High Shear Stress Reduces ERG Causing Endothelial-Mesenchymal Transition and Pulmonary Arterial Hypertension.

Background: Computational modeling indicated that pathological high shear stress (HSS; 100 dyn/cm) is generated in pulmonary arteries (PAs; 100-500 µm) in congenital heart defects causing PA hypertension (PAH) and in idiopathic PAH with occlusive vascular remodeling. Endothelial-to-mesenchymal transition (EndMT) is a feature of PAH. We hypothesize that HSS induces EndMT, contributing to the initiation and progression of PAH.

Combined Impact of Residual Mitral Regurgitation and Gradient After Mitral Valve Transcatheter Edge-to-Edge Repair.

Background: Reducing mitral regurgitation (MR) during mitral transcatheter edge-to-edge repair (M-TEER) may come at the cost of increased mitral valve gradient (MVG). The combined impact of residual MR and MVG on clinical outcomes after M-TEER is unknown.

Objectives: This study sought to evaluate the impact of postprocedure MR and MVG on clinical outcomes after M-TEER.

Evaluating Mitral TEER in the Management of Moderate Secondary Mitral Regurgitation Among Heart Failure Patients.

Background: Moderate secondary mitral regurgitation (SMR) represents a subgroup of heart failure (HF) patients with treatment restricted to medical therapy. Outcomes in patients with moderate SMR treated with mitral transcatheter edge-to-edge repair (M-TEER) are less well known.

Objectives: The aim of this study was to assess the safety and effectiveness of M-TEER in subjects with moderate SMR using the EXPANDed studies.

High Shear Stress Reduces ERG Causing Endothelial-Mesenchymal Transition and Pulmonary Arterial Hypertension.

Pathological high shear stress (HSS, 100 dyn/cm ) is generated in distal pulmonary arteries (PA) (100-500 μm) in congenital heart defects and in progressive PA hypertension (PAH) with inward remodeling and luminal narrowing. Human PA endothelial cells (PAEC) were subjected to HSS versus physiologic laminar shear stress (LSS, 15 dyn/cm ). Endothelial-mesenchymal transition (EndMT), a feature of PAH not previously attributed to HSS, was observed.

4D flow cardiovascular magnetic resonance recovery profiles following pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension.

Background: Four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR) allows comprehensive assessment of pulmonary artery (PA) flow dynamics. Few studies have characterized longitudinal changes in pulmonary flow dynamics and right ventricular (RV) recovery following a pulmonary endarterectomy (PEA) for patients with chronic thromboembolic pulmonary hypertension (CTEPH). This can provide novel insights of RV and PA dynamics during recovery.

Computational simulation-derived hemodynamic and biomechanical properties of the pulmonary arterial tree early in the course of ventricular septal defects.

Untreated ventricular septal defects (VSDs) can lead to pulmonary arterial hypertension (PAH) characterized by elevated pulmonary artery (PA) pressure and vascular remodeling, known as PAH associated with congenital heart disease (PAH-CHD). Though previous studies have investigated hemodynamic effects on vascular mechanobiology in late-stage PAH, hemodynamics leading to PAH-CHD initiation have not been fully quantified. We hypothesize that abnormal hemodynamics from left-to-right shunting in early stage VSDs affects PA biomechanical properties leading to PAH initiation.

The nested block preconditioning technique for the incompressible Navier-Stokes equations with emphasis on hemodynamic simulations.

We develop a novel iterative solution method for the incompressible Navier-Stokes equations with boundary conditions coupled with reduced models. The iterative algorithm is designed based on the variational multiscale formulation and the generalized- scheme. The spatiotemporal discretization leads to a block structure of the resulting consistent tangent matrix in the Newton-Raphson procedure.

Image-based scaling laws for somatic growth and pulmonary artery morphometry from infancy to adulthood.

Pulmonary artery (PA) morphometry has been extensively explored in adults, with particular focus on intra-acinar arteries. However, scaling law relationships for length and diameter of extensive preacinar PAs by age have not been previously reported for in vivo human data. To understand preacinar PA growth spanning children to adults, we performed morphometric analyses of all PAs visible in the computed tomography (CT) and magnetic resonance (MR) images from a healthy subject cohort [ = 16; age: 1-51 yr; body surface area (BSA): 0.

Integrated Image-Based Computational Fluid Dynamics Modeling Software as an Instructional Tool.

Computational modeling of cardiovascular flows is becoming increasingly important in a range of biomedical applications, and understanding the fundamentals of computational modeling is important for engineering students. In addition to their purpose as research tools, integrated image-based computational fluid dynamics (CFD) platforms can be used to teach the fundamental principles involved in computational modeling and generate interest in studying cardiovascular disease. We report the results of a study performed at five institutions designed to investigate the effectiveness of an integrated modeling platform as an instructional tool and describe "best practices" for using an integrated modeling platform in the classroom.

Evolution of hemodynamic forces in the pulmonary tree with progressively worsening pulmonary arterial hypertension in pediatric patients.

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling resulting in right ventricular (RV) dysfunction and ultimately RV failure. Mechanical stimuli acting on the vessel walls of the full pulmonary tree have not previously been comprehensively characterized. The goal of this study is to characterize wall shear stress (WSS) and strain in pediatric PAH patients at different stages of disease severity using computational patient-specific modeling.

Magnitude, decadal changes, and impact of regional background ozone transported into the greater Houston, Texas, area.

Two independent analyses of the daily maximum 8 h average ozone concentrations measured during the high ozone season (May through October) at Continuous Ambient Monitoring Stations are used to quantify the regional background ozone transported into the Houston-Galveston-Brazoria (HGB) area. The dependence on wind direction is examined, and long-term trends are determined using measurements made between 1998 and 2012. Both analyses show that the regional background ozone has declined during periods of continental outflow: i.