Deformation of Transcatheter Heart Valve Following Valve-in-Valve Transcatheter Aortic Valve Replacement: Implications for Hemodynamics

Effects of different valve-in-valve positions on the hydrodynamic properties of transcatheter aortic valves

OBJECTIVE

With the rise of transcatheter aortic valve-in-valve (ViV) procedures for high-risk patients with degenerated surgical aortic valves, precise positioning of the transcatheter heart valve (THV) within the surgical heart valve (SHV) is crucial for optimal functional outcomes. This study aims to explore the impact of implantation depth on functional outcomes post-ViV in a controlled in vitro setting.

METHODS

This study focused on the impact of valve positioning on fluid dynamics characteristics and subsequent ViV procedural outcomes. Rigorous in vitro experiments measured the structural parameters of the surgical valves, and based on these, the appropriate Taurus Elite valves were selected for pulse flow testing under simulated conditions of varying heart rates and cardiac outputs. Fluid dynamic evaluations were conducted on Taurus Elite THVs in sizes 21, 23, 26, 29 mm and SHVs from two brands: Hancock II (Medtronic, USA) and BalMedic (Balance Medical, China) across a range of diameters. In-depth analysis was performed at a cardiac output (CO) of 5 L/min and heart rate (HR) of 70 bpm, focusing on key metrics such as transvalvular pressure gradient (TVPG), effective orifice area (EOA), and total regurgitation fraction (TRF) at implantation depths of -2.5, 0, 2.5, and 5 mm to gain insights into the dynamic interaction between THV placement and hemodynamic performance. Anchoring force tests were also conducted for SHV-THV combinations at -2.5 and 0 mm depths to ensure safety of implantation.

RESULTS

Significant differences were observed in TVPG, EOA, and TRF across various SHV brands and sizes, emphasizing the importance of THV positioning. Specifically, Taurus Elite23 demonstrated superior TVPG performance at various depths compared to Taurus Elite21, indicating a better match with BalMedic19 and Hancock II21, especially at implantation depths ranging from -2.5 to 0 mm. Taurus Elite29 showed the lowest TVPG across all tested depths, making it the preferred choice for BalMedic25 and Hancock II27. These findings highlight the importance of selecting the appropriate THV model and determining the optimal implantation depth for different SHVs.

CONCLUSIONS

In different surgical valves, both the model and implantation depth of the interventional valve can affect its hemodynamic performance and valve opening-closing morphology. The recommended implantation of the interventional valve as shallowly as possible in this study has guiding significance in clinical valve-in-valve surgeries.

Deformation of Surgically Implanted Aortic Valves: CT Findings Prior to Valve-in-Valve Implantation and Association With Mechanism of Failure

Background

Degeneration of surgically implanted bioprosthetic valves (BPVs) has been linked to risk factors including BPV construct and patient comorbidities. However, the role of the intrinsic structural configuration and potential structural changes of the surgical BPV itself on valve failure is unclear.

Methods

Patients who underwent cardiac computed tomography prior to aortic valve-in-valve due to surgical BPV failure were enrolled. Assessment included BPV ring dimensions, strut angles, strut-to-strut distance, and projected geometric orifice area (PGOA), defined as the area of the circle connecting the distal aspects of the struts. These measurements were compared with those of nonimplanted surgical BPVs matched for valve type and size. Echocardiograms were obtained before the valve-in-valve procedure, and valve structure and function were assessed. Mechanism of BPV failure was classified as aortic stenosis, aortic regurgitation, or mixed.

Results

A total of 222 patients were included. Aortic stenosis occurred in 111 (50%), aortic regurgitation in 55 (24.8%), and mixed in 56 (25.2%). Moderate/severe ring deformation (eccentricity index >10%) was present in 17% of cases. Strut angles, strut-to-strut distance, and PGOA were all significantly smaller in implanted than in reference valves (all P < .0001). The greatest average strut angle decrease was seen in Mitroflow valves (10°, P < .0001). The Mitroflow valve had the highest reduction in PGOA (27.7%), followed by Hancock (15.1%) and Perimount (11.6%; P < .0001). Smaller ring dimensions, smaller PGOA, and smaller strut-to-strut distance were associated with failure by stenosis (all P < 0.05) in univariable but not multivariable analysis.

Conclusions

Potential intrinsic changes (frame deformation) affect stented surgical BPVs implanted in aortic position. Whether these changes are associated with early valve degeneration and failure remains unknown.

Initial Experience and Bench Validation of the CLEVE Prosthetic Leaflet Modification Procedure During Aortic and Mitral Valve-in-Valve Procedures

BACKGROUND

Some patients with failing surgical aortic or mitral valves are anatomically unsuitable for typical valve-in-valve procedures due to threatened coronary artery or left ventricular outflow tract obstruction, respectively.

