Author + information
- Received November 3, 2008
- Revision received December 9, 2008
- Accepted December 23, 2008
- Published online April 28, 2009.
- Itzhak Kronzon, MD*,
- Lissa Sugeng, MD†,
- Gila Perk, MD*,* (, )
- David Hirsh, MD*,
- Lynn Weinert, RDCS†,
- Miguel Angel Garcia Fernandez, MD† and
- Roberto M. Lang, MD‡
- ↵*Reprint requests and correspondence:
Dr. Gila Perk, Non-Invasive Cardiology, NYU School of Medicine, 550 First Avenue, TH-2, HW-228, New York, New York 10016
Objectives This study sought to assess the use of real-time (RT) 3-dimensional (3D) transthoracic and transesophageal echocardiography (TEE) in the evaluation of post-operative mitral valve dehiscence.
Background Mitral valve replacement or repair may be complicated by post-operative dehiscence of the valve or annuloplasty ring resulting in clinically significant mitral regurgitation or hemolysis. Diagnosis is generally performed using 2-dimensional transthoracic echocardiography and TEE. Recently, an RT 3D TEE probe has been developed to produce high-quality real-time images.
Methods We used RT 3D TEE to evaluate mitral regurgitation after mitral valve repair or replacement as a result of mitral ring dehiscence. We studied the additional information and diagnostic utility provided by RT 3D TEE.
Results Eighteen patients were studied (8 patients after repair and 10 after replacement). Real-time 3D TEE allowed accurate evaluation of the pathology, including definition of the type of ring or prosthesis used; description of the site, size, shape, and area of the dehisced segment; and clear definition of the origin of the mitral regurgitation.
Conclusions In mitral valve dehiscence, RT 3D TEE provides additional information about the exact anatomic characteristics of the dehiscence that can be used to help in planning the most appropriate corrective intervention.
Mitral valve replacement and repair may be complicated by post-operative paravalvular mitral regurgitation (MR) from a dehisced sewing ring (i.e., material defect between the ring and surrounding tissue). Traditionally, transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE) are used to describe the degree and anatomic substrate of the regurgitation. These techniques are limited in their spatial resolution.
Real-time (RT) 3-dimensional (3D) echocardiography (TTE and TEE) allows the acquisition of a pyramidal dataset, which can be used to display and analyze the size, shape, and motion of different cardiac structures from multiple perspectives. Unique cross sections can be visualized in any plane, and regions of interest can be extracted for detailed analysis (1).
We used RT 3D TEE to evaluate patients who presented with MR after mitral valve repair or replacement as a result of mitral ring dehiscence. We hypothesized that the unique diagnostic images obtained using RT 3D TEE would allow: 1) evaluation of the mitral valve and ring anatomy; 2) diagnosis of the presence of dehiscence and delineation of its characteristics; and 3) evaluation of whether the mitral regurgitation could be treated without the need for reoperation with identification of potential candidates for percutaneous occlusion of the paravalvular orifice.
Eighteen consecutive patients who previously underwent mitral valve surgery and were found post-operatively to have mitral ring or prosthetic valve ring dehiscence were studied (Table 1).All were referred for a clinically indicated TEE.
All patients underwent comprehensive 2-dimensional (2D) TTE and TEE. Mitral regurgitation was assessed and graded according to existing criteria. In addition, each patient had RT 3D TEE that included: 1) narrow-angle acquisition; 2) zoom mode; and 3) full-volume wide-angle acquisition mode (1). All studies were performed with a commercially available echocardiography unit (iE33, Philips Medical Systems, Andover, Massachusetts). Mitral ring dehiscence was diagnosed as a segment of separation between the prosthetic ring and the patient's native mitral annulus. Doppler color flow imaging was used to show the presence of mitral regurgitant flow through the dehisced segment. In patients with prosthetic ring dehiscence after mitral valve repair, the regurgitant jet appeared outside the ring but within the native valve annulus (para-ring), whereas in patients with a dehisced prosthetic mitral valve, the jet was paravalvular. The position, shape, and area of each dehiscence were measured and tabulated (Table 2).
