Anterior mitral leaflet laceration using the MitraCut technique for transapical transcatheter Tendyne implantation after unsuccessful Carillon indirect annuloplasty: a case report

Abstract

Background

The introduction of a transapical transcatheter beating heart replacement system has significantly expanded therapeutic options for patients with severely diseased mitral valves, particularly those ineligibles for traditional surgery or transcatheter repair. However, challenges, such as left ventricular outflow tract obstruction (LVOT-O) and the risk of dynamic systolic anterior motion (SAM) in cases with elongated anterior mitral leaflet (AML) post-prosthesis implantation, impede the widespread adoption of transcatheter mitral valve replacement (TMVR).

Case summary

In 2022, a 75-year-old male with severe mixed-genesis mitral regurgitation (MR) underwent Carillon Mitral Contour System annuloplasty. Recurrent heart failure admissions (New York Heart Association IV) and prohibitive risk for open-heart surgery (European System for Cardiac Operative Risk Evaluation II 8.27%) prompted evaluation for Tendyne TMVR with the MitraCut technique. This beating heart transapical approach involved scissor-mediated splitting of the elongated 27 mm AML, essential for mitigating LVOT-O risk and dynamic SAM. The screening echocardiogram revealed the poorly tethered AML near the thickened septum at the simulated neo-LVOT site.

Discussion

This case underscores the intricate management challenges associated with severe MR, highlighting the successful application of the MitraCut technique as a viable alternative in high-risk scenarios. The imperative for further research and clinical studies is emphasized to comprehensively elucidate outcomes and safety parameters, providing valuable insights for refining TMVR applications within this context.

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Video Abstract

Primary specialties involved other than cardiology

Cardiology, cardiothoracic surgery, anaesthesia, intensive care.

Introduction

Transcatheter mitral valve replacement (TMVR) has expanded the treatment landscape for patients with severely diseased mitral valves (MV) ineligible for conventional surgery.¹ Nevertheless, the broad acceptance of TMVR has been limited by the occurrence of life-threatening left ventricular outflow tract obstruction (LVOT-O), often due to elongated and poor tethered anterior mitral valve leaflet (AML). The implant of a TMVR prosthesis fixes the AML in a diastolic position and displaces it towards the neo-LVOT tract, which can predispose patients to the development of systolic anterior motion (SAM) and dynamic LVOT-O, even when the LVOT area is considered sufficient.²

Effectively addressing the challenge of preventing LVOT-O requires innovative solutions, given the technical complexity, time-consuming, and substantial additional risks associated with current approaches. In this case report, we showcase the successful and safe implementation of the MitraCut technique^3,4 as a surgical measure to prevent LVOT-O during TMVR. Notably, this technique demonstrated efficacy in a patient who had previously undergone indirect mitral annuloplasty.

Summary figure

Case presentation

A 75-year-old male patient (Table 1) with a complex medical history, including atrial fibrillation, pacemaker implantation for bradycardia, severe coronary artery disease with prior stent placement, and severe mitral regurgitation (MR), had been treated with a Carillon 12/18/80 mm Mitral Contour System (Cardiac Dimensions, Kirkland, WA) in December 2022. He presented with recurrent hospitalizations due to acute heart failure [New York Heart Association (NYHA) IV].

The patient’s regular medication regimen included oral anticoagulation, angiotensin-2 receptor blockers, phosphodiesterase-5 inhibitors, diuretics, a sodium/glucose co-transporter 2 inhibitor, sodium bicarbonate, a proton pump inhibitor, and statins. Baseline functional assessment revealed pronounced peripheral oedema, reliance on a walker for ambulation, dyspnoea at rest, and left thoracic pain with minimal physical exertion. Additionally, the patient presented with chronic kidney disease [Kidney Disease: Improving Global Outcomes (KDIGO) stage IV], severe secondary pulmonary artery hypertension (right ventricle systolic pressure of 91 mmHg), and severe obesity [body mass index (BMI) 44.1 kg/m²].

Upon admission, vital signs were recorded as follows: blood pressure (106/52 mmHg), heart rate (80 b.p.m.), respiratory rate (24 breaths per minute), and temperature (36°C).

