Strut chordal-sparing mitral valve replacement preserves long-term left ventricular shape and function in pigs.
OBJECTIVE
Mitral valve replacement with preservation of the entire subvalvular apparatus entails superior postoperative left ventricular function compared with other techniques. However, this option is often not possible because of valve pathology. We hypothesized that preservation of only 4 mitral valve secondary ("strut") chordae would be functionally and geometrically equivalent to total valve preservation in the long-term setting. In a porcine mitral valve replacement model we investigated the long-term effects of 3 surgical techniques on left ventricular function and geometry: (1) total preservation of the native valve, (2) strut chordal preservation, and (3) total excision of the subvalvular apparatus.


METHODS
Forty 60-kg pigs were randomized to 1 of the 3 techniques. Global and regional left ventricular function and dimensions were assessed with cardiovascular magnetic resonance and conductance catheter 90 days after mitral valve replacement. Groups were compared by multivariate analysis of variance.


RESULTS
There was no overall difference between groups 1 and 2. Group 3 animals had (1) greater base-apex diastolic and systolic lengths, and smaller short-axis diameters, and (2) lower sphericity indices, and greater base-apex and short-axis fractional shortening than groups 1 and 2. Regional analysis showed slimming and elongation to occur primarily in the basal left ventricular segments. Left ventricular contractility and hemodynamic parameters did not differ between groups.


CONCLUSIONS
Strut chordal preservation was equivalent to total valve preservation during mitral valve replacement, whereas total chordal resection caused significant left ventricular slimming with compensatory increases in fractional shortening. Therefore, to preserve left ventricular geometry, special attention must be paid to maintain the valvular-ventricular continuity through the strut chordae during mitral valve replacement. This concept may have important therapeutic implications for chordal-sparing mitral valve replacement.
Smerup
Morten
M
Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby Sygehus, Brendstrupgaardsvej, Denmark. morten.smerup@ki.au.dk
Funder
Jonas
J
Nyboe
Camilla
C
Høyer
Christian
C
Pedersen
Troels F
TF
Ribe
Lars
L
Ringgaard
Steffen
S
Kim
Won Yong
WY
Pedersen
Erik M
EM
Andersen
Niels T
NT
Nielsen
Sten L
SL
Hasenkam
J Michael
JM
D000818:Animals; D006348:Cardiac Surgical Procedures / Q000379:methods; D005260:Female; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000033:anatomy & histology*; D008943:Mitral Valve / Q000601:surgery*; D013552:Swine; D013997:Time Factors; D016277:Ventricular Function, Left