Tricuspid valve

Article written and reviewed by Dr Luca Moretti

The tricuspid valve is the anatomical complex between the right atrium and right ventricle that governs entry of venous blood during diastole and limits its return to the atrium during systole. Its name evokes three leaflets, but actual morphology is far more variable, with possible accessory leaflets, scallops, and functional two- or four-leaflet configurations; modern assessment therefore does not merely count the leaflets but describes hinges, commissures, chordae, papillary muscles, and their relationship with the ventricle.

For decades, the tricuspid valve was considered a passive valve whose regurgitation was expected to regress after correction of left-sided disease, but clinical experience has shown otherwise. Annular dilation, atrial fibrillation, pulmonary hypertension, right ventricular remodeling, and transvalvular devices can maintain or worsen regurgitation even after technically successful mitral or aortic treatment, until right-sided disease becomes autonomous and capable of causing congestion and organ damage.

The fundamental hemodynamic abnormalities are rare tricuspid stenosis and the more common tricuspid regurgitation. The latter includes primary forms in which valve tissue is diseased, secondary forms caused by remodeling of the annulus and chambers, and forms in which a lead crosses the orifice. These categories may overlap and change over time.

The tricuspid valve works in a low-pressure circuit that is particularly sensitive to changes in respiration and preload. Regurgitation can therefore vary with volume status, ventilation, and rhythm, and some findings may appear less conspicuous despite important consequences; a complete assessment must integrate anatomy, hemodynamics, right ventricular function, venous congestion, and clinical trajectory.

Anatomy of the tricuspid valve apparatus

The tricuspid annulus is elliptical, nonplanar, and dynamic. The septal portion is relatively fixed within the fibrous skeleton, whereas the more muscular anterior and posterior portions dilate with the atrium and ventricle. During systole, the normal annulus decreases in area and perimeter; in secondary regurgitation it becomes more circular, flatter, and larger, increasing the distance the leaflets must span.

Anatomical relationships explain many surgical and interventional difficulties: the atrioventricular node and bundle of His run near the anteroseptal region, the right coronary artery lies close to the posterior annular segment, the coronary sinus opens into the posteromedial right atrium, and the aorta is adjacent to the anteroseptal portion. Sutures, anchors, and devices must therefore be positioned with the risk of injuring the conduction system or coronary artery in mind.

The traditional description distinguishes anterior, septal, and posterior leaflets. The anterior leaflet is often the largest and most mobile; the septal leaflet inserts near the membranous septum and is relatively short; the posterior leaflet has indentations and marked variability. Three-dimensional studies have demonstrated phenotypes with two, three, or four functional leaflets, making nomenclature based on hinges and commissures preferable to forcing every valve into the classic scheme.

The commissures are generally anteroseptal, anteroposterior, and posteroseptal, but their position and number vary. Normal coaptation occurs below the annular plane along a broad surface. During transcatheter procedures, the most common jet in secondary regurgitation is located between the anterior and septal leaflets; identifying commissures and segments determines trajectory, orientation, and the risk of inadequate grasping.

The chordae arise from anterior, posterior, and septal papillary muscles or directly from the septum. The anterior papillary muscle is often the most developed and is connected to the moderator band; posterior groups are variable, while septal chordae may arise directly from the myocardium. The apparatus does not have the symmetry of the mitral valve, and a single lead can interfere with multiple structures during the cardiac cycle.

The right ventricle is part of the valve-ventricular unit. Its crescent shape, trabeculations, and infundibulum make simple ellipsoidal modeling unsuitable. Lateral and apical dilation displaces the papillary muscles, tensions the chordae, and reduces coaptation. The right atrium contributes by enlarging the annulus, particularly in atrial fibrillation with an initially preserved ventricle.

The valve is frequently crossed by pacemaker and defibrillator leads. A lead may lie freely in a commissure, rest against a leaflet, prevent its motion, adhere to the apparatus, perforate it, or become entangled in the chordae. Even without direct impingement, ventricular pacing, dilation, and pulmonary pressure can promote regurgitation; a causal relationship requires dynamic imaging.

