Kathetergeführter Mitralklappenersatz: aktueller Stand

Innovative Mitral Valve Repair Using a Novel Automated Suturing System: Preliminary Data

(1) Background and Objectives: Mitral regurgitation is a common valve disease requiring surgical repair. Even with satisfactory results, repair techniques may underlie subjectivity and variability and require long learning curves. A novel approach, the "Roman Arch" technique, may ease the technical burden. This study assessed an automated suturing device's feasibility and time efficiency for a proposed simplified technique. (2) Materials and Methods: Using the MiStitch™ and MiKnot™ devices (LSI Solutions, Inc., Victor, NY, USA), the suture pattern was performed in a cadaver model. Three surgeons with different expertise levels conducted the procedures. Repair and suture placement times were recorded and analyzed. (3) Results: The modified "Roman Arch" repair was completed on all ten human heart specimens with an average total repair time of 3:01 ± 00:59 min and a trend toward reduced times as experience increased. The study confirmed the technical feasibility with 90% of the attempts rated as rather satisfactory or very satisfactory. (4) Conclusions: The MiStitch™ system effectively facilitated the modified "Roman Arch" repair in an ex vivo setting, suggesting its potential to reduce the technical complexity of mitral valve repairs. Further studies are needed to confirm its efficacy and safety in clinical practice.

Feasibility evaluation of the transapical saddle-shaped valved stent for transcatheter mitral valve implantation

Background and Aims of Study

Transcatheter mitral valve implantation (TMVI) is a promising and minimally invasive treatment for high‐risk mitral regurgitation. We aimed to investigate the feasibility of a novel self‐expanding valved stent for TMVI via apical access.

Methods

We designed a novel self‐expanding mitral valve stent system consisting of an atrial flange and saddle‐shaped ventricular body connected by two opposing anchors and two opposing extensions. During valve deployment, each anchor was controlled by a recurrent string. TMVI was performed in 10 pigs using the valve prosthesis through apical access to verify technical feasibility. Echocardiography and ventricular angiography were used to assess hemodynamic data and valve function. Surviving pigs were killed 4 weeks later to confirm stent deployment.

Results

Ten animals underwent TMVI using the novel mitral valve stent. Optimal valve deployment and accurate anatomical adjustments were obtained in nine animals. Implantation failed in one case, and the animal died 1 day later due to stent mismatch. After stent implantation, the hemodynamic parameters of the other animals were stable, and valve function was normal. The mean pressure across the mitral valve and left ventricular outflow tract were 2.98 ± 0.91 mmHg and 3.42 ± 0.66 mmHg, respectively. Macroscopic evaluation confirmed the stable and secure positioning of the stents. No obvious valve displacement, embolism, or paravalvular leakage was observed 4 weeks postvalve implantation.

Conclusions

This study demonstrated that the novel mitral valve is technically feasible in animals. However, the long‐term feasibility and durability of this valved stent must be improved and verified.

The current diagnosis and treatment of high-risk patients with chronic primary and secondary mitral valve regurgitation

Mitral valve regurgitation (MR) is due primarily to either primary degeneration of the mitral valve with Barlow's or fibroelastic disease or is secondary to ischemic or nonischemic cardiomyopathies. Echocardiography is essential to assess MR etiology and severity, the remodeling of cardiac chambers and to characterize longitudinal chamber changes to determine optimal therapies. Surgery is recommended for severe primary MR if persistent symptoms are present or if left ventricle dysfunction is present with an EF <60% or a left ventricle end-systolic diameter ≥40 mm. For secondary MR, therapy of heart failure with vasodilators and diuretics improves forward cardiac output. Coronary artery bypass grafts (CABG) or percutaneous coronary intervention (PCI) should be considered for severe MR due to ischemia. This review summarizes the pathophysiology, the characteristics, the management and the different interventions for high risk patients with chronic primary and secondary MR.

Transcatheter mitral valve implantation using a novel system: preclinical results

BACKGROUND

This preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system (Mi-thos valve) composed of a self-expanding frame and a bovine pericardial tissue bioprosthesis.

METHODS

The valve was implanted in 26 sheep using a transapical approach for short- and long-term evaluation. The technical feasibility, safety, durability, and valve function were evaluated during and 6 months after the procedure using intracardiac and transthoracic echocardiography, multisliced computed tomography, histological analysis, and electron microscopy.

RESULTS

The success rate of valve implantation was 100%, and the immediate survival rate after surgery was 84%. Five animals died within 90 min after the development of the prosthetic valve due to an acute left ventricular outflow tract obstruction (n = 2) and sudden intraoperative ventricular fibrillation (n = 3). Twelve animals died within 1 month due to acute left heart dysfunction. Mild (n = 5) and moderate (n = 2) paravalvular leakage occurred in seven animals, and two moderate PVL animals died of chronic heart failure within three months. Multimodality imaging studies of the remaining seven animals showed excellent function and alignment of the valves, with no coronary artery obstruction, no left ventricular outflow tract obstruction, no severe transvalvular gradients and no paravalvular leakage. Macroscopic evaluation demonstrated stable, secure positioning of the valve, with full endothelialization of the valve leaflets without injury to the ventricular or atrial walls. Histological and electron microscopic examinations at six months showed no obvious macro- or microcalcification in the leaflets.

CONCLUSIONS

Preclinical studies indicate that transcatheter implantation of the Mi-thos valve is technically safe and feasible. The durability, functionality, and lack of leaflet calcification were all verified in animal experiments. The information from these preclinical studies will be applied to patient selection criteria and the first-in-human studies.