Valve-in-Valve Hemodynamics of 20-mm Transcatheter Aortic Valves in Small Bioprostheses

Computational Study on the Effects of Valve Orientation on the Hemodynamics and Leaflet Dynamics of Bioprosthetic Pulmonary Valves

Pulmonary valves do not display a fibrous annulus as do other valves in the heart; thus, pulmonary valves can be implanted at multiple orientations and locations within the right ventricular outflow tract (RVOT). This gives surgeons more freedom when implanting the valve but it also results in uncertainties regarding placement, particularly with respect to valve orientation. We investigate the pulmonary artery hemodynamics and valve leaflet dynamics of pulmonary valve replacements (PVRs) with various orientations via fluid-structure interaction (FSI) models. A canonical model of the branching pulmonary artery is coupled with a dynamic model of a pulmonary valve, and from this we quantify the effect of valve implant orientation on the postvalvular hemodynamics and leaflet dynamics. Metrics such as turbulent kinetic energy (TKE), branch pulmonary artery flow distributions, projected valve opening area (PVOA), and pressure differentials across the valve leaflets are analyzed. Our results indicate that off-axis orientation results in higher pressure forces and flow and energy asymmetry, which potentially have implications for long-term durability of implanted bioprosthetic valves.

Meta-Analysis of Valve-in-Valve Transcatheter Aortic Valve Implantation Versus Redo-surgical Aortic Valve Replacement in Failed Bioprosthetic Aortic Valve

This meta-analysis was conducted to compare clinical outcomes of valve-in-valve transcatheter aortic valve implantation (ViV-TAVI) versus redo-surgical aortic valve replacement (Redo-SAVR) in failed bioprosthetic aortic valves. We conducted a comprehensive review of previous publications of all relevant studies through August 2020. Twelve observational studies were included with a total of 8,430 patients, and a median-weighted follow-up period of 1.74 years. A pooled analysis of the data showed no significant difference in all-cause mortality (OR 1.15; 95% CI 0.93 to 1.43; p = 0.21), cardiovascular mortality, myocardial infarction, permanent pacemaker implantation, and the rate of moderate to severe paravalvular leakage between ViV-TAVI and Redo-SAVR groups. The rate of major bleeding (OR 0.36; 95% CI 0.16 to 0.83, p = 0.02), procedural mortality (OR 0.41; 95% CI 0.18 to 0.96, p = 0.04), 30-day mortality (OR 0.58; 95% CI 0.45 to 0.74, p <0.0001), and the rate of stroke (OR 0.65; 95% CI 0.52 to 0.81, p = 0.0001) were significantly lower in the ViV- TAVI arm when compared with Redo-SAVR arm. The mean transvalvular pressure gradient was significantly higher post-implantation in the ViV-TAVI group when compared with the Redo-SAVR arm (Mean difference 3.92; 95% CI 1.97 to 5.88, p < 0.0001). In conclusion, compared with Redo-SAVR, ViV-TAVI is associated with a similar risk of all-cause mortality, cardiovascular mortality, myocardial infarction, permanent pacemaker implantation, and the rate of moderate to severe paravalvular leakage. However, the rate of major bleeding, stroke, procedural mortality and 30-day mortality were significantly lower in the ViV-TAVI group when compared with Redo-SAVR.

Valve-in-Valve After Edwards INTUITY Valve Implantation in Small Aortic Annulus

The Edwards INTUITY aortic valve has in recent years played a significant role in facilitating surgical aortic valve replacement. Owing to the excellent hemodynamic characteristics and relatively new usage of this bioprosthetic aortic valve, the structural valve deterioration is an extremely rare complication; therefore, the treatment options of degenerated INTUITY valve with stenotic features have not been studied. We report the feasibility and safety of transcatheter valve-in-valve treatment for degenerated, stenotic INTUITY valve using the balloon expanding transcatheter aortic valve SAPIEN 3 in a small aortic annulus.

Principles of TAVR valve design, modelling, and testing

INTRODUCTION

Transcatheter aortic valve replacement (TAVR) has emerged as an effective minimally-invasive alternative to surgical valve replacement in medium- to high-risk, elderly patients with calcific aortic valve disease and severe aortic stenosis. The rapid growth of the TAVR devices market has led to a high variety of designs, each aiming to address persistent complications associated with TAVR valves that may hamper the anticipated expansion of TAVR utility.

AREAS COVERED

Here we outline the challenges and the technical demands that TAVR devices need to address for achieving the desired expansion, and review design aspects of selected, latest generation, TAVR valves of both clinically-used and investigational devices. We further review in detail some of the up-to-date modeling and testing approaches for TAVR, both computationally and experimentally, and additionally discuss those as complementary approaches to the ISO 5840-3 standard. A comprehensive survey of the prior and up-to-date literature was conducted to cover the most pertaining issues and challenges that TAVR technology faces.