Blood supply to the papillary muscles and right ventricular wall is provided mainly by the right coronary artery in right-dominant systems, with variable contributions from the left anterior descending artery. Right ventricular infarction can impair geometry and closing force without producing the typical papillary muscle rupture seen in the mitral valve. Ischemia, pacing, and sternotomy modify septal motion and can reduce longitudinal parameters despite less impaired global function.

Physiology and major forms of disease

During inspiration, reduced intrathoracic pressure increases venous return and right ventricular filling, while the normal tricuspid valve enlarges its opening and maintains a low gradient. During systole, modest right ventricular pressure allows thin leaflets to coapt, but this very delicacy makes the apparatus sensitive to annular dilation; respiratory variation is therefore part of normal physiology and explains why Doppler measurements should be averaged over appropriate cycles.

Tricuspid stenosis is almost always organic. Rheumatic heart disease fuses commissures and thickens leaflets, often together with mitral stenosis; other causes include carcinoid disease, inflammatory disorders, congenital abnormalities, and prosthetic obstruction. Increased right atrial pressure causes jugular venous distension, hepatomegaly, ascites, and edema, while low output limits exertion. The gradient rises with tachycardia and increased flow.

In primary tricuspid regurgitation, a lesion directly involves the leaflets, chordae, papillary muscles, or annulus. Endocarditis, carcinoid disease, Ebstein anomaly, trauma, iatrogenic injury, degeneration, rheumatic disease, and congenital disorders produce different anatomies. The regurgitant jet may be eccentric and focal, with severity disproportionate to annular dilation.

Secondary tricuspid regurgitation accounts for most cases. In the ventricular form, pulmonary hypertension, left-sided disease, cardiomyopathy, or pulmonary disease dilate the ventricle, displace the papillary muscles, and tether the leaflets. In the atrial form, atrial fibrillation and right atrial enlargement predominantly dilate the annulus with initially less tethering. Many patients show mixed components.

Device-related tricuspid regurgitation is diagnosed when the lead demonstrates causal interference or when the device plausibly contributes to remodeling. Impingement, adherence, entanglement, and perforation are direct mechanisms; pacing and dyssynchrony are indirect mechanisms. Removing a chronic lead may improve, leave unchanged, or worsen regurgitation and carries a risk of laceration.

In carcinoid disease, vasoactive mediators produce fibrous plaques, retraction, and immobility predominantly of the right-sided valves, with combined regurgitation and stenosis. Tricuspid endocarditis more often affects people with venous access, devices, or injection drug use and may cause vegetations, septic pulmonary emboli, and destruction. Ebstein anomaly consists of apical displacement of the septal and posterior leaflet insertions, with atrialization of part of the ventricle.

Significant regurgitation creates a vicious cycle: volume flows back into the atrium, increases diastolic return, and further dilates the ventricle and annulus. Venous congestion causes edema, ascites, enteropathy, renal failure, and hepatopathy; low output causes asthenia and cachexia. When right ventricular pressure falls because of advanced dysfunction, jet velocity and the estimated pulmonary pressure may appear falsely reassuring.

Right ventricular function depends strongly on coupling with the pulmonary circulation. A ventricle adapted to severe regurgitation ejects part of its stroke volume into the low-pressure atrium; eliminating backflow suddenly exposes the entire volume to pulmonary afterload. The TAPSE/pulmonary systolic pressure ratio is an imperfect index of coupling, useful as part of a multiparametric assessment and not as a universal futility threshold.

Clinical assessment and multimodality imaging

The history explores dyspnea, reduced endurance, swelling, weight gain, abdominal distension, early satiety, palpitations, and syncope. Left-sided heart disease, pulmonary hypertension, embolism, liver or kidney disease, carcinoid disease, endocarditis, and implanted devices are reconstructed. Progressive reduction in activity may conceal symptoms until congestion is advanced.

On physical examination, a prominent jugular V wave, hepatojugular reflux, pulsatile liver, ascites, and edema indicate elevated venous pressure. A holosystolic murmur at the lower sternal border increases with inspiration but may be faint in massive low-velocity regurgitation. Cyanosis, cachexia, and jaundice are late signs. Clinical assessment also helps recognize that a reported “dry weight” may already reflect congestion.

