Intermediate follow-up results from the multicenter engager European pivotal trial

A European update on transcatheter aortic valve implantation (TAVI) in the COVID era

Minimally invasive approaches for aortic valve replacement are now at the forefront of pathological aortic valve treatment. New trials show comparability of these devices to existing therapies, not only in high-risk surgical cohorts but also in low-risk and intermediate-risk cohorts. This review provides vital clinical and anatomical background to aortic valvular disease treatment guidelines, while also providing an update on transcatheter aortic valve implantation (TAVI) devices in Europe, their interventional trials and associated complications.

The evolution of device technology in transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) has rapidly evolved and changed the landscape of structural interventional cardiology. Advances in transcatheter heart valve (THV) prostheses and TAVI-enabling devices have simplified the procedure, reduced the risk of complications, improved short- and long-term outcomes and broadened the applications of TAVI, not only in challenging patients and complex anatomies but also in intermediate-risk or even in low-risk patients, where surgical valve replacement constitutes an effective and well-established therapy. In this review article, we provide an overview of the developments in TAVI devices which have played a vital role in TAVI evolution: we describe the prostheses that failed to reach clinical practice, we present the characteristics of the first valves that were tested in the clinical arena, we summarise the evidence from the first studies that highlighted the potential but also the limitations of TAVI, and we present the advanced next-generation THV prostheses that have an improved performance and safety profile.

Alternate Access for TAVI: Stay Clear of the Chest

Transcatheter aortic valve implantation (TAVI) is currently performed through an alternative access in 15% of patients. The transapical access is progressively being abandoned as a result of its invasiveness and poor outcomes. Existing data does not allow TAVI operators to favour one access over another - between transcarotid, trans-subclavian and transaortic - because all have specific strengths and weaknesses. The percutaneous trans-subclavian access might become the main surgery-free alternative access, although further research is needed regarding its safety. Moreover, the difficult learning curve might compromise its adoption. The transcaval access is at an experimental stage and requires the development of dedicated cavo-aortic crossing techniques and closure devices.

Conduction Disturbances After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has become a well-accepted option for treating patients with aortic stenosis at intermediate to high or prohibitive surgical risk. TAVR-related conduction disturbances, mainly new-onset left bundle-branch block and advanced atrioventricular block requiring permanent pacemaker implantation, remain the most common complication of this procedure. Furthermore, improvements in TAVR technology, akin to the increasing experience of operators/centers, have translated to a major reduction in periprocedural complications, yet the incidence of conduction disturbances has remained relatively high, with perhaps an increasing trend over time. Several factors have been associated with a heightened risk of conduction disturbances and permanent pacemaker implantation after TAVR, with prior right bundle-branch block and transcatheter valve type and implantation depth being the most commonly reported. New-onset left bundle-branch block and the need for permanent pacemaker implantation may have a significant detrimental association with patients’ prognosis. Consequently, strategies intended to reduce the risk and to improve the management of such complications are of paramount importance, particularly in an era when TAVR expansion toward treating lower-risk patients is considered inevitable. In this article, we review the available evidence on the incidence, predictive factors, and clinical association of conduction disturbances after TAVR and propose a strategy for the management of these complications.

Repositionable self-expanding aortic bioprosthesis

INTRODUCTION

Transcatheter aortic valve implantation/replacement (TAVI or TAVR) has been established as a first line therapy in patients with symptomatic severe aortic stenosis (AS) at high or prohibitive surgical risk and as an alternative in elderly patients with intermediate surgical risk. Since its first-in-human procedure in 2002, the past 15-years have shown rapid developments in TAVI technology with the introduction and further improvement of new transcatheter heart valves (THV). Areas covered: There are currently several THV systems available, based on balloon-expandable, self-expandable or other technologies. Some of these are repositionable and retrievable even after partial or full deployment, potentially reducing the risk of malpositioning. The aim of this review is to describe such repositionable self-expandable THV systems. Expert commentary: Repositionability potentially represents a crucial step towards higher safety and efficacy of TAVI. It is unclear if full self-expandability or a combination of self and mechanical expansion will be more advantageous.

Transcatheter aortic valve implantation: new hope in the management of valvular heart disease

Severe calcific aortic stenosis is relatively common, and unless treated with valve replacement it carries an adverse prognosis. A large number of patients, however, are denied surgery due to their advanced age or coexistent medical conditions that increase perioperative cardiovascular risks. Transcatheter aortic valve implantation (TAVI), a technique in which a bioprosthetic valve is inserted via a catheter and implanted within the diseased native aortic valve, is a new therapeutic modality for treatment of older patients with severe symptomatic aortic stenosis and other comorbidities, who have an inherently high surgical risk. This review will provide an overview of the pivotal trials in the development of TAVI; while also investigating important complications and limitations of the procedure and evaluating how new valves are being designed and clinically evaluated, with the ultimate goal of reducing potential complications and expanding the use of TAVI to lower-risk patient cohorts.

