Echocardiographic classification of chronic ischemic mitral regurgitation caused by restricted motion according to tethering pattern

Abstract

Although the mechanism of ischemic mitral regurgitation (MR) is understood, the echocardiographic picture of ischemic MR is not homogeneous. Ninety-two consecutive patients with chronic ischemic MR due to restricted motion were divided into two groups according to tethering pattern: the asymmetric group with predominant posterior tethering of both leaflets (54 patients) and the symmetric one with predominant apical tethering of both leaflets (38 patients). The mitral deformation indexes, LV global (volume, function and sphericity) and local (papillary muscle displacements and regional wall motion score index) remodeling were evaluated. All indexes of global LV remodeling were significantly higher in the symmetric than asymmetric group (all p < 0.0001), such as the posterior and lateral displacement of the anterior papillary muscle (both p < 0.04), the papillary muscle separation and the anterior papillary muscle wall motion index (both p < 0.0001). The origin as well as the direction of the jet was central in all patients of the symmetric group. In the asymmetric one the origin was central in 78% of the cases and arising from the medial commissure in 22% whereas the jet direction was posterior and central in 83% and 17% of patients, respectively. Therefore, it is possible to distinguish at least two subgroups of patients with ischemic MR due to restricted motion on the basis of tethering pattern, different degree of local and global LV remodeling and characteristics of the regurgitant jet.

Different Influences of Left Ventricular Remodeling on Anterior and Posterior Mitral Leaflet Tethering

“…1-5 Therefore, leaflet tethering can be heterogeneous according to the variability of the components of the MV complex. As one such case of heterogeneous tethering, differing degrees of anterior and posterior mitral leaflet (AML and PML) tethering have been reported, 6 but the corresponding mechanism has not been fully investigated.…”

Direction of persistent ischemic mitral jet after restrictive valve annuloplasty: Implications for interpretation of perioperative echocardiography

“…In our series, the MR jet direction was mainly posterior before surgery (72%) but rarely posterior after annuloplasty (20%). Consistently, Agricola et al (11) reported that the preoperative jet direction was posterior in the vast majority (83%) of their patients with ischemic MR. On the other hand, Zhu et al (6) reported that in a subset of patients (n=6) with persistent MR after surgery, postoperative MR jet direction was most frequently anterior (n=2) or central (n=4).…”

“…Moreover, eccentric MR can also be quantified by measuring vena contracta width, and Lesniak-Sobelga et al (13) have shown excellent correlation between vena contracta width and effective regurgitant orifice area, regurgitant volume and regurgitant fraction. Several echocardiographic studies have provided new insights into the mechanisms of ischemic MR (6,11). The basic mechanism of ischemic MR is leaflet tethering by the outward displacement of papillary muscles due to LV remodelling.…”

Papillary muscle approximation in mitral valve repair for secondary MR

“…The degree of tension exerted on the leaflets mainly depends on the entity of PMs displacement, which is the actual cause of the impaired coaptation and valve regurgitation observed in IMR. Tethering can have a symmetric or asymmetric pattern reflecting the direction of PM displacement vector, the localization of myocardial infarction zone and the severity of global ventricular dysfunction (15,16). Normally PMs provide a number of chordae that are attached to both leaflets, anterior and posterior, but with a substantial difference in case of symmetric or asymmetric tethering shape.…”