In-vivo motion of mitral valve annuloplasty devices.
OBJECTIVE
The long-term outcomes of mitral valve repairs are enhanced with an annuloplasty device. Although, in general, semirigid and rigid annuloplasty devices remodel the shape of the mitral valve annulus, the effect of geometric alteration on annular motion has not been fully assessed. Hence, the study aim was to investigate the influence of semi-rigid annuloplasty devices on the motion of the mitral valve annulus in adult sheep.


METHODS
Sonomicrometric crystals were attached to semi-rigid annuloplasty devices (CG Future Band and CG Future COMPOSITE Ring), as well as to intra- and epicardiac sites for motion assessment in 13 sheep. Following implantation, hemodynamic and sonomicrometric measurements were collected under normal sinus rhythm and during dobutamine challenge conditions.


RESULTS
Sonomicrometric measurements showed variations in the degree of device motion and timing of motion changes, depending on device size and type. Measurement of transverse device width demonstrated a pre-systolic decrease in width. For devices with the largest annular motion, the transverse device width increased during ventricular systole, with an out-of-phase increase in mitral annular septal-lateral distance during diastole. However, the geometric device septal-lateral distance showed minimal change across all devices, indicating maintenance of posterior remodeling geometry. Three-dimensional analyses revealed vertical elevation of the anterior annulus above the posterior annular plane during ventricular systole, consistent with anterior annular folding. The maximum calculated annular area occurred during early to mid-ventricular diastole, providing for maximal valve orifice area during opening of the mitral valve. The minimum annular area occurred near end-diastole to early systole, consistent with valve closing.


CONCLUSIONS
The study results suggest that semi-rigid posterior annuloplasty devices with absent or flexible anterior mitral valve annular segments allow for a dynamic anterior annulus while maintaining aggressive posterior annular remodeling. Future studies should be undertaken to investigate the interaction between the anterior mitral valve annulus and the aortic root following annuloplasty device implantation.
Redmond
Jerald
J
Medtronic, Inc., Minneapolis, MN 55449, USA. jerald.redmond@medtronic.com
Christiansen
Dean
D
Bergin
Cathy
C
Leuer
Lenny
L
Ryan
Tim
T
Rakow
Nancy
N
Barka
Noah
N
Billstrom
Tina
T
St Cyr
John A
JA
Shecterle
Linda M
LM
Grossi
Eugene
E
D000818:Animals; D004195:Disease Models, Animal; D004452:Echocardiography; D004867:Equipment Design; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation*; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D009200:Myocardial Contraction / Q000502:physiology*; D011474:Prosthesis Design; D012756:Sheep; D013599:Systole; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*