Which way in? The necessity of multiple approaches to transcatheter valve therapy

Transcatheter Aortic Valve Implantation Access Sites: Same Goals, Distinct Aspects, Various Merits and Demerits

Transcatheter aortic valve implantation (TAVI) has been established as a safe and efficacious treatment for patients with severe symptomatic aortic stenosis (AS). Despite being initially developed and indicated for high-surgical-risk patients, it is now offered to low-risk populations based on the results of large randomized controlled trials. The most common access sites in the vast majority of patients undergoing TAVI are the common femoral arteries; however, 10-20% of the patients treated with TAVI require an alternative access route, mainly due to peripheral atherosclerotic disease or complex anatomy. Hence, to achieve successful delivery and implantation of the valve, several arterial approaches have been studied, including transcarotid (TCr), axillary/subclavian (A/Sc), transapical (TAp), transaortic (TAo), suprasternal-brachiocephalic (S-B), and transcaval (TCv). This review aims to concisely summarize the most recent literature data and current guidelines as well as evaluate the various access routes for TAVI, focusing on the indications, the various special patient groups, and the advantages and disadvantages of each technique, as well as their adverse events.

Multimodality imaging for patient selection, procedural guidance, and follow-up of transcatheter interventions for structural heart disease: a consensus document of the EACVI Task Force on Interventional Cardiovascular Imaging: part 1: access routes, transcatheter aortic valve implantation, and transcatheter mitral valve interventions

Transcatheter therapies for the treatment of structural heart diseases (SHD) have expanded dramatically over the last years, thanks to the developments and improvements of devices and imaging techniques, along with the increasing expertise of operators. Imaging, in particular echocardiography, is pivotal during patient selection, procedural monitoring, and follow-up. The imaging assessment of patients undergoing transcatheter interventions places demands on imagers that differ from those of the routine evaluation of patients with SHD, and there is a need for specific expertise for those working in the cath lab. In the context of the current rapid developments and growing use of SHD therapies, this document intends to update the previous consensus document and address new advancements in interventional imaging for access routes and treatment of patients with aortic stenosis and regurgitation, and mitral stenosis and regurgitation.

Identifying Patients without a Survival Benefit following Transfemoral and Transapical Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) offers a novel treatment option for patients with severe symptomatic aortic valve stenosis, particularly for patients who are unsuitable candidates for surgical intervention. However, high therapeutical costs, socio-economic considerations, and numerous comorbidities make it necessary to target and allocate available resources efficiently. In the present study, we aimed to identify risk factors associated with futile treatment following transfemoral (TF) and transapical (TA) TAVR. Five hundred and thirty-two consecutive patients (82 ± 9 years, female 63%) who underwent TAVR between June 2009 and December 2016 at the Vienna Heart Center Hietzing were retrospectively analyzed to identify predictors of futility, defined as all-cause mortality at one year following the procedure for the overall patient cohort, as well as the TF and TA cohort. Out of 532 patients, 91 (17%) did not survive the first year after TAVR. A multivariate logistic model identified cerebrovascular disease, home oxygen dependency, wheelchair dependency, periinterventional myocardial infarction, and postinterventional renal replacement therapy as the factors independently associated with an increased one-year mortality. Our findings underscore the significance of a precise preinterventional evaluation, as well as illustrating the subtle differences in baseline characteristics in the TF and TA cohort and their impact on one-year mortality.

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.

Transcatheter Double Valve-in-Valve Replacement of Aortic and Mitral Bioprosthetic Valves

Transcatheter aortic valve replacement (TAVR) is an evolving method which has become the treatment of choice in high-risk patients with severe aortic stenosis. Unlike TAVR, the experience with transcatheter mitral valve replacement (TMVR) remains at an early stage because of challenges of valve development and possible complications such as valve displacement and subsequent left ventricular outlet tract (LVOT) obstruction. Here we report a case of transcatheter double valve-in-valve replacement (TDVIVR) in a patient with severe mitral and aortic bioprosthetic valve stenosis, followed by an extensive literature review of the latest techniques and challenges in this field.

