Posterior mitral leaflet extension: an adjunctive repair option for ischemic mitral regurgitation?
BACKGROUND
Residual or recurrent mitral regurgitation frequently occurs after mitral valve repair for ischemic mitral regurgitation with an annuloplasty ring. Because annuloplasty primarily addresses annular dilatation, we studied an adjunctive technique that might correct restricted leaflet (Carpentier type IIIb) systolic closing motion, which often accompanies annular dilatation in patients with ischemic mitral regurgitation.


METHODS
Six sheep had radiopaque markers placed on the left ventricle, mitral leaflets and annulus, and mitral subvalvular apparatus. A pericardial patch was sutured into the middle scallop of the posterior mitral valve leaflet and furled in with a reefing stitch placed in the radial axis. Posterolateral left ventricular myocardial ischemia was created by using proximal circumflex occlusion to induce acute ischemic mitral regurgitation. Under open-chest conditions, 3-dimensional marker coordinates were measured by using biplane videofluoroscopy at baseline and during acute ischemia both before and after release of the reefing stitch (leaflet extension); transesophageal echocardiography was used to grade ischemic mitral regurgitation.


RESULTS
Leaflet apical systolic tethering was not improved by leaflet extension, but ischemic mitral regurgitation decreased (control, 0.9 +/- 0.3*; ischemia, 2.4 +/- 0.3; leaflet extension, 1.5 +/- 0.3; *P < 0.002). Posterior mitral valve leaflet midline length (control, 1.45 +/- 0.09*; ischemia, 1.53 +/- 0.10; leaflet extension, 1.83 +/- 0.13*; *P < 0.001) and posterior mitral valve leaflet middle scallop area (control, 1.66 +/- 0.20 cm2*; ischemia, 1.91 +/- 0.22 cm2; leaflet extension, 2.36 +/- 0.22 cm2*; *P < 0.006) increased with leaflet extension because of patch unfurling (mean +/- 1 standard error of the mean; repeated-measures analysis of variance, Dunnet post-hoc test vs ischemia).


CONCLUSIONS
Posterior mitral valve leaflet extension ameliorated acute ischemic mitral regurgitation but did not correct the abnormal apically restricted systolic posterior mitral valve leaflet closing motion. This technique might be a useful adjunct repair in combination with ring annuloplasty for ischemic mitral regurgitation, but the clinical role of this adjunct remains to be defined in patients.
Langer
Frank
F
Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, Calif 94305-5247, USA.
Rodriguez
Filiberto
F
Cheng
Allen
A
Ortiz
Saskia
S
Nguyen
Tom C
TC
Zasio
Mary K
MK
Liang
David
D
Daughters
George T
GT
Ingels
Neil B
NB
Miller
D Craig
DC
D000818:Animals; D006348:Cardiac Surgical Procedures; D004108:Dilatation, Pathologic; D006439:Hemodynamics; D008943:Mitral Valve / Q000473:pathology / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000209:etiology / Q000601:surgery*; D017202:Myocardial Ischemia / Q000150:complications; D012756:Sheep; D013536:Suture Techniques