Valve-in-valve implantations: is this the new standard for degenerated bioprostheses? Review of the literature. Clin Res Cardiol. 2014;103:417-429. [PMID: 24445751 DOI: 10.1007/s00392-013-0653-3]

Transcatheter valve-in-valve implantation for degenerated bioprosthetic aortic and mitral valves - an update on indications, techniques, and clinical results

Introduction: Aortic and mitral bioprosthesis are the gold standard treatment to replace a pathological native valve. However, bioprostheses are prone to structural valve degeneration, resulting in limited long-term durability. During the past decade, the implantation of transcatheter stent-valves within degenerated aortic and mitral bioprostheses, (the so-called 'valve-in-valve' procedure), represents a valid alternative to redo surgery in patients with high-risk surgical profiles.Areas covered: We reviewed the clinical outcomes and the procedural details of transcatheter aortic and mitral valve-in-valve series according to current published literature and include a practical guide for valve sizing and stent-valve positioning and strategies to prevent complications.Expert opinion: In both aortic and mitral positions meticulous planning is fundamental in these procedures to avoid serious complications including patient prosthesis mismatch, coronary obstruction and left ventricular outflow tract obstruction.

Increased utilization of bioprosthetic aortic valve technology:Trends, drivers, controversies and future directions

Introduction: Bioprosthetic valves (BPV) implanted surgically or by transcatheter valve implantation (TAVI) comprise an overwhelming majority of substitute aortic valves implanted worldwide.Areas Covered: Prominent drivers of this trend are: 1) BPV patients have generally better outcomes than those with a mechanical valve, and remain largely free of anticoagulation and its consequences; 2) BPV durability has improved over the years; and 3) the expanding use of TAVI and valve-in-valve (VIV) procedures permitting interventional management of structural valve degeneration (SVD). Nevertheless, key controversies exist: 1) optimal anticoagulation regimens for surgical and TAVI BPVs; 2) the incidence, mechanisms and mitigation strategies for SVD; 3) the use of VIV for treatment of SVD, and 4) valve selection recommendations for difficult cohorts, (e.g. patients 50-70 years, patients <50, childbearing age women). This communication reviews trends in and drivers of BPV utilization, current controversies, and future directions affecting BPV use.Expert Opinion: Long-term data are needed in several areas related to aortic BPV use, including anticoagulation/antiplatelet therapy, especially following TAVI. TAVI and especially VIV durability and optimal use warrant will benefit greatly from long-term data. Certain populations may benefit from such high-quality data on multi-year outcomes, particularly younger patients.

Bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction technique in transcatheter aortic valve-in-valve procedures: a single-center initial experience

AIM

To describe six cases using the bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction technique to prevent coronary artery obstruction during transcatheter aortic valve-in-valve procedures.

METHODS

All patients presented degeneration of a bovine pericardium bioprosthesis [four Trifecta (19, 21, 23, and 25 mm); two Mitroflow (25 and 27 mm)] resulting in severe aortic stenosis (n = 5) or severe aortic regurgitation (n = 1). Procedures were performed under fluoroscopic and echocardiography guidance, and the transfemoral access was used to deliver a self-expanding valve. Data are expressed as frequency or median (Q1-Q3).

RESULTS

Age, EuroScore II, and Society of Thoracic Surgeons score were 81 years (75-83.2), 2.9% (2.6-10.7), and 2.7% (2.3-3.2), respectively. Median left and right coronary heights were 9.1 mm (6.2-10.3) and 12.4 mm (10-13.5), respectively, with a median virtual transcatheter heart valve-to-coronary distance of 2.9 mm on the left and 4.6 mm on the right side. Isolated left leaflet laceration was planned in four patients, and bileaflet in two. One unsuccessful right leaflet laceration was reported, corresponding to the first patient (success rate 87.5%). All other seven leaflets lacerations were successfully performed, with no intraprocedure complications. No coronary obstruction, in-hospital death, valve complication, cardiovascular event, or pacemaker implantation were reported. All patients are being followed in routine outpatient visits, and no adverse events were registered.

CONCLUSION

The high procedural success and low complication rate reported in this initial experience, demonstrates that the bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction technique can be a viable solution to prevent coronary obstruction in selected patients undergoing valve-in-valve procedures. Operator experience, periprocedural imaging and teamwork are essential to enable an accurate and successful procedure.

