Standardized Definition of Structural Valve Degeneration for Surgical and Transcatheter Bioprosthetic Aortic Valves

Structural valve deterioration of the Labcor Dokimos aortic prosthesis: a single-centre experience

OBJECTIVES

The goal of this study was to assess the performance and incidence of the deterioration of the Labcor Dokimos bioprosthetic aortic valve.

METHODS

We performed a retrospective medical chart review of 116 patients who underwent surgical aortic valve replacement with the Labcor Dokimos aortic valve between 2010 and 2018. Abstracted data included patient demographic and echocardiographic data. Patients were divided into 2 groups: patients with structural valve deterioration (SVD) and patients without SVD.

RESULTS

Among the patients with complete follow-up (n = 95), 10 patients were excluded because they died within a year; 85 patients were included in the final analysis. Of the 85 patients, 32 (38%) developed SVD; 22 (26%) had severe SVD, 15 (18%) of whom underwent reintervention. The most common aetiology of SVD was severe central aortic regurgitation, which was detected in 91% of the patients who had severe SVD. The average time from operation to severe SVD was 4.7 years with a minimum of 1.5 years and a maximum of 7.9 years.

CONCLUSIONS

Bioprosthetic aortic valve deterioration due to severe aortic regurgitation is common and occurs early with the Labcor Dokimos valve. This occurrence needs to be furthered investigated in larger registries.

Visions of TAVR Future: Development and Optimization of a Second Generation Novel Polymeric TAVR

Tissue-based transcatheter aortic valve (AV) replacement (TAVR) devices have been a breakthrough approach for treating aortic valve stenosis. However, with the expansion of TAVR to younger and lower risk patients, issues of long-term durability and thrombosis persist. Recent advances in polymeric valve technology facilitate designing more durable valves with minimal in vivo adverse reactions. We introduce our second-generation polymeric transcatheter aortic valve (TAV) device, designed and optimized to address these issues. We present the optimization process of the device, wherein each aspect of device deployment and functionality was optimized for performance, including unique considerations of polymeric technologies for reducing the volume of the polymer material for lower crimped delivery profiles. The stent frame was optimized to generate larger radial forces with lower material volumes, securing robust deployment and anchoring. The leaflet shape, combined with varying leaflets thickness, was optimized for reducing the flexural cyclic stresses and the valve's hydrodynamics. Our first-generation polymeric device already demonstrated that its hydrodynamic performance meets and exceeds tissue devices for both ISO standard and patient-specific in vitro scenarios. The valve already reached 900 × 106 cycles of accelerated durability testing, equivalent to over 20 years in a patient. The optimization framework and technology led to the second generation of polymeric TAV design- currently undergoing in vitro hydrodynamic testing and following in vivo animal trials. As TAVR use is rapidly expanding, our rigorous bio-engineering optimization methodology and advanced polymer technology serve to establish polymeric TAV technology as a viable alternative to the challenges facing existing tissue-based TAV technology.

Trifecta versus Perimount Magna Ease aortic valves: Failure mechanisms

Background

There are increasing reports of early externally mounted pericardial Trifecta bioprosthesis failure. We compared the hemodynamic performance of Trifecta and Carpentier–Edwards Perimount Magna Ease valves to determine the failure mechanism.

Methods

We retrospectively included 270 consecutive patients (age: 73.4 ± 8.2 years; 57.5% male; mean follow-up: 48.0 ± 20.3 months) who underwent aortic valve replacement from 2014 to 2021 at a single center and compared the Trifecta (N = 137) and Carpentier–Edwards Perimount Magna Ease valve (N = 133) patients.

Results

The prosthetic valve major aortic regurgitation incidence was higher for the Trifecta than that for the Carpentier–Edwards Perimount Magna Ease valve (6.3% vs. 0%, P < 0.009). Among the Trifecta failures, 33% developed structural valve deterioration, but all requiring redo aortic valve replacement developed major prosthetic valve aortic regurgitation. Freedom at 5 years from redo aortic valve replacement due to structural valve deterioration was significantly lower for Trifecta (89.4% vs. 100%, P = 0.003). The reoperation hazards were determined for Trifecta (vs. Carpentier–Edwards Perimount Magna Ease): 11.6 (1.47–90.9; P = 0.02), prosthetic valve aortic regurgitation: 2.38 (1.70–3.32; P < 0.01), structural valve deterioration: 20.82 (4.08–106.2; P < 0.01), 5-year mean transprosthetic pressure gradient: 1.14 per 1-point increase (1.03–1.24; P = 0.007), and urgent surgery: 10.1 (2.59–39.0; P = 0.001). The Cox regression analysis identified that prosthetic valve aortic regurgitation solely contributed to redo aortic valve replacement (hazard ratio: 2.38; confidence intervals: 1.70–3.32).

Conclusions

Significantly, more early failures occurred with the Trifecta valve than the Carpentier–Edwards Perimount Magna Ease valve but the Trifecta showed reasonable mean transprosthetic pressure gradient over time. Prosthetic valve aortic regurgitation and calcific structural valve deterioration synergistically contributed to Trifecta valve failure alternatively.

Durability of Bioprosthetic Valves in Patients on Dialysis

Purpose: This study focused on clarifying the durability of bioprosthetic valves in current practice.

Methods: A total of 238 consecutive patients who underwent aortic valve replacement at a single institution from 2011 to 2020 were reviewed. We evaluated valve-related outcomes such as structural valve deterioration (SVD), especially in dialysis patients who received bioprosthetic valve.

Results: Among the tissue valves implanted in 212 patients, 5 SVDs were recorded and 3 valves were replaced. All early valve failures occurred in relatively young dialysis patients and were recorded 3 to 5 years after the initial operation. Freedom from SVD at 6 years was 49.9% in patients on dialysis, compared with 100% in non-dialysis patients. Predictors of better survival in dialysis patients were better preoperative functional class and larger prosthetic valve size.

Conclusions: The durability of bioprosthetic valves in the aortic position was suboptimal in dialysis patients. Mechanical valves can be an option for young, healthy dialysis patients with a large aortic valve annulus.

Bioprosthetic aortic valve replacement in patients aged 50 years old and younger: Structural valve deterioration at long-term follow-up. Retrospective study

Background

Structural valve deterioration (SVD) remains the major determinant of bioprosthesis durability. The aim of this study was to investigate the SVD incidence, predictors and outcomes in patients aged 50 years and younger after bioprosthetic aortic valve replacement (bAVR).

Methods

We retrospectively analyzed 73 consecutive patients ≤50 years old who underwent bioprosthetic AVR at our center between 2005 and 2015. Median age at surgery was 44 (interquartile range [IQR]: 39-47) years. Follow-up was 93.2% complete at a median time of 7.2 (IQR: 5.5-9.5) years. Cumulative follow-up was 545.5 valve-years. Bioprosthesis SVD was determined by strict echocardiographic assessment.

