Intraoperative Application
The presence of IMR has a negative impact on survival rate, and there is a significantly graded relationship between IMR severity and reduced survival. The use of undersized ring annuloplasty for MV repair has become the preferred treatment strategy for IMR[48,49]. Although general consensus has been reached on coronary artery bypass grafting (CABG) and MV surgery for patients with severe MR, clinical dilemma exists in patients with mild to moderate MR[50]. Govindan Set al.reported that there was no significant change in the MV nonplanarity angle in patients with mild or moderate IMR who underwent revascularization alone when they received 2D, 3D TEE and MV assessment before and immediately after the CABG (n=20)[51]. These patients who undergo CABG surgery alone may leave them with obvious residual disease, while the inclusion of MV surgery in the CABG surgery will increase the perioperative risks[52]. A growing body of literature indicates an unacceptably high risk of persistent or recurrent IMR after reduction annuloplasty[7,53]; however, in patients without recurrent IMR, MV repair may be more beneficial than valve replacement, especially in terms of LV remodeling and function. Reduction annuloplasty is an effective treatment for annular dilatation, but it can make the posterior leaflet move forward and intensify the leaflet tethering[54,55]. Vergnat Met al. had made comparisons of 3D TEE data before and after a flat (n=9) or a saddle annuloplasty (n=9) was implanted in patients with severe IMR. They found that the shape of the ring affects the curvature of the leaflet. Implantation of a saddle ring kept annular nonplanarity and showed higher 3D leaflet curvature across the MV surface, whereas flat rings reduced annular nonplanarity and flattened leaflet significantly in all but the P1 region[56]. This strongly demonstrates that an imaging strategy that can reliably determine the risk of annuloplasty failure and predict recurrence preoperatively would be considered during surgical decision-making, so as to improve the surgical results.