Acute changes of mitral valve geometry during edge-to-edge repair: relationship with regurgitation etiology, procedural outcome and aging

Introduction Transcatheter mitral valve (MV) edge-to-edge repair (MTEER) is an established treatment in symptomatic severe functional (FMR) or degenerative mitral regurgitation (DMR) at high surgical risk. Purpose We sought to assess the immediate effect of MTEER intervention on MV annular geometry using 3-dimensional transesophageal echocardiography (3D TOE) and the potential relationships with MR etiology, procedural success and aging. Methods Forty-two out of initially screened 66 patients (pts) [mean±SD: ejection fraction: 45±11, range 25-60%, age: 77±10, range 43-92, 28 males, 14 females] were selected for analysis, having a proper 3D TOE quality, both before and immediately after MTEER. The following parameters were measured with offline analysis at end-diastole, both before and after intervention: mitral annular area (ANarea), annular circumference (ANcirc), anteroposterior diameter (AP), intercommissural diameter (ICM) and the ratio ICM/AP (sphericity index). The respective absolute differences (d) and % changes [(post-pre)/pre] were also calculated. Results When the absolute changes were considered, only AP was significantly decreased (-2.1±3.3 cm, paired t-test p<0.001). When % changes from baseline were considered, then both AP and ANarea were decreased (-5.0±9.0 and -3.5±9.0, one sample t-test: p=0.017/0.003 respectively). Pts with FMR (n=14) compared to DMR (n=28) had a trend: -to increase the ratio of ICM/AP from baseline to post-MTEER (FMR: 1.11±0.08 to 1.20±0.13, DMR: 1.20±0.09. to 1.16±0.16), with the respective % changes being twofold: +8±12 vs -4±15. -to decrease more the ANarea (% decrease: -5±7 vs -3±10). Pts with 2 clips (n=15) had a smaller % decrease of ANcirc (-1.3±6.0 vs -2.2±4.0, p=0.05). Pts (n=24) with the best MR improvement (>2 grades decrease of MR or final grade 1/4) had an almost 3 times greater % decrease in the AP (-8.3±7.0 vs -2.7±9.0, p=0.05). MV gradient post MTEER was not affected by the decrease of ANarea, having a weak inverse relationship with it, thus keeping smaller values despite the decreasing annular area (logarithmic R2=0.16, p=0.01). (figure 1) Pts with >=80 age (n=20) had at least 4 times less decrease of the AP post MTEER (1.4±10.0 vs 8.0±6.0, p=0.05). Age was linearly and inversely related to the % decrease of AP (r= -0.42, p=0.035). (figure 2) Conclusions MTEER intervention has an immediate effect on the geometry of mitral annulus, decreasing the diastolic area without compromising the transmitral hydraulics. MTEER in FMR eliminates sphericity and facilitates a more elliptical transformation of the annulus. Decrease of the AP is the dominant geometric feature of the intervention and is related with the MR improvement. However, the advancing age has a negative effect on this favorably expected positive rearrangement of geometry post MTEER.