Results

The overall survival-rate at 10/15 years and freedom from SVD at 10/12.5 years were 89.6 ± 5.2%/81.5 ± 9.1% and 73.5 ± 8.2%/41.9 ± 18.9%, respectively. SVD occurred at a median time of 8.2 (IQR: 6.0-9.9) years after bAVR. Age was not found as an independent predictor for SVD at the multivariable model, despite a higher rate of SVD in the age group ≤30 years. Freedom from reoperation due to SVD at 10/15 years was 71.3 ± 14.1%/13.6 ± 12.3%. Reoperation was performed at a median time of 10.0 (IQR: 8.9-11.9) years since first bAVR and was associated with a 100% 12-month survival.

Conclusions

In our study, the rate and time of SVD occurrence were comparable to those of other studies' older age groups. Strict echocardiographic monitoring of valve performance is mandatory to set the appropriate timing of eventual reoperation. This attitude can improve outcomes of bAVR in younger patients.

Standardized Aortic Valve Neocuspidization for Treatment of Aortic Valve Diseases

BACKGROUND

Aortic valve replacement is the traditional surgical treatment for aortic valve diseases, yet standardized aortic valve neocuspidization (AVNeo) is a promising alternative that is gaining popularity. The purpose of this article is to review the available published literature of AVNeo using glutaraldehyde-treated autologous pericardium, also known as the Ozaki procedure, including indications, outcomes, potential benefits, and modes of failure for the reconstructed valve.

METHODS

A comprehensive literature search was performed using keywords related to aortic valve repair, AVNeo, or Ozaki procedure. All articles describing performance of AVNeo were reviewed.

RESULTS

Reported early mortality after AVNeo varies from 0% to 5.88%. The largest cohort of patients in the literature includes 850 patients with an inhospital mortality rate of 1.88%. Cumulative incidence of aortic valve reoperation was 4.2% in the largest series. Reoperation was uncommon and mainly due to infective endocarditis or degeneration of the reconstructed valve (most commonly due to aortic valve regurgitation, rather than stenosis).

CONCLUSIONS

Aortic valve neocuspidization is a versatile and standardized alternative to aortic valve replacement with a biological prosthesis. Early to midterm outcomes from a number of centers are excellent and demonstrate the safety and durability of the procedure. Long-term outcomes and clinical trial data are necessary to determine which patients benefit the most from this procedure.

Computed tomography predictors of structural valve degeneration in patients undergoing transcatheter aortic valve implantation with balloon-expandable prostheses

OBJECTIVES

Computed tomography (CT) provides excellent anatomy assessment of the aortic annulus (AoA) and is utilized for pre-procedural planning of transcatheter aortic valve implantation (TAVI). We sought to investigate if geometrical characteristics of the AoA determined by CT may represent predictors of structural valve degeneration (SVD) in patients undergoing TAVI with balloon-expandable valves.

METHODS

This is a retrospective study on 124 consecutive patients (mean age: 79 ± 7 years; female: 61%) undergoing balloon-expandable TAVI prospectively enrolled in a registry. AoA maximum diameter (D_max), minimum diameter (D_min), and area were assessed using pre-procedural CT. SVD was identified during follow-up with transthoracic echocardiography documenting structural prosthetic valve abnormalities with or without hemodynamic changes.

RESULTS

The mean follow-up was 5.9 ± 1.7 years. SVD was found in 48 out of 124 patients (38%). AoA D_max, D_min, and area were significantly smaller in patients with SVD compared to patients without SVD (25.6 ± 2.2 mm vs. 27.1 ± 2.8 mm, p = 0.012; 20.5 ± 2.1 mm vs. 21.8 ± 2.1 mm, p = 0.001 and 419 ± 77 mm² vs. 467 ± 88 mm², p = 0.002, respectively). At univariable analysis, female sex, BSA, 23-mm prosthetic valve size, D_max < 27.1 mm, and a D_min < 19.9 mm were associated with SVD, whereas at multivariable analysis, only D_min < 19.9 mm (OR = 2.873, 95% CI: 1.191-6.929, p = 0.019) and female sex (OR = 2.659, 95% CI: 1.095-6.458, p = 0.031) were independent predictors of SVD.

CONCLUSIONS

Female sex and AoA D_min < 19.9 mm are associated with SVD in patients undergoing TAVI with balloon-expandable valves. When implanting large prostheses in order to avoid paraprosthetic regurgitation, caution should be observed due to the risk of excessive stretching of the AoA D_min, which may play a role in SVD.

KEY POINTS

• Long-term durability is a concern for transcatheter aortic valve bioprosthesis. • CT provides an excellent assessment of the aortic annulus's geometrical characteristics for prosthesis sizing before transcatheter aortic valve implantation (TAVI). • Female sex and a small minimum aortic annulus diameter measured with CT are independent predictors of structural valve degeneration in patients undergoing TAVI with balloon-expandable valves.

Double-Network Hydrogel Armored Decellularized Porcine Pericardium as Durable Bioprosthetic Heart Valves

Heart valves have extraordinary fatigue resistance which beat ≈3 billion times in a lifetime. Bioprosthetic heart valves (BHVs) made from fixed heteroplasm that are incrementally used in heart valve replacement fail to sustain the expected durability due to thrombosis, poor endothelialization, inflammation, calcification, and especially mechanical damage induced biocompatibility change. No effective strategy has been reported to conserve the biological properties of BHV after long-term fatigue test. Here, a double-network tough hydrogel is introduced, which interpenetrate and anchor into the matrix of decellularized porcine pericardium (dCell-PP) to form robust and stable conformal coatings and reduce immunogenicity. The ionic crosslinked hyaluronic acid (HA) network mimics the glycocalyx on endothelium which improves antithrombosis and accelerates endothelialization; the chemical crosslinked hydrophilic polyacrylamide (PAAm) network further enhances antifouling properties and strengthens the shielding hydrogels and their interaction with dCell-PP. In vitro and rabbit ex vivo shunt assay demonstrate great hemocompatibility of polyacrylamide/HA hydrogel hybrid PP (P/H-PP). Cell experiments and rat subcutaneous implantation confirm satisfactory endothelialization, biocompatibility, and anticalcification properties. For hydrodynamic experiment, P/H-PP gains full mark at different flow conditions and sustains excellent biomechanical and biological properties after 200 000 000 cycles. P/H double-network hydrogel armoring dCell-PP is a promising progress to extend BHV durability for clinical implantation therapy.

Cardiac Computed Tomography: Application in Valvular Heart Disease

The incidence and prevalence of valvular heart disease (VHD) is increasing and has been described as the next cardiac epidemic. Advances in imaging and therapeutics have revolutionized how we assess and treat patients with VHD. Although echocardiography continues to be the first-line imaging modality to assess the severity and the effects of VHD, advances in cardiac computed tomography (CT) now provide novel insights into VHD. Transcatheter valvular interventions rely heavily on CT guidance for procedural planning, predicting and detecting complications, and monitoring prosthesis. This review focuses on the current role and future prospects of CT in the assessment of aortic and mitral valves for transcatheter interventions, prosthetic valve complications such as thrombosis and endocarditis, and assessment of the myocardium.

