Role of real-time three-dimensional epicardial echocardiography in a novel transcatheter treatment techniques of mitral regurgitation:an acute in vivo animal study / 中华超声影像学杂志

ABSTRACT

Objective To evaluate the usefulness of real-time three-dimensional intraoperative epicardial echocardiography ( RT-3D IEE) in the process of transapical mitral valve repair and a new device's efficacy in an animal model . Methods Acute mitral regurgitation ( MR) was induced in 18 anesthetized domestic pigs as MR group by cutting chordae supporting the segment of the leaflet ( A2 , n = 9 ; P2 , n = 8 ;P3 , n = 1) ,while 15 pigs received no cutting chordae were chosed as normal mitral valve ( NMV ) group . The ValveClamp procedures were then transapically performed either on the prolapsing segment ( MR group) or A2/ P2 segment ( NMV group ) respectively solely under 3D epicardial echocardiographic guidance . Epicardial echocardiography was obtained before and after transcatheter interventions . Thirty days later all pigs were humanely killed to verify the location of implanted devices . Results In normal group , the preoperative max and mean mitral valve pressure gradient was higher than postoperative those ( P < 0 .0001) ,and no significant difference was found in other echocardiographic parameters . In MR group , the preoperative echocardiography showed that cutting the leaflet chordae caused severe ( n = 15 ) or moderate( n = 3) MR ,while postoperative immediate echo observed overt MR area reduction( P < 0 .0001) with 8 cases to slight ,5 cases to mild and 1 case eliminated .Furthermore ,the mean postoperative and max mitral valve pressure gradient significantly increased both in two groups ( P < 0 .0001 ) ,whereas no complications or other structural changes were observed ( P > 0 .05) .The autopsy report demonstrated that all ValveClamp devices were precisely placed to clamp either the prolapsing segments (MR group) of mitral valve or A2/P2 segments (NMV group) ,respectively .Conclusions Real-time three-dimensional epicardial echocardiography can independently monitor the new transcatheter mitral repair technique-ValveClamp , facilitating the overall procedure . Transapical implantation of ValveClamp device under epicardial echocardiographic guidance is effective in reducing acutely induced mitral regurgitation .