Large-scale computed tomography study of aortic arch and supra-aortic artery morphology: Variations and potential implications for arterial extracorporeal life support access.

BackgroundThe anatomy and morphology of the aortic arch and its supra-aortic arteries can vary significantly among individual patients. This variability may have a particular relevance in cardiovascular procedures or interventions, and specifically during the use of mechanical circulatory support. This importance accounts for a specific influence on hemodynamics in veno-arterial extracorporeal membrane oxygenation (V-A ECMO) through an axillary/subclavian artery access.

Morphology and calcification characterization in patients undergoing TAVI: A 3D statistical shape modelling study.

Aortic stenosis (AS) is a common valvular disease becoming more prevalent globally due to the aging of the population. Transcatheter aortic valve implantation (TAVI) is a minimally invasive intervention indicated for AS patients as alternative to surgical replacement. TAVI is to date an established procedure.

Sensitivity analysis for exploring the variability and parameter landscape in virtual patient cohorts of multi-vessel coronary artery disease.

Virtual patient cohorts (VPC) are crucial in clinical trials, offering a promising, cost-effective and ethically advantageous alternative to real clinical randomized controlled trials to evaluate the safety and efficacy of clinical decision support tools and medical devices. This article focuses on the role of sensitivity analysis (SA) in evaluating a VPC created through a virtual cohort generator, which includes a one-dimensional pulse wave propagation model of the coronary circulation. Given the inherent limitations of clinical data, a synthetic VPC was generated that captured the global population variability of the fractional flow reserve distribution observed in the FAME study, a real-world randomized clinical trial.

Interpretation of intra-operative strain differences in ascending thoracic aortic repair patients.

Local biaxial deformation plays a pivotal role in evaluating the tissue state of the ascending aorta and in driving intramural cell-mediated tissue remodeling. Unfortunately, the absence of anatomical markers on the ascending aorta presents challenges in capturing deformation. Utilizing our established intra-operative biaxial strain measurement method, we delineated local biaxial deformation characteristics in patients undergoing aortic valve replacement and coronary artery bypass graft surgery recipients (n = 20), and Aortic Repair surgery patients (n = 47).

A Multiscale Mathematical Model for Fetal Gas Transport and Regulatory Systems During Second Half of Pregnancy.

Fetal asphyxia, a condition resulting from the combined effects of hypoxia and hypercapnia, leads to approximately 900,000 annual deaths worldwide. One cause is umbilical cord compression during labor-induced uterine contractions, disrupting the transport of metabolites to and from the placenta, and resulting in asphyxia. Current fetal well-being assessment relies on monitoring fetal heart rate and uterine contractions as indicators of oxygen delivery to the brain.

A Multiscale Mathematical Model for the Fetal Blood Circulation of the Second Half of Pregnancy.

Doppler ultrasound is a commonly used method to assess hemodynamics of the fetal cardiovascular system and to monitor the well-being of the fetus. Indices based on the velocity profile are often used for diagnosis. However, precisely linking these indices to specific underlying physiology factors is challenging.

Explainable Machine Learning Based Prediction of Severity of Heart Failure Using Primary Electronic Health Records.

Heart Failure (HF) is a life-threatening condition. It affects more than 64 million people worldwide. Early diagnosis of HF is extremely crucial.

Significance of Dynamic Axial Stretching on Estimating Biomechanical Behavior and Properties of the Human Ascending Aorta.

Contrary to most vessels, the ascending thoracic aorta (ATA) not only distends but also elongates in the axial direction. The purpose of this study is to investigate the biomechanical behavior of the ascending thoracic aorta (ATA) in response to dynamic axial stretching during the cardiac cycle. In addition, the implications of neglecting this dynamic axial stretching when estimating the constitutive model parameters of the ATA are investigated.

Parameter subset reduction for imaging-based digital twin generation of patients with left ventricular mechanical discoordination.

Background: Integration of a patient's non-invasive imaging data in a digital twin (DT) of the heart can provide valuable insight into the myocardial disease substrates underlying left ventricular (LV) mechanical discoordination. However, when generating a DT, model parameters should be identifiable to obtain robust parameter estimations. In this study, we used the CircAdapt model of the human heart and circulation to find a subset of parameters which were identifiable from LV cavity volume and regional strain measurements of patients with different substrates of left bundle branch block (LBBB) and myocardial infarction (MI).

Efficient sensitivity analysis for biomechanical models with correlated inputs.

In most variance-based sensitivity analysis (SA) approaches applied to biomechanical models, statistical independence of the model input is assumed. However, often the model inputs are correlated. This might alter the interpretation of the SA results, which may severely impact the guidance provided during model development and personalization.

Generation of synthetic aortic valve stenosis geometries for in silico trials.

In silico trials are a promising way to increase the efficiency of the development, and the time to market of cardiovascular implantable devices. The development of transcatheter aortic valve implantation (TAVI) devices, could benefit from in silico trials to overcome frequently occurring complications such as paravalvular leakage and conduction problems. To be able to perform in silico TAVI trials virtual cohorts of TAVI patients are required.

Biomechanical Characterisation of Thoracic Ascending Aorta with Preserved Pre-Stresses.

Mechanical properties of an aneurysmatic thoracic aorta are potential markers of future growth and remodelling and can help to estimate the risk of rupture. Aortic geometries obtained from routine medical imaging do not display wall stress distribution and mechanical properties. Mechanical properties for a given vessel may be determined from medical images at different physiological pressures using inverse finite element analysis.

Guideline recommendations on minimal blood vessel diameters and arteriovenous fistula outcomes.

