Right Side Valves

Pulmonary & Tricuspid Valve — Echocardiography Flashcards with Doppler criteria, severity grading, and key clinical pitfalls.

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Q1 Describe the pulmonary valve anatomy, the definition of pulmonary stenosis, and the causes of subvalvular, supravalvular, and valvular pulmonary stenosis. ▾
  • Pulmonary valve anatomy:
    • Normal pulmonary valve is a three-leaflet valve.
    • Located anterior and to the left of the aortic valve.
    • Its long axis is perpendicular to the long axis of the aortic valve.
    • On 2D TTE, the pulmonary valve is viewed in long-axis alignment only, except in transposition of the great arteries.
    • In PSAX view, the aortic valve is seen in short axis while the pulmonary valve is seen in long axis.
  • Pulmonary stenosis definition:
    • PS refers to valvular stenosis, but subvalvular and supravalvular stenosis are possible.
  • Subvalvular stenosis:
    • Congenital form: largely due to RVOT obstruction from hypertrophied infundibular muscle bundles, also called double-chambered RV.
    • Commonly associated with a ventricular septal defect or caused by the VSD wall hitting jet that promotes muscle hypertrophy.
    • Acquired form: due to remodeling from previous intervention at that area.
  • Supravalvular stenosis:
    • Stenosis distal to the valve, at the main pulmonary artery or branches.
  • Valvular stenosis:
    • Almost always congenital, due to bicuspid or unicuspid dysplastic valve.
    • Rare causes: carcinoid and rheumatic valve disease.
    • In congenital PS due to bicuspid/unicuspid morphology, leaflet doming is common and is commonly associated with poststenotic dilatation of the pulmonary artery.
Q2 How is pulmonary stenosis diagnosed and graded? Include the DVI, color Doppler findings, and severity cutoff values. ▾
  • Establish the diagnosis before grading:
    • High velocity/gradient across the pulmonary valve may occur without valvular stenosis due to increased flow from:
      • Left-to-right intracardiac shunt
      • Thyrotoxicosis
      • Anemia
  • DVI (Doppler velocity index):
    • DVI = PW peak velocity just proximal to the valveCW peak velocity
    • DVI significantly < 1 is suggestive of stenosis.
    • Example from source: PW proximal velocity 1.7 m/s, CW peak velocity 2.5 m/s, DVI = 0.68.
  • Color flow Doppler:
    • Flow turbulence starting at the valve level is suggestive of stenosis.
  • Grading after diagnosis:
    • Use peak velocity and derived peak pressure gradient.
    • Other echocardiographic parameters have not been validated for this purpose.
PS severity Mild Moderate Severe
Peak velocity (m/s) < 3 3–4 > 4
Peak pressure gradient (mmHg) < 36 36–64 > 64
  • Subvalvular/RVOT stenosis grading:
    • Not accurate on TTE due to difficulty aligning the Doppler beam.
    • TEE can be helpful.
Q3 What is the clinical significance and etiology of pulmonary regurgitation? ▾
  • Clinical significance:
    • Trace to mild PR is normal in most people.
    • Significant PR exerts volume overload on the RV, causing:
      • RV dilatation with initially preserved function
      • Abnormal septal motion pattern consistent with RV volume overload
  • Etiology — Congenital:
    • Congenital abnormal leaflets
    • Post balloon valvuloplasty
    • RVOT dilatation post tetralogy of Fallot repair that involves RVOT enlargement
  • Etiology — Acquired (<1%):
    • Rheumatic
    • Endocarditis
    • Carcinoid
    • Pergolide induced
    • Pulmonary artery hypertension may cause dilatation of the pulmonary artery and annulus, resulting in abnormal PR.
Q4 How is pulmonary regurgitation severity graded? Include color Doppler, spectral Doppler, PW Doppler, RVOT/LVOT VTI, and the comprehensive grading table. ▾
  • Color flow Doppler:
    • Main parameters: jet length and vena contracta width.
    • Use vena contracta width / pulmonary annulus diameter ratio.
    • Key pitfall: in wide-open PR, the jet can be missed because of:
      • Low PR jet velocity
      • Laminar flow
      • Brief duration due to rapid pressure equilibrium between PA and RV
  • Spectral Doppler:
    • CW signal density and deceleration time correlate with severity.
    • Mild PR: faint CW signal with slow deceleration.
    • Severe PR: dense CW signal with rapid deceleration; with forward flow produces a "sine-wave" shape.
    • Severe PR cutoffs:
      • Pressure half-time < 100 msec
      • Deceleration time < 260 msec
    • PR index = PR durationtotal diastolic time
  • PW Doppler:
    • Sample volume in a pulmonary artery branch.
    • Diastolic flow reversal indicates severe PR.
  • RVOT VTI vs LVOT VTI:
    • RVOT VTI measured just proximal to the pulmonic valve compared to LVOT VTI provides a clue to PR severity, provided there is no significant aortic regurgitation or intracardiac shunt.