Design of an aortic polymeric valve with asymmetric leaflets and evaluation of its performance by finite element method

BACKGROUND

The geometry of leaflets plays a significant role in prosthetic valves' (PVs) performance. Typically, natural aortic valves have three unequal leaflets, which differ in size. The present study aims to design an asymmetric tri-leaflet polymeric valve with one large and two small leaflets based on commissure lengths and leaflet eccentricities.

METHODS

Eccentricity was related to commissure lengths based on the deformation of the free margins for the fully-opened state of leaflets. The polystyrene-block-polyethylene-polypropylene-block-polystyrene polymer characterized the material properties of the leaflets. The Finite Element Method (FEM) was used to evaluate performance parameters, including maximum geometric orifice area (GOA), average GOA, maximum von Mises stress, and leaflet's coaptation surface area (CSA).

RESULTS

Asymmetric valves with no eccentricity provided a low level of GOA because the asymmetric form of small leaflets caused them to close faster than the large leaflet, leading to a sudden drop in the GOA during systole. As the radial curve tends towards a straight line, an undesirable coaptation occurs, and peak stress increases despite higher GOAs. A new radial curve consisting of two straight lines connected by an arc that provided 25.64 mm² coaptation surface area (CAS) and 117.54 mm² average GOA, was proposed to improve coaptation and GOA.

CONCLUSION

The radial curve of leaflets affects the valve's performance more than other geometric parameters. The combination of straight lines and arcs for radial curves was selected as the reference model for asymmetric valves with one large and two small leaflets.

Comparison of Long-term Performance of Bioprosthetic Aortic Valves in Sweden From 2003 to 2018

IMPORTANCE

The performance of bioprosthetic aortic valves is usually assessed in single valve models or head-to-head comparisons. National databases or registries offer the opportunity to investigate all available valve models in the population and allows for a comparative assessment of their performance.

OBJECTIVE

To analyze the long-term rates of reintervention, all-cause mortality, and heart failure hospitalization associated with commonly used bioprosthetic aortic valves and to identify valve model groups with deviation in clinical performance.

DESIGN, SETTING, AND PARTICIPANTS

This population-based, nationwide cohort study included all adult patients who underwent surgical aortic valve replacement (with or without concomitant coronary artery bypass surgery or ascending aortic surgery) in Sweden between January 1, 2003, and December 31, 2018. Patients were identified from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry. Patients with concomitant valve surgery, previous cardiac surgery, and previous transcatheter valve replacement were excluded. Follow-up was complete for all participants. Data were analyzed from March 9, 2020, to October 12, 2021.

EXPOSURES

Primary surgical aortic valve replacement with the Perimount, Mosaic/Hancock, Biocor/Epic, Mitroflow/Crown, Soprano, and Trifecta valve models.

MAIN OUTCOMES AND MEASURES

The primary outcome was cumulative incidence of reintervention, defined as a subsequent aortic valve operation or transcatheter valve replacement. Secondary outcomes were all-cause mortality and heart failure hospitalization. Regression standardization and flexible parametric survival models were used to account for intergroup differences. Mean follow-up time was 7.1 years, and maximum follow-up time was 16.0 years.

RESULTS

A total of 16 983 patients (mean [SD] age, 72.6 [8.5] years; 10 685 men [62.9%]) were included in the analysis. The Perimount valve model group had the lowest and the Mitroflow/Crown valve model group had the highest cumulative incidence of reintervention. The estimated cumulative incidence of reintervention at 10 years was 3.6% (95% CI, 3.1%-4.2%) in the Perimount valve model group and 12.2% (95% CI, 9.8%-15.1%) in the Mitroflow/Crown valve model group. The estimated incidence of reintervention at 10 years was 9.3% (95% CI, 7.3%-11.3%) in the Soprano valve model group.

CONCLUSIONS AND RELEVANCE

Results of this study showed that the Perimount valve was the most commonly used and had the lowest incidence of reintervention, all-cause mortality, and heart failure hospitalization, whereas the Mitroflow/Crown valve had the highest rates. These findings highlight the need for clinical vigilance in patients who receive either a Soprano or Mitroflow/Crown aortic bioprosthesis.

The role of antibody responses against glycans in bioprosthetic heart valve calcification and deterioration

Bioprosthetic heart valves (BHVs) are commonly used to replace severely diseased heart valves but their susceptibility to structural valve degeneration (SVD) limits their use in young patients. We hypothesized that antibodies against immunogenic glycans present on BHVs, particularly antibodies against the xenoantigens galactose-α1,3-galactose (αGal) and N-glycolylneuraminic acid (Neu5Gc), could mediate their deterioration through calcification. We established a large longitudinal prospective international cohort of patients (n = 1668, 34 ± 43 months of follow-up (0.1–182); 4,998 blood samples) to investigate the hemodynamics and immune responses associated with BHVs up to 15 years after aortic valve replacement. Early signs of SVD appeared in <5% of BHV recipients within 2 years. The levels of both anti-αGal and anti-Neu5Gc IgGs significantly increased one month after BHV implantation. The levels of these IgGs declined thereafter but anti-αGal IgG levels declined significantly faster in control patients compared to BHV recipients. Neu5Gc, anti-Neu5Gc IgG and complement deposition were found in calcified BHVs at much higher levels than in calcified native aortic valves. Moreover, in mice, anti-Neu5Gc antibodies were unable to promote calcium deposition on subcutaneously implanted BHV tissue engineered to lack αGal and Neu5Gc antigens. These results indicate that BHVs manufactured using donor tissues deficient in αGal and Neu5Gc could be less prone to immune-mediated deterioration and have improved durability.

In a large cohort of patients who underwent aortic valve replacement, antibody responses to glycans present in bioprosthetic heart valves, notably galactose-α1,3-galactose and N-glycolylneuraminic acid, were implicated in valve calcification and deterioration.

Poly-2-methyl-2-oxazoline–modified bioprosthetic heart valve leaflets have enhanced biocompatibility and resist structural degeneration

Bioprosthetic heart valves (BHV) fabricated from glutaraldehyde-fixed heterograft tissue, such as bovine pericardium (BP), are widely used for treating heart valve disease, a group of disorders that affects millions. Structural valve degeneration (SVD) of BHV due to both calcification and the accumulation of advanced glycation end products (AGE) with associated serum proteins limits durability. We hypothesized that BP modified with poly-2-methyl-2-oxazoline (POZ) to inhibit protein entry would demonstrate reduced accumulation of AGE and serum proteins, mitigating SVD. In vitro studies of POZ-modified BP demonstrated reduced accumulation of serum albumin and AGE. BP-POZ in vitro maintained collagen microarchitecture per two-photon microscopy despite AGE incubation, and in cell culture studies was associated with no change in tumor necrosis factor-α after exposure to AGE and activated macrophages. Comparing POZ and polyethylene glycol (PEG)–modified BP in vitro, BP-POZ was minimally affected by oxidative conditions, whereas BP-PEG was susceptible to oxidative deterioration. In juvenile rat subdermal implants, BP-POZ demonstrated reduced AGE formation and serum albumin infiltration, while calcification was not inhibited. However, BP-POZ rat subdermal implants with ethanol pretreatment demonstrated inhibition of both AGE accumulation and calcification. Ex vivo laminar flow studies with human blood demonstrated BP-POZ enhanced thromboresistance with reduced white blood cell accumulation. We conclude that SVD associated with AGE and serum protein accumulation can be mitigated through POZ functionalization that both enhances biocompatibility and facilitates ethanol pretreatment inhibition of BP calcification.

