Transcatheter Aortic Valve-in-Valve Implantation for Patients With Degenerative Surgical Bioprosthetic Valves

Who Lives Longer, the Valve or the Patient? The Dilemma of TAVI Durability and How to Optimize Patient Outcomes

Over the past few years, transcatheter aortic valve implantation (TAVI) imposed itself as the first-choice therapy for symptomatic aortic stenosis (AS) in elderly patients at surgical risk. There have been continuous technological advancements in the latest iterations of TAVI devices and implantation techniques, which have bolstered their adoption. Moreover, the favorable outcomes coming out from clinical trials represent an indisputable point of strength for TAVI. As indications for transcatheter therapies now include a low surgical risk and younger individuals, new challenges are emerging. In this context, the matter of prosthesis durability is noteworthy. Initial evidence is beginning to emerge from the studies in the field, but they are still limited and compromised by multiple biases. Additionally, the physiopathological mechanisms behind the valve's deterioration are nowadays somewhat clearer and classified. So, who outlasts who-the valve or the patient? This review aims to explore the available evidence surrounding this intriguing question, examining the various factors affecting prosthesis durability and discussing its potential implications for clinical management and current interventional practice.

A 20-year journey in transcatheter aortic valve implantation: Evolution to current eminence

Since the first groundbreaking procedure in 2002, transcatheter aortic valve implantation (TAVI) has revolutionized the management of aortic stenosis (AS). Through striking developments in pertinent equipment and techniques, TAVI has now become the leading therapeutic strategy for aortic valve replacement in patients with severe symptomatic AS. The procedure streamlining from routine use of conscious sedation to a single arterial access approach, the newly adapted implantation techniques, and the introduction of novel technologies such as intravascular lithotripsy and the refinement of valve-bioprosthesis devices along with the accumulating experience have resulted in a dramatic reduction of complications and have improved associated outcomes that are now considered comparable or even superior to surgical aortic valve replacement (SAVR). These advances have opened the road to the use of TAVI in younger and lower-risk patients and up-to-date data from landmark studies have now established the outstanding efficacy and safety of TAVI in patients with low-surgical risk impelling the most recent ESC guidelines to propose TAVI, as the main therapeutic strategy for patients with AS aged 75 years or older. In this article, we aim to summarize the most recent advances and the current clinical aspects involving the use of TAVI, and we also attempt to highlight impending concerns that need to be further addressed.

Impact of high-pressure balloon aortic valvuloplasty on the hydrodynamic result after a transcatheter valve-in-valve procedure

OBJECTIVES

The aim of this study was to investigate the degree of functional improvement of a transcatheter heart valve (THV) for valve-in-valve after bioprosthetic valve fracture (BVF) of three small surgical aortic valve bioprostheses (SAVBP) using high-pressure balloon aortic valvuloplasty (HP-BAV) under standardized ex-vivo-conditions.

METHODS

A THV 26 mm (Evolut R) and SAVBP 21 mm (Perimount Magna Ease, Trifecta, and Epic supra [n = 4] were used. Mean pressure gradient (MPG), effective orifice area (EOA), geometric orifice area (GOA), minimal internal diameter (MID), and pinwheeling index (PWI) were analyzed before and after HP-BAV of the SAVBP using a noncompliant balloon. Fracturing of the SAVBP was done before implantation of the THV and the balloon pressures at the point of fracture were recorded.

RESULTS

The Magna Ease and Epic fractured at balloon pressures of 18 and 8 atm, respectively. The Trifecta did not fracture up to a balloon pressure of 30 atm but was dilated. HP-BAV led to increased THV expansion as evident by straightened coaptation lines of the Evolut R 26 mm with reduced PWI, increased MID, and increased GOA in all 21 mm SAVBP. Evolut R showed significantly lower MPG and higher EOA as ViV in all prostheses after HP-BAV (p < 0.001). MPG and EOA of Evolut R differed regarding the SAVBP. Evolut R presented the lowest MPG and highest EOA in Magna Ease and the highest MPG and lowest EOA in Epic supra.

CONCLUSIONS

The degree of function improvement of the same THV as ViV after HP-BAV depends on the surgical valve model. Functional improvement can also be achieved without valve fracture.

5-Year Follow-Up From the PARTNER 2 Aortic Valve-in-Valve Registry for Degenerated Aortic Surgical Bioprostheses

OBJECTIVES

The aim of this study was to report the outcomes of valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) at 5 years.

