Mitral suture annuloplasty corrects both annular and subvalvular geometry in acute ischemic mitral regurgitation.
OBJECTIVE
Papillary muscle displacement is an important element in the pathogenesis of ischemic mitral regurgitation (IMR). The effects of standard ring annuloplasty on subvalvular geometry are incompletely understood. The hypothesis was tested that annular reduction with a Panethtype suture annuloplasty would correct both annular and papillary muscle geometric abnormalities during acute left ventricular (LV) ischemia.


METHODS
Eight adult sheep underwent insertion of an adjustable, double-suture Paneth-type mitral annuloplasty and radiopaque markers on the left ventricle, mitral annulus, leaflet edges, and anterior (APM) and posterior (PPM) papillary muscle tips. Immediately after surgey, 3-D marker coordinates were determined during Control conditions and during proximal left circumflex occlusion before and after tightening the annuloplasty suture.


RESULTS
Acute IMR (MR grade 0.3 +/- 0.3 to 2.1 +/- 0.4, Control versus Ischemia) was associated with end-systolic LV dilatation (+27 +/- 16 ml, change relative to Control), greater septal-lateral (+4.6 +/- 3.1 cm) and commissure-commissure (+3.3 +/- 1.6 cm) mitral annular diameters, longer anterior (+1.5 +/- 0.9 cm) and posterior (+0.6 +/- 0.9 cm) papillary muscle tethering distances, greater distance from the APM to the anterior commissure (+0.9 +/- 0.8 cm), and shorter distance from the PPM to the poslerior commissure (-1.3 +/- 1.5 cm). Suture annuloplasty corrected the annular and subvalvular changes, and IMR returned to Control levels (0.5 +/- 0.5); only LV end-systolic volume (ESV) was different from Control (+25 +/- 18 ml) (mean +/- SD, p < 0.05 versus Control by RMANOVA and Dunnett's test).


CONCLUSIONS
Suture annuloplasty corrected ischemia-induced end-systolic distortions of the entire valvular-ventricular complex (i.e. inter-leaflet separation, mitral annular dilatation in both axes, and papillary muscle displacements), and abolished acute IMR, independent of any change in ESV. A better understanding of the effects of annular reduction on papillary muscle geometry may lead to improved subvalvular mitral repair techniques.
Tibayan
Frederick A
FA
Department of Cardiovascular and Thoracic Surgery, Stanford University School of Medicine, Stanford, CA, USA.
Rodriguez
Filiberto
F
Langer
Frank
F
Liang
David
D
Daughters
George T
GT
Ingels
Neil B
NB
Miller
D Craig
DC
D000818:Animals; D001794:Blood Pressure; D004195:Disease Models, Animal; D006339:Heart Rate; D008943:Mitral Valve / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000209:etiology / Q000601:surgery*; D017202:Myocardial Ischemia / Q000150:complications / Q000601:surgery*; D010210:Papillary Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D012756:Sheep; D013536:Suture Techniques; D020257:Ventricular Remodeling