Analysis of incidence and reasons for re-intervention after aortic valve replacement using the Trifecta aortic bioprosthesis

INTRODUCTION

Trifecta bioprosthesis claims favourable haemodynamic performance. However, reports of structural valve deterioration (SVD) raise concerns of its long-term durability. We assessed outcomes with the Trifecta valve over a 10-year period.

METHODS

All patients receiving Trifecta bioprostheses between October 2011 and October 2020 were included. Perioperative and survival characteristics were prospectively collated in an independent database. Re-intervention was recorded as a surrogate for SVD.

RESULTS

944 patients (mean age 72.82 years ± 8.13, 58% male) underwent aortic valve replacement with the Trifecta valve. At 10-years, 1.4% of patients required a redo operation, giving an overall freedom from re-intervention of 98.6%. The mean time to re-intervention was 48.87 months. Survival was 73.58% and 76.92% in patients who did not require re-intervention vs re-intervention group, respectively.

CONCLUSIONS

In a large, single-centre cohort, the Trifecta aortic bioprosthesis had a 1.4% all-cause re-intervention rate at 10-years, with insignificant impact on survival.

Haemodynamic differences between two generations of a balloon-expandable transcatheter heart valve

OBJECTIVES

This study aimed to investigate early haemodynamic and clinical performance of the SAPIEN 3 Ultra (S3 Ultra) transcatheter heart valve (THV) system in comparison to its precursor, the SAPIEN 3 (S3). Previous studies have indicated potential haemodynamic differences between the S3 Ultra and S3. Such differences may impact clinical outcome after transcatheter aortic valve implantation (TAVI).

METHODS

Postprocedural haemodynamic performance and 30-day clinical outcome were compared in patients who underwent TAVI receiving either the S3 or the new S3 Ultra prostheses. Multivariable analysis and propensity score matching (PSM) were used to identify factors associated with higher mean transvalvular gradients.

RESULTS

We included 697 patients (S3 Ultra: n=314, S3: n=383) from the multicentre RhineHeart TAVI Registry. Patients receiving the S3 Ultra prosthesis showed significantly higher postprocedural mean transvalvular gradients (14.2±4.8 vs 10.2±4.4 mm Hg; p<0.01). Multivariable logistic regression analyses and additional PSM revealed the use of the S3 Ultra to be associated with higher postprocedural mean transvalvular gradients (p<0.01). 30-day clinical outcomes, such as mortality, myocardial infarction, permanent pacemaker implantation and vascular complications were comparable between the groups.

CONCLUSIONS

The new S3 Ultra THV was associated with a higher postprocedural mean transvalvular gradient compared with the S3 system, while there was no difference in mortality or adverse clinical outcomes at 30 days. These echocardiographic differences will require long-term studies to assess the clinical relevance of this finding.

Characterization of Turbulent Flow Behind a Transcatheter Aortic Valve in Different Implantation Positions

The development of turbulence after transcatheter aortic valve (TAV) implantation may have detrimental effects on the long-term performance and durability of the valves. The characterization of turbulent flow generated after TAV implantation can provide fundamental insights to enhance implantation techniques. A self-expandable TAV was tested in a pulse replicator and the three-dimensional flow field was extracted by means of tomographic particle image velocimetry. The valve was fixed inside a silicone phantom mimicking the aortic root and the flow field was studied for two different supra-annular axial positions at peak systole. Fluctuating velocities and turbulent kinetic energy were compared between the two implantations. Velocity spectra were derived at different spatial positions in the turbulent wakes to characterize the turbulent flow. The valve presented similar overall flow topology but approximately 8% higher turbulent intensity in the lower implantation. In this configuration, axial views of the valve revealed smaller opening area and more corrugated leaflets during systole, as well as more accentuated pinwheeling during diastole. The difference arose from a lower degree of expansion of the TAV's stent inside the aortic lumen. These results suggest that the degree of expansion of the TAV in-situ is related to the onset of turbulence and that a smaller and less regular opening area might introduce flow instabilities that could be detrimental for the long-term performance of the valve. The present study highlights how implantation mismatches may affect the structure and intensity of the turbulent flow in the aortic root.

Mid-term clinical and haemodynamic results after aortic valve replacement with the Trifecta bioprosthesis

OBJECTIVES

The aim of this study was to evaluate the clinical and haemodynamic results after implantation of the Trifecta bioprosthesis.

METHODS

This study is a retrospective analysis of all patients undergoing Trifecta aortic valve replacement between 01 January 2012 and 31 December 2017 at the Ghent University Hospital. Univariable and multivariable analyses were performed to identify predictors of valve- and procedure-related complications and mortality. The haemodynamic performance was analysed by longitudinal Doppler echocardiography.

RESULTS

The mean age of the 182 patients was 77 [standard deviation (SD): 5.5] years; 54.9% were women. The mean follow-up was 39.8 (SD: 24.3) months. Overall survival at 1 and 5 years was 86% (SD: 3%) and 68% (SD: 4%), respectively, and overall freedom from structural valve deterioration was 100% and 98% at 1 and 5 years, respectively. There was no valve thrombosis nor early endocarditis. Urgent surgery was the only risk factor for early mortality in the multivariable analysis [P = 0.009, odds ratio 0.06, 95% confidence interval (CI) 0.01-0.5]. Preoperative atrial fibrillation was the most important predictor of late mortality (P = 0.001, hazard ratio 3.68, 95% CI 1.65-8.21). The average peak gradients were stable from discharge up to 1 and 5 years postoperatively [15 (SD: 6) and 17 (SD: 8) mmHg].

CONCLUSIONS

These results confirm the excellent clinical performance of the Trifecta valve, particularly in an elderly age group. Through the 7-year follow-up period, low transvalvular gradients persisted, and only a few patients needed reoperation. Although structural valve degeneration occurred rarely, it was unrelated to valve size or age at implantation; therefore, further long-term follow-up remains mandatory.

The Role of Multimodality Imaging in Left-Sided Prosthetic Valve Dysfunction

Prosthetic valve (PV) dysfunction (PVD) is a complication of mechanical or biological PV. Etiologic mechanisms associated with PVD include fibrotic pannus ingrowth, thrombosis, structural valve degeneration, and endocarditis resulting in different grades of obstruction and/or regurgitation. PVD can be life threatening and often challenging to diagnose due to the similarities between the clinical presentations of different causes. Nevertheless, identifying the cause of PVD is critical to treatment administration (thrombolysis, surgery, or percutaneous procedure). In this report, we review the role of multimodality imaging in the diagnosis of PVD. Specifically, this review discusses the characteristics of advanced imaging modalities underlying the importance of an integrated approach including 2D/3D transthoracic and transesophageal echocardiography, fluoroscopy, and computed tomography. In this scenario, it is critical to understand the strengths and weaknesses of each modality according to the suspected cause of PVD. In conclusion, for patients with suspected or known PVD, this stepwise imaging approach may lead to a simplified, more rapid, accurate and specific workflow and management.