BACKGROUND

TAVR for degenerated surgical bioprostheses in patients at high risk for reoperative surgery is an important treatment option that may delay or obviate the need for surgical intervention; however, long-term outcomes of this procedure are unknown.

METHODS

The PARTNER (Placement of Aortic Transcatheter Valves) 2 ViV and continued access registries prospectively enrolled patients with failed surgical bioprostheses at high risk for reoperation. Five-year clinical and echocardiographic follow-up data were obtained in 95.9% of patients.

RESULTS

In 365 (96 registry and 269 continued access) patients, the mean age was 78.9 ± 10.2 years, the mean Society of Thoracic Surgeons predicted risk of surgical mortality score was 9.1 ± 4.7%, and New York Heart Association functional class was III or IV in 90.4%. At 5 years, the Kaplan-Meier rates of all-cause mortality and any stroke were 50.6% and 10.5%, respectively. Using Valve Academic Research Consortium 3 definitions, the incidence of structural valve deterioration, related hemodynamic valve deterioration, or bioprosthetic valve failure at 5 years was 6.6%. Aortic valve re-replacement was performed in 6.3% (n = 14), the majority of which was due to stenosis (n = 6) and combined aortic insufficiency/paravalvular regurgitation (n = 3). The mean gradient, Doppler velocity index, paravalvular regurgitation, and quality of life measured by Kansas City Cardiomyopathy Questionnaire scores in survivors remained stable from 30 days postprocedure through 5 years.

CONCLUSIONS

At the 5-year follow-up, TAVR for bioprosthetic aortic valve failure in high surgical risk patients was associated with sustained improvement in clinical and echocardiographic outcomes.

Donkey pericardium compares favorably with commercial xenopericardia used in the manufacture of transcatheter heart valves

Transcatheter aortic valve implantation (TAVI) has gained considerable acceptance in the past decade due to its lower risks than conventional open-heart surgery. However, the deformation and delamination of the leaflets during the crimping procedure have raised questions about the durability and long-term serviceability of the pericardium tissue from which the leaflets are made. The collagen architecture, wall thickness and mechanical properties of donkey pericardium were investigated to assess its suitability as an alternative material for the manufacture of heart valves. Coupons sampled from different locations of donkey pericardium were investigated. Bovine, equine, and porcine pericardium specimens served as controls. The donkey pericardium had a similar surface morphology to that of the control pericardia except for the wavy topology on both the fibrous and serous sides. The average thickness of donkey pericardium (ca. 120 µm) was significantly lower than that from bovine (375 µm) and equine (410 µm), but slightly higher than that from porcine (99 µm) specimens. The interlaced wavy collagen bundles in the pericardium were composed of collagen fibers about 100 nm in diameter. This unique structure ensures that the donkey pericardium has a comparable ultimate tensile strength (UTS) and a much higher failure strain than the commercial pericardia used for the manufacture of heart valves. The donkey pericardium has an organized wavy collagen bundle architecture similar to that of bovine pericardium and has a satisfactory UTS and high failure strain. The thin and strong donkey pericardium might be a good candidate valve leaflet material for TAVI.

Long-term Transcatheter Aortic Valve Durability

Transcatheter aortic valve implantation (TAVI) has become the standard of care for high-risk and inoperable surgical patients and a valid alternative to surgery for low- and intermediate-risk patients with severe, symptomatic aortic stenosis. It is increasingly being used for younger, lower-risk patients, so it is important to ensure the durability for long-term transcatheter aortic valves. The lack of standard definitions of structural valve degeneration (SVD) had made comparison among studies on prosthetic valve durability problematic. The 2017 standardised definitions of SVD by the European Association of Percutaneous Cardiovascular Intervention), the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery, and the 2018 definitions by the Valve In Valve International Data group, has generated an increased uniformity in evaluations. This article examines the potential mechanisms and rates of SVD of transcatheter bioprostheses and the role of redo TAVI as a treatment option.

Transcatheter aortic valve-in-valve implantation for failed surgical bioprosthetic valves. A minimalist approach without contrast aortography or echocardiographic guidance

OBJECTIVES

To demonstrate safety, feasibility and short-term clinical outcomes after transcatheter aortic valve-in-valve (ViV) implantation under local anesthesia without contrast aortography or echocardiographic guidance.