Percutaneous techniques for treatment of tricuspid valve dysfunction in congenital heart disease - an emerging therapy

Introduction: Tricuspid valve (TV) dysfunction treatment experiences exponential growth of the interest over the last years. New techniques for percutaneous tricuspid valve treatment are either on the market or in the early stages of development.Areas covered: Deficiency of uniform guideline-based recommendations leads to diverse TV dysfunction treatment options. The current review describes the development of surgical techniques for TV dysfunction in Ebstein's anomaly and transition to a variety of new technologies. Then, the focus is on the potential of percutaneous interventions to reduce the total number of open-heart surgeries in patients with congenital heart disease (CHD) after TV replacement with a bioprosthesis to improve TV function.Expert opinion: TV dysfunction is usually a complex combination of anatomical cardiac features in CHD. Compared to adults with secondary TV dysfunction, CHD patients usually are younger and have experienced several open-heart surgeries at a young age. Therefore, TV dysfunction can affect long-term life expectancy and quality of life significantly. So far, surgery was the gold standard for TV dysfunction treatment. The duration of TV plasty or bioprosthesis is limited, while the risk of re-do operations increases with every procedure. Percutaneous TV implantation may reduce the total number of open-heart surgeries over a patient's life.

Feasibility of a Mitral Annuloplasty With the Capability for Peri- and Postoperative Adjustment

Surgical repair with implantation of a mitral annuloplasty ring is the gold standard treatment for mitral regurgitation. However, outcomes are variable and recurrent mitral regurgitation is not uncommon. A REshapeable Mitral Annuloplasty DevIce (REMADI) is proposed, which consists of a fully encapsulated low melting temperature alloy. The alloy is solid and rigid at body temperature and provides traction force to shape the annulus. When heated using a noncontact method, the alloy melts and the REMADI becomes malleable. The REMADI is engaged with the mitral valve annulus using anchors which automatically deploy upon contact. A passive beating porcine heart model was used to demonstrate the feasibility of the REMADI device, which was deployed, engaged, and used to reduce the diameter of the mitral valve annulus.

A Computational Study on Deformed Bioprosthetic Valve Geometries: Clinically Relevant Valve Performance Metrics

Transcatheter aortic valves (TAV) are symmetrically designed, but they are often not deployed inside cylindrical conduits with circular cross-sectional areas. Many TAV patients have heavily calcified aortic valves, which often result in deformed prosthesis geometries after deployment. We investigated the effects of deformed valve annulus configurations on a surgical bioprosthetic valve as a model for TAV. We studied valve leaflet motions, stresses and strains, and analog hydrodynamic measures (using geometric methods), via finite element (FE) modeling. Two categories of annular deformations were created to approximate clinical observations: (1) noncircular annulus with valve area conserved, and (2) under-expansion (reduced area) compared to circular annulus. We found that under-expansion had more impact on increasing stenosis (with geometric orifice area metrics) than noncircularity, and that noncircularity had more impact on increasing regurgitation (with regurgitation orifice area metrics) than under-expansion. We found durability predictors (stress/strain) to be the highest in the commissure regions of noncircular configurations such as EllipMajor (noncircular and under-expansion areas). Other clinically relevant performance aspects such as leaflet kinematics and coaptation were also investigated with the noncircular configurations. This study provides a framework for choosing the most challenging TAV deformations for acute and long-term valve performance in the design and testing phase of device development.

How to Avoid Coronary Occlusion During TAVR Valve-in-Valve Procedures

Transcatheter aortic valve-in-valve replacement has been recently reported as a less-invasive alternative to re-do surgery in patients with bioprosthetic valve failure. Although procedural success is achieved in the great majority of patients, this therapy is associated with several potential complications, and coronary occlusion is one of the most feared. This is a rare event, but it is associated with an extremely poor prognosis. In this review, the mechanisms, the identification of patients at high risk, the primary prevention strategies, and treatment of coronary occlusion will be discussed.