EXPERT COMMENTARY

The expansion of TAVR over SAVR and to new indications seems more promising than ever. With new challenges to come, new TAV design approaches, and materials used, are expected to emerge, and novel testing/modeling methods to be developed.

Implantation Depth and Rotational Orientation Effect on Valve-in-Valve Hemodynamics and Sinus Flow

BACKGROUND

This study evaluated the effect of transcatheter aortic valve implantation depth and rotation on pressure gradient (PG), leakage fractions (LF), leaflet shear stress, and sinus washout in an effort to understand factors that may dictate optimal positioning for valve-in-valve (ViV) procedures. Sinus flow stasis is often associated with prosthetic leaflet thrombosis. Although recent ViV in vitro studies highlighted potential benefits of transcatheter aortic valve supraannular implantation to minimize PGs, the relationship between transcatheter aortic valve depth and other determinates of valve function remains unknown. Among these, LFs, shear stress, and poor sinus washout have been associated with poorer valve outcomes.

METHODS

ViV hemodynamic performance was evaluated in vitro vs axial positions -9.8, -6.2, 0, and +6 mm and angular orientations 0, 30, 60, and 90 degrees in a degenerated surgical aortic valve. PGs, LFs, and sinus shear stress and washout were compared. Leaflet high-speed imaging and particle-image velocimetry were performed to elucidate hemodynamic mechanisms.

RESULTS

(1) The PG varies as a function of axial position, with supraannular deployments yielding a maximum benefit of 7.85 mm Hg less than PGs for subannular deployments irrespective of commissural alignment (p < 0.01); (2) in contrast, LF decreased in relationship to subannular deployment; and (3) at peak systole, sinus flow shear stress increased with deployment depth as did sinus washout with and without coronary flow.

CONCLUSIONS

First, supraannular axial deployment is associated with lower PGs irrespective of commissural alignment. Second, subannular deployment is associated with more favorable sinus hemodynamics and less LF. Further in vivo studies are needed to substantiate these observations and facilitate optimal prosthesis positioning during ViV procedures.

Optimizing hemodynamics of transcatheter aortic valve-in-valve implantation in 19-mm surgical aortic prostheses

OBJECTIVE

To demonstrate the feasibility of achieving good hemodynamic results with valve-in-valve transcatheter aortic valve replacement (ViV TAVR) for degenerated 19 mm surgical bioprosthetic valves.

BACKGROUND

Considerable controversy exists regarding ViV TAVR within 19mm surgical prostheses due to concerns of elevated valve gradients and mortality.

METHODS

Among all patient undergoing ViV TAVR between 7/2016 and 4/2017 for symptomatic severe bioprosthetic aortic stenosis (AS), five had a 19 mm surgical valve in place and were included in this publication. None of the patients had patient-prosthesis mismatch. Aggressive post-dilation was performed in four out of five cases using a special technique we describe below.

RESULTS

In all cases, mean aortic valve (AV) gradients significantly improved post-ViV TAVR, particularly after post-dilation. Interestingly, high pressure post-dilation of the ViV resulted in an increase in the diameter of surgical valve stent frame dimensions in nearly all patients who underwent post-dilation.

CONCLUSIONS

Good hemodynamic outcome is possible with aggressive post-dilation in patients with 19 mm failed surgical bioprostheses. High-risk patients with 19 mm failed surgical prostheses who do not otherwise have viable surgical options should be considered for ViV TAVR.

Valve-in-valve outcome: design impact of a pre-existing bioprosthesis on the hydrodynamics of an Edwards Sapien XT valve

Objectives

Bioprosthetic aortic heart valves are increasingly implanted in younger patients. Therefore, a strategy for potential valve failure should be developed before implanting the 'first valve'. The goal of this in vitro study was to provide insight into the effects of the design of a bioprosthesis on a valve-in-valve implanted Sapien XT valve.

Methods

The hydrodynamic performance of a 23-mm Sapien XT valve implanted in Vascutek Aspire, Edwards Perimount, Medtronic Mosaic and St. Jude Medical Trifecta heart valves was investigated in a left heart simulator. In addition to the hydrodynamic results, the leaflet dynamics were analysed in high-speed video recordings of the tests.

Results

All valve-in-valve combinations in this study fulfilled the minimum acceptance criteria defined by relevant approval standards (e.g. ISO 5840) but displayed significant differences in their performances. Small inner diameters of the bioprostheses were associated with increased mean pressure gradients, decreased effective orifice areas and geometric opening areas as well as with pin-wheeling and uneven leaflet motion. In addition, implantation in bioprostheses with internally mounted leaflets was associated with lower paravalvular leakage.

Conclusions

The results of this study suggest that a surgical bioprosthesis with a large inner diameter and internally mounted leaflets improves the heamodynamics and potentially the durability of a valve-in-valve combination. These results should give the attending physicians critical information to consider when deciding on a bioprosthesis for younger patients.

