A systematic review of transapical aortic valve implantation

An Updated Comprehensive Review of Existing Transcatheter Aortic Valve Replacement Access

For the past 20 years, transcatheter aortic valve replacement (TAVR) has been the treatment of choice for symptomatic aortic stenosis. The transfemoral (TF) access is considered the gold standard approach for TAVR. However, TF-TAVR cannot be performed in some patients; thus, alternative accesses are required. Our review paper generalises the TAVR accesses currently available, including the transapical, transaortic, trans-subclavian/axillary, transcarotid, transcaval, and suprasternal approaches. Their advantages and disadvantages have been analysed. Since there is no standard recommendation for an alternative approach, access selection depends on the expertise of the local cardiac team, patient characteristics, and access properties. Each TAVR centre is recommended to master a minimum of one non-TF access alternative. Of note, more evidence is required to delve into the clinical outcomes of each approach, at both early and long-term (Figure 1).

A Review of Alternative Access for Transcatheter Aortic Valve Replacement

With the advent of transcatheter aortic valve replacement (TAVR), appropriately selected intermediate-, high-, and extreme-risk patients with severe aortic stenosis (AS) are now offered a less invasive option compared to conventional surgery. In contemporary practice, TAVR is performed predominantly via a transfemoral arterial approach, whereby a transcatheter heart valve (THV) is delivered in a retrograde fashion through the iliofemoral arterial system and thoraco-abdominal aorta, into the native aortic valve annulus. While the majority of patients possess suitable anatomy for transfemoral arterial access, there is a subset of patients with extensive peripheral vascular disease that precludes this traditional approach to TAVR. Fortunately, innovation in the field of structural heart disease has led to the refinement of alternative access options for THV delivery. Selection of the most appropriate route of therapy mandates a careful consideration of multiple factors, including patient anatomy, technical feasibility, and equipment specifications. Furthermore, understanding the risks conferred by each access site for valve delivery-notably stroke, vascular injury, and major bleeding-is of paramount importance when selecting the approach that will best optimize the outcome for an individual. In this review, we provide a comprehensive summary of alternative approaches to transfemoral arterial TAVR as well as the available outcome data supporting each of these various techniques.

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.

A New Experimental Device for Transapical Access of the Aortic and Mitral Valves as well as the Aorta in its Various Segments

Objective

To present the results of a new experimental device developed to facilitate the transapical access in endovascular treatment of structural heart diseases. It aims to reduce the risk of bleeding and complications in this type of access and demonstrate the device as a safe, fast and effective alternative.

Methods

CorPoint is composed of three parts: introducer, base with coiled spring, and closing capsule. By rotating movements, the spring is introduced into the myocardium and progressively approaches the base to the surface of the heart. Guidewires and catheters are inserted through the hollow central part and, at the end of the procedure, the capsule is screwed over the base, therefore stopping any bleeding.

Results

The device was implanted in 15 pigs, weighing 60 kg each, through an anterolateral thoracotomy, while catheters were introduced and guided by fluoroscopy. All animals had minimal bleeding; introducers with diameter up to 22 Fr were used and various catheters and guidewires were easily handled. After finishing the procedure, the closing capsule was attached and no bleeding was observed at the site.

Conclusion

This new device has proved effective, fast and secure for the transapical access. This shows great potential for use, especially by ensuring an easier and direct access to the mitral and aortic valves; the shortest distance to be traveled by catheters; access to the ascending and descending aorta; decreased bleeding complications; decreased surgical time; and the possibility of allowing the technique to evolve and become totally percutaneous.

Predictors of length of stay and duration of tracheal intubation after transcatheter aortic valve implantation

BACKGROUND

While short-term outcomes for patients undergoing transcatheter aortic valve implantation (TAVI) have long been studied, there is very little data on their predictors. We aimed to identify the predictors of outcomes, such as intensive care unit (ICU) and in-hospital length of stay (LOS), duration of postoperative intubation and in-hospital mortality, after TAVI procedures.

