Regional Heterogeneity in the Mitral Valve Apparatus in Patients With Ischemic Mitral Regurgitation

Abstract

Background: Apical displacement of the coaptation point of the mitral valve (MV) in response to ischemic mitral regurgitation (IMR) represents remodeling of the MV apparatus. Whereas it implies chronicity, it lacks specificity in discriminating normal from a significantly remodeled MV apparatus. Regional aspects of MV remodeling have shown superior value over global remodeling in predicting recurrence after MV repair for IMR. Quite possibly, presence of specific regional changes in MV geometry that are unique to chronic IMR patients could also be used to diagnose the presence and track progression of remodeling. Knowledge of these changes in MV apparatus in patients with IMR can possibly be used to identify patients for surgical intervention before irreversible remodeling occurs.

Methods: Three-dimensional transesophageal echocardiographic data were collected from patients who underwent MV surgery for IMR (IMR group, n = 66), and from patients with normal valvular and biventricular function (control group, n = 10). The acquired data of the MV were geometrically analyzed to make regional comparisons between the IMR and the control group to identify measurements that reliably differentiate normal from remodeled MVs.

Results: Lengthening of the middle potion of the anterior annulus (A2 regional perimeter: 11.149 mm versus 9.798 mm, p = 0.0041), larger nonplanarity angle (147.985 versus 140.720 degrees, p = 0.0459), and increased tenting angle of the posteromedial scallop of the posterior leaflet (P3 tenting angle: 44.354 versus 40.461 degrees, p = 0.0435) were sufficient in differentiating between IMR and the control group.

Conclusions: Specific three-dimensional changes in MV geometry can be used to reliably identify a significantly remodeled valve apparatus.

Fig 1.

Mid esophageal four-chamber view of a regurgitant mitral valve, utilizing the vena contracta (VC) method to grade the severity of mitral regurgitation.

Fig 2.

Three-dimensional reconstruction of (A) ischemic and (B) normal mitral valves at mid systole, with anteroposterior and anterolateral-posteromedial points marked. Regions are also identified. (A = anterior, AL = anterolateral; P = posterior, PM = posteromedial.)

Fig 3.

Correlation plots describing the collinearity of regional measurements that differed between ischemic regurgitant valves and normal mitral valves. (AP = anteroposterior.)

Fig 4.

Annotated illustrations of the three-dimensional reconstructions previously presented, clearly labeling (A) A2 regional perimeter, (B) nonplanarity angle, and (C) P3 tenting angle. (A = anterior; AL = anterolateral; P = posterior; PM = posteromedial.)