[Screening analysis of proteolytic enzymes and their inhibitors in the leaflets of epoxy-treated bioprosthetic heart valves explanted due to dysfunction]

Bioprosthetic heart valves (BHVs) are known for their lower thrombogenicity rates and excellent hemodynamic parameters similar to native valves. However, the lifespan of these medical devices is limited to 15 years due to the structural valve degeneration. One of the mechanisms underlying functional impairment and calcification of BHVs includes proteolytic degradation of biomaterials. However, proteases found in xenogeneic BHVs tissue remain poorly studied. In this study using the dot blot assay, we have performed a screening analysis of proteolytic enzymes and their inhibitors in the leaflets of five BHVs explanted due to their dysfunction. Five aortic valves (AVs) explanted due to calcific aortic valve disease were studied as a comparison group. The results of the study have demonstrated that at least 17 proteases and 19 of their inhibitors can be found in BHVs. In the AVs 20 proteases and 21 their inhibitors were identified. Small quantitative differences were noted between proteomic profiles of the BHVs and AVs. Matrix metalloproteinases (MMPs) were expressed in BHVs and AVs at comparable levels, but the level of tissue inhibitors of metalloproteinases-1/-2 and RECK protein in implant tissues was lower than in natural valves. Probably, excessive activity of MMPs cannot be counterbalanced by their inhibitors in BHVs and therefore MMPs can degrade prosthetic biomaterial. Moreover, the detection of a wide range of proteolytic enzymes and their inhibitors in the degenerated BHVs suggests the existence of several pathophysiological pathways that can lead to structural valve degeneration.

The role of echocardiography in the management of structural valve degeneration of transcatheter valves

Transcatheter valve implantation in patients with aortic stenosis has evolved as an acceptable alternative to surgical aortic valve replacement in a subset of patients at excessively high risk from surgery. The structural valve degeneration (SVD) is a known phenomenon in catheter-based valves too, which was hitherto seen with surgical bioprosthetic valves. Echocardiography plays a pivotal role not only in early detection but also in the management of SVD of Transcatheter valves. The goal of this report is to agglomerate our experience of an unusual case of SVD of a catheter-based valve implanted inside the bioprosthetic aortic and mitral valve apparatus and its management with aortic and mitral valve replacement with mechanical valve prosthesis.

Neosinus and Sinus Flow After Self-Expanding and Balloon-Expandable Transcatheter Aortic Valve Replacement

OBJECTIVES

The aim of this study was to evaluate flow dynamics in the aortic sinus and the neosinus (NS) after transcatheter heart valve (THV) implantation in valve-in-valve (ViV).

BACKGROUND

Leaflet thrombosis may occur on THVs and affect performance and durability. Differences in flow dynamics may affect the risk for leaflet thrombosis.

METHODS

Hemodynamic assessment following THV implantation in a surgical aortic valve was performed in a left heart simulator under pulsatile physiological conditions. Assessment was performed using a 23-mm polymeric surgical aortic valve (not diseased) and multiple THV platforms, including self-expanding devices (26-mm Evolut, 23-mm Allegra, small ACURATE neo) and a balloon-expandable device (23-mm SAPIEN 3). Particle image velocimetry was performed to assess flow in the sinus and NS. Sinus and NS washout, shear stress, and velocity were calculated.

RESULTS

Sinus and NS washout was fastest and approximately 1 cardiac cycle for each with the Evolut, ACURATE neo, and Allegra compared with the SAPIEN 3, with washout in 2 and 3 cardiac cycles, respectively. The Allegra showed the largest shear stress distribution in the sinus, followed by the SAPIEN 3. In the NS, all 4 valves showed equal likelihoods of occurrence of shear stress <1 Pa, but the Allegra showed the highest likelihoods of occurrence for shear stress >1 Pa. The velocities in the sinus and NS were 0.05, 0.078, 0.080, and 0.075 m/s for Evolut, SAPIEN 3, ACURATE neo, and Allegra ViV, respectively.

CONCLUSIONS

Sinus and NS flow dynamics differ substantially among THVs after ViV. Self-expanding supra-annular valves seem to have faster washouts compared with an equivalent-size balloon-expandable THV.

Long-Term Echocardiographic Follow-Up After Transcatheter Aortic Valve Implantation to Assess Structural Valve Deterioration and Bioprosthetic Valve Failure

BACKGROUND

Indications for transcatheter aortic valve implantation (TAVI) in aortic stenosis are expanding and the life expectancy of patients following TAVI is increasing. Determining the long-term durability of TAVI valves is therefore important. Rates of long-term (≥5 years) structural valve deterioration (SVD) vary widely and there are currently no comparable data from Australia. The aim herein was to determine the incidence of haemodynamic SVD and bioprosthetic valve failure (BVF) using recently standardised definitions in a Western Australian cohort after at least 5 years.

METHODS

This is a retrospective cohort study of consecutive patients undergoing TAVI at Royal Perth Hospital between January 2009 and January 2015. Of 211 patients, 55 survived ≥5 years and had echocardiographic data available for review. Median time to the echocardiogram was 5.9 years (max 7.8 years); 49% male, mean age 83 years.

RESULTS

Of the 55 survivors who had echocardiograms available ≥5 years after TAVI, four (9%) had moderate haemodynamic SVD and one (2%) had severe SVD and BVF.

CONCLUSIONS

Our results suggest excellent long-term durability of contemporary TAVI valves in an Australian cohort with very low incidence of SVD and BVF. These findings add confidence to the expanding applications of TAVI valves.

The Transcatheter Tricuspid Valve-in-Valve Technique in Degenerated Bioprostheses Without Fluoroscopic Radiopaque Landmarks

Nonetheless, in principle, bioprosthetic heart valves are often preferred to mechanical valves in that not only do they obviate the need for high-level systemic anticoagulation and the attendant bleeding risks, but also higher rates of prosthetic valve thrombosis have been reported observed in the tricuspid position. The transcatheter tricuspid valve-in-valve (TVIV) procedure has expanded the horizons of cardiac surgery by allowing the implantation of stent-valves within degenerated bioprostheses in older adults and even young patients as the reported rate of the mortality of redo surgery in antecedent studies is at least 37%. Fluoroscopic guidance can assist the operator in implanting a bioprosthetic valve by radiopaque findings in the ideal position and depth; nonetheless, the complete radiolucency of some bioprosthetic valves represents a significant hurdle. In this state-of-the-art manuscript, we decided to deeply explain the appropriate heart-team approach in this scenario.