The clinical characteristics of the patients are summarized in Table 1. Using 2D TEE, the mitral prosthetic ring or mitral valve prosthesis was seen in each patient. The exact shape and type of the different mitral rings could not be assessed by the 2D TEE (Fig. 1).The RT 3D TEE showed the exact ring shape and type in patients with mitral valve repair, and the valvular anatomic appearance as seen from the atrial (surgeon's view) and the ventricular perspectives in those with prosthetic valve (Figs. 2 and 3).⇓⇓
The 2D TEE diagnosed dehisced mitral rings in most patients. A dehisced segment was defined as any material defect between ring and surrounding tissue. In 1 patient, dehiscence was suspected by the 2D images, but because of the lack of a mitral regurgitant jet through the gap between the native annulus and the ring, the diagnosis was ignored. The RT 3D TEE showed details of all of the dehisced segments; the exact site, size, shape, and area of the dehisced segment. These characteristics varied significantly; in 10 patients the dehiscence was posterior, in 4 it was lateral, in 1 patient medial, and in another, mainly anterior. In 2 patients, 2 sites of dehiscence were noted, and in 1 patient, 3 dehiscence sites were seen. The dehiscence shape varied from a slit (where the length is much larger than the width) to nearly a circular appearance. The severity of and the exact site of the mitral regurgitation (through the dehiscence/outside the ring, versus through the valve/through the ring, versus both) could be assessed in all patients.
We have shown that in patients with mitral valve dehiscence, RT 3D TEE provides additional information about the exact anatomic characteristics of the dehisced segment as well as the relationship between the dehiscence and the mitral regurgitant jet(s).
Dehiscence occurred mainly in a posterior or lateral location. There was only 1 anterior dehiscence. The reasons for the prevalent occurrence of the dehiscence in the posterior part of the ring are: 1) the posterior annulus is in the far surgical field, thus limiting view while suturing; 2) the surgeon tries to avoid the circumflex artery, and therefore performs more superficial suturing posteriorly; and 3) calcifications and fibrosis of the mitral annulus are more prevalent posteriorly, making it less amenable to suturing.
The information obtained by RT 3D TEE may provide important additional information that may be used in planning an appropriate intervention strategy. The number, location, shape, and site of the dehisced segment may be better identified on the beating heart. The presence of additional valve pathology may help in the type of surgery planned (dehiscence suturing alone or additional valve surgery).
Percutaneous transcatheter occlusion of the dehiscence orifice in paravalvular mitral regurgitation is now feasible (2,3). The key to the success of this procedure is the accurate determination of the dehiscence characteristics. This information is now available using RT 3D TEE, and should improve patient selection and results of this procedure. Figure 4shows the utility of RT 3D TEE imaging when performing such an occlusion.
Based on clinical presentation and echocardiographic findings, 10 patients underwent surgical repair. The site and dimension of the dehiscence were confirmed at the time of surgery in each patient. In addition, based on the RT 3D TEE results, 1 patient underwent a successful percutaneous closure of a dehisced mitral tissue prosthesis.
The study was not randomized. The findings were not confirmed by pathology or surgery in one-third of the patients. It is, however, thought that clear demonstration of the dehiscence and the regurgitant flow across it are self-explanatory, and are superior to pathologic findings with an empty heart.
RT 3D TEE is an important addition to the diagnosis of mitral valve anatomy and pathophysiology. In the case of mitral valve dehiscence, it provides additional information about the exact anatomic characteristics of the dehiscence. This in turn may help in planning the most appropriate method of corrective intervention.
Drs. Lang and Sugeng are on the Speakers' Bureau for and have received equipment grants from Phillips. Dr. Kronzon is on the Speakers' Bureau for Phillips.
- Abbreviations and Acronyms
- mitral regurgitation
- transesophageal echocardiography
- transthoracic echocardiography
- Received November 3, 2008.
- Revision received December 9, 2008.
- Accepted December 23, 2008.
- American College of Cardiology Foundation