BACKGROUND

Transcatheter ViV implantation is an emerging treatment modality for patients with degenerative surgical bioprostheses. Given the radiopaque properties of the surgical aortic valve (SAV) frame, ViV procedures can often be performed with fluoroscopic guidance alone.

METHODS

ViV implantation was performed in 37 patients with SAV failure under local anesthesia without contrast aortography. Clinical and echocardiographic data were obtained at baseline, discharge, and 30 days.

RESULTS

Mean age was 74 ± 10 years and STS predicted risk of mortality was 5.6 ± 2.4%. Mean transaortic gradient decreased from 39.4 ± 15.5 mmHg to 13 ± 6.3 mmHg at discharge (p < .001), and 20 ± 7.5 mmHg at 30 days (p < .001 compared to baseline), aortic valve area increased from 0.9 ± 0.3 cm² to 1.2 ± 0.4 cm² at 30 days (p = .007). No patient had more than mild aortic regurgitation. Hospital discharge occurred at a median of 2.6 ± 4.4 days. At 30-day follow-up there were no deaths, myocardial infarctions, strokes, repeat hospital admissions for heart failure, or renal failure. One patient (2.7%) required a new pacemaker. 93% of the patients were in New York Heart Association functional class I or II.

CONCLUSIONS

Transcatheter aortic ViV implantation for selected patients with degenerative surgical bioprostheses under local anesthesia without aortography or echocardiographic guidance is feasible and safe.

Transcatheter Aortic Valve-in-Valve Procedure in Patients with Bioprosthetic Structural Valve Deterioration

Surgical aortic valve replacement is the gold standard procedure to treat patients with severe, symptomatic aortic valve stenosis or insufficiency. Bioprosthetic valves are used for surgical aortic valve replacement with a much greater prevalence than mechanical valves. However, bioprosthetic valves may fail over time because of structural valve deterioration; this often requires intervention due to severe bioprosthetic valve stenosis or regurgitation or a combination of both. In select patients, transcatheter aortic valve replacement is an alternative to surgical aortic valve replacement. Transcatheter valve-in-valve (ViV) replacement is performed by implanting a transcatheter heart valve within a failing bioprosthetic valve. The transcatheter ViV operation is a less invasive procedure compared with reoperative surgical aortic valve replacement, but it has been associated with specific complications and requires extensive preoperative work-up and planning by the heart team. Data from experimental studies and analyses of results from clinical procedures have led to strategies to improve outcomes of these procedures. The type, size, and implant position of the transcatheter valve can be optimized for individual patients with knowledge of detailed dimensions of the surgical valve and radiographic and echocardiographic measurements of the patient's anatomy. Understanding the complexities of the ViV procedure can lead surgeons to make choices during the original surgical valve implantation that can make a future ViV operation more technically feasible years before it is required.

Impact of annular and supra-annular CoreValve deployment locations on aortic and coronary artery hemodynamics

CoreValve is widely used in transcatheter aortic valve replacement, but the impact of its deployment location on hemodynamics is unexplored despite a potential role in subsequent aortic and coronary artery pathologies. The objectives of this investigation were to perform fluid-structure interaction (FSI) simulations for a 29 mm CoreValve deployed in annular vs supra-annular locations, and characterize resulting hemodynamics including velocity and wall shear stress (WSS). Patient-specific geometry was reconstructed from computed tomography scans and CoreValve was deployed using a finite element approach. FSI simulations were then performed using a boundary conforming method and realistic boundary conditions. Results showed that CoreValve deployment location impacts hemodynamics in the ascending aorta and flow patterns in the coronary arteries. During peak-systole, annularly deployed CoreValve produced a jet-like flow structure impinging on the outer-curvature of the ascending aorta. Supra-annularly deployed CoreValve having a lateral tilt of 10° led to a more centered jet impinging further downstream. At mid-systole, valve leaflets of the annularly deployed CoreValve closed asymmetrically leading to disorganized flow patterns in the ascending aorta vs those from the supra-annular position. Supra-annularly deployed CoreValve also led to high-velocity para-valvular flow supplying the coronary arteries. CoreValve in the supra-annular position significantly (P < 0.05) elevated WSS within the first few diameters of both coronary arteries as compared to the annular position for many time points quantified. These results afforded by the advanced simulation methods may have important clinical implications given the role of aortic hemodynamics in dilation and the pro-atherogenic nature of WSS alterations in the coronary arteries.

