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Strut chordal-sparing mitral valve replacement preserves long-term left ventricular shape and function in pigs
Morten Smerup1, Jonas Funder, Camilla Nyboe
1Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby Sygehus, Brendstrupgaardsvej, Denmark. morten.smerup@ki.au.dk
The Journal of Thoracic and Cardiovascular Surgery
|November 26, 2005
Summary
Preserving mitral valve strut chordae during replacement surgery is as effective as total valve preservation for long-term left ventricular function. Complete removal of the subvalvular apparatus alters left ventricular geometry.
Area of Science:
- Cardiovascular Surgery
- Cardiac Mechanics
- Biomedical Engineering
Background:
- Mitral valve replacement (MVR) aims to restore cardiac function.
- Preserving the subvalvular apparatus (SVA) improves postoperative left ventricular (LV) function.
- SVA preservation is not always feasible due to valve pathology.
Purpose of the Study:
- To investigate the long-term functional and geometric equivalence of preserving mitral valve strut chordae versus total SVA preservation.
- To compare these techniques against total SVA excision in an animal model.
Main Methods:
- A porcine model of MVR was used with three techniques: total SVA preservation, strut chordal preservation, and total SVA excision.
- Left ventricular function and dimensions were assessed using cardiovascular magnetic resonance and conductance catheter 90 days post-MVR.
- Multivariate analysis of variance was employed for group comparisons.
Main Results:
- No significant differences in LV function or geometry were observed between total SVA preservation and strut chordal preservation.
- Total SVA excision resulted in LV slimming, altered sphericity, and increased fractional shortening compared to the other groups.
- Regional analysis indicated LV slimming and elongation primarily in basal segments.
Conclusions:
- Mitral valve strut chordal preservation is functionally and geometrically equivalent to total SVA preservation in the long-term.
- Total chordal resection leads to adverse LV remodeling, characterized by slimming and compensatory hyperkinesis.
- Maintaining valvular-ventricular continuity via strut chordae is crucial for preserving LV geometry during MVR, with implications for chordal-sparing procedures.