Second-generation transapical valves: the Medtronic Engager system

The Medtronic Engager aortic valve system is a second-generation transcatheter aortic valve implantation bioprosthesis combined with a delivery system designed for over-the-wire transapical implantation of the valve. The self-expandable stent has control arms to be placed into the native aortic sinuses to achieve correct positioning of the bioprosthesis in a predefined height. The purpose of the lower skirt is to reduce paravalvular leakage. A three-leaflet, bovine pericardium valve is mounted on the stent. The implantation is facilitated by the control arms and rotational positioning of the commissural posts. A multicentre feasibility study showed promising results. The results from the following European pivotal trial led to CE mark approval in 2013. Here, we describe technical details of the device and its implantation technique and highlight special steps of the procedure.

An up-to-date overview of the most recent transcatheter implantable aortic valve prostheses

Over the past decade transcatheter aortic valve implantation (TAVI) has evolved towards the routine therapy for high-risk patients with severe aortic valve stenosis. Technical refinements in TAVI are rapidly evolving with a simultaneous expansion of the number of available devices. This review will present an overview of the current status of development of TAVI-prostheses; describes the technical features and applicability of each device and the clinical data available.

Transcatheter/Hybrid Aortic Valves in the Young

Transcatheter aortic valve implantation (T-AVI) has been established as an alternative to conventional aortic valve replacement. The number of procedures is steadily rising and has reached comparable implant rates to conventional aortic valve replacement. The success of T-AVI is easily explained by their true minimally invasive nature, ease of use, and excellent hemodynamics. Whilst their use was initially limited to high-risk patients, current trends show that more and more intermediate-risk patients are now treated with theses prostheses. The question arises whether children would also benefit from this type of procedure. Percutaneous transcatheter pulmonary valve replacement is already becoming an important adjunct in the treatment of older children with failing right ventricular outflow tract conduits. Recently, several valve-in-valve procedures have been performed using T-AVI in failing bioprosthetic valves in young patients. There has also been a report of successful transcatheter neoaortic valve replacements in young patients after Fontan palliation. As an alternative to transcatheter valves, so called hybrid or sutureless rapid deployment aortic valves have recently been introduced into clinical practice. Although this concept is old, the current generation of these prostheses has been redesigned based on modern experiences with transcatheter valves. Current outcomes demonstrate that aortic valve replacement with sutureless valves could be a promising option for aortic stenosis, by facilitating minimally invasive surgery and minimizing cardiopulmonary bypass and cross clamping time. Therefore, the sutureless valve could prove to be an important alternative to conventional bioprosthetic aortic valve replacement in children too. In the current review, we provide an overview of the different types of transcatheter and sutureless aortic valve substitutes, discuss their advantages and short comings, and outline their clinical performance and potential benefits in a young patient population.

Transapical transcatheter aortic valve implantation using a new second-generation TAVI system - J-Valve™ for high-risk patients with aortic valve diseases: Initial results with 90-day follow-up

BACKGROUND

To evaluate the safety and efficacy of transcatheter aortic valve implantation (TAVI) for patients with aortic stenosis (AS) or pure/dominant aortic regurgitation (AR) using the J-Valve™ system.

METHODS

Twenty patients with isolated aortic valve disease (11 with pure/dominant AR and 9 with AS) at high risk for open-heart surgery were enrolled in this study. The mean Logistic Euro-SCORE I was 27.2±8.2% (mean age 74.5±4.7years). Four sizes of prosthesis were used for annular size up to 21 mm (n=1), 23mm (n=2), 25mm (n=10) and 27mm (n=7). Clinical and echocardiographic evaluations were performed at baseline, post-procedure and follow-up. The primary endpoint was all-cause mortality. Secondary endpoints were procedural success, major adverse events as well as echocardiographic performance.

RESULTS

TAVI with the J-Valve™ device was successfully performed in 19 patients (95%). Conversion to surgical valve replacement was necessary in one patient due to prosthesis embolization. No mortality occurred during 90 days follow-up. Pacemaker implantation for new onset conduction disorders was necessary in one patient (5%). For patient with severe AS, post-procedure TAVI resulted in favorable reduction of mean transvalvular gradients (55.3±8.5 vs. 16.4±13.3 mmHg, P<0.01). Mean transvalvular gradient was also favorable in AR patients after valve implantation (6.9±1mmHg). The majority of patients had none or trivial paravalvular regurgitation (17/19) while none had moderate or severe paravalvular regurgitation.

CONCLUSION

Trans-apical TAVI using the J-Valve™ prosthesis is potentially an effective treatment option for patients with AS or pure/dominant AR at high risk for open-heart surgery.

