Primary tricuspid regurgitation

Article written and reviewed by Dr Luca Moretti

Primary tricuspid regurgitation is systolic regurgitation caused by an intrinsic lesion of one or more components of the tricuspid valve: leaflets, chordae tendineae, papillary muscles or annulus. The definition is anatomopathological and does not indicate severity alone. Congenital prolapse, an infectious perforation, carcinoid-related retraction and traumatic chordal rupture all produce organic regurgitation, but require profoundly different diagnostic pathways and corrective techniques.

The disease must be distinguished from secondary tricuspid regurgitation, in which initially intact leaflets become incompetent because of annular dilatation or tethering caused by atrial and ventricular remodeling. Interference from a permanent transvenous lead is now also regarded as a distinct mechanism, addressed in device-related tricuspid regurgitation. By contrast, a biopsy instrument or catheter that directly severs a chord causes a primary iatrogenic lesion.

The distinction does not always remain pure. A chronic organic defect overloads the right atrium and ventricle, dilates the annulus and can add a functional component over time; the correct description then becomes a mixed mechanism with a dominant primary lesion. Attributing everything to dilatation would miss the surgical target, whereas calling isolated annular expansion related to atrial fibrillation or pulmonary hypertension primary would create the opposite error.

Compared with the unified framework of tricuspid regurgitation, this monograph follows the lesion itself: it reconstructs its etiology, anatomy, rate of progression and repairability. The timing of intervention depends not only on jet severity, but also on the right ventricle’s ability to recover, control of the cause and the possibility of obtaining a durable correction before hepatorenal injury develops.

Definition, pathological anatomy and etiologies

In Ebstein anomaly, delamination of the septal and posterior leaflets is incomplete and their functional insertion is displaced toward the apex. A portion of the right ventricle becomes “atrialized,” while the anterior leaflet is often large, redundant and fenestrated, with a sail-like appearance. The functional right ventricle may be small or dilated and dysfunctional. An atrial septal defect or patent foramen ovale, right-to-left shunting, cyanosis, paradoxical embolism, accessory pathways and tachyarrhythmias complete a phenotype that cannot be reduced to the measurement of regurgitation alone.

Apical displacement of the septal leaflet insertion point, indexed to body surface area, supports the diagnosis of Ebstein anomaly, but in adults assessment must extend to tissue that can actually be mobilized, rotation of the anterior leaflet, functional chamber volume, biventricular function, shunts and arrhythmias. Congenital tricuspid dysplasia, by contrast, preserves annular insertion but features thickened or hypoplastic leaflets, short, absent or malinserted chordae, clefts, double orifice or papillary abnormalities; both conditions require an adult congenital heart disease center.

In infective endocarditis, vegetations and inflammation may perforate or destroy a leaflet, sever chordae and create an acute flail leaflet. Intravenous drug use, venous catheters, hemodialysis, Staphylococcus aureus bacteremia and intracardiac material increase the risk; septic pulmonary emboli, cavitations and pulmonary infarctions point toward right-sided involvement. Disease associated with a CIED system also requires complete extraction of infected material, whereas a destroyed native valve without a device remains an organic valvular disorder.

Carcinoid heart disease results from chronic endocardial exposure to serotonin, tachykinins and other mediators released mainly by neuroendocrine tumors metastatic to the liver. Fibrous plaques coat the valvular surface and subvalvular apparatus; the leaflets become thickened, retracted and nearly immobile, causing regurgitation often associated with stenosis. Pulmonary valve involvement is common and should be sought deliberately. Left-sided valves are relatively protected by pulmonary inactivation, except in the presence of a right-to-left shunt, bronchial tumor or exceptionally high hormonal burden.

In rheumatic disease there is leaflet thickening and retraction, commissural fusion and chordal shortening. The result is often a mixed lesion, with a reduced valve area and inadequate coaptation. Isolated organic tricuspid involvement is rare: assessment for mitral and aortic disease is mandatory, as is distinction from the functional component generated by mitral valve disease, pulmonary hypertension and right-heart dilatation. Leaflet morphology, not the mere presence of regurgitation, establishes the etiology.