Effect of severe bioprosthetic valve tissue ingrowth and inflow calcification on valve-in-valve performance

While in vivo studies clearly demonstrate that supra-annular Valve-in-Valve (ViV) implantation provides the highest probability for optimal post-ViV pressure gradients (PG), there is still no physical insight into explaining anomalies where some supra-annular ViV implantations yield high pressure gradients while some sub-annular implantations yield low pressure gradients. The aim of this study is to explain how severe tissue ingrowth and calcification (TIC) in a surgical aortic valve (SAV) can be one physical mechanism leading to anomalous ViV performance characteristic. The ViV hemodynamic performance was evaluated as a function of axial positioning -9.8, -6.2, 0, and +6 mm in SAVs with and without TIC. Effective orifice area (EOA) and PG were compared. Leaflet high-speed imaging and particle image velocimetry were performed to elucidate flutter and forward jet characteristics. ViV without TIC showed significantly lower PG and greater EOA (p < 0.01). EOA and PG improve with supra-annular deployment (p < 0.01) while for ViV with TIC, EOA and PG worsen as the deployment varies from -9.8 mm to 0 mm (p < 0.01) only to recover at + 6 mm (p < 0.01). Separated jet flow at the TIC site, and consequently induced stronger TAV leaflet fluttering highlight the dynamic compromising nature of TIC on jet width and performance reduction. We conclude that the inflow TIC greatly influence ViV performance due to dynamic effects that results in a real anomalous performance characteristic different than that seen in most ViV in vivo. Further in vivo studies are needed to evaluate ViV outcomes in the presence of severe TIC in SAVs.

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.

Simplified Multistage Computational Approach to Assess the Fatigue Behavior of a Niti Transcatheter Aortic Valve During In Vitro Tests: A Proof-of-Concept Study

Nowadays, transcatheter aortic valve (TAV) replacement is an alternative to surgical therapy in selected high risk patients for the treatment of aortic stenosis. However, left ventricular contraction determines a severe cyclic loading for the implanted stent-frame, undermining its long-term durability. Technical standards indicate in vitro tests as a suitable approach for the assessment of TAV fatigue behavior: generally, they do not specify test methods but require to test TAV in the worst loading conditions. The most critical conditions could be different according to the specific valve design, hence the compartment where deploying the valve has to be properly identified. A fast and reliable computational methodology could significantly help to face this issue. In this paper, a numerical approach to analyze Nickel-Titanium TAV stent-frame behavior during in vitro durability tests is proposed. A simplified multistage strategy was adopted where, in each stage, only two of the three involved components are considered. As a proof-of-concept, the method was applied to a TAV prototype. Despite its simplifications, the developed computational framework gave useful insights into the stent-frame failures behavior during a fatigue test. Numerical results agree with experimental findings. In particular, the most dangerous condition was identified among a number of experimental tests, where different compartments and pressure gradients were investigated. The specific failure location was also correctly recognized. In conclusion, the presented methodology provides a tool to support the choice of proper testing conditions for the in vitro assessment of TAV fatigue behavior.

The role of inelastic deformations in the mechanical response of endovascular shape memory alloy devices

Nickel-titanium alloys are commonly adopted for producing cardiovascular minimally invasive devices such as self-expandable stents, aortic valves and stent-grafts. These devices are subjected to cyclic loads (due to blood pulsatility, leg or heart movements), that can induce fatigue fracture, and may also be subjected to very large deformations (due to crimping procedure, a tortuous physiological path or overloads), that can induce material yield. Recently, the authors developed a new constitutive model that considers inelastic strains due to not-completed reverse phase transformation (not all the stress-induced martensite turns back to austenite) or/and plasticity and their accumulation during cyclic loads. In this article, the model is implemented in the finite element code ABAQUS/Standard and it is used to investigate the effects of inelastic strain accumulation on endovascular nickel-titanium devices. In particular, the behavior of a transcatheter aortic valve is studied considering the following steps: (1) crimping, (2) expansion in a tube resembling a durability test chamber and (3) cyclic loads due to pressure variation applied on the inner surface of the tube. The analyses are performed twice, activating and not activating that part of the new model which describes the development of irreversible strain. From the results, it is interesting to note that plasticity has a very significant effect on the local material response, inducing stress modification from compression to tension. However, permanent deformations are concentrated in few zones of the stent frame and their presence does not affect the global behavior of the device that maintains its capability of recovering the original shape. In conclusion, this work suggests that at least for cardiovascular devices where the crimping is high (local strain may reach values of 8%-9%), taking into account inelastic effects due to plasticity and not-completed reverse phase transformation can be important, and hence using a suitable constitutive model is recommended.

Effect of transcatheter aortic valve size and position on valve-in-valve hemodynamics: An in vitro study

OBJECTIVE

Transcatheter heart valve implantation in failed aortic bioprostheses (valve-in-valve [ViV]) is an increasingly used therapeutic option for high-risk patients. However, high postprocedural gradients are a significant limitation of aortic ViV. Our objective was to evaluate Medtronic CoreValve Evolut R ViV hemodynamics in relation to the degree of device oversizing and depth of implantation.

