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Alteration of the 3-dimensional (3D) mitral valve (MV) geometry in transapical mitral valve-in-valve (VIV) procedure is not well-defined. We aimed to investigate the 3D post-procedural MV geometry change in patients who received two different types of prosthesis.
We enrolled 12 patients who had undergone tissue mitral valve surgery (degenerative mitral regurgitation, n=9; rheumatic mitral regurgitation, n=1; rheumatic mitral stenosis, n=1; ischemic mitral regurgitation, n=1) (Figure 1). After the median of 9.5 (IQR: 5.3-13.7) years post-MV replacement, all 12 patients had failed mitral bioprosthesis (2 had mitral stenosis and 10 had mitral regurgitation).
VIV procedure was performed using Edward Sapien XT valve in 6 patients, and Boston Lotus valve in the other 6 patients. 3D transesophageal echocardiography (TEE) was performed before and immediately after the procedure. 2D transthoracic echocardiography (TTE) was also performed before VIV procedure and during the follow-up period (3- and 6-month post-procedure). The severity of mitral regurgitation was graded as no regurgitation (0), mild (1+), moderate (2+), moderately-severe (3+) and severe (4+) on the basis of vena contracta, regurgitant volume, and effective regurgitant orifice area. All analysis of 3D MV geometry was performed using QLAB 10.4 (Philips, Andover, MA).
After VIV procedure, several 2D TTE parameters improved during the follow-up period when compared to the baseline TTE, including the severity of mitral regurgitation (0.67 ± 0.49 vs. 3.42 ± 1.17, p<0.001), trans-MV mean pressure gradient (6.67 ± 1.56 vs. 15.33 ± 6.77 mmHg, p<0.001), and pulmonary arterial systolic pressure (43.17 ± 18.58 vs. 66.83 ± 24.58 mmHg, p=0.001) (Figure 2). Interestingly, in 6 patients who received Edward Sapien XT VIV procedure, left ventricular end-diastolic volume improved when comparing the baseline, 3-month and 6-month follow-up TTE (82.17 ± 12.51 vs. 77.33 ± 9.18 vs. 77.17 ± 10.94 ml, p=0.022), which was not observed in the Boston Lotus group (Figure 3). Among 3D MV geometry analysis, many parameters showed improvement in comparison of the pre- and post-procedure 3D TEE, including anterolateral-posteromedial diameter, anteroposterior diameter, 3D annular perimeter, 3D annular area, annular ellipticity, and 3D leaflet total area both in the Edward and Lotus group (p<0.05) (Figure 4). The MV non-planar angle decreased in the Edward group while the aortic-mitral angle decreased in the Lotus group (Figure 4).
In this 12-patient series with mitral VIV implantation for previous mitral bioprosthesis failure, 2D TTE revealed lessened mitral regurgitation severity, decreased trans-MV pressure gradient as well as pulmonary hypertension in both the Edward and Lotus valve system.
More reduction of end-diastolic volume in the Edward group may imply better early left ventricular remodeling than in the Lotus group.
Among these cases whose MV function was restored by VIV procedure, 3D MV geometry analysis showed concordant improvements in MV annular size as well leaflet area.