Blunt chest trauma can rupture chordae or a papillary muscle, most often involving the anterior leaflet, leaving a flail segment. The low pressure of the right heart may initially make a major lesion tolerable, only for it to emerge months or years later with dilatation and heart failure. Penetrating injuries, right ventricular ischemia or infarction, and injury during surgery or catheterization are less common causes. In transplant recipients, repeated endomyocardial biopsies can catch chordae and produce progressive flail-related regurgitation.

Myxomatous degeneration causes redundant leaflets, chordal elongation, prolapse or rupture with flail and may accompany a Barlow-like mitral phenotype. Marfan, Loeys-Dietz and Ehlers-Danlos syndromes, together with some FLNA-related valvular disorders, alter the extracellular matrix and mechanical resistance of the apparatus. In lupus and antiphospholipid antibody syndrome, nonbacterial Libman-Sacks vegetations can thicken, erode or perforate a leaflet; cultures, clinical context and imaging distinguish this lesion from infective endocarditis.

Rare causes include endomyocardial fibrosis with entrapment of the apparatus, radiation therapy, tumors and drug-induced serotonergic valvular disease from agents such as historical appetite suppressants or ergot derivatives. History-taking should specify medications, systemic diseases, rheumatic fever, neuroendocrine neoplasia, infections, trauma and procedures. Advanced age with isolated annular dilatation is not sufficient to diagnose primary degeneration.

Pathophysiology, natural history and clinical presentation

Tolerance depends largely on the speed of onset. With an infectious perforation or acute traumatic rupture, the right atrium and ventricle have not yet developed the compliance and volume needed to compensate, so large atrial systolic waves, reduced pulmonary blood flow, hypotension and congestion can appear rapidly; moreover, hemodynamic severity does not always correspond to a striking color Doppler jet because ventricular and atrial pressures may equalize early.

In chronic disease, the right ventricle increases total stroke volume and the atrium dilates, maintaining acceptable forward output for years. This adaptation, however, is biologically costly. Wall stress, papillary muscle deformation and annular dilatation further reduce coaptation, transforming a focal lesion into diffuse regurgitation. Atrial fibrillation eliminates atrial contribution and accelerates annular expansion, creating a cycle of progression.

The right ventricle ejects part of its stroke volume into the atrium, a low-impedance pathway, and TAPSE, S′ or ejection fraction may therefore appear reassuring even as contractile reserve declines. After correction, the entire volume must instead face the pulmonary vascular bed and effective afterload rises abruptly, explaining why unrecognized preoperative dysfunction may manifest as right-sided failure after a technically perfect procedure.

Right atrial pressure is transmitted to the venae cavae, liver and kidneys. Hepatic congestion, cholestasis and fibrosis are associated with hypoalbuminemia and coagulopathy; increased renal venous pressure reduces filtration and diuretic responsiveness. Ascites, intestinal congestion, early satiety and malabsorption promote sarcopenia and frailty. At this stage, risk no longer belongs only to the valve, but to a partially reversible multiorgan syndrome.

Fatigue and reduced exercise capacity may precede edema and ascites because forward output fails to increase adequately during exertion. The symptom profile can also help identify the etiology: palpitations may reflect accessory pathways or arrhythmias in Ebstein anomaly and atrial fibrillation in chronic forms; cyanosis suggests a right-to-left shunt; fever with pleuritic pain or hemoptysis points toward endocarditis; flushing and diarrhea suggest carcinoid syndrome even when systemic symptoms are partly controlled.

On physical examination, jugular venous pressure is elevated with large cv/V waves, the liver may be pulsatile and edema, ascites and effusions may be present. The holosystolic murmur at the lower sternal border increases with inspiration; however, it may be soft in massive low-velocity regurgitation. In Ebstein anomaly, widely split heart sounds and multiple sounds reflect delayed closure and a redundant anterior leaflet, whereas associated carcinoid or rheumatic stenosis adds a flow-dependent diastolic rumble.

Natural history varies profoundly with the cause: a focal prolapse may remain stable and then worsen after chordal rupture, carcinoid disease progresses with persistent hormonal exposure, rheumatic disease with scarring and recurrences, whereas in Ebstein anomaly the trajectory depends on anatomy, shunts and arrhythmias. In all these forms, the onset of symptoms, increasing diuretic requirements, progressive dilatation or deterioration of the right ventricle indicates that observation is no longer a neutral strategy.

