Tricuspid Valve Prolapse

Tricuspid valve prolapse is systolic displacement of one or more tricuspid leaflets into the right atrium by 2 mm or more beyond the annular plane. It is usually benign, and often accompanies mitral valve prolapse.

It is found in under 1% of the general population and in about 20 to 40% of patients with mitral valve prolapse. Most patients are asymptomatic and the valve functions normally or with mild regurgitation.

Causes include myxomatous degeneration (Barlow disease), connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), rheumatic disease, congenital abnormalities, endocarditis, blunt chest trauma, chordal rupture, repeated endomyocardial biopsies after transplantation, and lead related injury.

Pathophysiology.

Myxomatous change thickens the leaflets with excess proteoglycan and weakens the chordae. Elongated or ruptured chordae allow the leaflet to billow or become flail.

Prolapse prevents coaptation and causes eccentric regurgitation. Severe regurgitation from a flail leaflet overloads the right ventricle, causing dilatation and systemic congestion.

Prolapse is graded as billowing (leaflet body displaced more than 2 mm into the right atrium beyond the annular plane, with the tip still coapting) or flail (leaflet tip reversed into the atrium with chordal rupture).

Most patients have no symptoms. Palpitations, atypical chest pain and fatigue occur. A mid-systolic click that is louder on inspiration and a late systolic murmur are heard at the left lower sternal edge. A flail leaflet gives acute or subacute right heart failure with oedema, ascites and raised jugular venous pressure.

• Echocardiography (apical four chamber, right ventricular inflow and subcostal views): leaflet displacement of 2 mm or more beyond the annular plane. Three dimensional imaging localises the prolapsing segment (anterior, septal or posterior leaflet) and shows chordal rupture.
• Grade tricuspid regurgitation: severe is vena contracta 7 mm or more, effective regurgitant orifice area 40 mm2 or more, regurgitant volume 45 mL or more, with hepatic vein systolic flow reversal. Measure right ventricular size, function (TAPSE under 17 mm abnormal) and pulmonary pressure.
• Cardiac MRI or CT when echocardiographic views are limited.
• Examine the mitral valve, aortic root and skeleton for connective tissue disease. Genetic testing (FBN1 and related genes) when features suggest it.
• Ambulatory ECG for palpitations; blood cultures if fever.

Differential diagnosis.

• Ebstein anomaly (apical displacement of the septal leaflet by 8 mm/m2 or more).
• Functional regurgitation with leaflet tethering (tenting, not prolapse).
• Rheumatic, carcinoid and endocarditic disease, and lead related regurgitation.
• Right atrial dilatation giving apparent prolapse.

Asymptomatic with mild or no regurgitation. No drug treatment. Reassure. Competitive sport is permitted when regurgitation is mild, right ventricular function is normal and there is no arrhythmia. Endocarditis prophylaxis is not needed unless there is a prosthetic valve or previous endocarditis.

Symptoms.

• Palpitations: metoprolol tartrate 25 to 50 mg orally twice daily (maximum 200 mg daily); monitor heart rate and blood pressure; reduce in severe hepatic impairment.
• Atrial fibrillation: anticoagulate by CHA2DS2-VASc score with apixaban 5 mg twice daily (2.5 mg twice daily when two of age 80 or over, weight 60 kg or under, creatinine 133 micromol/L or over); rhythm control as indicated.
• Congestion: furosemide 40 to 80 mg orally daily titrated to dry weight, with spironolactone 25 to 50 mg daily (potassium under 5.0 mmol/L, eGFR over 30; check at 1 and 4 weeks).

Severe regurgitation from prolapse or flail leaflet.

• Surgery is indicated for symptomatic severe regurgitation, or asymptomatic severe regurgitation with progressive right ventricular dilatation or falling function, and at the time of left sided valve surgery.
• Repair is preferred over replacement (leaflet resection, neochordae, annuloplasty ring, or edge-to-edge technique). Bioprosthetic replacement when repair is not feasible.
• Transcatheter edge-to-edge repair is an option for suitable anatomy at high surgical risk.
• Antithrombotic therapy: warfarin to INR 2.0 to 3.0 for 3 months after repair with a ring or bioprosthetic replacement, then aspirin 75 to 100 mg daily.

Infective endocarditis or trauma. Treat the cause, and refer for repair when destruction or flail leaflet causes severe regurgitation.

Monitoring. Mild regurgitation: clinical review and echocardiography every 3 to 5 years. Moderate: yearly. Severe: every 6 to 12 months, with earlier review for symptoms.

Referral and escalation. Refer moderate or severe regurgitation, flail leaflet, connective tissue disease, right ventricular dilatation or heart failure to a valve service. Urgent referral for acute heart failure after trauma.

Special groups.

• Pregnancy: mild disease is well tolerated; severe regurgitation needs specialist care; Marfan syndrome needs aortic assessment.
• Children and young adults: screen first degree relatives when connective tissue disease or familial prolapse is found.
• Kidney or liver impairment: reduce apixaban to 2.5 mg twice daily when two of age 80 or over, weight 60 kg or under, creatinine 133 micromol/L or over; adjust loop diuretic dose by response and eGFR, and avoid spironolactone when eGFR is 30 mL/min/1.73 m2 or under or potassium is over 5.0 mmol/L.