Objective: Clinical guidelines provide recommendations on the minimal blood vessel diameters required for arteriovenous fistula creation but the evidence for these recommendations is limited. We compared vascular access outcomes of fistulas created in agreement with the ESVS Clinical Practice Guidelines (i.e.

Deep Learning Method for Estimation of Morphological Parameters Based on CT Scans.

In this study, we propose a Convolutional Neural Network (CNN) with an assembly of non-linear fully connected layers for estimating body height and weight using a limited amount of data. This method can predict the parameters within acceptable clinical limits for most of the cases even when trained with limited data.

Hemodynamics-driven mathematical model of third heart sound generation.

The proto-diastolic third heart sound (S3) is observed in various hemodynamic conditions in both normal and diseased hearts. We propose a novel, one-degree of freedom mathematical model of mechanical vibrations of heart and blood that generates the third heart sound, implemented in a real-time model of the cardiovascular system (CircAdapt). To examine model functionality, S3 simulations were performed for conditions mimicking the normal heart as well as heart failure with preserved ejection fraction (HFpEF), atrioventricular valve regurgitation (AVR), atrioventricular valve stenosis (AVS) and septal shunts (SS).

A review study of fetal circulatory models to develop a digital twin of a fetus in a perinatal life support system.

Background: Preterm birth is the main cause of neonatal deaths with increasing mortality and morbidity rates with decreasing GA at time of birth. Currently, premature infants are treated in neonatal intensive care units to support further development. However, the organs of, especially, extremely premature infants (born before 28 weeks of GA) are not mature enough to function optimally outside the womb.

From evidence-based medicine to digital twin technology for predicting ventricular tachycardia in ischaemic cardiomyopathy.

Survivors of myocardial infarction are at risk of life-threatening ventricular tachycardias (VTs) later in their lives. Current guidelines for implantable cardioverter defibrillators (ICDs) implantation to prevent VT-related sudden cardiac death is solely based on symptoms and left ventricular ejection fraction. Catheter ablation of scar-related VTs is performed following ICD therapy, reducing VTs, painful shocks, anxiety, depression and worsening heart failure.

A realistic arteriovenous dialysis graft model for hemodynamic simulations.

Objective: The hemodynamic benefit of novel arteriovenous graft (AVG) designs is typically assessed using computational models that assume highly idealized graft configurations and/or simplified boundary conditions representing the peripheral vasculature. The objective of this study is to evaluate whether idealized AVG models are suitable for hemodynamic evaluation of new graft designs, or whether more realistic models are required.

Methods: An idealized and a realistic, clinical imaging based, parametrized AVG geometry were created.

Improved Quantification of Cell Density in the Arterial Wall-A Novel Nucleus Splitting Approach Applied to 3D Two-Photon Laser-Scanning Microscopy.

Accurate information on vascular smooth muscle cell (VSMC) content, orientation, and distribution in blood vessels is indispensable to increase understanding of arterial remodeling and to improve modeling of vascular biomechanics. We have previously proposed an analysis method to automatically characterize VSMC orientation and transmural distribution in murine carotid arteries under well-controlled biomechanical conditions. However, coincident nuclei, erroneously detected as one large nucleus, were excluded from the analysis, hampering accurate VSMC content characterization and distorting transmural distributions.

Uncertainty Quantification of Regional Cardiac Tissue Properties in Arrhythmogenic Cardiomyopathy Using Adaptive Multiple Importance Sampling.

Computational models of the cardiovascular system are widely used to simulate cardiac (dys)function. Personalization of such models for patient-specific simulation of cardiac function remains challenging. Measurement uncertainty affects accuracy of parameter estimations.

Optic nerve sheath diameter assessment by neurosonology: A review of methodologic discrepancies.

Background And Purpose: Reported cutoff values of the optic nerve sheath diameter (ONSD) for the diagnosis of elevated intracranial pressure (ICP) are inconsistent. This hampers ONSD as a possible noninvasive bedside monitoring tool for ICP. Because the influence of methodological differences on variations in cutoff values is unknown, we performed a narrative review to identify discrepancies in ONSD assessment methodologies and to investigate their effect on reported ONSD values.

Intra-Operative Video-Based Measurement of Biaxial Strains of the Ascending Thoracic Aorta.

Local biaxial deformation measurements are essential for the in-depth investigation of tissue properties and remodeling of the ascending thoracic aorta, particularly in aneurysm formation. Current clinical imaging modalities pose limitations around the resolution and tracking of anatomical markers. We evaluated a new intra-operative video-based method to assess local biaxial strains of the ascending thoracic aorta.

Computationally guided in-vitro vascular growth model reveals causal link between flow oscillations and disorganized neotissue.

Disturbed shear stress is thought to be the driving factor of neointimal hyperplasia in blood vessels and grafts, for example in hemodialysis conduits. Despite the common occurrence of neointimal hyperplasia, however, the mechanistic role of shear stress is unclear. This is especially problematic in the context of in situ scaffold-guided vascular regeneration, a process strongly driven by the scaffold mechanical environment.

An Automated Algorithm for Optic Nerve Sheath Diameter Assessment from B-mode Ultrasound Images.

Background And Purpose: The optic nerve sheath diameter (ONSD) is a promising surrogate marker for the detection of raised intracranial pressure (ICP). However, inconsistencies in manual ONSD assessment are thought to affect ONSD and the corresponding ONSD cutoff values for the diagnosis of elevated ICP, hereby hampering the full potential of ONSD. In this study, we developed an image intensity-invariant algorithm to automatically estimate ONSD from B-mode ultrasound images at multiple depths.