Non-transfemoral access sites for transcatheter aortic valve replacement

Transfemoral access is currently the standard and preferred access site for transcatheter aortic valve replacement (TAVR), though novel approaches are emerging to expand treatment options for the increasing numbers of patients with a contraindication for the traditional route. Previous publications have provided comparisons between two TAVR access sites, primarily transfemoral versus one of the novel approaches, while others have compared three or four novel approaches. The aim of this report is to provide a comprehensive summary of publications that analyse and compare the six non-transfemoral access sites currently described in the literature. These include the transapical, transaortic, axillary/subclavian, brachiocephalic, transcarotid, and transcaval approaches. Though there remains little consensus as to the superiority or non-inferiority of TAVR approaches, and there has yet to be randomized clinical trials to support published findings, with careful patient and procedural selection, outcomes for novel approaches have been reported to be comparable to standard transfemoral access when performed by skilled physicians. As such, choice of procedure is primarily based on registry data and the judgement of surgical teams as to which approach is best in each individual case. As TAVR continues to be an increasingly widespread treatment, search for the optimal access site will grow, and focus should be placed on the importance of educating surgeons as to all possible approaches so they may review and chose the most appropriate technique for a given patient.

Recent developments and controversies in transcatheter aortic valve implantation

Interventional cardiology has been revolutionised by transcatheter aortic valve implantation (TAVI), which has become established as the benchmark treatment for severe aortic stenosis in patients at high risk for surgical aortic valve replacement (AVR). Increased procedural familiarity and progression in device technology has enabled improvements to be made in complication rates, which have led to a commensurate expansion in the use of TAVI; it is now a viable alternative to AVR in patients at intermediate surgical risk, and has been used in cohorts such as those with bicuspid aortic valves or pure, severe aortic regurgitation. Given the rapid expansion in the use of TAVI, including cohorts of younger patients with fewer co-morbidities, attention must be paid to further reducing remaining complications, such as cardiac tamponade or stroke. To this end, novel techniques and devices have been devised and trialled, with varying levels of success. Furthermore, significant work has gone into refining the technique with exploration of alternative imaging modalities, as well as alternative access routes to provide greater options for patients with challenging vascular anatomy. Whilst significant progress has been made with TAVI, areas of uncertainty remain such as the management of concomitant coronary artery disease and the optimum post-procedure antiplatelet regimen. As such, research in this field continues apace, and is likely to continue as use of TAVI becomes more widespread. This review provides a summary of the existing evidence, as well as an overview of recent developments and contentious issues in the field of TAVI.

Never Too Late: A Case Report on Transcatheter Aortic Valve Implantation in a 97-Year-Old Patient

Aortic valve stenosis is a well-recognized valvular problem in the aging population. Transcatheter aortic valve implantation (TAVI) is becoming an increasingly popular treatment alternative to surgical aortic valve replacement for frail elderly individuals with symptomatic severe aortic valve stenosis. There are multiple research reports documenting the effectiveness of TAVI in octogenarians; however, few authors discuss the success of this procedure in nonagenarians. This case report depicts the successful transfemoral implantation of a prosthetic aortic valve in a 97-year-old man. Moreover, the current literature on TAVI outcomes in nonagenarians is reviewed.

Transcatheter aortic valves produce unphysiological flows which may contribute to thromboembolic events: An in-vitro study

PURPOSE

Transcatheter aortic valve implantation (TAVI) has been associated with large incidence of ischemic events, whose sources are still unclear. In fact, sub-acute complications cannot be directly related to the severity of the calcification in the host tissues, nor with catheter manipulation during the implant. A potential cause could be local flow perturbations introduced by the implantation approach, resulting in thrombo-embolic consequences. In particular, contrary to the surgical approach, TAVI preserves the presence of the native leaflets, which are expanded in the paravalvular space inside the Valsalva sinuses. The purpose of this study is to verify if this configuration can determine hemodynamic variations which may promote blood cell aggregation and thrombus formation.

METHODS

The study was performed in vitro, on idealized models of the patient anatomy before and after TAVI, reproducing a range of physiological operating conditions on a pulse duplicator. The fluid dynamics in the Valsalva sinuses was analyzed and characterized using phase resolved Particle Image Velocimetry.

RESULTS

Comparison of the flow downstream the valve clearly indicated major alterations in the fluid mechanics after TAVI, characterized by unphysiological conditions associated with extended stagnation zones at the base of the sinuses.

CONCLUSION

The prolonged stasis observed in the Valsalva sinuses for the configuration modelling the presence of transcatheter aortic valves provides a fluid dynamic environment favourable for red blood cell aggregation and thrombus formation, which may justify some of the recently reported thromboembolic and ischemic events. This suggests the adoption of anticoagulation therapies following TAVI, and some caution in the patients׳ selection.