OBJECTIVES

The authors assessed the clinical and benchtop efficacy of the novel CLEVE (CLEveland Valve Electrosurgery) leaflet modification technique in patients with the previous concerns.

METHODS

Eight patients with degenerated aortic valve replacement (AVR) and 6 patients with mitral valve replacement (MVR) at high risk for obstruction of left main coronary artery (AVR) or left ventricular outflow tract (MVR) were treated. The threatening prosthetic leaflet was punctured using electrosurgical techniques and dilated progressively, followed by deployment of a balloon-expandable valve into the modified leaflet. Benchtop analyses were performed using the same techniques to assess the response of the surgical leaflet ex vivo.

RESULTS

Successful leaflet clearance was achieved in all without evidence of ostial coronary artery obstruction (AVR) or left ventricular outflow tract obstruction (MVR). One patient experienced left main trunk obstruction due to suspected embolization of material that was treated percutaneously (patient expired due to further complications). No other complications at 30 days. On the benchtop, the procedure demonstrated complete clearance of the threatening leaflet, with detachment from one of the surgical posts in the AVR model and splitting across the leaflet edge in the MVR model.

CONCLUSIONS

Patients with a degenerated surgical valve who are unsuitable for a valve-in-valve replacement due to anatomic concerns regarding displacement of the index prosthetic leaflet can be successfully treated after using the CLEVE method of leaflet modification. Further studies of the procedure should be considered.

Bioprosthetic Valve Fracture for Transcatheter Aortic Valve-in-Valve Replacement: A Systematic Literature Review

Transcatheter aortic valve-in-valve replacement presents a viable, minimally invasive approach to replacing degraded bioprosthetic surgical valves. The major drawback of this technique is poor hemodynamics in the form of patient-prosthesis mismatch and high transvalvular gradients. This is commonly attributable to the reduced valvular diameter from the transcatheter heart valve fixed inside the degraded bioprosthesis. Maximizing this diameter by bioprosthetic valve fracture occurs through a noncompliant, high-pressure balloon to splay the degraded valve outward. Despite its novelty, this has demonstrated improved hemodynamic outcomes and optimal valvular expansion with slightly increased operative risk. In this review, we highlight the technique of bioprosthetic valve fracture, types of suitable balloons and valves, timing in relation to valve-in-valve implantation, safety and efficacy, implications, and future directions.

Decoding High Post-TAVR Gradients: Insights From 4 Clinical Scenarios

Echocardiography is a well-established tool for evaluating bioprosthetic valve performance after transcatheter aortic valve replacement. The presence of higher-than-expected echocardiographic gradients is not an uncommon finding and can be related to different clinical settings. This case series proposes a practical and multiparametric approach to interpreting high residual gradients after transcatheter aortic valve replacement. We examine 4 common clinical scenarios: 1) pressure recovery; 2) high-flow state; 3) prosthesis-patient mismatch; and 4) suboptimal valve expansion. For each scenario, a comprehensive echocardiographic analysis, along with invasive hemodynamic evaluation, is reported.

A multimodal approach to predict prosthesis-patient mismatch in patients undergoing valve-in-valve trans-catheter aortic valve implantation

AIMS

The valve-in-valve transcatheter-aortic-valve-implantation (VIV-TAVI) represents an emerging procedure for the treatment of degenerated aortic bio-prostheses, and the occurrence of patient-prosthesis mismatch (PPM) after VIV-TAVI might affect its clinical efficacy. This study aimed to test a multimodal imaging approach to predict PPM risk during the TAVI planning phase and assess its clinical predictivity in VIV-TAVI procedures.

METHODS

Consecutive patients undergoing VIV-TAVI procedures at our Institution over 6 years were screened and those treated by self-expandable supra-annular valves were selected. The effective orifice area (EOA) was calculated with a hybrid Gorlin equation combining echocardiographic data with invasive hemodynamic assessment. Severe PPM was defined according to such original multimodality assessment as EOAi≤0.65 cm2/m2 (if BMI < 30 kg/m2) or < 0.55 cm2/m2 (if BMI ≥ 30 kg/m2). The primary endpoint was a composite of all-cause mortality and valve-related re-hospitalization during the clinical follow-up.

RESULTS

A total of 40 VIV-TAVI was included in the analysis. According to the pre-specified multimodal imaging modality assessment, 18 patients (45.0 %) had severe PPM. Among all baseline clinical and anatomical characteristics, estimated glomerular filtration rate before VIV-TAVI (OR 0.872, 95%CI[0.765-0.994],p = 0.040), the echocardiographic pre-procedural ≥moderate AR (OR 0.023, 95%CI[0.001-0.964],p = 0.048), the MSCT-derived effective internal area (OR 0.958, 95%CI[0.919-0.999],p = 0.046) and the implantation depth (OR 2.050, 95%CI[1.028-4.086],p = 0.041) resulted as independent predictors of severe PPM at multivariable logistic analysis. At a mean follow-up of 630 days, patients with severe PPM showed a higher incidence of the primary endpoint (9.1%vs.44.4 %;p = 0.023).