Transcatheter aortic valve replacement (TAVR): Recent updates

Within the last two decades, transcatheter aortic valve replacement (TAVR) has revolutionized the management of symptomatic severe aortic stenosis (AS). Newer generations of transcatheter valve design, optimized imaging planning, growing operator experience, and technical refinements have driven enhancements in safety and reduction of procedural complications over time. These improvements have allowed expansion to lower risk patients, in which TAVR confirmed favorable outcomes compared to surgical aortic valve replacement (SAVR). Based on current evidence, the 2020 AHA/ACC guidelines provided updated recommendations on indications for TAVR, with several clinical indications remain with SAVR. As TAVR expands to younger, low-risk patients with longer life expectancies, different issues of utmost importance have emerged, such as long-term durability, bioprosthetic valve performance, coronary reaccess, prognostic impact of conduction disturbances and paravalvular leak, reintervention after TAVR, and optimal pharmacological management after the procedure. In this review, we provide an update of recent clinical guidelines and available data from clinical trials and registries, and highlight novel strategies to further reduce procedural complications.

Transcatheter Aortic Valve Leaflet Thrombosis: Prevalence, Management, and Future Directions

PURPOSE OF REVIEW

We review the pathology, prevalence, diagnosis, hemodynamics, risk factors, prognosis, and treatment of leaflet thrombosis (LT), and suggest future directions in this field.

RECENT FINDINGS

The latest meta-analysis showed the prevalence of overall LT is 5.4% (clinical LT of 1.2% and subclinical LT of 15.1%). Either subclinical or clinical LT is not associated with risk of mortality; however, clinical LT is associated with increased risk of stroke. Although LT can be reduced by oral anticoagulation therapy (OAT), routine use of OAT as primary prevention for high-risk patients is not recommended due to increased risk of mortality. Four-dimensional computed tomography plays an important role in the diagnosis of LT and the accumulation of qualitative or qualitative assessments of hypoattenuated leaflet thickening would provide more clues to clarify effective OAT strategies. In addition, further studies are warranted to evaluate the efficacy of other anticoagulants in low-intermediate risk patients.

Transcatheter solutions for transcatheter aortic valve replacement dysfunction: is redo transcatheter aortic valve replacement a durable option?

As transcatheter aortic valve replacement (TAVR) expands into a younger and lower risk cohort of patients, many important clinical questions are raised, including the one of overall valve durability. Bioprosthetic valve dysfunction (BVD) is a complex clinical issue, of which structural valve deterioration (SVD) is a subcategory. Similar to surgical bioprosthesis, transcatheter heart valves (THVs) can fail over the years however, data on long-term THVs durability is lacking, especially in the lower risk cohort. Surgical explant with open aortic surgery or a second THV, described as redo-TAVR, are feasible options when the first THV fails. However long-term data in these patients is even more limited. Important clinical considerations such as the mechanism(s) of THV dysfunction, the type and timing of the second procedure must be carefully considered. There are also inherently important clinical concerns regarding redo-TAVR, such as coronary access and higher post procedure gradients. In the present keynote lecture, we review the diagnosis of THV dysfunction and transcatheter options available when SVD occurs.

Long-term durability after surgical aortic valve replacement with the Trifecta and the Intuity valve-a comparative analysis

OBJECTIVES

Long-term durability of surgical bio-prostheses is a key factor, especially in the era of transcatheter aortic valve replacement. We compared the incidence of structural valve deterioration (SVD) between patients undergoing surgical aortic valve replacement (SAVR) with the Trifecta (Abbott Laboratories, Abbott Park, IL, USA) or the Intuity valve (Edwards Lifesciences, Irvine, CA, USA).

METHODS

Between April 2010 and May 2020, 1118 patients underwent SAVR with the Trifecta (n = 346) and the Intuity (n = 772) valve at a single centre. A total of 1070 patients (Trifecta n = 298, Intuity n = 772) were analysed after the exclusion of patients with pure regurgitation and endocarditis. Retro- and prospective echocardiographic and clinical follow-up was performed. Cox proportional hazards regression models were performed to identify prognostic factors for SVD, aortic re-interventions and mortality.

RESULTS

With 27 cases (Trifecta n = 23, Intuity n = 4) of SVD observed, cumulative incidence of SVD was significantly higher in the Trifecta cohort (P < 0.001). Implantation of a Trifecta valve [hazard ratio (HR) 11.20; 95% confidence interval 3.79-33.09], log-transformed preoperative creatinine (HR 2.47; 1.37-4.44) and sex (male HR 0.42; 0.19-0.92) emerged as prognostic factors of SVD. A significantly higher cumulative incidence of re-interventions was observed in the Trifecta cohort (P = 0.004) and valve type was an independent time-varying risk factor (HR at 12 months 2.78; 95% confidence interval 1.42-5.45). Overall, no significant differences in all-cause mortality were observed between the groups (log-rank test: P = 0.052).

CONCLUSIONS

SVD was significantly more frequent in patients receiving a Trifecta valve and its implantation was an independent risk factor for the occurrence of SVD and aortic valve re-interventions. This comparative analysis of 2 low-gradient bioprosthesis put the long-term durability of the Trifecta valve in question and need to be taken into consideration when performing bioprosthetic SAVR.

A systematic review on durability and structural valve deterioration in TAVR and surgical AVR

Mechanical valves and bioprosthetic heart valves are widely used for aortic valve replacement (AVR). Mechanical valves are associated with risk of bleeding because of oral anticoagulation, while the durability and structural valve deterioration (SVD) represent the main limitation of the bioprosthetic heart valves. The implantation of bioprosthetic heart valves is increasing precipitously due aging population, and the widespread use of transcatheter aortic valve replacement (TAVR). TAVR has become the standard treatment for intermediate or high surgical risk patients and a reasonable alternative to surgery for low risk patients with symptomatic severe aortic stenosis. Moreover, TAVR is increasingly being used for younger and lower-risk patients with longer life expectancy; therefore it is important to ensure the valve durability for long-term transcatheter aortic valves. Although the results of mid-term durability of the transcatheter heart valves are encouraging, their long-term durability remains largely unknown. This review summarises the definitions, mechanisms, risk factors and assessment of SVD; overviews available data on surgical bioprosthetic and transcatheter heart valves durability.

Native Aortic Valve Disease Progression and Bioprosthetic Valve Degeneration in Patients With Transcatheter Aortic Valve Implantation

Supplemental Digital Content is available in the text.

Background:

Major uncertainties remain regarding disease activity within the retained native aortic valve, and regarding bioprosthetic valve durability, after transcatheter aortic valve implantation (TAVI). We aimed to assess native aortic valve disease activity and bioprosthetic valve durability in patients with TAVI in comparison with subjects with bioprosthetic surgical aortic valve replacement (SAVR).

