Abstract
Three-dimensional (3D) transthoracic echocardiography has advantages over traditional two-dimensional (2D) echocardiography in visualizing tricuspid valve morphology in Ebstein's anomaly. We describe the application of intra-operative 3D transesophageal echocardiography during a tricuspid valve repair procedure in a patient with Ebstein's anomaly. Intra-operatively three-dimensional transesophageal echocardiographic (3D TEE) data sets revealed morphology and function of the tricuspid valve, right ventricle outflow tract (RVOT) and pulmonary valve before and after repair. Tricuspid valve leaflet morphology and coaptation as visualized with 3D TEE proved to be consistent with intra-operative findings. Analysis of the tricuspid valve, RVOT and pulmonary valve in the multi-planar review (MPR) mode revealed a bicuspid pulmonary valve, which had not been noticed on the preoperative 2D echocardiographic work-up. In this patient with Ebstein's anomaly, 3D TEE provided additional information on morphology and function of tricuspid valve, RVOT and pulmonary valve.
1. Introduction
Ebstein's anomaly, occurring in about 1–5 per 200,000 births accounts for <1% of all cases of congenital heart disease [1]. It is characterized by adherence of the septal and posterior leaflets of the tricuspid valve to the underlying myocardium. This results in an apical displacement of the valvular annulus into the right ventricle. The tricuspid orifice rotates around the aortic root, below the anatomic atrioventricular junction [2], making it difficult to visualize by two-dimensional (2D) echocardiography. Three-dimensional (3D) transthoracic echocardiography, however, has proven to be capable of showing the morphology and coaptation of the tricuspid leaflets [3–5].
Until today no information is available on 3D TEE and Ebstein's anomaly.
2. Materials and methods
A 17-year-old woman, diagnosed with Ebstein's anomaly shortly after birth, was suffering from progressive exercise intolerance, and had undergone several transvenous catheter ablations for recurrent atrial arrhythmias. She was admitted for longitudinal reconstructive surgery of the right ventricle and tricuspid valve.
2D transthoracic echocardiography revealed no abnormalities of the aortic and mitral valve. An enlarged and dilated right atrium was visualized, resulting in dyssynchronous contractions of the intraventricular septum. The tricuspid valve was displaced apically. Coaptation of the leaflets was non-existent, resulting in a severe tricuspid regurgitation. Across the pulmonary valve a pressure gradient of 13 mmHg was measured (v=1.8 m/s). 3D echocardiography had not been possible in the preoperative work-up because of an irregular cardiac rhythm, making it impossible to obtain a full-volume data set at that time.
After induction of anesthesia a 3D TEE was performed with an x7-2t MATRIX-array transducer connected to an iE33 ultrasound system (Philips, Andover, MA, USA). A full volume data set was made up of seven sub volumes and acquired during a 10 s mechanical ventilation hold to avoid motion artifacts during acquisition. Images were analysed on the online workstation Philips Qlab 3D quantification (3DQ advanced) (Philips, Andover, MA, USA).
In the multi-planar review (MPR)-mode three orthogonal cutting planes can be moved independently of each other through the data set [6]. This ability to ‘walk through’ the 3D data set in any 2D image plane and during any time in the cardiac cycle allows a much better appreciation of the complex anatomy and function, allowing visualization of the valvular orifice during systole, revealing a double orifice of malcoaptation, responsible for the severe tricuspid regurgitation. Such a precise description of the tricuspid valve anatomy by conventional 2D echocardiography remains difficult [3].
With the MPR-mode the location of malcoaptation relative to the separate leaflets and its surface could be assessed, showing two separate zones. These findings were confirmed by surgery. Scanning through the 3D color data set revealed multiple insufficiency jets through the tricuspid valve.
In addition, the right ventricle outflow tract (RVOT) and pulmonary valve were analysed in the MPR-mode, showing how the tricuspid orifice rotates around the aortic root [2] and its extent of displacement towards the RVOT (Video 1 ). This revealed a bicuspid pulmonary valve (Video 2 ), which is virtually impossible to image with 2D echocardiography, explaining the increased velocity (v=1.8 m/s) over the pulmonary valve.
Surgical correction was performed by mobilizing the anterior and posterior leaflets from the annulus and right ventricle wall and a longitudinal plication of the atrialized right ventricle as described before [7]. The anterior leaflet was rotated clockwise to the downsized anatomical annulus. Some hypertrophic trabeculae between the anterior leaflet and ventricle wall were resected from the RVOT, relieving subvalvular obstruction. After surgical correction a new full-volume data set was acquired and leaflet coaptation was evaluated using MPR-mode revealing a (much smaller) remaining zone of malcoaptation between the anterior and septal leaflet.
The patient had an uncomplicated recovery from surgery. Postoperative 2D transthoracic echocardiography four days after surgery showed much improved tricuspid valve function with only mild residual regurgitation.
3. Conclusion
3D TEE with MPR-mode provided additional information on morphology and function of tricuspid valve, RVOT and pulmonary valve in a patient with Ebstein's anomaly.
