Tricuspid Stenosis

Tricuspid stenosis is a valvular heart disease characterized by narrowing of the tricuspid orifice, i.e., the valve that separates the right atrium from the right ventricle. This narrowing creates an obstacle to the anterograde blood flow during diastole, resulting in a pressure gradient between the two right heart chambers. In the presence of significant stenosis, right atrial pressure progressively increases, leading to a picture of systemic venous congestion.

Tricuspid stenosis is a relatively rare condition and, in most cases, is associated with other valvular diseases, particularly mitral stenosis. Isolated tricuspid stenosis is exceptional. In clinical practice, it is mostly observed in patients with multivalvular rheumatic disease or in the setting of congenital heart diseases (e.g., tricuspid atresia) and chronic systemic inflammatory disorders.

Etiology, Pathogenesis and Pathophysiology

The most common cause of acquired tricuspid stenosis is rheumatic heart disease, often in the context of multivalvular involvement. Chronic rheumatic inflammation leads to fibrosis and calcification of the valvular leaflets, commissural fusion, and thickening of the chordae tendineae.

Less frequent causes include: infective endocarditis, especially in patients with central venous catheters or intravenous drug use, where the tricuspid valve is often involved; cardiac tumors (e.g., myxomas, carcinoids) with direct infiltration or fibrogenic substance production; carcinoid syndrome with serotonin-induced valvular fibrosis, typically affecting the right-sided valves; iatrogenic causes: post-surgical, post-mediastinal radiotherapy, or secondary to intracardiac devices; congenital diseases: rare, but isolated stenosis may occur in complex malformations (tricuspid atresia, annular dysplasia).

Under physiological conditions, the tricuspid orifice area ranges from 6 to 9 cm². Stenosis becomes clinically significant when the valve area drops below 2 cm², while values below 1.5 cm² lead to hemodynamic alterations such as increased right atrial pressure, a diastolic transvalvular gradient, and reduced right ventricular filling.

Since the right ventricle receives less blood, stroke volume is reduced, and progressive systemic venous congestion develops. The right atrium increases its pressure and dilates to overcome the obstruction, but it does not hypertrophy due to its limited contractile capacity. When atrial pressure exceeds 10–15 mmHg, symptoms of congestion appear: pulsatile hepatomegaly, ascites, and peripheral edema.

In advanced stages, atrial dilation may lead to atrial fibrillation, which further worsens diastolic function and reduces cardiac output.

In isolated tricuspid stenosis, pulmonary artery pressure is usually normal. However, when associated valvular diseases are present (especially mitral lesions), pulmonary hypertension may coexist, aggravating the clinical picture.

Clinical Presentation

The clinical manifestations of tricuspid stenosis are usually subtle and often masked by symptoms of the associated mitral valve disease. The predominant picture is one of low output and systemic venous congestion.

The most common symptoms include:

• Fatigue and reduced exercise tolerance due to decreased cardiac output;
• Exertional dyspnea, generally mild unless coexistent with pulmonary or left-sided valvular disease;
• Peripheral edema, jugular vein distension, hepatomegaly, ascites, abdominal distension, and in severe cases anasarca, all due to systemic venous congestion.

Specific signs often observed include:

• Prominent a wave in the jugular venous pulse, indicating elevated right atrial pressure;
• Presystolic diastolic murmur at the lower left sternal border, enhanced with inspiration (Carvallo’s sign) and the Rivero-Carvallo maneuver;
• Positive hepatojugular reflux and pulsatile hepatomegaly.

In severe cases, progression may lead to cachexia, malabsorption, and intestinal lymphatic stasis, complications typical of chronic venous congestion.

Diagnosis

The diagnosis of tricuspid stenosis is based on a careful integration of history, physical examination, and imaging. In most cases, the condition is suspected in the context of multivalvular disease, especially mitral, or in patients with otherwise unexplained systemic venous congestion.

On ECG, signs of right atrial enlargement are seen: tall, peaked P waves (P pulmonale) in leads II and V1. These may be absent in atrial fibrillation. Precordial leads may show right axis deviation and occasionally signs of right ventricular hypertrophy, although these are rare in the absence of associated pulmonary hypertension.

On chest X-ray, right-sided cardiac enlargement may be evident, with prominence of the right heart border in posteroanterior projection and right atrial enlargement. In advanced cases, signs of systemic venous congestion appear: elevated diaphragm due to hepatomegaly, increased hepatic shadow, right pleural effusion, and enlarged superior vena cava.

Transthoracic echocardiography is the gold standard for diagnosing tricuspid stenosis. Two-dimensional imaging allows for morphological assessment of the valve, while Doppler study enables quantification of the stenosis’s hemodynamic severity.

Main echocardiographic findings include:

• Thickened leaflets with reduced mobility;
• “Doming” appearance during diastole, similar to mitral stenosis;
• Presence of commissural fusion;
• Diastolic transvalvular gradient on Doppler, proportional to stenosis severity;
• Estimation of tricuspid valve area by continuity equation or specific formulas.

Right heart catheterization provides direct pressure measurements and allows for accurate calculation of the diastolic right atrioventricular gradient. It is indicated when echocardiography is inconclusive or prior to surgery.

Differential diagnosis includes other causes of systemic venous congestion, such as:

• Right heart failure due to right ventricular dysfunction (post-pulmonary embolism, right-sided cardiomyopathy);
• Constrictive pericarditis, which mimics congestion signs with uniformly elevated diastolic pressures in all chambers;
• Carcinoid syndrome, which may involve the tricuspid valve but is accompanied by typical systemic symptoms and multivalvular right-sided involvement.

Treatment and Prognosis

Medical therapy aims to reduce venous congestion and control arrhythmias. Diuretics are used to reduce systemic venous hypertension, anticoagulants are indicated in atrial fibrillation, and endocarditis prophylaxis is recommended in the presence of significant valvular lesions or intracardiac devices.

Surgical treatment is indicated in symptomatic patients with severe tricuspid stenosis (valve area < 1.5 cm²) and includes:

• Valvulotomy or commissurotomy in patients with pliable, non-calcified valves;
• Tricuspid annuloplasty in the presence of annular dilation;
• Valve replacement with a bioprosthesis (preferred due to the low right-sided pressure gradient) in cases of severely fibrotic or calcified valves.

Tricuspid stenosis is often addressed during surgery for other valvular lesions, especially mitral. Proper timing is essential: early surgery in the presence of even mild symptoms improves prognosis.

Prognosis depends on the severity of the stenosis, the presence of associated valvular diseases, and the timeliness of treatment. Without intervention, progressive venous congestion may lead to malabsorption, congestive hepatic failure, and significant reduction in quality of life.

Timely surgical treatment allows for good hemodynamic recovery, especially if performed before the onset of irreversible hepatic damage or cachexia.

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