are not widely used in clinical practice. In this review we present two basic approaches for using machine learning (ML) to assess vascular age: parameter estimation and risk classification. We then summarize their role in...

The development and use of medical devices are subject to regulations and approval activities to enter the market. These are mandatory for manufacturers and have important implications for all involved professionals. In fact, the innovation process, starting from a clinical need, includes the identification of a solution and its implementation, and...

Background and Aims Ambulatory-BP-monitoring (ABPM) is recommended for hypertension diagnosis and management in hemodialysis subjects due to high accuracy and strong associations with outcomes. The agreement and prediction of averaged intradialytic BP readings and home BP readings with ABPM and clinical outcomes is not known. This study assesses in...

Background: In hemodialysis patients, left ventricular hypertrophy (LVH) contributes to high cardiovascular mortality. We examined cardiovascular mortality prediction by the recently proposed Peguero-Lo Presti voltage since it identifies more patients with electrocardiographic (ECG) LVH than Cornell or Sokolow-Lyon voltages. Methods: A total of...

Aortic pulse wave velocity (PWV) is directly related to arterial stiffness. Different methods for the determination of PWV coexist. The aim of this prospective study was to evaluate the prognostic value of PWV in high-risk patients with suspected coronary artery disease undergoing invasive angiography and to compare 3 different methods for assessin...

In December 2019, an outbreak of pneumonia caused by a novel Coronavirus (COVID-19) spread rapidly worldwide. Although the clinical manifestations of COVID-19 are dominated by respiratory symptoms, the cardiovascular system is extensively affected at multiple levels. Due to the unprecedented consequences of the COVID-19 pandemic, the ARTERY society...

Introduction: Microgravity in space is known to cause major alterations in the cardiovascular system. Left ventricular ejection time (LVET) can be measured by the time from the onset point of the pressure wave to the incisura of the dicrotic notch. The aim of this study was to simulate microgravity by head-down tilt bedrest (HDT) to examine changes...

Background Vascular aging, defined by aortic pulse wave velocity (aoPWV), as well as coronary artery calcium (CaC), are emerging risk predictors. Purpose To investigate the prognostic role of functional (vascular aging) and structural (CaC) arterial parameters in individuals without established cardiovascular disease. Methods We utilized our rece...

Heart failure (HF), hypertension, and abnormal nocturnal blood pressure dipping are highly prevalent in hemodialysis patients. Atrial fibrillation (AF) and HF might be important mediators for the association of abnormal dipping patterns with worse prognosis. Thus, the aim of this study is to investigate the association of dipping with mortality in...

VascAgeNet is a new European network which will join forces in order to refine, harmonize and promote the vascular ageing concept. It aims to bring innovations in cardiovascular research from bench to bedside and to establish assessment of vascular ageing in clinical practice. The interdisciplinary, inter-country and intersectional approach will en...

Cardiovascular Disease (CVD) is the leading cause of morbidity and mortality worldwide, regardless of gender, ethnicity or income. Evidence that vascular age, as opposed to chronological age, is better related to the prognosis of CVD is convincing. Despite recent technological advances for the measurement of vascular ageing, unmet needs remain whic...

Background: Steady state hemodynamics [Stroke Volume - SV, cardiac output, peripheral resistance (Rp)] have attracted researchers in hypertension for decades. However, due to technical difficulties, they never entered clinical medicine. Objective: To investigate the performance of a model-based algorithm, utilizing brachial pressure waveforms obtai...

Background Excess mortality in hemodialysis patients is mostly of cardiovascular origin. We examined the association of heart rate turbulence (HRT), a marker of baroreflex sensitivity, with cardiovascular mortality in hemodialysis patients.MethodsA population of 290 prevalent hemodialysis patients was followed up for a median of 3 years. HRT catego...

Introduction: Arterial properties are linked to the presence and severity of coronary artery disease (CAD). Coronary blood flow is strongly and inversely related to arterial stiffness. Thus, the aim of this prospective study was to evaluate the prognostic value of PWV in high-risk patients with suspected CAD and to compare three different methods f...