Transoesophageal echocardiography (TEE) revealed a left ventricular ejection fraction of 65% and severe mixed-genesis MR (vena contracta, 0.8 cm; EROA, 0.53 cm²; R-Vol 89 mL), resulting from severe mitral annulus dilatation (42 mm) and marked left atrial enlargement (left atrial volume index, 93.3 mL/m²) (Figure 1A and B). After multidisciplinary heart team assessment, repeated treatment of the severe MR was indicated, but the patient was considered at prohibitive risk for open-heart surgery [European System for Cardiac Operative Risk Evaluation (EuroSCORE) II] 8.27%). Since transcatheter edge-to-edge MV repair was not considered feasible, due to the unfavourable anatomy of the MV leaflets (short, <5 mm, and degenerated posterior mitral leaflet), the decision was made to proceed with implanting a tether-based Tendyne TMVR system.

Following standardized computer tomographic (CT) segmentation and virtual device implantation, the patient was considered eligible to receive a standard profile (SP) 33M transcatheter heart valve. However, due to the anticipated risk of LVOT-O with a cross-sectional neo-LVOT area of 399.6 mm² in end-systole and an elongated, poorly supported AML (27 mm) nearly striking the septum at the simulated neo-LVOT (Figure 2), the decision was made to perform a dedicated beating heart transapical scissor-mediated splitting of the AML (MitraCut technique), just before TMVR (Summary figure and Figures 3A–D).

Under general anaesthesia, standard beating heart transapical access was obtained. A shortened 24-F Gore DrySeal Flex sheath (W.L. Gore & Associates, Inc.) was employed for improved handling and inserted over a standard-length dilator at the transapical access site (Summary figure A). Endoscopic scissor (Ceramo HCR, MRT-2; Fehling Surgical Instrument, Inc.) insertion was guided by three-dimensional TEE and fluoroscopic evaluation, ensuring accurate alignment of the scissor tips for the AML splitting in the A2 scallop region (Figure 3A–D). Subsequently, the sheath was exchanged for the Tendyne delivery system, and the prosthesis was successfully implanted (Figure 3E). The final TEE evaluation did not show any paravalvular leakage (PVL) or any LVOT-O. Notably, the prior indirect annuloplasty with Carillon device did not impact the deployment or seating of the Tendyne valve (Figure 4).

After the procedure, the patient was transferred to the intensive care unit, where he initially required inotropic support and nitric oxide (20 ppm) ventilation for concomitant pulmonary artery hypertension. The patient was extubated 25 h after the procedure and was transferred to the normal station and discharged from the hospital 14 days after the procedure, respectively, without any cardiac complication. The post-operative TTE showed a well-functioning transcatheter heart valve (mean gradient, 2 mmHg) without PVL, prosthesis thrombosis, and LVOT-O.

At the 6-month follow-up, the patient is alive and maintains stable clinical conditions.

Discussion

This case report illustrates the complex management of severe MR in a high-risk patient with multiple comorbidities, employing innovative techniques. The successful application of the MitraCut technique highlights its potential to mitigate the risks of SAM and dynamic LVOT-O in complex TMVR scenarios.⁵

Russo et al.⁶ have provided comprehensive insights into LVOT-O predictors after TMVR, involving various factors such as prosthesis-, patient-, and procedure-related elements. However, they all converged around a common factor, which is the critical threshold of the neo-LVOT area that varies from 1.7 to 1.9 cm².

Although scissor-mediated AML laceration has been well-documented in small LVOT area cases, there is limited scientific evidence supporting the use of the MitraCut technique before Tendyne system implantation in cases with an adequate LVOT area, especially following Carillon Mitral Contour System implantation. In our case report, despite a sufficiently predicted neo-LVOT area (almost 400 mm²), placing the Tendyne system without prior AML splitting in a patient with an elongated and poorly supported AML would have fixed the AML in diastole by moving it towards the LVOT, potentially resulting in SAM and dynamic LVOT-O (Figure 5D and F).