Optimising the Haemodynamics of Aortic Valve-in-valve Procedures

Bioprosthetic surgical valves are increasingly implanted during cardiac surgery, instead of mechanical valves. These tissue valves are associated with limited durability and as a result transcatheter valve-in-valve procedures are performed to treat failed bioprostheses. A relatively common adverse event of aortic valve-in-valve procedures is residual stenosis. Larger surgical valve size, supra-annular transcatheter heart valve type, as well as higher transcatheter heart valve implantation depth, have all been shown to reduce the incidence of elevated post-procedural gradients. With greater understanding of technical considerations and surgical planning, valve-in-valve procedures could be more effective and eventually may become the standard of care for our increasingly ageing and comorbid population with failed surgical bioprostheses.

A Decade Later, Continued Transformation of Transcatheter Aortic Valve Replacement

The emergence of transcatheter aortic valve replacement as an effective treatment option in appropriately selected patients with severe aortic valve stenosis has proven to be revolutionary to the fields of interventional cardiology and cardiac surgery. As percutaneous technologies continue to mature and indications for transcatheter valve therapy concurrently expand, the contemporary management of valvular heart disease necessitates a multidisciplinary heart team approach that considers the indication, multimodality imaging, anesthetic and procedural strategy, and selection of the appropriate valve prosthesis for each patient. We provide an overview of the historical development of transcatheter aortic valve replacement, commercially available and investigative devices, landmark clinical trial data, and developments on the horizon that aim to further advance the care of patients with aortic valve disease.

Valve-in-Valve Transcatheter Aortic Valve Implantation: A Novel Approach to Treat Paravalvular Leak

Enlarging or "cracking" a surgical stented bioprosthetic valve during valve-in-valve transcatheter aortic valve implantation (TAVI) increases orifice area, reducing transvalvular energy losses. We demonstrate that TAVI with valve cracking can be used to treat paravalvular leak (PVL) while providing optimal aortic valve physiology. A 61-year-old woman with a history of aortic valve replacement with a stented bioprosthesis presented with heart failure. Transthoracic echocardiography revealed severe prosthetic aortic valve stenosis with PVL and severe regurgitation. The patient underwent valve-in-valve TAVI with valve cracking. This successfully treated both the stenosis and the PVL with regurgitation.

Late degeneration of transcatheter aortic valves: pathogenesis and management

There is a growing body of evidence demonstrating the durability of current transcatheter aortic valve implantation (TAVI) devices up to 5 years. However, it is well known that transcatheter aortic valves can degenerate in a manner similar to surgical bioprostheses. In this review we briefly discuss the modes of failure of trans-catheter aortic valves and their potential management.

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.

Morphology, Clinicopathologic Correlations, and Mechanisms in Heart Valve Health and Disease

The clinical and pathological features of the most frequent intrinsic structural diseases that affect the heart valves are well established, but heart valve disease mechanisms are poorly understood, and effective treatment options are evolving. Major advances in the understanding of the structure, function and biology of native valves and the pathobiology, biomaterials and biomedical engineering, and the clinical management of valvular heart disease have occurred over the past several decades. This communication reviews contemporary considerations relative to the pathology of valvular heart disease, including (1) clinical significance and epidemiology of valvular heart disease; (2) functional and dynamic valvular macro-, micro- and ultrastructure; (3) causes, morphology and mechanisms of human valvular heart disease; and (4) pathologic considerations in valve replacement, repair and, potentially, regeneration of the heart valves.

Heart valve health, disease, replacement, and repair: a 25-year cardiovascular pathology perspective

The past several decades have witnessed major advances in the understanding of the structure, function, and biology of native valves and the pathobiology and clinical management of valvular heart disease. These improvements have enabled earlier and more precise diagnosis, assessment of the proper timing of surgical and interventional procedures, improved prosthetic and biologic valve replacements and repairs, recognition of postoperative complications and their management, and the introduction of minimally invasive approaches that have enabled definitive and durable treatment for patients who were previously considered inoperable. This review summarizes the current state of our understanding of the mechanisms of heart valve health and disease arrived at through innovative research on the cell and molecular biology of valves, clinical and pathological features of the most frequent intrinsic structural diseases that affect the valves, and the status and pathological considerations in the technological advances in valvular surgery and interventions. The contributions of many cardiovascular pathologists and other scientists, engineers, and clinicians are emphasized, and potentially fruitful areas for research are highlighted.