Transcatheter aortic valve implantation--update and evidence

Transcatheter aortic valve implantation (T-AVI) has become the standard of care for high-risk patients suffering from severe aortic valve stenosis. More than 60,000 implants have been performed to date. While the first-generation T-AVI devices had some specific issues, the advancements in these first-generation devices and the development of second-generation devices significantly reduced the incidence of peri-procedural complications. The two major access routes are the transfemoral (TF) and the transapical (TA) approach. Both approaches have their advantages and should be considered equal alternatives for finding the best treatment option for the individual patient. Currently there are discussions about extending the indication to patients with lower risk profiles. However, there is no real evidence to justify an expansion, as results of surgical aortic valve replacement in low and intermediate risk patients are excellent.

Successful trans-apical aortic valve implantation for a high risk patient with aortic stenosis using a new second-generation TAVI device - J-Valve system

Transcatheter aortic valve implantation (TAVI) has evolved as a routine procedure to treat selected high-risk patients with severe aortic stenosis. The new J-Valve™ prosthesis is designed for antegrade transapical implantation, it is characterized by a porcine aortic prosthesis attaching to a self-expandable Nitinol stent. The key feature of the device are three U-shape anatomically oriented devices - “graspers” which could facilitate intuitive ‘self-positioning’ valve implantation. Hereby, we report a successful case of trans-apical TAVI in an elderly high-risk patient with severe aortic stenosis using J-Valve™ system.

Real-time magnetic resonance-guided aortic valve replacement using Engager valve

PURPOSE

New-generation stented bioprostheses coupled with better imaging modalities are expanding the clinical utility of transcatheter aortic valve replacement (TAVR). This study aimed at evaluating the feasibility of real-time cardiovascular magnetic resonance (rtCMR) -guided TAVR using the Medtronic Engager aortic valve system in a preclinical model.

DESCRIPTION

The Engager delivery device was slightly modified to make it CMR-compatible. Ten Yucatan swine underwent rtCMR-guided transapical TAVR. Postplacement phase-contrast and first-pass perfusion CMR sequences were used to evaluate for aortic regurgitation and myocardial perfusion, respectively.

EVALUATION

Real-time CMR provided excellent visualization of cardiac anatomy during TAVR. Nine of 10 animals had proper valve placement in the aortic annulus as determined by CMR and confirmed by necropsy inspection. Postplacement phase-contrast scans confirmed no intravalvular or paravalvular leaks. Perfusion scans demonstrated sufficient coronary flow. Roentgenographs confirmed proper placement of the prostheses.

CONCLUSIONS

The Engager valve can be implanted transapically under rtCMR guidance with a modified, CMR-compatible delivery device in a preclinical model. Cardiovascular magnetic resonance allowed for accurate preplacement evaluation, real-time guidance, and postplacement functional assessment.

Transapical transcatheter aortic valve implantation using the second-generation self-expanding Symetis ACURATE TA valve

Transapical transcatheter aortic valve implantation (TA-TAVI) is the recognized first choice surgical TAVI access. Expansion of this well-established treatment modality with subsequent broader patient inclusion has accelerated development of second-generation TA-TAVI devices. The Swiss ACURATE TA Symetis valve allows for excellent anatomical positioning, resulting in a very low incidence of paravalvular leaks. The self-expanding stent features an hourglass shape to wedge the native aortic valve annulus. A specially designed delivery system facilitates controlled release aided by tactile operator feedback. The ACURATE TA valve made of three native porcine non-coronary leaflets has received CE approval in September 2011. Since then, this valve is the third most frequently implanted TAVI device with over 1200 implants in Europe and South America. Results from the Symetis ACURATE TA™ Valve Implantation ('SAVI') Registry showed a procedural success rate of 98.0% and a survival rate of 93.2% at 30 days. This presentation provides technical considerations and detailed procedural aspects of device implantation.

Impact of access on TAVI procedural and midterm follow-up: a meta-analysis of 13 studies and 10,468 patients

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) may be performed using the transfemoral (TF) or transapical (TA) approach in most patients with aortic stenosis. The impact of access choice on peri-procedural and midterm results remains to be defined.

METHODS

Medline and Cochrane Library were searched for articles describing differences in baseline, peri-procedural, and midterm outcomes among patients undergoing TF or TA TAVI. The primary end-point was all-cause mortality after at least 1-year follow-up, while secondary end-points were 30 days mortality and in-hospital complications (bleeding and cerebrovascular events). The independent impact of access choice was evaluated with pooled analysis using a random-effect model.

RESULTS

Thirteen studies with 10,468 patients were included. TF was the most exploited strategy (69.5% vs. 30.5%). After adjusting for confounding variables, 30-day and midterm follow-up mortality (median 365 days, range 222-400) were lower in TF patients with a pooled adjusted odds ratio of 0.81 (0.68-0.97 I(2) 99%) and 0.85 (0.80-0.90 I(2) 96%), respectively. Regarding periprocedural outcomes, TF reduced risk of bleedings and strokes (OR of 0.74 [0.66-0.82 I(2) 95%] and 0.91 [0.83-0.99] I(2) 86%, respectively).

CONCLUSIONS

The TF approach reduces mortality in TAVI patients, due to lower rates of periprocedural bleedings and strokes.