The Transapical Route for TAVR - Cardiac Interventions Today (2023)

Since Alan Cribier, MD, performed the first human transcatheter aortic valve replacement (TAVR) via an antegrade transfemoral (TF) approach in 2002,¹The procedure has quickly emerged as an alternative treatment option for patients with aortic stenosis (AS). Recent results from the PARTNER study showed that TAVI is superior to the standard of care in patients with severe symptomatic AS who are not eligible for open surgery.²The prospective randomized arm demonstrated that TAVI is an alternative treatment for patients undergoing high-risk surgery that have similar 1-year outcomes compared to surgical AVR.³Today, the procedure is most commonly performed via a retrograde TF approach.⁴or through an antegrade transapical (TA) approach, where the device is inserted through the apex of the left ventricle.⁵However, alternative access routes through the subclavian artery or ascending aorta are being clinically examined.^6,7In this article, we discuss the clinical and technical history of TA TAVR, current clinical outcomes, and possible future options using this approach.

HISTORY

The number of patients with calcifying AS is constantly increasing due to the demographic change of our population, since it occurs mainly in older patients. The comorbidities and the general state of this group of patients mean that older patients with severe symptomatic AD have insufficient admission and care, despite their very poor prognosis for drug treatment.⁸This combination of unmet clinical need and the desire to find less invasive interventional/surgical treatment options has prompted the development of TAVR, which not only avoids the trauma of a median sternotomy, but also does not have to be performed during cardioplegic arrest with surgery. cardiopulmonary. derivation

However, early in the development phase, it was recognized that adequate vascular access is key to the success of the procedure. Given the size of the devices currently in use (the smallest is 16-18F and the largest is 22-24F) and the significant number of elderly AS patients who also have peripheral vascular disease, severe aortic atherosclerosis, or other vascular comorbidities, it is not surprising that an alternative approach to TAVR was sought, possibly independent of vascular access.

The TA approach to heart valve repair was used in the early years of cardiac surgery to perform closed mitral valve commissurotomies and more recently for some left ventricular assist devices. Based on this experience, pioneers Dr. Michael Mack and Dr. Friedrich Mohr introduced TA TAVR in 2004 as a transcatheter heart valve technique that can be used independently of vascular access.^9,10

Transcatheter heart valve therapy has clearly grown from a single specialty in this early phase to an area where cardiologists and surgeons work hand-in-hand during the diagnostic and therapeutic phases of patient treatment. As a result, in 2007 the PARTNER EU study was carried out, the first European feasibility study using the TF and TA approaches. The focus of this study was determined by the joint decision of the cardiac team, comprised of interventional cardiologists, cardiac surgeons, anesthesiologists, geriatricians, and cardiac imaging specialists.¹¹

As a result, TA TAVR with Edwards Sapien transcatheter heart valve (Edwards Lifesciences) received the CE mark in Europe in 2008 (Figure 1). Today, 3 years later, the second generation Edwards Sapien XT heart valve (Edwards Lifesciences) remains the only CE-marked device for TA TAVR in Europe (Figure 2A). Modifications to the prosthetic valve included reducing its profile, potentially facilitating implantation, and refining the pericardial leaflet shape and preconditioning to improve valve durability and performance. With the Ascendra II Delivery System (Edwards Lifesciences), the second generation of the Ascendra TA Delivery System, it is now possible to place 23 and 26mm prostheses through a 22F sheath. Additionally, in 2010, a 29mm Edwards Sapien XT was approved for use in patients with large aortic annulus, but still requires the original Ascendrade delivery system with a 26F introducer sheath.

POTENTIAL STRENGTHS AND WEAKNESSES

The approach through the left ventricular apex rarely limits the size of the device advanced into the left ventricle, so the TA approach is currently the only option for implanting the larger 29mm Edwards Sapien XT bioprosthesis.

Antegrade passage of the device through the native aortic valve is generally technically easier than the retrograde approach currently used during TF-TAVR. This is of particular importance in patients with degenerative bioprostheses, where the degenerated xenograft is traumatized during retrograde transcatheter heart valve insertion, which can lead to acute severe aortic regurgitation with catastrophic consequences. It also explains why there is often a short interval between balloon valvuloplasty and valve insertion in AT procedures, which is particularly helpful in patients with compromised left ventricular function who are at risk of hemodynamic instability during this time.

The short distance between the device access point and the native aortic valve and the straight orientation of the device enhance direct digital control of its position. This is particularly important in patients at risk of prosthetic displacement due to asymmetric septal hypertrophy or after mitral valve replacement.

