Tricuspid valve area

TVA · Continuity equation or pressure half-time; planimetry is rarely feasible. Severity is graded chiefly by mean gradient

Normal range & thresholds

Normal 7–9 cm².
Severe tricuspid stenosis^[4,7]:

Mean diastolic gradient ≥5 mmHg (at a heart rate of 70–80/min)
Inflow VTI >60 cm; peak E velocity ≥1.0–1.5 m/s
Pressure half-time ≥190 ms
Continuity-derived valve area ≤1.0 cm²
Enlarged right atrium, dilated inferior vena cava

Because right-sided gradients are small, a mean gradient of 5 mmHg represents severe obstruction — the number looks trivial and is not. Report the heart rate and the respiratory phase with it.

Pathophysiology

Tricuspid stenosis obstructs systemic venous return, so its consequences are entirely upstream: a raised right atrial pressure, hepatic congestion, ascites and peripheral oedema, typically with a clear chest — the classic clinical clue that the obstruction is right-sided. The gradient is small in absolute terms because the driving pressures are low, and it varies markedly with respiration, rising on inspiration as venous return increases. Almost all cases coexist with mitral stenosis (rheumatic) or with tricuspid regurgitation.^[4]

Raised by

After balloon valvuloplasty or valve replacement
Overestimated when the pressure half-time is applied in the presence of significant tricuspid regurgitation or an atrial septal defect

Lowered by

Rheumatic disease — the commonest cause, and essentially always with mitral involvement; isolated rheumatic tricuspid stenosis is a diagnosis to doubt
Carcinoid heart disease — thickened, retracted, fixed leaflets in a semi-open position, usually with severe regurgitation as well
Device-related: pacemaker and defibrillator leads causing adhesion, and lead-associated fibrosis — increasingly recognised
Prosthetic tricuspid valve stenosis or thrombosis (the most thrombosis-prone position)
Infective endocarditis with a large vegetation; right atrial myxoma or thrombus obstructing inflow
Congenital tricuspid stenosis or atresia; Whipple disease, Fabry, endomyocardial fibrosis; extrinsic compression

Technique & pitfalls

Use the RV-focused apical 4-chamber and the parasternal RV inflow views; align the beam carefully with inflow.
Average over the respiratory cycle, or report at end-expiration — the gradient varies substantially with respiration, more than any left-sided valve.
Report the heart rate; average 5–10 cycles in atrial fibrillation, which is nearly always present.
The pressure half-time constant (190 ms) is less well validated than the mitral one — treat it as supportive, not definitive, and say so.^[4]
Assess the coexisting tricuspid regurgitation, and always examine the mitral valve, because the aetiology is usually shared.
3D TOE and CMR help when the anatomy is unclear or a device lead is implicated.

Pseudo-change & artefact

Respiratory variation not accounted for — the dominant artefact.
Tachycardia and atrial fibrillation raising the mean gradient.
Coexisting significant tricuspid regurgitation invalidating both the pressure half-time and the continuity equation.
An atrial septal defect decompressing the right atrium and lowering the gradient.
Poor Doppler alignment — underestimates.
Volume status: a diuresed patient has a lower gradient at an unchanged valve area.

Treatment thresholds

Severe tricuspid stenosis → surgery, class I when symptomatic, and at the time of left-sided valve surgery when the tricuspid valve is significantly stenotic. Repair is preferred where feasible; a bioprosthesis is generally preferred to a mechanical valve in the tricuspid position, because of the high thrombosis risk.^[6,7]
Percutaneous balloon tricuspid valvuloplasty may be considered in isolated tricuspid stenosis without significant regurgitation — a small and select group.^[7]
Device-related tricuspid stenosis may require lead extraction, with or without valve intervention.
Carcinoid: valve intervention alongside somatostatin analogue therapy and control of the primary tumour.
Diuretics are the mainstay of symptom relief but do not address the obstruction.

Next step

Next: quantify coexisting tricuspid regurgitation and examine the mitral and aortic valves — the aetiology is nearly always shared.
Then: assess right atrial size, IVC, hepatic vein Doppler and the systemic consequences (liver function, ascites).
Then: TOE, 3D imaging or CMR for leaflet anatomy and device-lead interaction; carcinoid screening (urinary 5-HIAA) where the appearance suggests it.
Then: right heart catheterisation with simultaneous RA and RV pressures where the echo gradient and the clinical picture disagree; then Heart Team.

Drugs

Diuretics and salt restriction — symptomatic relief of systemic congestion; the mainstay medically.
Rate control lengthens diastole and reduces the gradient.
Anticoagulation for atrial fibrillation and for prosthetic tricuspid valves, which thrombose more than any other position.
Somatostatin analogues in carcinoid, to control the syndrome and slow valve deterioration.
Secondary rheumatic fever prophylaxis where relevant.
No drug relieves the obstruction.

Reversibility

Not reversible medically. Surgical repair or replacement relieves the obstruction immediately, and systemic congestion, hepatic dysfunction and ascites resolve over weeks to months provided right ventricular function is preserved. The important qualifier is that patients with tricuspid disease frequently present late, with cardiac cirrhosis and a failing right ventricle, and those consequences are only partly reversible — the argument for earlier referral in this most neglected of the four valves.^[6,7]