Chapter 9 Tricuspid Valve
Introduction
The tricuspid valve is the largest of the four heart valves and ranges from 4 to 6 cm2 in area. The tricuspid valve has anterior, septal, and posterior leaflets. The anterior leaflet usually is the largest, with a width of 2.2 cm. The septal and posterior leaflets are notably smaller and measure roughly 1.5 and 2.0 cm, respectively, based on autopsy series.1 Our experience shows that the posterior leaflet often is the smallest. In many cases, the posterior leaflet is not only the smallest, it is also quite rudimentary. Disease processes of the tricuspid valve are relatively uncommon. The tricuspid valve can frequently be incompetent because of factors separate from the valve itself. Specific examples of such incompetence include right ventricular annular dilation, tricuspid annular dilation, or both as well as pulmonary hypertension. In the presence of pathology that directly involves the valve, such as bacterial endocarditis or tricuspid valve prolapse, identification of specific leaflet involvement often is critical for addressing surgical management, particularly to determine whether tricuspid valve replacement would be indicated compared with tricuspid annuloplasty.2
Advantages of Real-Time Three-Dimensional Echocardiography
Tricuspid Valve Pathology
Tricuspid stenosis is a rare pathology virtually always caused by rheumatic heart disease, especially in adults. Congenital tricuspid atresia is seen in complex congenital heart disease but is not covered in this chapter. There have now been several reports of tricuspid stenosis caused by pacemaker leads.3 An example of tricuspid stenosis is shown in Figure 9-1 (Video 9-1).
Flail tricuspid valve leaflet has become a fairly frequently detected problem, especially in tertiary centers with transplantation programs, where the tricuspid valve frequently is damaged in the process of right ventricular biopsy. Rheumatic tricuspid valve disease rarely results in the tethering of the valve leaflets so profoundly as to prevent coaptation.4–6 This problem is a frequent outcome in carcinoid triscupid valve disease (Figure 9-2; Video 9-2). Tricuspid regurgitation is a not-infrequent complication of right ventricular pacemakers, with the wire causing the regurgitation by perforating a leaflet or by pinning one of the leaflets open. Tricuspid regurgitation is common and even normal when it is mild. Tricuspid regurgitation frequently is seen as a result of primary or secondary pulmonary hypertension. Although any left heart abnormality can cause secondary pulmonary hypertension, mitral valve disease is particularly common, resulting in tricuspid regurgitation.
Transthoracic Versus Transesophageal Real-Time Three-Dimensional Echocardiography
In marked contrast to the aortic valve, and particularly the mitral valve, obtaining satisfactory images from the transesophageal approach in the tricuspid valve has been found to be more challenging. 2D images of the tricuspid valve are of only fair quality by transesophageal echocardiography (TEE), and 3D images have a similar problem; although the images may be diagnostic, there is significant echo dropout of the tricuspid leaflets. However, this can be overcome by optimizing the 2DTEE images for the best possible tricuspid imaging before moving to the 3D mode: 3D zoom, live 3D, or 3D full volume. Figure 9-2 shows a 3DTEE image of the pacemaker wire traversing through the tricuspid valve. An example of a tricuspid valve vegetation imaged by RT3DTEE is shown in Figure 9-3 (Video 9-3). In this case, the patient has a vegetation on both the mitral valve and the tricuspid valve. Both Figures 9-1 and 9-2 illustrate a constant in RT3DTEE imaging. Even in cases in which the image has been optimized to show the tricuspid valve, the left-sided valves typically are more optimally visualized.