CONCLUSION

In VIV-TAVI using self-expandable supra-annular valves, a multimodal imaging approach might improve clinical outcome predicting severe PPM occurrence.

Subclinical valve leaflet thrombosis following bioprosthetic aortic valve replacement

PURPOSE OF REVIEW

Subclinical leaflet thrombosis (SLT) is often an incidental finding characterized by a thin layer of thrombus involving one, two or three leaflets, with typical appearance on multi-detector computed tomography (MDCT) of hypo-attenuating defect at the aortic side of the leaflet, also called hypo-attenuating leaflet thickening (HALT). SLT may occur following both transcatheter aortic replacement (TAVR) or biological surgical aortic valve replacement (SAVR). The aim of this review is to present an overview of the current state of knowledge on the incidence, diagnosis, clinical impact, and management of SLT following TAVR or SAVR.

RECENT FINDINGS

SLT occurs in 10-20% of patients following TAVR and is somewhat more frequent than following SAVR (5-15%). SLT may regress spontaneously without treatment in about 50% of the cases but may also progress to clinically significant valve thrombosis in some cases. Oral anticoagulation with vitamin K antagonist is reasonable if SLT is detected by echocardiography and/or MDCT during follow-up and is generally efficient to reverse SLT. SLT is associated with mild increase in the risk of stroke but has no impact on survival. SLT has been linked with accelerated structural valve deterioration and may thus impact valve durability and long-term outcomes.

SUMMARY

SLT is often an incidental finding on echocardiography or MDCT that occurs in 10-20% of patients following TAVR or 5-15% following biological SAVR and is associated with a mild increase in the risk of thrombo-embolic event with no significant impact on mortality but may be associated with reduced valve durability.

Durability of transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is now utilised as a less invasive alternative to surgical aortic valve replacement (SAVR) across the whole spectrum of surgical risk. Long-term durability of the bioprosthetic valves has become a key goal of TAVI as this procedure is now considered for younger and lower-risk populations. The purpose of this article is to present a state-of-the-art overview on the definition, aetiology, risk factors, mechanisms, diagnosis, clinical impact, and management of bioprosthetic valve dysfunction (BVD) and failure (BVF) following TAVI with a comparative perspective versus SAVR. Structural valve deterioration (SVD) is the main factor limiting the durability of the bioprosthetic valves used for TAVI or SAVR, but non-structural BVD, such as prosthesis-patient mismatch and paravalvular regurgitation, as well as valve thrombosis or endocarditis may also lead to BVF. The incidence of BVF related to SVD or other causes is low (<5%) at midterm (5- to 8-year) follow-up and compares favourably with that of SAVR. The long-term follow-up data of randomised trials conducted with the first generations of transcatheter heart valves also suggest similar valve durability in TAVI versus SAVR at 10 years, but these trials suffer from major survivorship bias, and the long-term durability of TAVI will need to be confirmed by the analysis of the low-risk TAVI versus SAVR trials at 10 years.

Bioprosthetic Aortic Valve Thrombosis: Definitions, Clinical Impact, and Management: A State-of-the-Art Review

Bioprosthetic aortic valve thrombosis is frequently detected after transcatheter and surgical aortic valve replacement due to advances in cardiac computed tomography angiography technology and standardized surveillance protocols in low-surgical-risk transcatheter aortic valve replacement trials. However, evidence is limited concerning whether subclinical leaflet thrombosis leads to clinical adverse events or premature structural valve deterioration. Furthermore, there may be net harm in the form of bleeding from aggressive antithrombotic treatment in patients with subclinical leaflet thrombosis. This review will discuss the incidence, mechanisms, diagnosis, and optimal management of bioprosthetic aortic valve thrombosis after transcatheter aortic valve replacement and bioprosthetic surgical aortic valve replacement.

