Ineffective Orifice Area: Practical Limitations of Accurate EOA Assessment for Low-Gradient Heart Valve Prostheses.

Purpose: The goal of this study was to demonstrate the range in effective orifice area (EOA) values that may be possible given the ISO 5840 definition of EOA and the practical limits in the accurate measurement of pressure differential across large diameter valves.

Methods: A 31 mm mechanical valve was tested on a commercially available pulse duplicator configured for mitral valve testing and tuned to nominal conditions. The experimental data was used as a basis for performing Monte Carlo analyses with published specifications for commonly used pressure sensors as well as measurement equipment accuracy requirements described in ISO 5840.

An Evaluation of the Influence of Coronary Flow on Transcatheter Heart Valve Neo-Sinus Flow Stasis.

Transcatheter heart valve (THV) leaflet thrombosis in the neo-sinus and associated reduced leaflet motion is of clinical concern due to risks of embolism and worsened valve hemodynamics. Flow stasis in the neo-sinus (the space between the native and THV leaflets) is a known risk factor, but the role of proximal coronary flow is yet to be investigated. We tested two replicas of FDA approved commercial THVs-intra-annular and supra-annular (similar to the SAPIEN 3 and CoreValve families)-in a left heart simulator with coronary flow.

Transcatheter aortic valve deployment influences neo-sinus thrombosis risk: An in vitro flow study.

Objectives: We investigated the impact of (transcatheter heart valve) THV expansion at the level of the native annulus and implant depth on valve performance and neo-sinus flow stasis.

Background: Flow stasis in the neo-sinus is one of the identified risk factors of THV thrombosis.

Methods: A 29 mm CoreValve and 26 mm SAPIEN 3 were deployed under different expansions (CoreValve, SAPIEN 3) and implant depths (CoreValve) within a patient-derived aortic root in a pulse duplicator.

A mechanistic investigation of the EDWARDS INTUITY Elite valve's hemodynamic performance.

Objective: Rapid deployment surgical aortic valve replacement has emerged as an alternative to the contemporary sutured valve technique. A difference in transvalvular pressure has been observed clinically between RD-SAVR and contemporary SAVR. A mechanistic inquiry into the impact of the rapid deployment valve inflow frame design on the left ventricular outflow tract and valve hemodynamics is needed.

The Fluid Mechanics of Transcatheter Heart Valve Leaflet Thrombosis in the Neosinus.

Background: Transcatheter heart valve (THV) thrombosis has been increasingly reported. In these studies, thrombus quantification has been based on a 2-dimensional assessment of a 3-dimensional phenomenon.

Methods: Postprocedural, 4-dimensional, volume-rendered CT data of patients with CoreValve, Evolut R, and SAPIEN 3 transcatheter aortic valve replacement enrolled in the RESOLVE study (Assessment of Transcatheter and Surgical Aortic Bioprosthetic Valve Dysfunction With Multimodality Imaging and Its Treatment with Anticoagulation) were included in this analysis.

Aortic Regurgitation Generates a Kinematic Obstruction Which Hinders Left Ventricular Filling.

An incompetent aortic valve (AV) results in aortic regurgitation (AR), where retrograde flow of blood into the left ventricle (LV) is observed. In this work, we parametrically characterized the detailed changes in intra-ventricular flow during diastole as a result of AR in a physiological in vitro left-heart simulator (LHS). The loss of energy within the LV as the level of AR increased was also assessed.

On the Mechanics of Transcatheter Aortic Valve Replacement.

Transcatheter aortic valves (TAVs) represent the latest advances in prosthetic heart valve technology. TAVs are truly transformational as they bring the benefit of heart valve replacement to patients that would otherwise not be operated on. Nevertheless, like any new device technology, the high expectations are dampened with growing concerns arising from frequent complications that develop in patients, indicating that the technology is far from being mature.

Valve Type, Size, and Deployment Location Affect Hemodynamics in an In Vitro Valve-in-Valve Model.

Objectives: The purpose of this study was to optimize hemodynamic performance of valve-in-valve (VIV) according to transcatheter heart valve (THV) type (balloon vs. self-expandable), size, and deployment positions in an in vitro model.

Background: VIV transcatheter aortic valve replacement is increasingly used for the treatment of patients with a failing surgical bioprosthesis.

The Effect of Valve-in-Valve Implantation Height on Sinus Flow.

Valve-in-valve transcatheter aortic valve replacement (VIV-TAVR) has proven to be a successful treatment for high risk patients with failing aortic surgical bioprostheses. However, thrombus formation on the leaflets of the valve has emerged as a major issue in such procedures, posing a risk of restenosis, thromboembolism, and reduced durability. In this work we attempted to understand the effect of deployment position of the transcatheter heart valve (THV) on the spatio-temporal flow field within the sinus in VIV-TAVR.

How Can We Help a Patient With a Small Failing Bioprosthesis?: An In Vitro Case Study.

Objectives: The aim of this study was to investigate the hemodynamic performance of a transcatheter heart valve (THV) deployed at different valve-in-valve positions in an in vitro model using a small surgical bioprosthesis.

Background: Patients at high surgical risk with failing 19-mm surgical aortic bioprostheses are not candidates for valve-in-valve transcatheter aortic valve replacement, because of risk for high transvalvular pressure gradients (TVPGs) and patient-prosthesis mismatch.

Methods: A 19-mm stented aortic bioprosthesis was mounted into the aortic chamber of a pulse duplicator, and a 23-mm low-profile balloon-expandable THV was deployed (valve-in-valve) in 4 positions: normal (bottom of the THV stent aligned with the bottom of the surgical bioprosthesis sewing ring) and 3, 6, and 8 mm above the normal position.