Objectives: Hemodialysis patients have premature arterial stiffness, and the relationship between pulse wave velocity (PWV) and blood pressure (BP) may be different than in other hypertensives. Previous studies in such patients showed that when BP decrease is accompanied by PWV decrease the survival is improved. This study examines the prognostic...

Structural and functional dysfunction in both the macro- and microvasculature are a feature of essential hypertension. In a healthy cardiovascular system, the elastic properties of the large arteries ensure that pulsations in pressure and flow generated by cyclic left ventricular contraction are dampened, so that less pulsatile pressure and flow ar...

The Ankle Brachial Index (ABI) is the most commonly used method for the investigation of peripheral artery disease (PAD) in clinical settings, but has a low sensitivity for detecting PAD in asymptomatic patients. It is calculated only based on the systolic blood pressure in the limbs and ignores the shape of the pressure waves. Therefore, we invest...

Introduction and purpose Hemodialysis patients have premature arterial stiffness, and the relationship between pulse wave velocity (PWV) and blood pressure (BP) may be different than in other hypertensives. Previous studies showed that when BP decrease is accompanied by PWV decrease the survival is improved. The aim of this study is to examine the...

This is a comment on Salvi et al. Hypertension 2019;74:117-129.

Slow breathing is a relaxation exercise with class B, IIa recommendation by the AHA for lowering blood pressure (BP). Biofeedback on the effect of the exercise may improve patient adherence and enhance the BP lowering effect. Conversely, standard BP measurements with occlusion cuffs interfere with relaxation. Hence, the pulse transit time (PTT) is...

This is a preprint of a comment on an article of P. Salvi et al . published in JAHA: DOI: 10.1161/JAHA.118.011440

Rationale Patients with end-stage renal disease are characterized by increased cardiovascular and all-cause mortality because of advanced remodeling of the macrovascular and microvascular beds. Objective The aim of this study was to determine whether retinal microvascular function can predict all-cause and cardiovascular mortality in patients with...

Mortality in hemodialysis patients still remains unacceptably high. Enhanced arterial stiffness is a known cardiovascular risk factor, and pulse wave velocity (PWV) has proven to be a valid parameter to quantify risk. Recent studies showed controversial results regarding the prognostic significance of PWV for mortality in hemodialysis patients, whi...

Background: Association of Ambulatory Blood Pressure Monitoring (ABPM) with mortality depends on cardiac function in hemodialysis patients. Evidence for the predictive power of central Systolic Pressure (cSBP) is inconclusive. Thus, this study aimed to investigate the additional information of ambulatory cSBP in risk prediction in a cohort of hemod...

Background: Evidence on the utility of ambulatory BP monitoring for risk prediction has been scarce and inconclusive in patients on hemodialysis. In addition, in cardiac diseases such as heart failure and atrial fibrillation (common among patients on hemodialysis), studies have found that parameters such as systolic BP (SBP) and pulse pressure (PP...

Background: There is increasing evidence that the method of calibration directly influences the association between brachial systolic blood pressure (bSBP) and estimated aortic systolic blood pressure (aSBP) and subsequently affects prognostic and diagnostic differentiation power of the latter. Objective: The aim of this study was to investigate...

Heart rate variability (HRV) analysis is a non-invasive tool for assessing cardiac health. Entropy measures quantify the chaotic properties of HRV, but they are sensitive to the choice of their required parameters. Previous studies therefore have performed parameter optimization, targeting solely their particular patient cohort. In contrast, this w...

A novel in-vitro test (T50-test) assesses ex-vivo serum calcification propensity which predicts mortality in HD patients. The association of longitudinal changes of T50 with all-cause and cardiovascular mortality has not been investigated. We assessed T50 in paired sera collected at baseline and at 24 months in 188 prevalent European HD patients fr...