Methods:

In a multicenter cross-sectional observational cohort study, patients with TAVI or bioprosthetic SAVR underwent baseline echocardiography, computed tomography angiography, and ¹⁸F-sodium fluoride (¹⁸F-NaF) positron emission tomography. Participants (n=47) were imaged once with ¹⁸F-NaF positron emission tomography/computed tomography either at 1 month (n=9, 19%), 2 years (n=22, 47%), or 5 years (16, 34%) after valve implantation. Patients subsequently underwent serial echocardiography to assess for changes in valve hemodynamic performance (change in peak aortic velocity) and evidence of structural valve dysfunction. Comparisons were made with matched patients with bioprosthetic SAVR (n=51) who had undergone the same imaging protocol.

Results:

In patients with TAVI, native aortic valves demonstrated ¹⁸F-NaF uptake around the outside of the bioprostheses that showed a modest correlation with the time from TAVI (r=0.36, P=0.023). ¹⁸F-NaF uptake in the bioprosthetic leaflets was comparable between the SAVR and TAVI groups (target-to-background ratio, 1.3 [1.2–1.7] versus 1.3 [1.2–1.5], respectively; P=0.27). The frequencies of imaging evidence of bioprosthetic valve degeneration at baseline were similar on echocardiography (6% versus 8%, respectively; P=0.78), computed tomography (15% versus 14%, respectively; P=0.87), and positron emission tomography (15% versus 29%, respectively; P=0.09). Baseline ¹⁸F-NaF uptake was associated with a subsequent change in peak aortic velocity for both TAVI (r=0.7, P<0.001) and SAVR (r=0.7, P<0.001). On multivariable analysis, ¹⁸F-NaF uptake was the only predictor of peak velocity progression (P<0.001).

Conclusions:

In patients with TAVI, native aortic valves demonstrate evidence of ongoing active disease. Across imaging modalities, TAVI degeneration is of similar magnitude to bioprosthetic SAVR, suggesting comparable midterm durability.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02304276.

Transcatheter valve-in-valve implantation in degenerated surgical aortic and mitral bioprosthesis: Current state and future perspectives

The use of bioprosthetic valves for treating patients with severe valve disease has increased over the last 2 decades, and, as a consequence, a growing number of patients with failing surgical bioprosthesis is expected in the near future. In this setting, valve-in-valve (ViV) transcatheter aortic/mitral valve replacement (TAVR and TMVR) has emerged as an alternative to redo surgery. Despite the increasing experience in ViV procedures, the development of these techniques faces several specific challenges, mainly related to the unique anatomical and physiological characteristics presented in ViV-TAVR/TMVR. Subsequently, various approaches have been proposed to overcome ViV-related complications and pitfalls. A growing body of evidence is currently available concerning early- and long-term clinical outcomes of patients undergoing ViV-TAVR/TMVR. These data should be comprehensively evaluated by the Heart Team in the decision-making process involving patients with failing surgical bioprostheses. In this review, we aimed to delineate the technical challenges and risks associated with ViV-TAVR and ViV-TMVR, provide an updated overview of the main clinical results, and summarize the future perspectives of this evolving field.

Transcatheter aortic valve replacement for structural degeneration of previously implanted transcatheter valves (TAVR-in-TAVR): a systematic review

OBJECTIVES

Transcatheter aortic valve replacement (TAVR) represents a valid treatment for patients with aortic valve stenosis and high or intermediate surgical risk. However, biological transcatheter valves can also experience a structural degeneration after years, and a redo-TAVR procedure (TAVR-in-TAVR) can be a valid option. We revised the current available literature for indications, procedural and technical details and outcome on TAVR-in-TAVR procedures for degenerated TAVR valves.

METHODS

A systematic search was conducted in the public medical database for scientific articles on TAVR-in-TAVR procedures for degenerated transcatheter valves. Data on demographics, indications, first and second transcatheter valve type and size, mortality, complications and follow-up were extracted and analysed.

RESULTS

A total of 13 studies (1 multicentre, 3 case series, 9 case reports) were included in this review, with a total amount of 160 patients treated with TAVR-in-TAVR procedures for transcatheter valve failure. The mean age was 74.8 ± 7.8 with 84 males (52.8%). The mean elapsed time from the first TAVR procedure was 58.1 ± 23.4 months. Main indication for TAVR-in-TAVR was pure stenosis (38.4%, with mean gradient of 44.5 ± 18.5 mmHg), regurgitation (31.4%), mixed stenosis and regurgitation (29.5%) and leaflet thrombosis (8.8%). Procedural success rate was 86.8%, with second TAVR valve malposition occurred in 4 cases (2.5%). The hospital mortality rate was 1.25% (2/160). Post-procedural echocardiographic control showed moderate regurgitation in 5.6% of patients (9/160) and residual transvalvular mean gradient ≥20 mmHg in 5% of cases. Postoperative complications included major vascular complications (8.7%), new pacemaker implantation (8.7%), acute kidney failure (3.7%), stroke (0.6%) and coronary obstruction (0.6%). The mean follow-up time was 6 ± 5.6 months with 1 non-cardiovascular death reported.

CONCLUSIONS

TAVR-in-TAVR represents a valid alternative to standard surgery for the treatment of degenerated transcatheter valves in high-risk patients. Despite these promising results, further studies are required to assess durability and haemodynamic performances of the second TAVR valve.

SUBJ COLLECTION

117, 122, 125.

Aortic and mitral bioprosthetic valve dysfunction: surgical or percutaneous solutions?

In the last years, there has been a trend to prefer biological prostheses, especially among young patients, with the aim to avoid anticoagulant treatment. Surgical tissue valves have so far demonstrated their solid long-term durability. However, younger age has been identified as one of the main risk factors for developing structural valve deterioration (SVD). As a consequence, the proportion of subjects at risk for valve dysfunction will constantly rise in the near future. However, while surgical reintervention has always been considered the gold standard for treatment of prosthesis deterioration, the introduction of transcatheter heart valves could offer new therapeutical options, particularly among high-risk patients, aiming a second less invasive chance. The recent standardization of valve durability definitions will soon allow a more comprehensive understanding of the mechanism underlying SVD and guide the choice of prosthesis for patients needing valve replacement.

Recellularization of xenograft heart valves reduces the xenoreactive immune response in an in vivo rat model

OBJECTIVES

Our aim was to address the role of autologous mesenchymal stem cell recellularization of xenogenic valves on the activation of the xenoreactive immune response in an in vivo rat model.

METHODS

Explanted aortic valve constructs from female Hartley guinea pigs were procured and decellularized, followed by recellularization with autologous Sprague-Dawley rat mesenchymal stem cells. Aortic valve xenografts were then implanted into the infrarenal aorta of recipient rats. Grafts were implanted as either autologous grafts, non-decellularized (NGP), decellularized and recellularized xenografts (RGP). Rats were euthanized after 7 and 21 days and exsanguinated and the grafts were explanted.

