Tricuspid Stenosis: Causes, Pathophysiology, Diagnosis, Management and Prevention

Tricuspid Stenosis: Causes, Pathophysiology, Diagnosis and Management

~Introduction

Tricuspid stenosis (TS) is a relatively rare valvular heart disease characterized by narrowing of the tricuspid valve orifice, which impedes the flow of blood from the right atrium to the right ventricle during diastole. Although it is uncommon compared to other valvular disorders such as mitral or aortic stenosis, tricuspid stenosis has significant clinical implications, particularly when it coexists with other valvular lesions, most commonly mitral stenosis of rheumatic origin.

Tricuspid stenosis can result from a variety of pathological processes that cause leaflet thickening, fusion of commissures, or subvalvular apparatus fibrosis. The condition leads to elevated right atrial pressures, systemic venous congestion, and reduced right ventricular filling, ultimately impairing cardiac output. Understanding its etiology, hemodynamic impact, and management strategies is crucial for proper diagnosis and treatment.

~Anatomy and Physiology of the Tricuspid Valve

The tricuspid valve is located between the right atrium and right ventricle. It consists of three leaflets — anterior, posterior, and septal — supported by chordae tendineae and papillary muscles. The normal tricuspid valve orifice area ranges from 7 to 9 cm², which allows for unrestricted flow of blood during ventricular diastole.

During diastole, the valve opens fully to allow blood to pass from the right atrium to the right ventricle. When the valve becomes narrowed due to pathological changes, it restricts this flow, leading to increased pressure in the right atrium and systemic venous circulation. The right ventricle, consequently, receives less blood, reducing the overall cardiac output.

~Etiology of Tricuspid Stenosis

1. Rheumatic Heart Disease

The most common cause of tricuspid stenosis worldwide is rheumatic fever. In rheumatic disease, the inflammatory process leads to fibrosis, thickening, and fusion of the valve leaflets and commissures. Rheumatic involvement of the tricuspid valve almost always occurs in conjunction with other valvular lesions, especially mitral stenosis. Isolated rheumatic tricuspid stenosis is extremely rare.

2. Congenital Tricuspid Stenosis

Congenital tricuspid stenosis is rare and usually presents in infancy or early childhood. It may occur as part of complex congenital heart defects such as Ebstein’s anomaly, where abnormal leaflet attachment leads to restricted valve motion and stenotic physiology.

3. Carcinoid Heart Disease

Carcinoid tumors, particularly those metastasizing to the liver, secrete serotonin and other vasoactive substances that cause endocardial fibrosis. The tricuspid and pulmonary valves are especially vulnerable because these substances reach the right heart before being inactivated in the lungs. The result is plaque-like fibrotic thickening, leading to tricuspid stenosis (and often regurgitation).

4. Endocarditis and Iatrogenic Causes

Chronic infection from infective endocarditis, particularly in intravenous drug users, can cause scarring and deformation of the valve. Additionally, prosthetic valve degeneration or iatrogenic injury following cardiac interventions may lead to tricuspid valve obstruction.

5. Other Rare Causes

• Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) can lead to fibrotic or inflammatory involvement of the valve.

• Metabolic disorders, such as Fabry’s disease, and exposure to certain drugs like methysergide or ergot derivatives, have also been implicated.

~Pathophysiology

Tricuspid stenosis creates a mechanical obstruction to blood flow from the right atrium to the right ventricle. This obstruction results in:

1. Elevated right atrial pressure: The atrium has to contract more forcefully to push blood through the narrowed orifice, leading to atrial dilation and hypertrophy.

2. Systemic venous congestion: Because blood cannot move freely forward, venous return backs up into the systemic circulation, causing jugular venous distension, hepatomegaly, ascites, and peripheral edema.

3. Reduced right ventricular filling: The right ventricle receives less blood, which decreases pulmonary blood flow and ultimately reduces left ventricular preload and cardiac output.

4. Low cardiac output symptoms: Fatigue and weakness result from decreased systemic perfusion.

Over time, these hemodynamic changes can coexist with other right-sided valvular lesions, particularly tricuspid regurgitation, and complicate the overall clinical picture.

~Clinical Features

The symptoms and signs of tricuspid stenosis are primarily due to systemic venous congestion rather than pulmonary congestion (as seen in left-sided lesions). The condition develops slowly and often presents in adulthood.

Symptoms

• Fatigue and weakness: Due to decreased cardiac output.

• Abdominal discomfort and distension: Caused by hepatic congestion and ascites.

• Swelling of legs and ankles: Due to peripheral edema.

• Anorexia and early satiety: Resulting from hepatic enlargement and congestion.

• Palpitations: From atrial fibrillation or flutter, which are common in long-standing disease.

• Cold extremities: Due to diminished forward flow.

Signs

• Jugular venous distension (JVD): With prominent "a" waves reflecting right atrial contraction against a stenotic valve.

• Hepatomegaly: The liver may be tender and pulsatile due to elevated venous pressures.

• Ascites and peripheral edema: From chronic venous congestion.

• Murmur: A low-pitched, diastolic rumbling murmur best heard at the lower left sternal border, which increases with inspiration (Carvallo’s sign).

• Opening snap: Occasionally audible due to stiffened valve leaflets.

• Slow rising jugular venous pulse and cyanosis may be seen in advanced cases.

~Diagnostic Evaluation

A combination of clinical examination and imaging techniques is necessary for accurate diagnosis and assessment of severity.

1. Electrocardiogram (ECG)

• May show right atrial enlargement (tall P waves in inferior leads).