Potential weaknesses of the TA route include the need for a limited left lateral minithoracotomy with the associated potential for postoperative pain and the need for general anesthesia. Additionally, perforating the left ventricular apex and inserting the catheter device is not without risk and can lead to acute bleeding complications during implantation.¹²However, the incidence of major left ventricular hemorrhage during implantation is low, as are long-term complications such as left ventricular aneurysms.¹³they are rarely reported.

GUIDELINES AND RESULTS REPORTED

In 2008, the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery published the European guidelines for TAVR following CE marking of the Edwards Sapien and CoreValve systems (Medtronic, Inc., Minneapolis, MN).¹⁴TAVI is currently considered an alternative treatment option for AS patients presenting with high-risk surgical AVR based on an alogistic EuroSCORE > 20. Surgical AVR remains the gold standard for the treatment of AR in the population. low risk.

This view is now supported by the results of the PARTNER study, the world's first randomized, prospectively controlled study of TAVI versus standard medical therapy (Cohort B).²and surgical AVR (Cohort A).³In inoperable patients randomized to TAVR, there was a 20% reduction in mortality (30.7% with TAVR vs. 50.7% with standard care) at 1-year follow-up compared with medical treatment. In patients at high risk of surgical SVA, TAVR was not found to be inferior in terms of 30-day and 1-year mortality, with a 1-year survival rate of 75.8% (TAVR) and 73.2% (SVA surgical).

The PARTNER EU study was the first feasibility study to use the TF and TA approaches with the Edwards Sapien bioprosthesis.¹¹The access route was determined by joint decision of the multidisciplinary cardiac team and in accordance with the best practices for TF or TATAVR at that time. This resulted in a selection bias between the two groups, as expected, and explains why the incidence of risk factors such as coronary artery disease, peripheral vascular disease, previous coronary artery bypass graft transplantation and carotid artery disease was significantly higher in the TA cohort, resulting in a higher logistic EuroSCORE of 33.8% compared to 25.7% for TF. Despite this apparent selection bias, many have concluded that the lower mortality for the TF group of 8% at 30 days (TA 19%) and 21% at 1 year (TA 49%) was a direct consequence of the access road.

However, it is important to note that the PARTNER EU study was not designed to compare TF versus TA, but rather to demonstrate the feasibility of the two types of implantation. Furthermore, it is important to note that this study was conducted in Europe in the second half of 2007 and recruited patients at a time when there was very little experience with TAVI. Of a total of nine participating centers, 78% had no initial experience with TA TAVR compared to 44% with TF TAVR.

Since then, the number of TA-TAVR procedures has increased rapidly and monocentric experiences with excellent results have recently been published. Using 299 patients, Kempfert et al. from Herzzentrum Leipzig in Leipzig, Germany, reported an improvement in outcomes, with a decrease in 30-day mortality from 11.3% in their first 150 patients to 6% in their most recent experience.¹⁵

In addition, the SOURCE registry began in 2008 following the commercialization of the Edwards Sapien transcatheter heart valve in Europe. It is currently the largest dataset on a TAVR experience (N=2339), including the largest cohort of patients who underwent TA access (N=1398).^sixteenIn this registry, 55% of patients underwent TA-TAVR compared to 45% treated with TFaccess. Patients who underwent TA TAVR showed significantly higher comorbidities, which is not surprising considering that the access pathway at participating centers is often the result of cardiac team discussions with a "TF first" approach. . The mean logistic EuroSCORE in the TA group was 29% versus 25.8% in the TF group.

Mortality for the TA group at 30 days was 10.3% and a 1-year survival rate of 72% was reported. Regarding the discussions about the different access routes mentioned in the context of the PARTNER-EU study, it should be noted that a direct comparison between the TA and TF cohorts, as already mentioned, is still made difficult by the different characteristics of the patients. However, the 30-day mortality of 6.3% was slightly lower and the 1-year survival rate of 81% was slightly higher in TF compared to the TA group of patients. In certain risk groups, such as B. Patients with a logistic EuroSCORE < 20, the 1-year survival rate of approximately 80% in each group was not significantly different between TF and TA. As expected, the largest difference in survival between the two groups was found in the first two months post-procedure/postoperative. Thereafter, the Kaplan-Meier survival curves for both groups are almost parallel to each other.^sixteen

Postoperative complications in the TA cohort included vascular/access-related complications (2.4%), myocardial infarction (0.5%), and stroke (2.5%). As expected, the incidence of major vascular/access complications was quite low in the TA group. However, when they did occur, they were mainly attributed to left ventricular apex complications or aortic root trauma. These complications were highly predictive of a higher 30-day mortality rate.17 Over time, the incidence of these serious complications decreased, possibly reflecting the learning curve of participating centers.^sixteen

