Tricuspid & Pulmonic Valve Disease and Pulmonary Hypertension Assessment

Tricuspid Valve Disease

Trace-to-mild tricuspid regurgitation (TR) is a normal finding in most structurally normal hearts and requires no further workup. Pathologic TR, however, is overwhelmingly functional/secondary — annular dilation driven by RV pressure or volume overload (pulmonary hypertension, left heart disease, atrial fibrillation) rather than primary leaflet disease. Primary causes include rheumatic disease (leaflet thickening, doming, commissural fusion — less common on the TV than the MV), infective endocarditis, myxomatous prolapse, Ebstein anomaly, blunt trauma, and pacemaker/ICD lead-related TR from leaflet impingement, adhesion, or perforation. Carcinoid heart disease produces a distinctive pattern: thickened, retracted, immobile tricuspid (and pulmonic) leaflets that fail to coapt or open properly, because the lungs normally inactivate circulating serotonin and other vasoactive substances, sparing the left heart from the same process.

TR severity is graded using an integrated approach, not a single number:

Hepatic vein systolic flow reversal is one of the most specific signs of severe TR and should be actively sought whenever significant TR is suspected.

Tricuspid stenosis (TS) is rare and almost always rheumatic, typically accompanying mitral stenosis rather than occurring in isolation. A mean transtricuspid gradient greater than 5 mmHg (measured at a normal heart rate) is generally accepted as hemodynamically significant, though pressure half-time methodology is far less validated for TS than for MS.

Pulmonic Valve Disease

Like TR, trivial-to-mild pulmonic regurgitation (PR) is a common incidental finding in normal hearts. Pathologic PR most often follows repaired tetralogy of Fallot (the classic cause of severe, free PR requiring long-term surveillance), pulmonary hypertension with annular dilation, endocarditis, or carcinoid involvement of the right heart.

Pulmonic stenosis (PS) is overwhelmingly congenital and is the most common congenital lesion of the semilunar valves. Severity is graded by peak instantaneous gradient/velocity, analogous to but numerically distinct from aortic stenosis grading:

Pulmonary Hypertension Assessment

Echocardiography screens for pulmonary hypertension (PH) primarily through the tricuspid regurgitant jet. Right ventricular systolic pressure (RVSP), which equals pulmonary artery systolic pressure (PASP) in the absence of pulmonic stenosis, is calculated with the modified Bernoulli equation:

RVSP = 4 x (TR Vmax)^2 + RAP

Right atrial pressure (RAP) is not measured directly — it is estimated from inferior vena cava (IVC) diameter and its inspiratory collapse:

Because TR Vmax alone drives most of the RVSP value, ASE echo-probability criteria grade the likelihood of PH directly from this velocity:

Supportive secondary signs (used to adjudicate the intermediate category and corroborate high-probability cases) include an RV/LV basal diameter ratio >1.0, a flattened or D-shaped interventricular septum, pulmonary artery acceleration time <105 ms (often with midsystolic notching), and an elevated early diastolic pulmonic regurgitant velocity. Right heart catheterization remains the diagnostic gold standard, with hemodynamic PH defined as a mean PA pressure >20 mmHg at rest — the echo estimate is a screening tool, not a substitute.

Right ventricular size and function must be assessed alongside pressure estimation, since RV failure — not the pressure number alone — drives symptoms and prognosis. Tricuspid annular plane systolic excursion (TAPSE), an M-mode measurement of longitudinal annular displacement, is the most widely used single quantitative index:

TAPSE is easy to acquire and reproducible, but it is a load-dependent, single-segment (basal free wall) measurement and can be misleadingly normal in regional RV dysfunction or after cardiac surgery — always interpret it alongside RV size, FAC, and qualitative wall motion rather than in isolation.

Acquiring a Reliable RVSP

The TR jet used for RVSP must be optimized carefully: align the CW Doppler beam as parallel as possible to the jet, interrogating from multiple windows (parasternal RV inflow, apical four-chamber, subcostal) and taking the best, most complete envelope. Underestimating TR Vmax directly underestimates RVSP through the squared term in the Bernoulli equation, so a faint or truncated envelope should never be accepted at face value. When TR is trivial or absent, RVSP cannot be reliably estimated, and the study should instead rely on the secondary structural and Doppler signs above, reported qualitatively as low, intermediate, or high probability of pulmonary hypertension rather than as a specific pressure value.

RVSP is specific to the right ventricle and pulmonary artery in the absence of pulmonic stenosis; if pulmonic stenosis is present, RV systolic pressure and PA systolic pressure diverge and must be reported separately, since the RVSP calculation no longer directly represents pulmonary artery pressure.