The Effect of Valve-in-Valve Implantation Height on Sinus Flow

Valve-in-valve transcatheter aortic valve replacement (VIV-TAVR) has proven to be a successful treatment for high risk patients with failing aortic surgical bioprostheses. However, thrombus formation on the leaflets of the valve has emerged as a major issue in such procedures, posing a risk of restenosis, thromboembolism, and reduced durability. In this work we attempted to understand the effect of deployment position of the transcatheter heart valve (THV) on the spatio-temporal flow field within the sinus in VIV-TAVR. Experiments were performed in an in vitro pulsatile left heart simulator using high-speed Particle Image Velocimetry (PIV) to measure the flow field in the sinus region. The time-resolved velocity data was used to understand the qualitative and quantitative flow patterns. In addition, a particle tracking technique was used to evaluate relative thrombosis risk via sinus washout. The velocity data demonstrate that implantation position directly affects sinus flow patterns, leading to increased flow stagnation with increasing deployment height. The particle tracking simulations showed that implantation position directly affected washout time, with the highest implantation resulting in the least washout. These results clearly demonstrate the flow pattern and flow stagnation in the sinus is sensitive to THV position. It is, therefore, important for the interventional cardiologist and cardiac surgeon to consider how deployment position could impact flow stagnation during VIV-TAVR.

Results of surgical aortic valve replacement and transapical transcatheter aortic valve replacement in patients with previous coronary artery bypass grafting

OBJECTIVES

To evaluate the results of aortic valve replacement through sternotomic approach in redo scenarios (RAVR) vs transapical transcatheter aortic valve replacement (TAVR), in patients in the eighth decade of life or older already undergone previous coronary artery bypass grafting (CABG).

METHODS

One hundred and twenty-six patients undergoing RAVR were compared with 113 patients undergoing TaTAVR in terms of 30-day mortality and Valve Academic Research Consortium-2 outcomes. The two groups were also analysed after propensity-matching.

RESULTS

TaTAVR patients demonstrated a higher incidence of 30-day mortality (P = 0.03), stroke (P = 0.04), major bleeding (P = 0.03), worse 'early safety' (P = 0.04) and lower permanent pacemaker implantation (P = 0.03). TaTAVR had higher follow-up hazard in all-cause mortality [hazard ratio (HR) 3.15, 95% confidence interval (CI) 1.28-6.62; P < 0.01] and cardiovascular mortality (HR 1.66, 95% CI 1.02-4.88; P = 0.04). Propensity-matched patients showed comparable 30-day outcome in terms of survival, major morbidity and early safety, with only a lower incidence of transfusions after TaTAVR (10.7% vs RAVR: 57.1%; P < 0.01). A trend towards lower Acute Kidney Injury Network Classification 2/3 (3.6% vs RAVR 21.4%; P = 0.05) and towards a lower freedom from all-cause mortality at follow-up (TaTAVR: 44.3 ± 21.3% vs RAVR: 86.6 ± 9.3%; P = .08) was demonstrated after TaTAVR, although cardiovascular mortality was comparable (TaTAVR: 86.5 ± 9.7% vs RAVR: 95.2 ± 4.6%; P = 0.52). Follow-up freedom from stroke, acute heart failure, reintervention on AVR and thrombo-embolisms were comparable (P = NS). EuroSCORE II (P = 0.02), perioperative stroke (P = 0.01) and length of hospitalization (P = 0.02) were the determinants of all-cause mortality at follow-up, whereas perioperative stroke (P = 0.03) and length of hospitalization (P = 0.04) impacted cardiovascular mortality at follow-up.

CONCLUSIONS

Reported differences in mortality and morbidity after TaTAVR and RAVR reflect differences in baseline risk profiles. Given the lower trend for renal complications, patients at higher perioperative renal risk might be better served by TaTAVR.

The expanding indications of transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI), also known as transcatheter aortic valve replacement, is increasingly performed worldwide and is a technology that is here to stay. It has become the treatment of choice for inoperable patients and an alternative option for patients at high surgical risk with severe aortic stenosis. Early results of TAVI in intermediate-risk patients appear promising although larger randomized trial results are awaited before the widespread adoption of this technology in this big pool of patients. In patients with bicuspid aortic stenosis and degenerated surgical bioprostheses, TAVI has been shown to be feasible and relatively safe, though certain important considerations remain. Indications for TAVI are likely to grow as newer generation and improved devices and delivery systems become available.