At our institution, using the pre-operative imaging, an AML value with a length ≤ 25 mm is not considered a risk of SAM. Furthermore, following the recommendations from Abbott Tendyne Vascular, patients should initially be evaluated for a SP valve. In cases where suitable anatomy is lacking, consideration of a low-profile valve is recommended. For this group of patients, the predicted neo-LVOT, averaged over end-systole and end-diastole, should be larger than 325 mm².

The current TMVR literature comprises heterogeneous reports about the applicability of the AML laceration to prevent LVOT-O using the LAMPOON technique or alcohol septal ablation for neo-LVOT modulation.⁷ However, the MitraCut technique may be superior to other wire-based interventional techniques in terms of vascular complications, extensive physician expertise, and decreased fluoroscopic time. Particularly, the direct transapical approach allows for more precise positioning of the AML cut. Instead, in the LAMPOON technique, the trajectory of the pull of the ‘flying V’ with electrocautery may result in AML laceration without ideal alignment with the LVOT.⁷ Lastly, the likelihood of apical access complications associated with the MitraCut approach is reduced due to the use of a smaller guiding sheath (26Fr) compared with the inserted valve system (34Fr).

Despite ongoing efforts for developing dedicated TMVR devices and distinct implantation techniques, along with reliable pre-procedural imaging,^8,9 LVOT-O remains a major exclusion criterion in native TMVR.¹⁰ In recent clinical trials, around 50% of patients were excluded based on LVOT-O and/or anatomical considerations.^11–13 Even among individuals with a failing bioprosthesis, such as MV-in-valve, valve-in-ring, or those with mitral annulus calcification, the risk of neo-LVOT-O exceeds that observed in native TMVR cases, with rates ranging from 2.2% to 2.6%.¹⁴ Thus, the MitraCut technique offers a promising solution to address this challenge and to further expand the TMVR application.

Recently, the ShortCut^TM mitral device (Pi-Cardia Ltd.) has been presented as promising tool for mechanical AML laceration, effectively preventing anticipated LVOT-O during TMVR.¹⁵ This contributes to the increasing endorsement of MitraCut and the ShortCut^TM (Pi-Cardia Ltd.) device in a TA approach, providing a secure and valuable alternative for patients with MV disease who have limited treatment options.

Conclusion

The successful use of the MitraCut technique highlights its potential in high-risk scenarios, contributing to evidence-based decision-making in challenging TMVR situations. Further studies are needed to expand its utility, offering hope for improved outcomes in patients with limited treatment options.

Lead author biography

Dr Davide de Manna is an accomplished cardiothoracic resident currently pursuing additional training at Hannover Medical School (Hannover, Germany) to enhance his expertise in endovascular and transcatheter skills. He completed his MD degree in 2016 at University of Rome ‘Tor Vergata’ and subsequently embarked on a cardiothoracic surgery internship at the University of Verona (Italy) from 2018 to 2023. Driven by his passion for structural heart disease, transplantation, and robotic surgery, he has shown dedication to advancing his knowledge and skills in this field.

Acknowledgements

We extend our gratitude to the healthcare professionals at Hannover Medical School for their dedicated care in the pre-hospital and intraoperative settings. Special thanks to Mr Vilkama Thomas, an experienced proctor, whose insights greatly contributed to the procedure’s success. We acknowledge Dr Jan Carsten, a cardio anaesthetist, for his pivotal role in ensuring procedural success outlined in our paper. His expertise in managing the patient post-operatively in the intensive care unit significantly enhanced the research quality and its potential impact on patient care.

Consent: The authors confirm that consent for the submission and publication of this case report, including images and associated text, was obtained from the patient in line with the Committee on Publication Ethics (COPE) guidance.

Funding: This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. J.B. received honoraria for lectures/consulting from Novartis, Vifor, Bayer, Pfizer, Boehringer Ingelheim, AstraZeneca, Cardior, CVRx, BMS, Amgen, Corvia, Norgine, Edwards, and Roche not related to this article and research support for the department from Zoll, CVRx, Abiomed, Norgine, and Roche, not related to this article.

Data availability

The data underlying this article are available in the article.

References

Author notes