Transthoracic echocardiography is the first-line examination. Dedicated apical four-chamber, parasternal, short-axis, and subcostal views identify the leaflets, annulus, coaptation, leads, vena cava, and hepatic veins. 3D imaging reconstructs the en face orifice and clarifies morphology. Image quality varies with acoustic windows, the anterior location of the valve, and device-related shadowing.

Regurgitation severity is assessed by integrating vena contracta, PISA, 3D vena contracta area, density and shape of the continuous-wave Doppler signal, systolic flow reversal in the hepatic veins, chamber dilation, and flow. Jet area depends on pressure and settings. In extreme forms, the “massive” and “torrential” categories describe grades beyond conventional severe, particularly useful for procedures and follow-up.

Right ventricular function cannot be represented by a single number. TAPSE and S’ velocity measure regional longitudinal motion and are load-dependent; fractional area change, free-wall strain, and 3D ejection fraction add additional perspectives. After correction of regurgitation, effective afterload increases and function may appear worse, a phenomenon that should be anticipated during patient selection.

Pulmonary systolic pressure is estimated from jet velocity plus right atrial pressure. In very severe regurgitation, rapid pressure equalization truncates the profile and underestimates the value. The inferior vena cava is influenced by ventilation, athletic status, and abdominal pressure. When the decision depends on pulmonary vascular resistance or data are discordant, right-heart catheterization directly measures pressure and flow.

Transesophageal echocardiography visualizes leaflet hinges and leads and is indispensable for many procedures, although distance from the anterior chest wall may reduce resolution. Gated CT defines the annulus, right coronary artery, access routes, leads, and relationship with devices; magnetic resonance measures right ventricular volumes and function with high accuracy and indirectly quantifies regurgitation. Arrhythmias and devices may limit it.

Laboratory testing and organ imaging complete staging. Creatinine, sodium, albumin, bilirubin, transaminases, INR, complete blood count, and natriuretic peptides reflect congestion and reserve but may become abnormal only late. Hepatic ultrasonography and fibrosis indices help distinguish congestion from primary liver disease. Prognosis depends on multiorgan damage, not only on the echocardiographic grade.

Cardiopulmonary exercise testing distinguishes ventilatory limitation, chronotropic incompetence, and reduced cardiac output in ambiguous cases. Normal venous pressure at rest does not exclude exertional congestion; exercise catheterization or a fluid challenge is reserved for experienced centers and selected questions. Testing should not delay intervention in a patient with severe anatomy and already documented progressive organ damage.

Principles of surgical and transcatheter treatment

Medical therapy reduces congestion and treats the cause. Loop diuretics, mineralocorticoid receptor antagonists, and sequential combinations are tailored to renal function, sodium, and blood pressure; effective diuresis can reduce annular size and regurgitation but cannot reconstruct chordae or leaflets. Treatment of left-sided heart failure, rhythm control, specific therapy for pulmonary hypertension when indicated, and treatment of carcinoid disease modify loading conditions.

The most important issue is timing. Late intervention after right ventricular dysfunction, hepatopathy, and frailty carries high risk and limited benefit; early intervention for a nonsevere lesion exposes the patient without advantage. Guidelines recommend correction of severe tricuspid disease during left-sided valve surgery and consider annuloplasty for less severe regurgitation with a dilated annulus to prevent progression.

In symptomatic severe primary disease, surgery is indicated before severe right ventricular dysfunction if risk is acceptable. A minimally symptomatic patient with progressive dilation may also be a candidate. In isolated secondary regurgitation, the decision is more complex: advanced right ventricular dysfunction, severe pulmonary vascular disease, and irreversible organ damage are excluded while the likelihood of recovery is assessed.

Surgical repair is preferred when feasible. A prosthetic ring reduces and stabilizes the dilatable portion of the annulus; sutures, patches, neochordae, or leaflet-augmentation techniques address specific lesions and tethering. Bicuspidization alone may be less durable in marked dilation. Replacement is reserved for destroyed tissue, extreme tethering, or unreliable repair, preserving the apparatus and conduction system whenever possible.