METHODS

We conducted a retrospective cohort study of 162 consecutive patients with aortic valve disease, who were admitted to a tertiary hospital of Liverpool for TAVI, during a five-year period. The data was collected using of the hospital's structured database on November 2014.

RESULTS

By using a multivariate analysis we found that any postoperative bleeding [odds ratio (OR) 2.71; 95% confidence interval (CI): 1.41-5.24] was the independent predictor of prolonged ICU-LOS, while older age (OR 1.11; 95% CI: 1.05-1.17) and transapical TAVI (OR 4.11; 95% CI: 1.94-8.71) were the predictors of prolonged in-hospital LOS. Additionally, patients treated with oral inotropic agents, preoperatively (OR 5.77; 95% CI: 2.21-15.01), non-diabetics (OR 3.07; 95% CI: 1.12-8.42) and those with any postoperative bleeding (OR 3.53; 95% CI: 1.68-7.43) had a significantly greater probability in remaining intubated postoperatively. The multivariate analysis did not reveal any predictor of in-hospital mortality.

CONCLUSIONS

The above predictors permit the early identification of TAVI patients at high risk for longer hospitalization and increased mechanical ventilation. This piece of information is crucial for clinicians and administrators contributing to more efficient patient care planning and better allocation of healthcare resources.

Suture Forces for Closure of Transapical Transcatheter Aortic Valve Replacement: A Mathematical Model

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of severe aortic stenosis in intermediate, high-risk, and inoperable patients. TAVR has multiple access routes, including transfemoral (TF), transapical (TA), direct aortic (DA), axillary, transcarotid, and transcaval. The most commonly applied algorithm is a TF-first approach, where only when patients are unsuitable for TF are alternatives such as TA considered. An infrequent - but dreaded - risk is left ventricular (LV) apical bleeding from tearing or rupture with the TA approach. With burgeoning transcatheter mitral technology that requires a TA approach, the study aim was to develop a mathematical model to determine suture forces for TA closure.

METHODS

Preoperative cine-cardiac magnetic resonance imaging (MRI) was used to acquire three-dimensional (3D) LV geometry at end-systole and end-diastole. Endocardial and epicardial boundaries were manually contoured using MeVisLab, a surface reconstruction software. 3D surfaces of endocardium and epicardium were reconstructed, and surfaces at end-systole were used to create a 3D LV finite element (FE) mesh. TA access was mimicked by developing a 10-mm defect within the LV FE model. The LV apex was closed using a virtual suture technique in FE analysis with the application of two virtual sutures. After virtual closure, a FE analysis was performed of LV model diastolic filling and systolic contraction.

RESULTS

Proof of concept was achieved to develop an LV transapical access site and perform FE analysis to achieve closure. The FE method of virtual suture technique successfully approximated the LV apical defect. The peak axial forces on virtual sutures at end-diastole and end-systole were 0.445N and 0.736N, respectively.

CONCLUSIONS

A LV TA access model was mathematically developed that could be used to evaluate the suture tension of the TA closure process. Further development of this approach may be useful to risk-stratify patients in the future for LV apical tearing. Video 1: Cine cardiac magnetic resonance imaging of the left ventricle. Video 2: Slow motion animation of left ventricular baseline simulation. Video 3: Animation of the virtual suturing process.

Echocardiographic imaging of procedural complications during balloon-expandable transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) using a balloon-expandable valve is an accepted alternative to surgical replacement for severe, symptomatic aortic stenosis in high risk or inoperable patients. Intraprocedural transesophageal echocardiography (TEE) offers real-time imaging guidance throughout the procedure and allows for rapid and accurate assessment of complications and procedural results. The value of intraprocedural TEE for TAVR will likely increase in the future as this procedure is performed in lower surgical risk patients, who also have lower risk for general anesthesia, but a greater expectation of optimal results with lower morbidity and mortality. This imaging compendium from the PARTNER (Placement of Aortic Transcatheter Valves) trials is intended to be a comprehensive compilation of intraprocedural complications imaged by intraprocedural TEE and diagnostic tools to anticipate and/or prevent their occurrence.

