Comparison of the novel Medtentia double helix mitral annuloplasty system with the Carpentier-Edwards Physio annuloplasty ring: morphological and functional long-term outcome in a mitral valve insufficiency sheep model

Comparison of flexible, open with semi-rigid, closed annuloplasty-rings for mitral valve repair

Background

Mitral regurgitation is a frequent valvular disease, with an increasing prevalence. We analysed the long-term outcomes of mitral valve repair procedures conducted over the last 10 years in our clinic using almost exclusively two different annuloplasty ring types.

Methods

A single-centre, retrospective analysis of mitral valve surgeries conducted between January 2005 and December 2015 for patients undergoing first-line mitral valve repair with either open (Cosgrove) or closed (CE Physio / Physio II) annuloplasty (OA or CA, respectively) rings.

Results

In total, 1120 patient documentations were available of which 528 underwent OA and 592 patients CA. The median age of patients was 64.0 years and 41.1% were female. The majority of these patients underwent the procedure because of degenerative valve disease. Rates of successful repair were about 90%, 72 h procedural mortality was 0.6% and the rate of re-intervention was 0.6% within the first 30 days. Functional (mitral regurgitation, left ventricular ejection fraction, left ventricular end-diastolic and systolic diameter and New York Heart Association class) as well as hard outcomes were comparable. 77.7 and 74.4% of patients were alive at the 10-year follow-up in the OA and CA groups, respectively. Upon multivariable adjustment, the hazard ratio was 0.926 (95% CI: 0.642–1.3135; p = 0.681).

Conclusions

The functional outcome and survival rates up to 10 years after mitral valve repair were comparable using open and closed annuloplasty rings. Whether this means these rings are interchangeable or a carefully selection of the best-for-the-patient devices will be subject of future investigations.

Post-operative echocardiographic evaluation of bioprosthetic mitral valve implantation in sheep

The ovine model is generally considered to be the best for testing bioprosthetic heart valve durability. Although echocardiography is the method of choice for the interim evaluation of the valve, literature on sheep echocardiography is scarce. Within the context of a study on treatment of pericardial heart valve prostheses, 19 adolescent sheep underwent transthoracic echocardiography six days after mitral implantation of bioprosthetic valves. Echocardiographic examination was performed under mild anesthesia and animals were put in a right lateral decubitus position. Four images were obtained: right parasternal long axis four and five chamber views, right parasternal long axis view with left ventricular outflow, and right parasternal short axis view through the mitral valve. We measured aortic annulus and velocity time integral over the aortic valve to determine stroke volume, cardiac output and cardiac index. The mitral valve was evaluated through color Doppler imaging for valvular and paravalvular leakages. Pulsed wave spectral Doppler was used for the measurement of velocities, pressures and velocity time integrals. For the evaluation of valve stenosis deceleration time and pressure half-time were determined. Effective orifice area of the mitral valve was derived. And, although not measured, other structures could clearly be visualized: right and left ventricle and atrium, wall thicknesses, tricuspid valve. This study shows that echocardiography in sheep is feasible, and that right parasternal images, obtained in animals in a right lateral decubitus position, are well qualified for the interim evaluation of bioprosthetic valves implanted in the mitral position. Besides the implanted valve, other cardiac structures like atria and ventricles can be visualized and evaluated.