Transcatheter mitral valve replacement in degenerated calcified native mitral valves: is the currently available technology suitable?

Transcatheter mitral valve replacement: there is still work to be done

Transcatheter mitral valve replacement (TMVR) is a novel therapeutic option for patients with severe mitral regurgitation (MR) at high or prohibitive surgical risk. Most TMVR technologies under investigation use either a trans-apical or a trans-septal approach via dedicated multistep anchoring systems. Transcatheter mitral valve replacement offers several potential advantages over transcatheter repair, notably a greater and more sustained MR reduction. At the same time, significant engineering challenges and potential disadvantages must be acknowledged. Preclinical and clinical studies have shown promising results, demonstrating TMVR feasibility. Nevertheless, further development, testing, and trials are needed before considering TMVR as a definitive therapeutic option for MR in a wide range of anatomical scenarios.

Transcatheter mitral valve replacement in native mitral valve with severe mitral annular calcification: Skirting the Sapien 3 to reduce the risk of paravalvular leaks

Background

Mitral annular calcification (MAC) may represent a significant challenge for heart surgeons with an extremely high perioperative risk during mitral valve (MV) surgery. The risk is further increased when patients fail to be eligible for any percutaneous treatment, particularly because circumferential calcifications involving the anterior leaflet suggest a critical obstruction of the left ventricular outflow tract (LVOT).

Objectives

The objective of this study was to evaluate residual mitral regurgitation (MR) after surgical mitral valve replacement using a Sapien 3 Ultra (Edwards Lifesciences, CA, USA) transcatheter aortic valve implantation (TAVI) prosthesis, reinforced with a pericardial skirt, in high-risk selected patients with severe MAC.

Methods

Since 2020, five high-risk patients (mean age 70 years; 63–76; four women) with severe mitral disease in the context of severe MAC (computed tomography-based mean MAC Score 8.2 ± 1.1) were operated on after we adopted this novel technique. The operations were performed under general anesthesia, using a transapical TAVI delivery system to position the Sapien 3 in the mitral position under direct vision. To reinforce and avoid paravalvular leakages, a pericardial skirt was previously sewn around the prosthesis, securing it to the annulus and perivalvular atrial surface.

Results

Sapien 3 Ultra implantation was successful without residual MR in all five patients (mild paravalvular leak in one case). Four patients had a 29-mm valve implanted, while one had a 26-mm valve implanted. Predilatation of the native annulus was never performed. Perfusion and clamping times were 134 ± 53 mins and 108 ± 43 mins, respectively. The presence of the pericardial skirt reduced the risk of leakage between the prosthesis and the rigid calcium surface, with final mean and maximal gradients of the TAVI prosthesis of 4.1 and 10.8 mmHg, respectively. There were no left ventricular outflow tract obstructions (mean LVOT gradient of 8 ± 1 mmHg). All patients were discharged, and neither mortality nor prosthetic dysfunction, nor residual mitral regurgitation was recorded. During follow-up, the last patient treated (MAC Score 10, severe calcification of the mitro-aortic junction) returned to our attention with a significant recurrent jet originating from the anterolateral commissure, currently medically treated, given the prohibitive redo risk.

Conclusion

Direct open surgical implantation of the Sapien 3 valve can be safely done in patients with severe MAC in dedicated centers. Reinforcing the TAVI prosthesis by sewing a pericardial skirt led to satisfactory perioperative and early postoperative results, reducing paravalvular leakages. Complex anatomies have a CERTAIN risk of recurrence.

Mitral Annular Calcification and Calcific Mitral Stenosis: Therapeutic Challenges and Considerations

PURPOSE OF REVIEW

Mitral annular calcification (MAC) and associated calcific mitral stenosis (MS) are frequent in the aging population, although optimal management remains debated and outcomes are poor. This article summarizes challenges in the diagnosis and therapy of calcific MS, the indications for valve intervention, procedural concerns, and emerging treatment options.

RECENT FINDINGS

Surgical mitral valve replacement is the procedure of choice in symptomatic patients at acceptable surgical risk, with transcatheter mitral valve replacement (TMVR) being evaluated in clinical trials as an alternative for patients at prohibitive surgical risk. Significant challenges exist with the currently available technology and outcomes have been suboptimal. Optimizing the patient-selection process by using multimodality imaging tools has proven to be essential. MAC and calcific MS is an increasingly prevalent, challenging issue with poor outcomes. While surgical valve replacement can be performed in patients with acceptable surgical risk, TMVR can be considered for patients at higher risk. Clinical trials are underway to optimize outcomes. Dedicated device designs and techniques to minimize risk of left ventricular outflow tract obstruction, paravalvular leakage, and device embolization are to be awaited.

Pitfalls in TAMVI: experience with the repositionable Lotus® Valve System

Background

Simultaneous transapical implantation of transcatheter heart valves in the native mitral and aortic position may be considered as an alternative to surgical valve replacement in high-risk patients presenting with combined valve disease.

Case presentation

A 59-year-old female with severe aortic stenosis, severe mitral stenosis with mild mitral insufficiency, persistent atrial fibrillation, severe chronic obstructive pulmonary disease and NYHA class of IV was evaluated by our interdisciplinary heart team. Due to the calculated Euroscore II, logistic Euroscore with 10% and 17% a decision was made towards a transapical TAVI approach. The implantation of a Sapien 3 (Edwards Lifesciences) valve in the aortic position was performed and the perioperative TEE showed a good result. The preoperative imaging revealed a narrow LVOT with risk for post interventional left ventricular outflow tract obstruction. Accordingly, it was decided against the use of balloon-expanding valves for the mitral valve position in the interdisciplinary team, as it is not repositionable. Instead, it was decided for the use of a Lotus (Boston Scientific) valve, as it is repositionable and therefore possible to retract in case of LVOT obstruction. In the present case of double valve intervention, the implantation attempt of a fully repositionable transcatheter heart valve into the native mitral annulus resulted in acute LVOT obstruction requiring immediate removal of the device. The patient was extubated and experienced uneventful postoperative recovery.

Conclusions

The case shows that improved preoperative work-up is necessary for better prediction of significant LVOT obstruction following transcatheter mitral valve implantation. In borderline cases, the use of a fully repositionable device is preferred.