Etiologic diagnosis, quantification and staging

Transthoracic echocardiography should answer “what is the lesion?” before “how much regurgitation is present?”. The right-ventricle-focused apical four-chamber, parasternal inflow, short-axis and subcostal views display different segments. Because the valve may have more than three leaflets and variable commissures, three-dimensional en face imaging improves identification of prolapse, flail, cleft, perforation, restriction and the relationship between the jet and the lesion.

Transesophageal echocardiography is indicated when transthoracic imaging does not define the anatomy, in endocarditis and for procedural planning. Ebstein anomaly shows apical displacement, atrialization and a sail-like anterior leaflet; carcinoid disease shows thick, fixed leaflets; rheumatic disease shows commissural fusion and shortened chordae; trauma and degeneration show an everted free margin or a segment moving beyond the annular plane. A mobile mass must be distinguished from strands, thrombus and nonbacterial vegetation using context, location and microbiology.

Severity requires a multiparametric assessment. Clearly abnormal morphology, a large flow convergence zone, an eccentric wall-hugging jet, a wide vena contracta, a dense continuous triangular signal with an early peak, systolic flow reversal in the hepatic veins and chamber dilatation all contribute to the diagnosis. Color Doppler alone is unreliable: it depends on gain, Nyquist limit, pressure and jet direction.

On the conventional scale, a biplane vena contracta of at least 7 mm, a PISA radius of at least 9 mm under the specified technical conditions, an EROA of at least 40 mm², a regurgitant volume of at least 45 mL and a regurgitant fraction of at least 50% support the severe category. The tricuspid orifice, however, is often elliptical, multiple and dynamic; hemispheric PISA may underestimate it, especially with eccentric or very low-velocity jets. Atrial fibrillation and atrial compliance can alter hepatic venous flow.

The TVARC classification extends severity to massive and torrential grades, which is useful in patients referred for transcatheter treatment. Vena contracta values of 7-13.9 mm, 14-20.9 mm and at least 21 mm correspond to severe, massive and torrential regurgitation, respectively; EROA values of 40-59, 60-79 and at least 80 mm², with regurgitant volumes of 45-59, 60-74 and at least 75 mL, follow the same progression. Three-dimensional vena contracta area adds information without assuming a circular shape. These grades describe the quantitative extreme, but by themselves are not indications for intervention.

The right ventricle should be assessed using basal and longitudinal dimensions, fractional area change, TAPSE, S′, free-wall strain and three-dimensional volumes, together with the atrium, annulus, vena cava and pulmonary flow. Every index is load-dependent and has geometric limitations. Less negative free-wall strain signals subclinical dysfunction, but thresholds such as −16% should not be used in isolation to declare an indication or futility.

Cardiac magnetic resonance is the reference standard for right ventricular volumes and ejection fraction when echocardiography is incomplete or discordant. Regurgitant volume can be calculated by subtracting forward pulmonary flow from right ventricular stroke volume, after checking for shunts and other regurgitant lesions. An RVEF of 45% or less has been associated with worse prognosis after transcatheter interventions, but it is not a universal threshold beyond which every treatment is futile.

CT defines annular dimensions and shape, its relationship to the right coronary artery, the venae cavae, access routes and geometry for annuloplasty or transcatheter replacement. In the interventional pathway, transesophageal echocardiography assesses tissue quality and grasping feasibility, whereas CT simulates anchoring and interactions. A large flail gap, perforation or rigid carcinoid leaflets may make TEER unsuitable even if regurgitation is technically visible.

Right heart catheterization is recommended in the specialist work-up of candidates for surgery or a transcatheter procedure, particularly when pulmonary hypertension is suspected. In severe regurgitation, Doppler velocity may underestimate pressure because ventricular and atrial pressures equalize; invasive hemodynamics calculates vascular resistance and distinguishes a precapillary component. Thermodilution may be inaccurate in extreme regurgitation, making comparison with the Fick method and complete oximetry useful.