Deformation in transcatheter heart valves: Clinical implications and considerations

Transcatheter aortic valve replacement (TAVR) has emerged as a preferred treatment modality for aortic stenosis, marking a significant advancement in cardiac interventions. Transcatheter heart valves (THVs) have also received approval for treating failed bioprosthetic valves and rings across aortic, mitral, tricuspid, and pulmonic positions. Unlike surgically implanted valves, which are sewn into the annulus, THVs are anchored through relative oversizing. Although THVs are designed to function optimally in a fully expanded state, they exhibit a certain degree of tolerance to underexpansion. However, significant deformation beyond this tolerance can adversely affect the valve's hemodynamics and durability, ultimately impacting patient outcomes. Such post-implantation deviations from the valve's intended three-dimensional design are influenced by a variety of physiological and anatomical factors unique to each patient and procedure, leading to underexpansion, eccentric expansion, and vertical deformation. These deformation patterns increase leaflet stress and strain, potentially causing fatigue and damage. This review article delves into the extent of THV deformation, its impact on leaflet function, hypoattenuating leaflet thickening, and structural valve degeneration. It provides an in-depth analysis of deformation specifics in different procedural contexts, including TAVR in native aortic stenosis, aortic and mitral valve-in-valve procedures, and redo-TAVR. Additionally, the review discusses strategies to mitigate THV deformation during the procedure, offering insights into potential solutions to these challenges.

Risk of Sinus Sequestration During Redo Transcatheter Aortic Valve Implantation: The Prevalence, Predictors, and Risk Stratification

The number of patients who underwent transcatheter aortic valve implantation (TAVI) with the potential for reintervention is steadily increasing; however, there is a risk of sinus sequestration (SS) during a redo TAVI. The prevalence, predictors, and risk stratification of the risk for SS remain uncertain. We analyzed computed tomography acquired from 263 patients who underwent TAVI between 2021 and 2022: balloon-expandable valve (BEV) (71%) and self-expandable valve (SEV) (29%). Patients were considered at risk for SS if they met the following: (1) BEV frame > sinotubular junction (STJ) or SEV neocommissure greater than the STJ and (2) valve-to-STJ <2 mm. The risk of left, right, and any SS in 51%, 50%, and 65%, respectively, did not differ between BEV and SEV. The predictors of any SS were the height of the left and right coronary cusp (odds ratio [OR] 0.81 and 0.71, cutoff 18.6 and 19.2 mm, respectively) and STJ minus the annulus diameter (OR 0.65, cutoff 3.7 mm) in BEV, and STJ diameter (OR 0.47, cutoff 27.6 mm) in SEV. The number of predictors stratified the risk of any SS: low risk with BEV at 0 predictors (14% at risk of SS), intermediate risk at 1 predictor (65%), high risk at 2 or 3 predictors (81% and 95%), and low risk with SEV at 0 predictors (33%) versus high risk at 1 predictor (91%). In conclusion, 2/3 of patients who underwent TAVI were at risk of SS. The height of the coronary cusp and the STJ diameter were associated with and adequately stratified the risk of SS.

Deformation of transcatheter heart valves with mitral valve-in-valve

BACKGROUND

The use of oversizing in mitral valve-in-valve (MViV) procedures can lead to non-uniform expansion of transcatheter heart valves (THV). This may have implications for THV durability.

AIMS

The objective of this study was to assess the extent and predictors of THV deformation in MViV procedures.

METHODS

We examined 33 patients who underwent MViV with SAPIEN prostheses. The extent of THV deformation (deformation index, eccentricity, neosinus volume, asymmetric leaflet expansion and vertical deformation) and hypoattenuating leaflet thickening (HALT) were assessed using cardiac computed tomography (CT), performed prospectively at 30 days post-procedure. For descriptive purposes, the THV deformation index was calculated, with values >1.00 representing a more hourglass shape.

RESULTS

Non-uniform underexpansion of THV was common after MViV implantation, with a median expansion area of 74.0% (interquartile range 68.1-84.1) at the narrowest level and a THV deformation index of 1.21 (1.13-1.29), but circularity was maintained with eccentricity ranging from 0.24 to 0.28. The degree of oversizing was a key factor associated with greater underexpansion and a higher deformation index (β=-0.634; p<0.001; β=0.594; p<0.001, respectively). Overall, the incidence of HALT on the 30-day postprocedural CT was 27.3% (9 of 33). Most patients (32 of 33) were on anticoagulation therapy, but the prothrombin time and international normalised ratio (PT-INR) at the time of the CT scan was <2.5 in 23 of 32 patients. Among patients with a PT-INR of <2.5, HALT was predominantly observed with a high THV deformation index of ≥1.18.

CONCLUSIONS

THV deformation, i.e., underexpansion and an hourglass shape, commonly occurs after MViV implantation and is negatively affected by excessive oversizing. Optimising THV expansion during MViV could potentially prevent HALT.

Identification of CT-derived Internal Area in Failed Surgical Stented Bioprostheses for Valve-in-Valve Implantation

In participants who underwent valve-in-valve transcatheter aortic valve replacement, hypoattenuating intra-annular material within the failed surgical bioprostheses reduced the CT-derived internal area and interfered with expansion of intra-annular-positioned implanted valves, leading to postprocedural patient-prosthesis mismatch.