A Novel Echocardiographic Parameter to Confirm Low-Gradient Aortic Stenosis Severity.

Background: In patients with low-gradient (LG) aortic stenosis (AS), confirming disease severity and indication of intervention often requires dobutamine stress echocardiography (DSE) or aortic valve calcium scoring by computed tomography. We hypothesized that the mean transvalvular pressure gradient to effective orifice area ratio (MG/EOA, in mm Hg/cm) measured during rest echocardiography identifies true-severe AS (TSAS) and is associated with clinical outcomes in patients with low-flow, LG-AS.

Objectives: The purpose of this study was to evaluate the diagnostic and prognostic value of MG/EOA ratio.

Leaflet Mechanical Stress in Different Designs and Generations of Transcatheter Aortic Valves: An in Vitro Study.

Background: It is unknown whether bioprostheses used for transcatheter aortic valve implantation will have similar long-term durability as those used for surgical aortic valve replacement. Repetitive mechanical stress applied to the valve leaflets, particularly during diastole, is the main determinant of structural valve deterioration. Leaflet mechanical stress cannot be measured in vivo.

In vitro Doppler versus catheter transvalvular pressure gradients in balloon-expandable versus self-expanding transcatheter aortic valves.

Objectives: The objective of this in vitro study was to compare Doppler versus catheter transvalvular pressure gradients (TPG) in third generations balloon-expandable (BE) versus self-expanding (SE) transcatheter heart valves (THV).

Background: TPG is a key parameter to assess and follow valve hemodynamic function following transcatheter aortic valve implantation (TAVI). It remains uncertain and debated whether, and to which extent, TPGs differ according to the type of THV, that is, BE versus SE and to the method used for TPG measurement, that is, Doppler echocardiography versus cardiac catheterization.

Leaflet stress quantification of porcine vs bovine surgical bioprostheses: an study.

Calcified aortic stenoses are among the most prevalent form of cardiovascular diseases in the industrialized countries. This progressive disease, with no effective medical therapy, ultimately requires aortic valve replacement - either a surgical or very recently transcatheter aortic valve implantation. Increase leaflet mechanical stress is one of the main determinants of the structural deterioration of bioprosthetic aortic valves.

In vitro correlation between the effective and geometric orifice area in aortic stenosis.

Background: Planimetry of aortic stenosis can be performed when Doppler measurements are unavailable. We sought to evaluate if, as advised in guidelines, the geometric orifice area (GOA) threshold value of 1 cm² was concordant with the threshold of 1 cm² of the effective orifice area (EOA), and the factors influencing the contraction coefficient (EOA/GOA ratio).

Methods: In an in vitro mock circulatory system, we tested 6 degrees of AS severity (3 severe and 3 non-severe), and 3 levels of flow (<150 ml/s, 150-200 ml/s, >250 ml/s).

Effects of hemodynamic conditions and valve sizing on leaflet bending stress in self-expanding transcatheter aortic valve: An in vitro study.

Transcatheter aortic valve (TAV) replacement has become a viable alternative to surgery for high and intermediate risk patients with severe aortic stenosis. This technology may extend to the younger and lower risk patients. In this population, long-term durability of the TAV is key.

A bench test study of bioprosthetic valve fracture performed before versus after transcatheter valve-in-valve intervention.

Aims: Bioprosthetic valve fracture (BVF) may improve transvalvular gradients and transcatheter heart valve (THV) expansion during VIV interventions. However, the optimal timing of BVF is unknown. We assessed the impact of timing of BVF (before versus after) for valve-in-valve (VIV) intervention, on hydrodynamic function and THV expansion.

A novel method to quantitate bioprosthetic valve leaflet mechanical stress: a numerical and in vitro study.

An original in vitro/in silico method was developed to estimate the local and global mechanical stress applied on the bioprosthetic valve leaflet, which can be important for better understanding of the valve durability. A non-contact system based on stereophotogammetry and digital image correlation enabled filming and studying the valve leaflet movement frame by frame and performing three-dimensional analysis. The deformation was applied in a finite element model in order to calculate the local mechanical stress applied.

Valve-in-Valve Transcatheter Aortic Valve Replacement and Bioprosthetic Valve Fracture Comparing Different Transcatheter Heart Valve Designs: An Ex Vivo Bench Study.

Objectives: The authors assessed the effect of valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) followed by bioprosthetic valve fracture (BVF), testing different transcatheter heart valve (THV) designs in an ex vivo bench study.

Background: Bioprosthetic valve fracture can be performed to improve residual transvalvular gradients following VIV TAVR.

Methods: The authors evaluated VIV TAVR and BVF with the SAPIEN 3 (S3) (Edwards Lifesciences, Irvine, California) and ACURATE neo (Boston Scientific Corporation, Natick, Massachusetts) THVs.

Overexpansion of the SAPIEN 3 Transcatheter Heart Valve: An Ex Vivo Bench Study.

Objectives: This study assessed the effect of overexpansion beyond labeled size (diameter) of transcatheter heart valves through an ex vivo bench study.

Background: Transcatheter heart valves function optimally when expanded to specific dimensions. However, clinicians may sometimes wish to overexpand balloon-expandable valves to address specific clinical challenges.

Effect of size and position of self-expanding transcatheter valve on haemodynamics following valve-in-valve procedure in small surgical bioprostheses: an in vitro study.

Aims: The valve-in-valve (ViV) procedure has become a valuable alternative for the treatment of failed surgical bioprostheses (BP) in high-risk patients. However, in small BP, the clinical outcomes have been suboptimal due to high post-procedural gradients. We aimed to examine the effect of size and position of the self-expanding transcatheter heart valve (THV) CoreValve on the haemodynamics of ViV within small BP.