In vitro evaluation of implantation depth in valve-in-valve using different transcatheter heart valves

AIMS

Transcatheter heart valve (THV) implantation in failed bioprosthetic valves (valve-in-valve [ViV]) offers an alternative therapy for high-risk patients. Elevated post-procedural gradients are a significant limitation of aortic ViV. Our objective was to assess the relationship between depth of implantation and haemodynamics.

METHODS AND RESULTS

Commercially available THVs used for ViV were included in the analysis (CoreValve Evolut, SAPIEN XT and the Portico valve). THVs were implanted in small surgical valves (label size 19 mm) to simulate boundary conditions. Custom-mounted pulse duplicators registered relevant haemodynamic parameters. Twenty-eight experiments were performed (13 CVE, 5 SXT and 10 Portico). Ranges of depth of implantation were: CVE: -1.2 mm to 15.7 mm; SXT: -2.2 mm to 7.5 mm; Portico: 1.4 mm to 12.1 mm. Polynomial regression established a relationship between depth of implantation and valvular mean gradients (CVE: p<0.001; SXT: p=0.01; Portico: p=0.002), as well as with EOA (CVE: p<0.001; SXT: p=0.02; Portico valve: p=0.003). In addition, leaflet coaptation was better in the high implantation experiments for all valves.

CONCLUSIONS

The current comprehensive bench testing assessment demonstrates the importance of high device position for the attainment of optimal haemodynamics during aortic ViV procedures.

Transcatheter aortic valve implantation with a Sapien 3 Commander 20 mm valves in patients with degenerated 19 mm bioprosthetic aortic valve

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) in patients with degenerated bioprosthetic aortic valve has been successfully performed as an alternative to surgery. We describe our initial experience of valve-in-valve TAVI in five patients, using new generation Edwards Sapien 3 transcatheter heart valves implanted into degenerated 19 mm bioprosthetic valves. 20-mm Edwards S3 valves were offered for compassionate use. All patients had significant aortic valve stenosis.

METHODS AND RESULTS

The main vascular access was achieved and pre-closed with two Proglide closure devices in one patient and Prostar closure devices in four patients. For each TAVI procedure an Edwards 14 French sheath was inserted without complication and sutured in place. The Sapien 3 Commander delivery system was inserted and the valve was aligned in the descending aorta. The 20-mm Sapien 3 valve was deployed with slow continuous inflation during rapid right ventricular pacing. The cranial edge of the Edwards S3 valve was aligned with the cranial radiopaque markers of bioprosthesis to minimize paravalvular leak. Post-deployment angiography, transesophageal echocardiography and aortogram confirmed absence of mild aortic insufficiency and no increase in trans-aortic gradient when compared to a naïve 19 mm bioprosthetic valve.

CONCLUSION

Valve-in-valve TAVI with the Edwards S3 transcatheter heart valve for degenerative bioprosthetic aortic valves is technically feasible. The proper position of the stented valve minimizes the risk for post-procedure paravalvular insufficiency and provides good transaortic pressure gradient. © 2016 Wiley Periodicals, Inc.

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. Some of the most common complications that plague current TAV devices include malpositioning, crimp-induced leaflet damage, paravalvular leak, thrombosis, conduction abnormalities and prosthesis-patient mismatch. In this article, we provide an in-depth review of the current state-of-the-art pertaining the mechanics of TAVs while highlighting various studies guiding clinicians, regulatory agencies, and next-generation device designers.

Role of transcatheter aortic valve implantation (TAVI) versus conventional aortic valve replacement in the treatment of aortic valve disease

Conventional aortic valve replacement (AVR) surgery has been in clinical use since 1960. Results, particularly in high-risk populations such as the very elderly and frail, continue to improve in response to the challenges posed by this growing segment of the patient population. Transcatheter aortic valve implantation (TAVI) is a fairly recent development, performed for the first time in 2002. The last decade has seen an exponential growth in the application of this technology in higher-risk populations. Results of recent randomized prospective trials demonstrate both the future promise and current problems of the TAVI approach. Many patients deemed inoperable for AVR have been treated successfully by TAVI. However, elevated procedural and late mortality rates, excessive early and late stroke, and a significant incidence of periprosthetic aortic valve insufficiency and patient-prosthesis mismatch all suggest caution in extending this technology to patients able to undergo conventional AVR with a low risk of early or late complications.

The First Case of Successful Transcatheter Aortic Valve Implantation Using CoreValve in Korea

Surgical replacement of the aortic valve is the standard therapy for severe aortic valve stenosis. However, it is generally associated with increased mortality and morbidities in older individuals. Transcatheter aortic valve implantation (TAVI) is a less invasive procedure and has shown similar clinical outcomes as surgical treatment in elderly patients at high risk for conventional surgery. In this report, we describe the first case of TAVI using a CoreValve in Korea. An 84-year-old man with symptomatic severe aortic valve stenosis was successfully treated by transfemoral TAVI. The patient was discharged without any significant complications and remained free of adverse clinical event for a follow-up duration of 6 months.