In this regard, it might be interesting that recent data from the SOURCE registry show that no apical complications occurred in a subgroup of TA-TAVR patients with previous coronary artery bypass grafts (n=357). This may explain why their 30-day mortality rate of 10% was similar compared to patients who underwent TF-TAVR.¹⁸

Multivariate analyzes of the SOURCE registry identified EuroSCORE > 30% and renal failure as predictors of 30-day mortality after TA TAVR.17 In contrast, analysis of TA TAVR data from the Leipzig Heart Center showed that respiratory function poor (defined as vital capacity <70%) and concomitant (>mild) mitral regurgitation independently predict mortality. However, neither of the two classical risk assessment algorithms (Society of Thoracic Surgeons Score > 15%, Logistic EuroSCORE > 30%) could predict the results.¹⁵

It is important to note that all patients in the PARTNER studies and the SOURCE registry were treated with the first-generation Edwards Sapien prosthetic valve. The first results of the feasibility study with the new generation of AT equipment, the Edwards Sapien XT, have recently been presented. PREVAIL TA (Placement of Aortic Balloon Expandable Transcatheter Valves Trial) was a prospective, multicenter, nonrandomized clinical trial evaluating the Edwards Sapien XT transcatheter heart valve, including the next-generation ascending-transapical delivery system. Mortality at 30 days was 8.7% for the entire cohort and 3.5% for patients who received the 29-mm valve, lower rates than previously reported for TA TAVR.¹⁹

A particular group of patients who may further benefit from the development of transcatheter heart valve techniques are those facing a new open heart surgery due to degeneration of a previously implanted bioprosthesis. In this group of patients, TAVR is increasingly being used for valve-in-valve treatment. The TA approach is a very attractive option in this context, as it guarantees antegrade access to bioprostheses in the aortic position, which may reduce the risk of intraprocedural acute prosthetic failure. In addition, the TA approach has also been used to treat degenerated mitral bioprostheses with excellent results.^20,21Unlike TAVR on the native aortic valve, the failed aortic bioprosthesis facilitates positioning, prevents conduction abnormalities from occurring, and protects the coronary arteries.

FUTURE OPTIONS

TA TAVR has been extensively described in previous reviews.5 However, it is still evolving and will continue to undergo various modifications and improvements that will hopefully improve patient outcomes. Recently, TA TAVR has been shown to be performed even through an endoscopic approach.²²

In addition, new devices with additional technical features have been developed to improve feasibility and safety during implantation, such as: B. the JenaValve device (Figure 2B). This self-expanding, repositionable and retractable TA TAVR valve has an exclusive anchoring and self-centering system. This design should reduce potential mitral valve distortion and conduction disturbances. A multicenter study was initiated in 2010 to evaluate TA delivery with the JenaValve,²³and the device has recently received the CE mark in Europe.

Reports of first experiences with the SymetisAcurate device (Symetis, Ecublens, Switzerland) have recently been presented. Developed for TA TAVR, this transcatheter self-expanding heart valve consists of a porcine biologic valve attached to a nitinol self-expanding stent. Allows for anatomical orientation and facilitates intuitive implantation through tactile feedback. The recently reported initial experience in 40 patients was encouraging.²⁴

DIPLOMA

The dynamic development of transcatheter heart valve technology is the result of the excellent partnership between cardiologists and cardiac surgeons, supported by the technical teams that developed this technology. As a result, in less than a decade, TAVR has become a standard of care for patients who are unfit or considered high risk for surgical AVR.

Valve technology, delivery systems, and interventional/surgical techniques continue to evolve and improve, and it remains to be seen how this will improve patient outcomes. There is currently no evidence to favor any particular approach overall and the Heart Team approach ensures that the various approaches to TAVI are used in the best interest of the patient to reduce the risks associated with the procedure and improve outcomes. In this sense, having TA TAVR available is of great help since it is currently the least restricted approach due to vascular access. However, the key to the future development of TAVR is collaboration among the members of the multidisciplinary cardiac team.

Rafal Dworakowski, MD, PhD works in the Department of Cardiothoracic Surgery at King's College Hospital/King's HealthPartners in London, UK. He has revealed that he has no financial interest in connection with this article.

Olaf Wendler, MD, PhD, FRCS, is Clinical Director, Cardiovascular Services, King's College Hospital/King'sHealth Partners in London, UK. He has disclosed that he is a paid consultant to Edwards Lifesciences and receives grants/research funding from Edwards Lifesciences and is a paid consultant to Medtronic. dr. Wendler can be reached at +44 20 3299 4341; olaf.wendler@nhs.net.

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