ECG, NT-proBNP, creatinine, sodium, bilirubin, transaminases, albumin, INR and complete blood count define arrhythmias and organ reserve. In Ebstein anomaly, CMR, cardiopulmonary exercise testing and rhythm monitoring are useful. In endocarditis, blood cultures before antibiotics when possible and imaging for pulmonary embolic complications are required. In carcinoid disease, 5-HIAA and NT-proBNP track exposure and injury; an NT-proBNP below 260 pg/mL makes significant carcinoid heart disease unlikely, without excluding echocardiography when suspicion remains high.

Etiologic treatment, timing and surgery

Loop diuretics, sometimes combined with a thiazide and a mineralocorticoid receptor antagonist, relieve edema and ascites; dose, renal function, sodium and potassium require close monitoring. Selective paracentesis and nutritional treatment may stabilize advanced congestion. No drug reconstructs a chord, releases a commissure or restores mobility to a fibrotic leaflet: improvement after diuresis does not justify indefinitely postponing referral.

The cause must be controlled in parallel. Endocarditis and its complications require an Endocarditis Team, targeted antibiotics and removal of every infectious focus. In carcinoid disease, somatostatin analogues and oncologic therapy reduce mediator production but do not reverse mature plaques. Secondary prophylaxis limits rheumatic recurrences in indicated patients; in Ebstein anomaly, arrhythmias, accessory pathways and shunts are part of the strategy. Anticoagulation is guided by atrial fibrillation, prostheses and thromboembolic risk, not by the mere presence of regurgitation.

The 2025 ESC/EACTS guidelines recommend surgery for symptomatic severe primary regurgitation in the absence of severe right ventricular dysfunction or severe pulmonary hypertension, class I C. In asymptomatic patients, right ventricular dilatation or deterioration of right ventricular function justifies considering surgery before severe biventricular dysfunction or severe pulmonary hypertension develops, class IIa C. No single volume, TAPSE, strain value or RVEF replaces longitudinal assessment.

When left-sided valve surgery is planned, concomitant treatment of severe primary tricuspid regurgitation is recommended, class I B, and treatment of moderate primary regurgitation should be considered, class IIa B. The advantage is intervention before volume overload and an isolated reoperation increase risk. The decision must, however, verify that the finding is truly organic and not merely a dynamic jet altered by loading conditions.

Repair is preferable when it can be complete and durable. A rigid or semirigid ring stabilizes geometry, but it should be combined with correction of the lesion: closure of a cleft or perforation, neochordae, papillary muscle reimplantation, enlargement patch, commissuroplasty or leaflet reconstruction. Isolated annuloplasty does not correct a flail leaflet and may fail if retraction or tethering prevents coaptation.

In Ebstein anomaly, cone repair mobilizes leaflet tissue, rotates it and creates a circumferential coaptation surface; plication of the atrialized portion, shunt treatment and arrhythmia surgery are individualized. Symptoms, objective reduction in exercise capacity, cyanosis, paradoxical embolism, arrhythmias and progressive right ventricular enlargement or deterioration all contribute to timing. The experience of a high-volume ACHD center is critical for repairability and outcomes.

In right-sided endocarditis, during appropriate therapy, indications include persistent bacteremia for at least one week, severe acute regurgitation with right ventricular dysfunction refractory to diuretics, recurrent pulmonary emboli requiring ventilatory support, left-sided involvement or a residual vegetation larger than 20 mm after recurrent emboli. An isolated vegetation is not sufficient. Radical debridement and repair limit prosthetic material when residual tissue allows it.

After trauma, correction before advanced dilatation may allow papillary muscle reimplantation, neochordae, patch reconstruction and ring annuloplasty with good durability. In carcinoid disease or advanced rheumatic disease, diffusely rigid leaflets and a shortened apparatus make replacement more common; in carcinoid disease the pulmonary valve must be assessed at the same time. Hormonal control, anesthesia prepared for carcinoid crisis and oncologic coordination reduce perioperative risk.

Valve replacement is required with extensive infectious destruction, severe dysplasia, diffuse fibrosis or a repair that cannot be made durable. A bioprosthesis is often chosen in the right-sided position, but age, feasibility of anticoagulation, thrombosis, future valve-in-valve and lifetime strategy must be discussed. Pacing and conduction should be planned so that, whenever possible, a new lead does not cross the repair or prosthesis.