RESULTS

The NGP grafts demonstrated significant burden of granulocytes (14.3 cells/HPF) and CD3+ T cells (3.9 cells/HPF) compared to the autologous grafts (2.1 granulocytes/HPF and 0.72 CD3+ T cells/HPF) after 7 days. A lower absolute number of infiltrating granulocytes (NGP vs autologous, 6.4 vs 2.4 cells/HPF) and CD3+ T cells (NGP vs autologous, 2.8 vs 0.8 cells/HPF) was seen after 21 days. Equivalent granulocyte cell infiltration in the RGP grafts (2.4 cells/HPF) compared to the autologous grafts (2.1 cells/HPF) after 7 and 21 days (2.8 vs 2.4 cells/HPF) was observed. Equivalent CD3+ T-cell infiltration in the RGP grafts (0.63 cells/HPF) compared to the autologous grafts (0.72 cells/HPF) after 7 and 21 days (0.7 vs 0.8 cells/HPF) was observed. Immunoglobulin production was significantly greater in the NGP grafts compared to the autologous grafts at 7 (123.3 vs 52.7 mg/mL) and 21 days (93.3 vs 71.6 mg/mL), with a similar decreasing trend in absolute production. Equivalent immunoglobulin production was observed in the RGP grafts compared to the autologous grafts at 7 (40.8 vs 52.7 mg/mL) and 21 days (29.5 vs 71.6 mg/mL).

CONCLUSIONS

Autologous mesenchymal stem cell recellularization of xenogenic valves reduces the xenoreactive immune response in an in vivo rat model and may be an effective approach to decrease the progression of xenograft valve dysfunction.

Late leaflet dehiscence in a bovine bioprosthesis-mimicked COVID-19 infection

Symptoms mimicking COVID-19 infection, pulmonary emboli, or septicemia delayed diagnosis of aortic bioprosthesis failure. A 71-year-old man was admitted emergently with shortness of breath, fever, cough, and chest pain. Echocardiography performed after 2 days showed diastolic regurgitation in an aortic perimount pericardial bioprosthesis implanted 12 years previously. An urgent reoperation disclosed that one pericardial cusp was torn from the stent of the valve. We have not previously encountered sudden pericardial leaflet dehiscence of an internally mounted pericardial valve that caused heart failure and found no literature report like our finding.

Durability of Transcatheter Heart Valves: Standardized Definitions and Available Data

Transcatheter aortic valve replacement is a well-established alternative to surgical aortic valve replacement in high-risk patients with severe symptomatic aortic stenosis. Currently, this technique is shifting towards younger patient groups with intermediate- and low-risk profile, which raises the question about long-term durability. Despite acceptable results up to 5 years, little is currently known about valve performance beyond 5 years. Since valve deterioration, thrombosis and endocarditis seem to be the main factors affecting valve durability, precise and widely accepted definitions of these parameters were stated by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) in 2017, followed by the Valve in Valve International Data (VIVID) group definitions in 2018 and the Valve Academic Research Consortium 3 (VARC-3) definitions in 2021. Until the introduction of these definitions, interstudy comparisons were difficult due to missing uniformity. Since the release of these recommendations, an increasing number of studies have reported their data on long-term durability using these new criteria. The aim of the present article is to discuss the current definitions on bioprosthetic valve durability, and to summarize the available data on long-term durability of transcatheter aortic valves.

Longitudinal Hemodynamics of Aortic Bioprosthetic Valve in Hemodialysis Patients

We examined the hemodynamic profile of bioprosthetic aortic valves in patients on hemodialysis (HD), longitudinally, and assess the incidence of adverse changes detected by echocardiography. Of 1,146 consecutive patients with severe aortic stenosis who underwent bioprosthetic aortic valve replacement (AVR), 148 patients had end-stage renal disease requiring HD. Each patient on HD was matched one-to-one with a non-HD patient on the basis of propensity scores. The mean follow-up period was 3.3 years for the HD group and 5.9 years for the non-HD group. Follow-up information was available for 95.2%. Postoperative trends of valve hemodynamics derived from linear mixed-effect models showed significant group vs time interactions between the two groups. Stable hemodynamics was consistently observed in the non-HD group, whereas the HD group showed a decrease of -0.06 cm²/y (95% confidence interval (CI), -0.10 to -0.02) in effective orifice area, an increase of 0.8 mm Hg/year (95% CI, 0.4-1.1) in mean pressure gradient, and an increase of 0.08 m/s/year (95%CI, 0.02-0.13) in peak velocity. Cumulative incidence function of SVD more than stage 2 was significantly higher in the HD group (13.1% vs 3.1% at 5 years, Gray test p = 0.01). In a multivariable Fine-Gray analysis, diabetes was independently associated with SVD more than stage 2 in the HD group (subhazard ratio, 1.91; 95% CI, 1.25-2.89; p = 0.02). Survival free-from stenotic-type SVD was significantly lower in HD patients undergoing bioprosthetic AVR. Diabetes was independently associated with postoperative stenotic-type SVD in HD patients.

Brillouin confocal microscopy to determine biomechanical properties of SULEEI-treated bovine pericardium for application in cardiac surgery

BACKGROUND

Heart valves are exposed to a highly dynamic environment and underlie high tensile and shear forces during opening and closing. Therefore, analysis of mechanical performance of novel heart valve bioprostheses materials, like SULEEI-treated bovine pericardium, is essential and usually carried out by uniaxial tensile tests. Nevertheless, major drawbacks are the unidirectional strain, which does not reflect the in vivo condition and the deformation of the sample material. An alternative approach for measurement of biomechanical properties is offered by Brillouin confocal microscopy (BCM), a novel, non-invasive and three-dimensional method based on the interaction of light with acoustic waves.

OBJECTIVE

BCM is a powerful tool to determine viscoelastic tissue properties and is, for the first time, applied to characterize novel biological graft materials, such as SULEEI-treated bovine pericardium. Therefore, the method has to be validated as a non-invasive alternative to conventional uniaxial tensile tests.

METHODS

Vibratome sections of SULEEI-treated bovine pericardium (decellularized, riboflavin/UV-cross-linked and low-energy electron irradiated) as well as native and GA-fixed controls (n = 3) were analyzed by BCM. In addition, uniaxial tensile tests were performed on equivalent tissue samples and Young's modulus as well as length of toe region were analyzed from stress-strain diagrams. The structure of the extracellular matrix (ECM), especially collagen and elastin, was investigated by multiphoton microscopy (MPM).

RESULTS

SULEEI-treated pericardium exhibited a significantly higher Brillouin shift and hence higher tissue stiffness in comparison to native and GA-fixed controls (native: 5.6±0.2 GHz; GA: 5.5±0.1 GHz; SULEEI: 6.3±0.1 GHz; n = 3, p < 0.0001). Similarly, a significantly higher Young's modulus was detected in SULEEI-treated pericardia in comparison to native tissue (native: 30.0±10.4 MPa; GA: 31.8±10.7 MPa; SULEEI: 42.1±7.0 MPa; n = 3, p = 0.027). Native pericardia showed wavy and non-directional collagen fibers as well as thin, linear elastin fibers generating a loose matrix. The fibers of GA-fixed and SULEEI-treated pericardium were aligned in one direction, whereat the SULEEI-sample exhibited a much denser matrix.

CONCLUSION

BCM is an innovative and non-invasive method to analyze elastic properties of novel pericardial graft materials with special mechanical requirements, like heart valve bioprostheses.