METHODS

Evolut R devices of 23 and 26 mm were implanted within 21-, 23-, and 25-mm Hancock II bioprostheses. Small and gradual changes in implantation depth were attempted. Hemodynamic testing was performed in a pulse duplicator under ISO-5840 standard.

RESULTS

A total of 47 bench-testing experiments were performed. The mean gradient of the 26-mm Evolut R in 23- and 25-mm Hancock II was lower than 23-mm Evolut R (P < .001). However, the mean gradient of 26-mm Evolut R in 21-mm Hancock II bioprostheses R (ranging from 21.30 ± 0.23 to 24.30 ± 0.22 mm Hg) was worse than 23-mm Evolut R (ranging from 15.94 ± 0.18 to 20.35 ± 0.16 mm Hg, P < .001). Furthermore, our results suggest that supra-annular implantation of 23-mm and 26-mm Evolut R devices within the bioprostheses can lead to lower gradient and improved leaflet coaptation. Regardless of implantation depth, superior transvalvular gradient is expected with 26-mm Evolut R than 23-mm Evolut R in a nonstenotic Hancock II with a true internal diameter > 17.5 mm.

CONCLUSIONS

The current comprehensive bench-testing assessment demonstrates the importance of both transcatheter heart valve size and device position for the attainment of optimal hemodynamics during ViV procedures. Additional in vitro testing may be required to develop hemodynamics-based guidelines for device sizing in ViV procedures in degenerated surgical bioprostheses.

Transcatheter Valve Underexpansion Limits Leaflet Durability: Implications for Valve-in-Valve Procedures

Transcatheter aortic valve (TAV) implantation within a failed bioprosthetic valve is a growing trend for high-risk patients. The non-compliant stent of the previous prosthesis may prevent full expansion of the TAV, which has been shown to distort the leaflet configuration, and has been hypothesized to adversely affect durability. In this study, TAV leaflet fatigue damage under cyclic pressurization in the setting of stent underexpansion by 0 (fully expanded), 1, 2 and 3 mm was simulated using finite element analysis to test this hypothesis. In the 2 and 3 mm underexpanded devices, the TAV leaflets exhibited severe pin-wheeling during valve closure, which increased leaflet stresses dramatically, and resulted in accelerated fatigue damage of the leaflets. The leaflet fatigue damage in the 1 mm underexpanded case was similar to that in the fully expanded case. Clinically a range of 10-15% underexpansion is generally considered acceptable; however, it was observed in this study that ≥2 mm (≥9.1%) underexpansion, will significantly impact device durability. Further study is necessary to determine the impact of various deployment conditions, i.e. non-uniform and non-circular deployments and different implantation heights, on differing TAV devices, but it is clear that the normal TAV leaflet configuration must be preserved in order to preserve durability.

Tricuspid valve-in-valve implantation for failing bioprosthetic valves: an evolving standard of care

Redo surgery for bioprosthetic tricuspid valve failure is associated with high morbidity and mortality. In recent years, transcatheter tricuspid valve-in-valve (VIV) therapy utilizing ballon-expandable transcatheter valves has become available. The tricuspid Valve-in-Valve International Data (VIVID) registry initial results represent the largest experience with tricuspid VIV therapy, demonstrating high procedural success rates with low 30 days mortality and excellent survival free of repeat tricuspid intervention in 1 year. Although longer clinic and hemodynamic follow-up will be needed to fully understand the role of this therapy, these data support the safety, feasibility and beneficial effects of tricuspid VIV therapy. For patients with bioprosthetic tricuspid valve failure, tricuspid VIV is likely to become a first-line treatment option.

Transcatheter Replacement of Failed Bioprosthetic Valves

Background—

Transcatheter valve implantation inside failed bioprosthetic surgical valves (valve-in-valve [ViV]) may offer an advantage over reoperation. Supra-annular transcatheter valve position may be advantageous in achieving better hemodynamics after ViV. Our objective was to define targets for implantation that would improve hemodynamics after ViV.

