bubble_chart Overview

Isolated tricuspid valve stenosis is extremely rare. Tricuspid stenosis is almost always accompanied by mitral and/or aortic valve disease, along with tricuspid regurgitation. As a sequela of rheumatic fever, the pathological changes are similar to those of mitral stenosis, namely fibrous thickening of the valve leaflets, vegetations at the edges, and adhesion or fusion of the three valve leaflets, forming a triangular stenotic orifice. The lesions may also extend to the chordae tendineae and papillary muscles. However, the severity and extent of tricuspid valve lesions are milder than those of the mitral valve, with rare subvalvular fusion and little calcification. After stenosis develops, blood flow from the right atrium to the right ventricle is obstructed, leading to right atrial enlargement and increased pressure. Due to impaired venous return, chronic elevation of venous pressure results in signs such as jugular vein distension, hepatomegaly, ascites, and peripheral edema. The right ventricle atrophies due to reduced blood flow. When accompanied by mitral valve disease, the right ventricle may hypertrophy.

bubble_chart Clinical Manifestations

The main symptoms of tricuspid stenosis are caused by congestion in the gastrointestinal tract, liver, and spleen, such as discomfort in the liver area, loss of appetite, indigestion, and abdominal distension and fullness. Sometimes accompanied by lack of strength and swelling of the limbs. In cases of pure tricuspid stenosis, cardiopulmonary symptoms are often not obvious. For patients also suffering from mitral stenosis, the cardiopulmonary symptoms are milder than those with pure mitral stenosis due to reduced blood flow in the right ventricle.

Physical examination may reveal grade I cyanosis of the cheeks and jaundice (caused by chronic liver depression and blood stasis). Jugular vein distension is present, sometimes even with pulsation. The liver is enlarged, firm, and tender, and presystolic pulsation may occasionally be palpated. In patients with ascites, the abdomen is distended, and shifting dullness can be detected. Cardiac examination shows an enlarged right heart border. The first heart sound at the tricuspid area is accentuated, and an opening snap may be heard after the second heart sound. A presystolic or diastolic rumbling murmur can be heard at the fourth intercostal space along the left sternal border, and sometimes a tremor can be palpated. During deep inspiration, due to increased negative intrathoracic pressure and augmented right atrial blood flow, the murmur becomes significantly louder, which helps differentiate it from mitral stenosis.

bubble_chart Auxiliary Examination

X-ray examination: The posteroanterior view shows the lower part of the right heart border extending to the right, with widening of the shadow of the superior vena cava. In pure tricuspid stenosis, the lung fields are clear, and there is no pulmonary artery enlargement or pulmonary congestion.

The electrocardiographic characteristic is an increased P wave, but no signs of right ventricular hypertrophy.

Echocardiographic examination: The echo pattern of the tricuspid valve is similar to that of mitral stenosis. In patients with tricuspid stenosis, the biphasic curve disappears, the EF slope decreases, and a "wall-like" change appears. There is paradoxical movement of the septal leaflet during diastole, and the right atrium is enlarged; when the right ventricular end-diastolic pressure rises, the AC interval prolongs. Cross-sectional echocardiography shows thickening of the tricuspid valve membrane and restricted opening movement during diastole.

Right heart catheterization reveals a significant increase in right atrial pressure. There is a notable presystolic or diastolic pressure gradient between the right atrium and right ventricle, generally ranging from 0.5 to 1.1 kPa (4 to 8 mmHg).

Cardiac angiography: The catheter tip is placed in the right atrium. Right anterior oblique cineangiography can demonstrate thickening of the tricuspid valve leaflets, reduced movement, and contrast medium flowing through the stenotic valve orifice into the right ventricle during diastole, with prolonged emptying time of the contrast medium in the right atrium.

bubble_chart Diagnosis

The diagnosis of isolated tricuspid stenosis is not difficult, but in cases of combined valvular disease, tricuspid stenosis is often overlooked, so vigilance is necessary. Right heart catheterization should be performed when needed. In certain suspicious cases, intraoperative digital exploration of the right atrium can confirm the diagnosis.

bubble_chart Treatment Measures

The treatment of tricuspid stenosis is, in principle, the same as that for mitral stenosis. However, closed commissurotomy is prone to tearing the valve membrane, leading to severe insufficiency, and is no longer recommended.

(1) Tricuspid commissurotomy: This is suitable for cases with simple commissural fusion and well-preserved valve membrane tissue. Through a right atrial incision, the fused commissures between the anterior and septal leaflets, as well as the posterior and septal leaflets, are carefully incised under direct vision to separate them into two leaflets. Incising the fused commissures between the anterior and posterior leaflets may easily result in severe insufficiency, so caution is advised.

(2) Tricuspid valve replacement: This is indicated for cases with severe valve membrane deformity or combined insufficiency. The procedure is performed through a right atrial incision. The steps of excising the valve membrane, placing sutures, and implanting a prosthetic valve are essentially the same as those for mitral valve replacement. However, the following points should be noted: ① The tricuspid annulus is not very sturdy, so pledgeted mattress sutures should be used to prevent tearing; ② In the area of the septal leaflet, sutures should not pass through the annulus to avoid injury to the conduction bundle; ③ Given the high risk of postoperative thrombosis in the tricuspid valve and the lower pressure it bears compared to the aortic and mitral valves, a bioprosthetic valve is more suitable.

bubble_chart Differentiation

Right atrial myxoma can also produce clinical manifestations of tricuspid stenosis when the tumor obstructs the valve orifice. However, the medical history is short, the disease progresses rapidly, and echocardiography reveals a distinctive cloud-like image, which aids in differentiation.