• Atrial fibrillation may be present in advanced stages.

• Right ventricular hypertrophy is usually absent, distinguishing it from other right-sided pathologies.

2. Chest X-ray

• May reveal enlarged right atrium.

• Pulmonary vascular markings are typically normal or reduced (since flow into pulmonary circulation is decreased).

• The cardiac silhouette may show right heart border prominence.

3. Echocardiography

Echocardiography is the gold standard for diagnosing tricuspid stenosis.

• Two-dimensional (2D) echocardiography shows thickened leaflets, restricted motion, and doming during diastole.

• Doppler echocardiography allows for estimation of the tricuspid valve area and transvalvular pressure gradient.

  • Normal area: 7–9 cm²

  • Mild stenosis: >1.5 cm²

  • Moderate: 1.0–1.5 cm²

  • Severe: <1.0 cm²

• Color Doppler imaging helps detect associated tricuspid regurgitation and evaluate flow patterns.

4. Cardiac Catheterization

Cardiac catheterization is used when noninvasive methods are inconclusive or when surgical intervention is planned. It measures the pressure gradient across the tricuspid valve and evaluates for other valvular or coronary abnormalities.

5. Magnetic Resonance Imaging (MRI)

MRI provides detailed images of right atrial and ventricular morphology and function, though it is less commonly needed for diagnosis.

~Hemodynamic Changes

• Right atrial pressure: Elevated with a prominent "a" wave.

• Right ventricular diastolic pressure: Low compared to the atrial pressure, indicating obstruction.

• Cardiac output: Reduced.

• Mean diastolic gradient: Greater than 2 mmHg suggests significant stenosis.

These findings correlate with the degree of obstruction and the patient’s symptoms.

~Complications

Tricuspid stenosis can lead to several complications if left untreated:

1. Right heart failure: Due to persistent venous congestion and volume overload.

2. Atrial fibrillation: Resulting from atrial enlargement.

3. Thromboembolism: Due to sluggish right atrial flow.

4. Hepatic congestion and cirrhosis: “Cardiac cirrhosis” may develop in long-standing cases.

5. Coexistent valve disease: Particularly mitral stenosis or regurgitation, complicating management.

~Management of Tricuspid Stenosis

The management approach depends on the severity of stenosis, the presence of symptoms, and associated valvular lesions.

1. Medical Management

Medical therapy provides symptomatic relief but does not correct the underlying obstruction.

• Diuretics: To reduce venous congestion, ascites, and edema. Commonly used agents include furosemide or spironolactone.

• Salt restriction: Helps control fluid retention.

• Digoxin: Useful in cases of atrial fibrillation with rapid ventricular rate or in patients with right heart failure.

• Anticoagulation: Indicated if atrial fibrillation or thromboembolic risk is present.

However, medical therapy alone is insufficient for long-term management in moderate to severe cases.

2. Interventional and Surgical Treatment

a. Percutaneous Balloon Tricuspid Valvuloplasty (PBTV)

PBTV is a minimally invasive procedure used in selected patients with pliable, non-calcified rheumatic tricuspid valves. A balloon catheter is inserted via venous access and inflated across the valve to separate fused commissures, thereby increasing the orifice area.

• Success rates are high in rheumatic cases without severe calcification.

• It is often performed in conjunction with mitral valvotomy when both valves are involved.

b. Surgical Commissurotomy

Open or closed commissurotomy may be performed if PBTV is not feasible. It involves direct separation of fused leaflets and removal of fibrotic tissue.

c. Tricuspid Valve Replacement

Indicated when the valve is severely fibrotic, calcified, or non-repairable. Both bioprosthetic and mechanical valves can be used, although bioprosthetic valves are preferred to minimize thromboembolic risk, given the low-pressure environment of the right heart.

3. Management of Associated Conditions

Since tricuspid stenosis is often accompanied by mitral stenosis or tricuspid regurgitation, these must be addressed simultaneously during surgical intervention to ensure optimal hemodynamic outcomes.

~Prognosis

The prognosis of tricuspid stenosis depends on the underlying cause, the degree of stenosis, and the success of treatment. When corrected surgically or via balloon valvotomy, long-term outcomes are generally favorable, especially when coexisting left-sided lesions are treated effectively.

However, untreated severe tricuspid stenosis can lead to progressive right heart failure, cirrhosis, and poor quality of life due to persistent venous congestion.

~Prevention

Primary prevention involves the control of rheumatic fever through:

• Early treatment of streptococcal infections with antibiotics.

• Regular follow-up and secondary prophylaxis in patients with rheumatic heart disease.

• Avoidance of carcinoid-inducing agents and drug-induced valvulopathy (e.g., ergotamine derivatives).

Early recognition and management of rheumatic heart disease remain key to reducing the incidence of tricuspid stenosis globally.

~Conclusion

Tricuspid stenosis, though rare, is a significant valvular disorder that can severely compromise right heart function. It is most often a sequela of rheumatic heart disease but can also result from carcinoid syndrome, congenital defects, or iatrogenic injury. The disease leads to right atrial enlargement, venous congestion, and reduced cardiac output, manifesting primarily with systemic congestion symptoms.

Early diagnosis through echocardiography and timely intervention — whether medical, percutaneous, or surgical — can substantially improve patient outcomes. In modern cardiology, with effective rheumatic fever prevention and advances in valvular repair techniques, the long-term prognosis for tricuspid stenosis has markedly improved. Continued vigilance in managing coexistent valvular lesions and addressing systemic causes remains essential for optimal care.