Bioprostheses are often preferred in the tricuspid position to avoid high-intensity anticoagulation for mechanical valves, but they may degenerate; mechanical prostheses carry substantial thrombotic risk under low-pressure conditions. Choice considers age, access to follow-up, other prostheses, and the future possibility of valve-in-valve treatment. Conduction block may require pacing, which should be planned to avoid new interference.

Transcatheter edge-to-edge repair approximates the leaflets, most often the anterior and septal leaflets. Favorable anatomy includes a gap that is not excessive, a localizable jet, sufficient tissue, and adequate imaging; a large gap, extreme tethering, an entrapping lead, and calcification complicate grasping. Randomized studies have shown reduced regurgitation and improved quality of life in selected patients, while effects on mortality and hospitalization still depend on follow-up and the population studied.

Transcatheter annuloplasty reduces annular size; orthotopic replacement eliminates regurgitation but abruptly increases right ventricular afterload and requires anticoagulation and assessment of access routes. Heterotopic caval valve replacement reduces congestion without correcting the native orifice and has specific indications. Device selection depends on phenotype, not on a universal hierarchy.

In patients with leads, extraction, repositioning, leadless or epicardial pacing, and the valve procedure must be planned together. A lead extracted from adhesions may lacerate a leaflet; leaving it in place may obstruct the device or lead to it being “jailed” by a prosthesis, limiting future revisions. The electrophysiologist, extraction specialist, surgeon, and interventionalist jointly balance pacing dependence, infection risk, and valve outcome.

Transcatheter selection is not based solely on surgical risk. Coaptation gap, jet location, tethering height, number of leaflets, image quality, presence of leads, caval dimensions, and right ventricular reserve guide the choice among TEER, annuloplasty, replacement, or no procedure. An incomplete but substantial reduction may be clinically useful; a prosthesis that abolishes regurgitation may be harmful if the ventricle cannot tolerate the new load.

Follow-up, prognosis, and organization of care

Severe tricuspid regurgitation is associated with mortality and hospitalization independently of many comorbidities. Risk increases with right ventricular dysfunction, pulmonary pressure, renal and hepatic failure, low output, and frailty. The absence of striking symptoms is not protective: chronic congestion may progress while the patient reduces exertion and laboratory values remain nearly normal.

Serial follow-up records weight, diuretic dose, functional capacity, rhythm, venous signs, renal and hepatic function, and comparable echocardiographic parameters. Follow-up becomes more frequent with important regurgitation, progressive dilation, or recent intervention. An isolated change in TAPSE or vena contracta may reflect loading conditions and technique; a consistent trend across multiple domains indicates true progression.

After surgery, a reference examination documents residual regurgitation, gradient, right ventricular function, pulmonary pressure, and the status of the annulus or prosthesis. After a transcatheter procedure, device stability, regurgitation, stenosis, access sites, and leads are assessed. Reduction from torrential to moderate may provide clinical benefit even without complete abolition, whereas important residual regurgitation limits remodeling.

Prosthetic surveillance includes thrombosis, degeneration, endocarditis, and mismatch. Fever, new congestion, hemolysis, an increased gradient, or changes in heart sounds require earlier imaging. Antibiotic prophylaxis, antithrombotic therapy, and device management depend on the type of procedure and individual risk; there is no identical regimen for every transcatheter implant.

The right-heart Heart Team integrates advanced imaging, heart failure, interventional cardiology, cardiac surgery, electrophysiology, anesthesia, and hepatorenal expertise. Selection must establish whether symptoms arise from regurgitation, whether the ventricle can tolerate correction, which anatomy is treatable, and which goals are realistic. Futility risk is a clinical diagnosis that must be reasoned, not an automatic consequence of age.

The tricuspid valve illustrates the principle that valvular disease is not confined to the leaflets. The atrium, ventricle, pulmonary circulation, liver, kidneys, and devices all participate in the disease and its outcome. Early recognition of the mechanism makes it possible to correct the cause, combine repair with left-sided surgery when appropriate, or choose a transcatheter procedure before congestion makes technical success clinically insufficient.