Splitting the anterior mitral leaflet impairs left ventricular function in an ovine model

Laurencie Brunel; Zoe A Williams; Konstantin Yastrebov; Benjamin M Robinson; Innes K Wise; Hugh S Paterson; Paul G Bannon

doi:10.1093/ejcts/ezac539

Splitting the anterior mitral leaflet impairs left ventricular function in an ovine model

Eur J Cardiothorac Surg. 2022 Dec 2;63(1):ezac539. doi: 10.1093/ejcts/ezac539.

Authors

Laurencie Brunel¹, Zoe A Williams², Konstantin Yastrebov³, Benjamin M Robinson⁴, Innes K Wise⁵, Hugh S Paterson⁶, Paul G Bannon^{4

6}

Affiliations

¹ Veterinary Specialists of Sydney, Miranda, NSW, Australia.
² DVC Research Portfolio, The University of Sydney, NSW, Australia.
³ Prince of Wales Medical School, Faculty of Medicine and Health, The University of New South Wales, NSW, Australia.
⁴ Institute of Academic Surgery and Baird Institute for Applied Heart and Lung Surgery, Camperdown, NSW, Australia.
⁵ Department of Laboratory Animal Services, The University of Sydney, NSW, Australia.
⁶ Central Clinical School-Surgery, Faculty of Medicine and Health, The University of Sydney, NSW, Australia.

PMID: 36440952
DOI: 10.1093/ejcts/ezac539

Abstract

Objectives: During mitral valve replacement, the anterior mitral leaflet is usually resected or modified. Anterior leaflet splitting seems the least disruptive modification. Reattachment of the modified leaflet to the annulus reduces the annulopapillary distance. The goal of this study was to quantify the acute effects on left ventricular function of splitting the anterior mitral leaflet and shortening the annulopapillary distance.

Methods: In 6 adult sheep, a wire was placed around the anterior leaflet and exteriorized through the left ventricular wall to enable splitting the leaflet in the beating heart. Releasable snares to reduce annulopapillary distance were likewise positioned and exteriorized. A mechanical mitral prosthesis was inserted to prevent mitral incompetence during external manipulations of the native valve. Instantaneous changes in left ventricular function were recorded before and after shortening the annulopapillary distance, then before and after splitting the anterior leaflet.

Results: After splitting the anterior leaflet, preload recruitable stroke work, stroke work, stroke volume, cardiac output, left ventricular end systolic pressure and mean pressure were significantly decreased by 26%, 23%, 12%, 9%, 15% and 11%, respectively. Shortening the annulopapillary distance was associated with significant decreases in the end systolic pressure volume relationship, preload recruitable stroke work, stroke work and left ventricular end systolic pressure by 67%, 33%, 15% and 13%, respectively. Shortening the annulopapillary distance after splitting the leaflet had no significant effect.

Conclusions: Splitting the anterior mitral leaflet acutely impaired left ventricular contractility and haemodynamics in an ovine model. Shortening the annulopapillary distance after leaflet splitting did not further impair left ventricular function.

Keywords: Mitral valve; Mitral valve replacement; Valvular-ventricular interactions Left ventricular function.

MeSH terms

Animals
Hemodynamics
Mitral Valve Insufficiency* / surgery
Mitral Valve* / surgery
Sheep
Stroke Volume
Ventricular Function, Left

Grants and funding

Baird Institute of Applied Heart and Lung Research