Methods and Results—

Cases from the Valve-in-Valve International Data (VIVID) registry were analyzed using centralized core laboratory assessment blinded to clinical events. Multivariate analysis was performed to identify independent predictors of elevated postprocedural gradients (mean ≥20 mm Hg). Optimal implantation depths were defined by receiver operating characteristic curve. A total of 292 consecutive patients (age, 78.9±8.7 years; 60.3% male; 157 CoreValve Evolut and 135 Sapien XT) were evaluated. High implantation was associated with significantly lower rates of elevated gradients in comparison with low implantation (CoreValve Evolut, 15% versus 34.2%; P =0.03 and Sapien XT, 18.5% versus 43.5%; P =0.03, respectively). Optimal implantation depths were defined: CoreValve Evolut, 0 to 5 mm; Sapien XT, 0 to 2 mm (0–10% frame height); sensitivities, 91.3% and 88.5%, respectively. The strongest independent correlate for elevated gradients after ViV was device position (high: odds ratio, 0.22; confidence interval, 0.1–0.52; P =0.001), in addition to type of device used (CoreValve Evolut: odds ratio, 0.5; confidence interval, 0.28–0.88; P =0.02) and surgical valve mechanism of failure (stenosis/mixed baseline failure: odds ratio, 3.12; confidence interval, 1.51–6.45; P =0.002).

Conclusions—

High implantation inside failed bioprosthetic valves is a strong independent correlate of lower postprocedural gradients in both self- and balloon-expandable transcatheter valves. These clinical evaluations support specific implantation targets to optimize hemodynamics after ViV.

Transcatheter Tricuspid Valve-in-Valve Implantation for the Treatment of Dysfunctional Surgical Bioprosthetic Valves

Background—

Off-label use of transcatheter aortic and pulmonary valve prostheses for tricuspid valve-in-valve implantation (TVIV) within dysfunctional surgical tricuspid valve (TV) bioprostheses has been described in small reports.

Methods and Results—

An international, multicenter registry was developed to collect data on TVIV cases. Patient-related factors, procedural details and outcomes, and follow-up data were analyzed. Valve-in-ring or heterotopic TV implantation procedures were not included. Data were collected on 156 patients with bioprosthetic TV dysfunction who underwent catheterization with planned TVIV. The median age was 40 years, and 71% of patients were in New York Heart Association class III or IV. Among 152 patients in whom TVIV was attempted with a Melody (n=94) or Sapien (n=58) valve, implantation was successful in 150, with few serious complications. After TVIV, both the TV inflow gradient and tricuspid regurgitation grade improved significantly. During follow-up (median, 13.3 months), 22 patients died, 5 within 30 days; all 22 patients were in New York Heart Association class III or IV, and 9 were hospitalized before TVIV. There were 10 TV reinterventions, and 3 other patients had significant recurrent TV dysfunction. At follow-up, 77% of patients were in New York Heart Association class I or II ( P <0.001 versus before TVIV). Outcomes did not differ according to surgical valve size or TVIV valve type.

Conclusions—

TVIV with commercially available transcatheter prostheses is technically and clinically successful in patients of various ages across a wide range of valve size. Although preimplantation clinical status was associated with outcome, many patients in New York Heart Association class III or IV at baseline improved. TVIV should be considered a viable option for treatment of failing TV bioprostheses.

In-hospital outcome of transcatheter vs. surgical aortic valve replacement in patients with aortic valve stenosis: complete dataset of patients treated in 2013 in Germany

BACKGROUND

Transvascular (TV-AVI) or transapical (TA-AVI) aortic valve implantation (TAVI) is a treatment option for patients with aortic stenosis being at high or prohibitive risk for surgical aortic valve implantation (SAVR). Randomized data demonstrated that these subgroups can safely been treated with TAVI. However, a comparison of SAVR and TAVI in intermediate and low-risk patients is missing. Therefore, the aim of the analysis was to compare TAVI and SAVR in all patients who were treated for aortic valve stenosis in Germany throughout 1 year.

METHODS

The mandatory quality assurance collects data on the in-hospital outcome from all patients (n = 20,340) undergoing either SAVR or TAVI in Germany. In order to compare the different treatment approaches patients were categorized into four risk groups using the logistic EuroScore I (ES). In-hospital mortality and peri- and postprocedural complications were analyzed.

RESULTS

The in-hospital mortality did not differ between TV-AVI and SAVR in the low risk group (ES <10 %: TV-AVI 2.4 %, SAVR 2.0 %, p = 0.302) and was significantly higher for SAVR in all other risk groups (ES 10-20 %: TV-AVI 3.5 %, SAVR 5.3 %; p = 0.025; ES 20-30 %: TV-AVI 5.5 %, SAVR 12.2 %, p < 0.001; ES >30 %: TV-AVI 6.5 %, SAVR 12.9 %, p = 0.008). TA-AVI had a significantly higher mortality in all risk groups compared to TV-AVI. In comparison to SAVR, TA-AVI had a higher mortality in patients with ES <10, comparable mortality in ES 10-20 %, and lower mortality in patients with an ES >20 %. The overall stroke rate was 2.3 %. It occurred more frequently in patients with an ES <10 % treated with a transapical approach (SAVR 1.8 %, TV-AVI 1.9 %, TA-AVI 3.1 %, p < 0.01). There were no statistically significant differences in all other comparisons.

