Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty

Abstract

Background: Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if prerepair three-dimensional (3D) echocardiography combined with a novel valve-modeling algorithm would be predictive of IMR recurrence 6 months after repair.

Methods: Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR and in 21 patients with normal mitral valves. A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair.

Results: Preoperative annular geometry was similar in all IMR patients, and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) than in patients in whom IMR did not recur (n=37) (tethering index: 3.91 ± 1.01 vs 2.90 ± 1.17, p = 0.008; tethering angles of A3: 23.5° ± 8.9° vs 14.4° ± 11.4°, p = 0.012; P2: 44.4° ± 8.8° vs 28.2° ± 17.0°, p = 0.002; and P3: 35.2° ± 6.0° vs. 18.6° ± 12.7°, p < 0.001). Multivariate logistic regression analysis revealed the preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84 to 1.00; p < 0.001).

Conclusions: 3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle of 29.9° or larger, chordal-sparing valve replacement rather than valve repair should be strongly considered.

Figure 1

Annular segmentation technique. (A) 3D echocardiographic volume containing the mitral valve with cross-sectional planes at 10-degree increments. (B) Representative 2D cross-section with green dots representing the selected annular points. Oblique (C), intercommissural (D), and transvalvular (E) annular views of a single real-time 3D derived mitral annular model with annular landmarks and the 36 annular data points (circles). The least squares plane has been superimposed on the annulus in each view. The least squares plane is depicted by a horizontal line in C and D and by the check boxes in E. AA, anterior mitral annulus; AC, anterior commissure; AL, anterolateral annulus; AML, anterior mitral leaflet; AoV, aortic valve; L, lateral aspect of the annulus; CW, commissural width; LA, left atrium; LV, left ventricle; LVOT, left ventricular outflow tract; MTD, mitral transverse diameter; MVO, mitral valve orifice; PA, posterior mitral annulus; PC, posterior commissure; PM, posteromedial annulus; PML, posterior mitral leaflet; S, septal aspect of the annulus; SL, septolateral diameter.

Figure 2

Leaflet segmentation technique. (A) Template of transverse cross-sections every 1 mm along intercommissural axis. (B) One of the 2D cross-sections represented by the white dashed line in A; the atrial surface of the mitral valve leaflets and the coaptation zone is interactively marked (green curves), resulting in a 500 to 1,000 point data set for each valve. The white and red dashed lines are both within least squares annular plane. Determination of MVTa, ATA, and PTA are shown in B and C. AC, anterior commissure; AML, anterior mitral leaflet; AoV, aortic valve; ATA, anterior tethering angle; Coapt, coaptation; LA, left atrium; LV, left ventricle; LVOT, left ventricle outflow tract; MVTa, mitral valve tethering area; PC, posterior commissure; PML, posterior mitral leaflet; PTA, posterior tethering angle.

Figure 3

Preoperative regional mitral valve tethering. (A) Regional mitral valve tethering area (MVTa (tethering distribution)) for all groups. MVTa is plotted as a function of intercommissural distance, expressed as a percentage of the distance travelled from the anterior commissure (AC). The positions of the AC and posterior commissure (PC) are, respectively, 0% and 100%. (B) Regional MVTa for patients with non-recurrent and recurrent IMR. Dashed lines represent standard deviations. Shaded areas indicate regions where MVTa differs significantly between groups. (C) Three-dimensional echocardiographic virtual models of a representative normal mitral valve and preoperative mitral valves that will and will not develop recurrent IMR after undersized ring annuloplasty. Top row; oblique commissure-to-commissure view, middle row; oblique septolateral view, bottom row; left ventricular view. AC, anterior commissure; IMR, ischemic mitral regurgitation; MVTa, mitral valve tethering area; PC, posterior commissure.

Figure 4

Preoperative regional tethering angles. (A) Regional anterior tethering angle (ATA (tethering angle distribution)) for all groups. ATA is plotted as a function of intercommissural distance. (B) Regional ATA for patients with non-recurrent and recurrent IMR. Dashed lines represent standard deviations. Shaded areas indicate regions where ATA differs significantly between both groups. (C) Regional posterior tethering angle (PTA (tethering angle distribution)) for all groups. (D) Regional PTA for patients with non-recurrent and recurrent IMR. IMR, ischemic mitral regurgitation.

Figure 5

Receiver operating characteristic (ROC) curve for preoperative P3 tethering angle as a predictor of IMR recurrence after undersized mitral ring annuloplasty (optimal cut-off value 29.9°).