Transcatheter aortic valve implantation: current trends and future directions

Transcatheter aortic valve implantation (TAVI) has been increasingly utilized for the treatment of severe symptomatic aortic stenosis in inoperable and high surgical risk patients. Recent advances in valve technology include repositionable scaffolds and smaller delivery systems, as well as improvement in periprocedural imaging. These advances have resulted in reduction of vascular complications, rates of paravalvular aortic regurgitation and periprocedural stroke and improved overall outcomes. Increasingly, TAVI is the preferred treatment for high-risk surgical patients with severe aortic stenosis. Consequently, there is growing interest for the use of TAVI in lower surgical risk patients. Furthermore, the role of TAVI has expanded to include valve-in-valve procedures for the treatment of degenerative bioprosthetic valves and bicuspid aortic valves. Questions remain in regard to the optimal management of concurrent coronary artery disease, strategies to minimize valve leaflet restriction and treatment of conduction abnormalities as well as identifying newer indications for its use.

Challenges in valve-in-valve therapy

At present, the majority of surgical heart valves (SHVs) implanted are bioprosthetic valves. Over time however, these are prone to structural deterioration, which may manifest as valvular stenosis, regurgitation or a combination of the two. Re-operation is the current standard of care for these patients but this itself carries a significant risk of mortality and morbidity. As a natural extension of transcatheter aortic valve implantation (TAVI), now an evidence based solution for severe aortic stenosis in high-risk patients, valve-in-valve (VIV) therapy is evolving into an alternative option in selected patients with structural biological valvular deterioration in all four-valve positions. The first of these VIV procedures was performed in Germany in 2007, for failing aortic valve prosthesis and later, reported in other positions. As with any novel emerging therapy, there is a learning curve to the procedure and the operator must be aware of the potential challenges. In this review we describe some of these challenges with the aim of providing awareness as well as guidance on attaining a successful outcome.

Recent advances in echocardiography for valvular heart disease

Echocardiography is the imaging modality of choice for the assessment of patients with valvular heart disease. Echocardiographic advancements may have particular impact on the assessment and management of patients with valvular heart disease. This review will summarize the current literature on advancements, such as three-dimensional echocardiography, strain imaging, intracardiac echocardiography, and fusion imaging, in this patient population.

Development of an algorithm to plan and simulate a new interventional procedure

OBJECTIVES

The number of implanted biological valves for treatment of valvular heart disease is growing and a percentage of these patients will eventually undergo a transcatheter valve-in-valve (ViV) procedure. Some of these patients will represent challenging cases. The aim of this study was to develop a feasible algorithm to plan and in vitro simulate a new interventional procedure to improve patient outcome.

METHODS

In addition to standard diagnostic routine, our algorithm includes 3D printing of the annulus, hydrodynamic measurements and high-speed analysis of leaflet kinematics after simulation of the procedure in different prosthesis positions as well as X-ray imaging of the most suitable valve position to create a 'blueprint' for the patient procedure.

RESULTS

This algorithm was developed for a patient with a degenerated Perceval aortic sutureless prosthesis requiring a ViV procedure. Different ViV procedures were assessed in the algorithm and based on these results the best option for the patient was chosen. The actual procedure went exactly as planned with help of this algorithm.

CONCLUSIONS

Here we have developed a new technically feasible algorithm simulating important aspects of a novel interventional procedure prior to the actual procedure. This algorithm can be applied to virtually all patients requiring a novel interventional procedure to help identify risks and find optimal parameters for prosthesis selection and placement in order to maximize safety for the patient.

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.

The power of disruptive technological innovation: Transcatheter aortic valve implantation

We sought to evaluate the principles of disruptive innovation, defined as technology innovation that fundamentally shifts performance and utility metrics, as applied to transcatheter aortic valve implantation (TAVI). In particular, we considered implantation procedure, device design, cost, and patient population. Generally cheaper and lower performing, classical disruptive innovations are first commercialized in insignificant markets, promise lower margins, and often parasitize existing usage, representing unattractive investments for established market participants. However, despite presently high unit cost, TAVI is less invasive, treats a "new," generally high risk, patient population, and is generally done by a multidisciplinary integrated heart team. Moreover, at least in the short-term TAVI has not been lower-performing than open surgical aortic valve replacement in high-risk patients. We conclude that TAVI extends the paradigm of disruptive innovation and represents an attractive commercial opportunity space. Moreover, should the long-term performance and durability of TAVI approach that of conventional prostheses, TAVI will be an increasingly attractive commercial opportunity.