CONCLUSIONS

This study demonstrates that TAVI provides excellent outcomes in all risk categories. Compared with SAVR, TV-TAVI yields similar in-hospital mortality among low-risk patients and lower in-hospital mortality among intermediate and high-risk patient populations.

Comparison of transcatheter aortic valve and surgical bioprosthetic valve durability: A fatigue simulation study

Transcatheter aortic valve (TAV) intervention is now the standard-of-care treatment for inoperable patients and a viable alternative treatment option for high-risk patients with symptomatic aortic stenosis. While the procedure is associated with lower operative risk and shorter recovery times than traditional surgical aortic valve (SAV) replacement, TAV intervention is still not considered for lower-risk patients due in part to concerns about device durability. It is well known that bioprosthetic SAVs have limited durability, and TAVs are generally assumed to have even worse durability, yet there is little long-term data to confirm this suspicion. In this study, TAV and SAV leaflet fatigue due to cyclic loading was investigated through finite element analysis by implementing a computational soft tissue fatigue damage model to describe the behavior of the pericardial leaflets. Under identical loading conditions and with identical leaflet tissue properties, the TAV leaflets sustained higher stresses, strains, and fatigue damage compared to the SAV leaflets. The simulation results suggest that the durability of TAVs may be significantly reduced compared to SAVs to about 7.8 years. The developed computational framework may be useful in optimizing TAV design parameters to improve leaflet durability, and assessing the effects of underexpanded, elliptical, or non-uniformly expanded stent deployment on TAV durability.

Percutaneous pulmonary and tricuspid valve implantations: An update

The field of percutaneous valvular interventions is one of the most exciting and rapidly developing within interventional cardiology. Percutaneous procedures focusing on aortic and mitral valve replacement or interventional treatment as well as techniques of percutaneous pulmonary valve implantation have already reached worldwide clinical acceptance and routine interventional procedure status. Although techniques of percutaneous pulmonary valve implantation have been described just a decade ago, two stent-mounted complementary devices were successfully introduced and more than 3000 of these procedures have been performed worldwide. In contrast, percutaneous treatment of tricuspid valve dysfunction is still evolving on a much earlier level and has so far not reached routine interventional procedure status. Taking into account that an “interdisciplinary challenging”, heterogeneous population of patients previously treated by corrective, semi-corrective or palliative surgical procedures is growing inexorably, there is a rapidly increasing need of treatment options besides redo-surgery. Therefore, the review intends to reflect on clinical expansion of percutaneous pulmonary and tricuspid valve procedures, to update on current devices, to discuss indications and patient selection criteria, to report on clinical results and finally to consider future directions.

Valve-in-Valve Therapy for Failed Surgical Bioprosthetic Valves: Clinical Results and Procedural Guidance

With improved life expectancy and increased use of bioprosthetic heart valves, more elderly and frail patients present with degenerative surgical heart valve disease. The valve-in-valve procedure is an attractive alternative to a conventional open redo procedure. Although it is a novel extension of established transcatheter aortic valve implantation for severe aortic stenosis in a high-risk population, it is gaining momentum worldwide, particularly for aortic and mitral positions. Success depends on the operator being familiar with emerging transcatheter heart valve technology and morphology as well as that of the existing surgical heart valve, patient selection, accurate sizing, an ideal implantation position.

Valve-in-valve procedure: importance of the anatomy of surgical bioprostheses

Transcatheter aortic valve implantation is an accepted and established alternative to surgical aortic valve replacement for patients with severe symptomatic aortic valve stenosis and multiple comorbidities that would make open surgery a high-risk option. It has also evolved as a suitable treatment option for degenerative surgical heart valve disease, with considerable experience in the aortic and mitral positions. To enable a successful procedure, avoiding malposition, valve embolization and coronary obstruction, clinicians should be familiar with the design, fluoroscopic appearances and implantation technique of the degenerated surgical bioprosthetic valve in situ, as well as its compatibility with currently available transcatheter valves.