TRI-SCORE supports risk estimation for isolated surgery using age at least 70 years, NYHA III-IV, signs of right-sided heart failure, furosemide at least 125 mg/day, eGFR below 30 mL/min, elevated bilirubin, LVEF below 60% and at least moderate right ventricular dysfunction. The score does not determine who should be excluded: above all, it shows how late referral after organ injury can transform a potentially reparative procedure into a high-risk operation.

Transcatheter therapies, follow-up and prognosis

The 2025 European guidelines state that transcatheter treatment should be considered to improve quality of life and right-heart remodeling in high-risk patients with severe regurgitation who remain symptomatic despite optimal medical therapy, provided there is no severe right ventricular dysfunction or precapillary pulmonary hypertension. The recommendation applies to the overall tricuspid population; evidence dedicated to primary etiologies remains much more limited.

Tricuspid transcatheter edge-to-edge repair requires mobile leaflets, graspable tissue, adequate visualization and a non-excessive gap, often with anteroseptal coaptation. In a cohort of 339 patients, the 13% with primary prolapse or flail achieved acute reduction and safety comparable with secondary regurgitation, but the evidence is observational and does not demonstrate equivalence to a durable surgical repair. Perforation, active endocarditis, a large flail segment and fixed carcinoid or rheumatic leaflets are unfavorable anatomies.

Transcatheter annuloplasty may be reasonable when a substantial annular component has developed on top of the primary lesion, but it does not treat focal destruction. Orthotopic replacement offers more complete reduction when gap and anatomy preclude repair; however, it requires sufficient ventricular reserve to tolerate the abrupt increase in afterload. Bleeding, thrombosis, interaction with the right coronary artery, conduction disturbances and new pacemaker implantation are part of the trade-off.

In TRISCEND II, EVOQUE plus medical therapy improved mainly symptoms and quality of life at one year compared with medical therapy alone, with more major bleeding and pacemaker implantation. The trial does not provide a primary-etiology-specific demonstration. Caval valve prostheses reduce venous reflux without correcting the valve and are mainly palliative; valve-in-valve or valve-in-ring can instead treat a failed bioprosthesis or repair in an experienced center.

Active endocarditis contraindicates elective transcatheter implantation. Experience in a native valve with Ebstein anomaly or carcinoid disease is still anecdotal, whereas a degenerated bioprosthesis may provide more predictable anchoring. The availability of a technology does not make every anatomy treatable: the likelihood of eliminating the lesion, risk of stenosis, ventricular recoverability, expected durability and future strategy must be weighed by the Heart Team.

The standardized 2026 pathway proposes early referral to a Heart Valve Centre for at least moderate regurgitation, especially with symptoms or progressive ventricular involvement. Asymptomatic moderate or severe disease without remodeling requires clinical assessment, echocardiography and laboratory tests approximately every six months; lower stable grades may be reviewed annually or at tailored intervals. Etiology influences the schedule more than the quantitative category alone.

In active carcinoid disease, NT-proBNP, 5-HIAA and echocardiography are generally repeated every three to six months according to disease activity and therapy; surveillance always includes the pulmonary valve and, after replacement, prosthetic thrombosis and degeneration. In Ebstein anomaly, ACHD follow-up includes rhythm, oxygen saturation, CMR and exercise capacity. After endocarditis, recurrence, residual regurgitation and new embolic events are sought, applying antibiotic prophylaxis recommended for previous endocarditis or prosthetic material during high-risk dental procedures.

After surgery or a transcatheter intervention, an examination before discharge serves as the reference; early review within four to twelve weeks, reassessment at six to twelve months and then at least annually are appropriate, with individual tailoring. Residual or recurrent regurgitation, gradient, right-heart volumes and function, pulmonary pressure, renal and hepatic function, rhythm, pacing system, thrombosis and signs of endocarditis are measured. NYHA class, KCCQ and walking capacity describe perceived benefit, which cannot be replaced by color Doppler alone.

New symptoms, escalating diuretic requirements, atrial fibrillation, enlargement of the atrium, annulus or ventricle, worsening strain or RVEF and rising bilirubin, creatinine or NT-proBNP prompt earlier review. Prognosis depends on etiology, control of the cause, pulmonary hypertension, ventricular function and hepatorenal reserve. The best window is not when congestion becomes intolerable, but when the lesion remains correctable and the right heart can still remodel.