Advances in the management of severe aortic stenosis

BACKGROUND

Recent developments in the management of severe aortic stenosis have resulted in a paradigm shift in the way we view the condition. Patients previously denied intervention in the form of surgical aortic valve replacement (SAVR) are now candidates for transcatheter aortic valve implantation and the risk and age profiles of those undergoing SAVR are rising with the ageing population. This review article is designed to provide an overview of developments in the surgical management of severe aortic stenosis. We also discuss the expanding role of minimally invasive surgical approaches to outline the current techniques available to treat patients with severe aortic stenosis.

METHODS

PubMed was searched using the terms 'severe aortic stenosis', 'surgical aortic valve replacement', 'transcatheter aortic valve replacement', 'mechanical aortic valve replacement' and 'sutureless aortic valve replacement'. Selection of articles was based on peer review, journal and relevance. Where possible articles from high-impact factor peer review journals were included.

RESULTS

Minimally invasive operative approaches include mini-sternotomy and mini-thoracotomy. Sutureless aortic prostheses reduce aortic cross-clamp time and cardiopulmonary bypass time; however, long-term follow-up data are unavailable at this time. Mechanical prostheses are advised for those under 60.

CONCLUSION

Multiple advances in the surgical management of aortic stenosis have occured in the past decade. An evolving spectrum of surgical and transcatheter interventions is now available depending on patient age and operative risk.

Access and closure of the left ventricular apex: state of play

Calcific aortic stenosis is the most frequent manifestation of valvular heart disease. The preferred treatment for patients of all age groups is surgical aortic valve replacement. Recently, transcatheter aortic valve implantation (TAVI) has become the standard of care for patients that are deemed to be at high risk for open heart surgery. The most common access route for TAVI is the retrograde transfemoral (TF) approach, followed by the antegrade transapical (TA) approach. Both access routes have distinct indications. While the TF route is least invasive and the access of choice at most centers, the apical route is used complementary in patients with poor femoral access. In addition, the TA approach holds various benefits such as a short distance from the operator to the annulus facilitating exact positioning of the valve and the possibility to accommodate larger sheaths. Furthermore, the TA approach not only provides direct access to the aortic valve but also the mitral valve allowing for a wide range of interventions. Various apical closure devices are currently being developed under the premise of increasing overall safety of the TA-TAVI approach by further standardizing the procedure, alleviating left ventricular access and minimizing the risk of complications, such as apical bleeding. The aim of this article is to give an overview of current devices for apical closure. The ideal apical closure device should be easy to put in place, leave a minimum of foreign material, provide complete hemostasis and have a minimal risk of displacement. So far the range of commercially available devices in Europe is very limited with only one CE-certified device on the market and one device that is expected to receive CE-certification soon. Off-the-shelf closure devices could help flatten the initial operator learning curve and facilitate a safe apical access, ultimately leading to an entirely percutaneous TA-TAVI approach.

The "Chimney approach" for transcatheter aortic valve implantation: A strategy for trans axillarian bareback approach in patients with no other access options

AIM

to describe the procedural steps and to report the short term follow up of our initial experience with an axillarian bareback Dacron graft based technique that could potentially reduce the rate of vascular and ischemic complications during transcatheter aortic valve implantation in patients with contraindications to trans-femoral approach and with patent left internal mammary arterial graft to left anterior descending coronary artery (LIMA-LAD) or small caliber axillarian/subclavian arteries.

METHODS AND RESULTS

Four patients were treated with TAVI implantation with a trans axillarian bareback approach. Three out of four had a patent LIMA-LAD graft. In three patients, femoral approach was not considered as an option for the presence of diffuse peripheral vascular disease, while in one for the small caliber of iliac-femoral arteries. All procedures were performed under general anaesthesia. No procedural complications occurred.

CONCLUSIONS

In this initial experience, the axillarian bareback approach technique allowed a safe and successful TAVI implant in a subgroup of patients with a high risk of procedural complications due to the presence of a patent LIMA-LAD or vessels of small caliber. Considering the increasing number of patients referred for TAVI, in the next future the axillarian bareback approach could represent a safer alternative to direct cannulation in patients with severe aortic stenosis with no other access options.