Tricuspid valve disease involves the atrioventricular valve apparatus that separates the right atrium (RA) from the right ventricle (RV). Tricuspid regurgitation (TR) and tricuspid stenosis (TS) are commonly encountered. Isolated tricuspid valve disease is rare. It most often occurs as a secondary condition. TR is more common than TS and usually develops in association with pulmonary hypertension in patients with mitral stenosis or regurgitation. Most patients with rheumatic tricuspid valve disease present with TR or a combination of stenosis and regurgitation. Rheumatic TS does not occur as an isolated lesion, but it often accompanies mitral and aortic valve disease. Some patients may develop TR in association with trauma or infective endocarditis. TS is nearly always rheumatic in origin. However, congenital tricuspid atresia, RA tumors, tricuspid valve vegetations, the presence of a pacemaker lead, or compression caused by extracardiac tumors may produce a clinical picture similar to that of TS. In addition, in patients with carcinoid syndrome, endomyocardial fibrosis may lead to obstruction of RV inflow, resulting in a clinical presentation similar to that of TS.
For patients with tricuspid valve disease, echocardiography is the preferred examination.
Echocardiography provides excellent images and may be used to detect and quantitate tricuspid regurgitation. It also permits assessment of the dimensions of cardiac chambers, determination of RV and pulmonary pressures, and delineation of associated valvular diseases. If acoustic windows are poor, transthoracic echocardiograms may be suboptimal. In such instances, transesophageal echocardiography is helpful.
In TS, electrocardiograms (ECGs) show tall right atrium (RA) P waves and no RV hypertrophy. Chest radiographs show a dilated RA without an enlarged pulmonary-artery segment.
The echocardiographic changes of the tricuspid valve in TS include the following:
Diastolic doming of the valve
Thickening of the leaflets and restriction in the motion of the leaflets
Reduction in the separation of the commissures of the leaflets
A diminished tricuspid opening
With transesophageal echocardiography, depiction of the details of valvular structure is improved. On Doppler echocardiography, a delayed slope of antegrade flow is seen; such findings compare well with cardiac catheterization findings in the quantification of TS and in the assessment of associated TR.
ECG findings are frequently nonspecific. Incomplete right bundle-branch block, Q waves in lead V1, and atrial fibrillation are often noted.
The main purpose of echocardiographic imaging is to diagnose TR, assess its severity, and estimate pulmonary arterial pressure and the status of RV function. In secondary TR, clinically significant enlargement of the tricuspid annulus, right atrium, and right ventricle are found. In patients with TR caused by endocarditis, echocardiography may reveal vegetations on the valve or a flail valve leaflet. Transesophageal echocardiography may depict the TR vividly.
Doppler echocardiograms depicting TR are provided below.
Tricuspid regurgitation (TR). Apical 4-chamber color Doppler echocardiogram shows a large mosaic blue jet fanning downward from the coaptation point of the tricuspid valve into the right atrium. The area of the color jet and the extent of penetration into the RA may be used to determine the severity of TR. On this image, the TR appears to be severe.
Doppler echocardiographic assessment of a tricuspid regurgitation (TR) jet may be useful in predicting the severity of pulmonary hypertension. The distance from the baseline to the peak of the TR is measured (in centimeters) and expressed as velocity (V). This value is then used to determine the gradient across the tricuspid valve (in millimeters of mercury) as 4 X V2. On this image, V is 3.25 cm; therefore, the calculated gradient is approximately 42 mm Hg. By adding the right atrial pressure (usually taken as 10 mm Hg) to this value, the systolic right ventricular and pulmonary arterial pressure may be determined. In this patient, the systolic pulmonary arterial pressure is 52 mm Hg, which represents moderate pulmonary hypertension.