Clear demonstration of the different mechanisms of severe mitral regurgitation caused by mitral ring dehiscence during transesophageal echocardiography

A 55-year-old man was admitted to the outpatient clinic with dyspnea that occurs with minimal effort. He had a mitral repair with a Memo annuloplasty ring due to severe mitral regurgitation (MR) associated with annular dilation caused by atrial fibrillation 3 years ago and there was no residual MR in the postoperative echocardiography. Transthoracic echocardiography revealed a left ventricular ejection fraction of 55% and moderate-severe MR. Transesophageal echocardiography (TEE) was decided as a next step. Rocking prosthetic ring and dehiscence were present in the TEE views respectively, with a severe MR (Fig. 1a, Video 1, 2). There were two MR jets. As observed in the TEE views, the first jet originated from the perimitral ring, while the second jet came from the basal portion of the posterior mitral leaflet (PML), which was suitable with the location of the mitral ring suture (Fig.1b, Video 3). Interestingly, mitral ring dehiscence possibly led to the occurrence of a defect in the PML of the junction zone, and this defect emerged as another source of MR (Fig. 1c, 1d, Video 4). Another surgical treatment was planned.

Figure 1.

(a) Three-dimensional transesophageal echocardiography imaging of the mitral ring dehiscence. (b) The first jet originated from the perimitral ring (arrow) and the second jet (asterisk) came from the basal portion of the posterior mitral leaflet. (c) Image of the defect in the basal portion of the posterior mitral leaflet in the mid-esophageal transesophageal echocardiography view. (d) Increase of the mitral regurgitation jet from the defect in the basal portion of the posterior mitral leaflet, which possibly occurred after the separation of the mitral ring suture

Ring dehiscence is a rare clinical entity that usually leads to severe MR and requires urgent or emergent surgical reoperation (1). Endocarditis, trauma, or procedure-related issues may be responsible for triggering the dehiscence process, and progressive left ventricular geometric remodeling may also provoke the recurrence (2, 3). The characteristics of the tissue at the ring attachment areas are another important factor; therefore, weak and calcified tissues are more prone to separation from the ring (3). Also, attachment of the mitral ring to the basal portion of the PML in the previous surgery may lead to a predisposition for ring dehiscence, and the suture site on the PML served as an independent source of MR besides the jet from the perimitral ring. In this case, the TEE demonstrative images are presented to highlight this rare clinical condition.

Video 1

Rocking motion of the prosthetic mitral ring was present in the bicommissural transesophageal echocardiography view.

Video 2

Three-dimensional transesophageal echocardiography imaging of the mitral ring dehiscence.

Video 3

Severe mitral regurgitation was observed in the mid-esophageal transesophageal echocardiography views with two distinct jets: the first mitral regurgitation jet originated from the perimitral ring (asterisk) and the second one arose from the basal portion of the posterior mitral leaflet (arrow), which was suitable with the location of the mitral ring suture.

Video 4

Dehiscence of the mitral ring possibly caused the occurrence of the defect in the posterior mitral leaflet of the junction zone, and this defect emerged as another source of mitral regurgitation.