TMVR: first successful Valve-in-Band in animal model after annuloplasty failure

Clinical context and challenges of the Valve-in-Band

While surgical repair remains the gold standard for treating severe primary mitral regurgitation (MR), the failure of an initial annuloplasty presents the clinician with a complex challenge. Open-heart reintervention is associated with substantial perioperative risk for the patient. Although transcatheter mitral valve replacement (TMVR) is an attractive option, its application after the placement of an annuloplasty band — a technique known as Valve-in-Band (ViB) — remains largely unexplored. The main obstacle lies in a theoretical concern regarding the lack of circumferential radial support provided by a band, unlike a complete ring, which could compromise the anchoring of the prosthesis.

Study objectives and hypotheses

This technical note reports the first transcatheter ViB procedure performed on a large animal model (68 kg Yucatan pig) mimicking a mitral repair failure. The primary objective is to evaluate the technical feasibility and acute safety of implanting a 23 mm Edwards Sapien Ultra valve within a 28 mm annuloplasty band previously positioned under cardiopulmonary bypass. The authors test the hypothesis that the combined support of the band, the native anterior leaflet, and the mitral annulus can provide sufficient radial support to stabilize the device without embolization or left ventricular outflow tract obstruction.

Experimental protocol and study design

This preclinical study takes the form of a technical note reporting a first-in-animal experiment of the "valve-in-band" (ViB) type. The objective was to evaluate the technical feasibility of transcatheter mitral valve replacement (TMVR) following the failure of a surgical band annuloplasty.

The protocol was conducted on a unique porcine model: a 20-month-old Yucatan mini pig sow weighing 68 kg. The procedure was structured according to the following surgical and interventional steps:

• Phase chirurgicale initiale : Réalisation d'une sternotomie en « clamshell » sous circulation extracorporelle (CEC) pour la mise en place d'une bande d'annuloplastie mitrale de 28 mm. La bande a été volontairement surdimensionnée pour induire une insuffisance mitrale (IM) expérimentale. Un atrium gauche dilaté a été simulé pour permettre l'accès transcathéter.
• Transcatheter intervention: Deployment of a 23 mm Edwards Sapien Ultra valve within the band (ViB) using the Commander delivery system.

The procedure was guided by fluoroscopy. Analysis methods to validate technical success included intraoperative echocardiography, specifically aimed at detecting potential embolization, paravalvular leak (PVL), or left ventricular outflow tract (LVOT) obstruction, while measuring the resolution of mitral regurgitation. No control group was used for this technical proof of concept.

Results of the first Valve-in-Band (ViB) procedure in a porcine model

This technical note reports the results of a proof of concept conducted on a large animal model (female Yucatan mini-pig, 68 kg, 20 months). The objective was to evaluate the feasibility of implanting a transcatheter valve into an annuloplasty band, a configuration that is theoretically unstable due to a lack of circumferential radial support.

Technical success and deployment

L'intervention a été réalisée sous circulation extracorporelle (CEC) via une sternotomie en clamshell pour la pose initiale de l'anneau, suivie d'un accès transcathéter par l'oreillette gauche simulée. Les paramètres de l'implantation sont les suivants :

Hemodynamic and functional assessment

Immediate post-procedural observations confirm the effectiveness of the Valve-in-Band device. Contrary to theoretical concerns regarding the lack of 360° rigid support, the valve demonstrated remarkable stability. Key results include:

• Mitral regurgitation (MR) resolution: Echocardiography confirmed the disappearance of MR after the deployment of the 23 mm prosthesis.
• Mechanical stability: Stable fixation of the Edwards Sapien Ultra valve without any episode of embolization.
• Absence of structural complications: No cases of paravalvular leak (PVL) were detected.
• Outflow safety: No left ventricular outflow tract (LVOT) obstruction was observed.

Qualitative and mechanical observations

Per-procedural analysis highlighted that the native anterior leaflet and the mitral annulus actively contribute to the circumferential radial support necessary for prosthesis maintenance. This anatomical interaction compensates for the opening of the surgical annuloplasty band. The animal tolerated the entire procedure without acute perioperative complications, thus validating the short-term safety of this approach in a model of failing mitral repair.

A proof of concept for the Valve-in-Band

This pioneering study in a porcine model demonstrates the technical feasibility of transcatheter mitral valve replacement (TMVR) within a failing annuloplasty band. Until now, the lack of complete circumferential radial support — inherent to bands compared to closed rings — hindered the adoption of Valve-in-Band (ViB) due to concerns regarding instability. The results obtained with a 23 mm Edwards Sapien Ultra valve (deployed in a 28 mm band) indicate that the native anterior leaflet and the mitral annulus provide sufficient structural support to prevent embolization and ensure peri-prosthetic sealing.

Limits and perspective

The weak point lies in the preliminary nature of this report (n=1) and its acute experimental framework. The 68 kg animal tolerated the procedure without left ventricular outflow tract (LVOT) obstruction or paravalvular leak (PVL), but the lack of chronic follow-up does not allow for the assessment of long-term mechanical stability or late thrombosis risks. Unlike conventional Valve-in-Ring procedures, ViB requires validation on remodeled human anatomies where the band geometry can vary significantly.

Summary of key results

This proof of concept on a porcine model (68 kg) demonstrates the technical feasibility of "valve-in-band" (ViB) valve replacement by implanting a 23 mm Edwards Sapien Ultra prosthesis into a 28 mm annuloplasty band. The results validate stable fixation without embolization, total resolution of mitral regurgitation, and the absence of left ventricular outflow tract (LVOT) obstruction or paravalvular leak.

In concrete terms, for the practitioner:

• Alternative to reintervention: Consider the ViB technique as a future minimally invasive option for treating mitral valve repair failures, thus avoiding the high perioperative risks of a second open-heart surgery.
• Sufficient radial support: No longer fear the absence of complete circumferential support; the study shows that the native anterior leaflet and the annulus ensure effective anchoring of the transcatheter valve within the band.
• Hemodynamic safety: The use of a balloon-expandable valve provides immediate stability, paving the way for percutaneous annulus modification strategies to optimize clinical outcomes.

Technical lexicon of the study

Valve-in-band (ViB): Transcatheter intervention procedure consisting of implanting a valvular bioprosthesis inside a previously placed mitral annuloplasty band, aimed at treating an initial surgical repair failure.

Band annuloplasty: A mitral valve repair technique using a partial prosthetic support (band) to stabilize the mitral annulus, unlike complete rings, raising the question of the radial support required for a transcatheter valve.

Mitral regurgitation (MR): Regurgitation of blood from the left ventricle to the left atrium; in this experimental model, it was induced by oversizing a 28 mm band in a 68 kg porcine subject.

LVOT (Left Ventricular Outflow Tract) obstruction: Potential complication where the implanted valve or the native anterior mitral leaflet obstructs the ejection flow from the left ventricle to the aorta.

Paravalvular leak (PVL): Abnormal passage of blood between the outer wall of the transcatheter valve and the tissues or annuloplasty band, indicating a sealing defect of the prosthetic interface.

Circumferential radial support: Mechanical resistance exerted by the mitral annulus and the native anterior leaflet, allowing, according to the study, to stabilize a balloon-expanded valve despite the absence of a closed surgical ring.

Commander Delivery System: Specific device used for the precise delivery and deployment of the Edwards Sapien Ultra valve under fluoroscopic guidance.

Information intended for healthcare professionals. This content may contain errors or truncated summaries. We recommend always verifying with the original source article. Delynov disclaims all responsibility regarding the use of this information. This document is not intended for patients or the general public.