Mid-term results of 150 TAVI comparing apical versus femoral approaches

Background

Transcatheter aortic-valve implantation (TAVI) is a new therapeutic choice for treating aortic stenosis in patients considered high risk for surgery. This blooming therapeutic technique still requires evaluation of medium and long term outcome.

Method

We hereby report our results of the first 150 consecutive patients to receive TAVI implants in our population recruited from July 2009 to March 2013 in a retrospective and monocentric study. We analyzed long term morbidity and mortality criteria. We compared the apical and femoral approach results and researched predictors of cardiac mortality.

Results

The mean monitoring period was 387.62 days, mean Euroscore was 21.8, and mean Society of Thoracic Surgeons (STS) risk score was 9.2. The success rate for the procedure was 94.6 %. A total of 39 patients died. The mortality rates at the immediate perioperative point, 30 days, 1 year, and 2 years, were 4 %, 11.3 %, 22.7 %, and 26 %, respectively. As regards complications, there were 10 hemodynamic complications (6.6 %) and 20 vascular (13.3 %), 11 cardiac tamponades (7.4 %), eight mechanical (5.3 %), ten major hemorrhagic (6.7 %), 14 pulmonary (9.3 %), and 18 infectious complications (12 %). When comparing the rates of reported complications in terms of different approaches, we observed significantly more hemodynamic complications in the apical group (p = 0.049). Pulmonary complications were also significantly more common in cases of apical approach (p = 0.029). The majority of the patients reported clear functional improvement throughout their follow-up.

Conclusion

The results of the first 150 patients to receive the implant at the Nancy University Teaching Hospital (CHU Nancy) were consistent with findings in the literature. TAVI proved a credible and effective alternative to surgical valve replacement for patients at high risk during surgery.

Incidence, Severity, and Outcomes of Acute Kidney Injury in Octogenarians following Heart Valve Replacement Surgery

Background. The study investigates the occurrence, severity, and outcomes of acute kidney injury (AKI) in octogenarians following heart valve surgery. Methods. All patients, age >80 years, not on dialysis and without kidney transplant, undergoing heart valve replacement at Mayo Clinic, Rochester, in the years 2002-2003 were enrolled. AKI was diagnosed based on AKIN criteria. Results. 209 octogenarians (88.0% aortic valve, 6.2% mitral valve, 1.0% tricuspid valve, and 4.8% multivalve) with (58.4%) and without CABG were studied. 34 (16.3%) had preexisting CKD. After surgery, 98 (46.8%) developed AKI. 76.5% of the AKI were in Stage 1, 9.2% in Stage 2, and 14.3% in Stage 3. 76.5% CKD patients developed AKI. Length of hospital stay was longer for AKI patients. More AKI patients were discharged to care facilities. Patient survival at 30 days and 1 year for AKI versus non-AKI was 88.8 versus 98.7%, p = 0.003, and 76.5 versus 88.3%, p = 0.025, respectively. With follow-up of 3.94 ± 0.28 years, Kaplan-Meier analysis showed a reduced survival for AKI octogenarians. Preexisting CKD and large volume intraoperative fluid administration were independent AKI predictors. Conclusions. Nearly half of the octogenarians developed AKI after valve replacement surgery. AKI was associated with significant functional impairment and reduced survival.

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

TAVI (transcatheter aortic valve implantation) is a less invasive treatment of the stenotic aortic valve while avoiding midline sternotomy and cardiopulmonary bypass. A crimped biological valve on a self-expanding or balloonexpandable stent is inserted antegradely or retrogradely under fluoroscopy, and deployed on the beating heart. Among the worldwide TAVI programs, many different concepts have been established for the choice of the access site. Whether retrograde or antegrade TAVI should be considered the superior approach is matter of an ongoing debate. The published literature demonstrates safety of all techniques if performed within a dedicated multidisciplinary team. Since there is no data providing evidence if one approach is superior to another, we conclude that an individualized patient-centered decision making process is most beneficial, taking advantage of the complementarity of the different access options. The aim of this article is to give an overview of the current practice of access techniques for transcatheter based valve treatment and to outline the respective special characteristics.