Parameter Mild Moderate Severe
PV morphology Normal Normal or abnormal Abnormal / may not be visible
RV size Usually normal Normal/dilated Dilated
Jet size Thin, < 10 mm length, narrow origin Intermediate Broad origin, variable length
CW jet density/contour Soft Dense Dense, early termination
Deceleration time — — Short, < 260 msec
Pressure half-time — — < 100 msec
PR index — — < 0.77
Diastolic flow reversal in branch PA — — Prominent
RVOT VTI vs LVOT VTI Slightly increased Intermediate Greatly increased
Q5 Describe tricuspid valve anatomy and leaflet identification in the RV inflow view. ▾
  • Tricuspid valve anatomy:
    • Most anatomically complex valve.
    • Usually composed of 3 leaflets: anterior, posterior, and septal.
    • Variants with fewer or more leaflets are not very common.
    • Anterior leaflet is the largest; septal leaflet is typically the smallest.
    • Septal leaflet inserts into the membranous septum more apically than the mitral valve insertion.
    • The TV always follows the RV; in complex congenital heart disease such as L-transposition, identifying the TV identifies the RV.
  • Leaflet identification — general:
    • In 2D TTE, usually two leaflets are viewed at a time, making identification complicated.
    • A 3D data set-derived method by Addeita K et al. has led to more accurate leaflet identification.
    • Main TTE views: RV inflow, PSAX, apical 4-chamber, RV focused view.
  • RV inflow view:
    • The leaflet to the right is always the anterior leaflet.
    • If the septum is viewed: always an anterior-septal combination.
    • If the septum is not viewed: anterior-septal or anterior-posterior combinations are possible.
  • Leaflet identification rules also apply to TEE views similarly.
Q6 In the PSAX and apical 4-chamber/RV-focused views, how are the tricuspid leaflets identified? ▾
  • PSAX view:
    • The leaflet closest to the aortic valve is either anterior or septal, but never posterior.
    • The leaflet arising from the RV free wall is either anterior or posterior, but never septal.
    • Almost half of cases: anterior-posterior combination.
    • Other possibilities: septal-posterior, septal-anterior, anterior alone, and septal-anterior-posterior.
    • When anterior-posterior is viewed:
      • Aortic valve is always in view.
      • TV coaptation point is central.
    • When septal-anterior or septal-posterior is viewed:
      • Aortic valve is not well visualized because the septal leaflet inserts into the membranous septum below the aortic valve.
      • Coaptation point is eccentric and closer to the aorta.
    • When all three leaflets are seen:
      • Septal leaflet closer to the aorta
      • Anterior leaflet in the middle
      • Posterior leaflet at the RV free wall
  • Apical 4-chamber / RV-focused views:
    • In apical 4-chamber view, the TV leaflet near the septum is always the septal leaflet.
    • RV focused view: septal-posterior combination.
    • Slight anterior angulation: LVOT is viewed (apical 5-chamber) and TV shows septal-anterior combination.
    • Slight posterior angulation: coronary sinus is viewed and TV shows septal-posterior combination.
    • When neither coronary sinus nor LVOT is viewed: septal-anterior or septal-posterior is possible.
Q7 What are the causes and echocardiographic assessment of tricuspid stenosis? ▾
  • General:
    • TS is the least common valvular stenosis lesion.
  • Etiology:
    • Rheumatic:
      • Almost always associated with rheumatic mitral stenosis.
      • Suggested by tricuspid leaflets diastolic doming.
    • Carcinoid:
      • Due to endocardial deposition of fibrotic plaques.
      • Typically involves right heart valves, not left-sided valves, because vasoactive substances (5-HT, histamine, tachykinins, prostaglandins) are inactivated in the lungs and liver.
      • Liver metastasis causes right heart involvement.
      • Intracardiac shunt or lung involvement allows left-sided involvement.
      • Leaflets are thickened, fibrosed, retracted giving a frozen valve appearance with very limited mobility.
      • Carcinoid TS is almost always associated with significant tricuspid regurgitation.
    • Rare causes:
      • Congenital
      • Pacemaker lead associated
      • Lupus valvulitis
      • Obstruction by a mass
  • TS assessment:
    • Primarily performed by CW Doppler.
    • TV inflow velocities are affected by respiration, so velocities should be:
      • Averaged throughout the respiratory cycle, or
      • Obtained at end-expiration breath hold.
    • In atrial fibrillation, average TV inflow velocities from 3 to 8 beats.
    • Mean pressure gradient ≥ 5 mmHg indicates significant TS.
    • However, mean gradient is affected by TR: greater TR → higher inflow gradient.
    • TV pressure half-time can be used, with limitations similar to mitral stenosis, including the effect of significant pulmonic regurgitation.
    • Valve area by continuity equation has been used but should not be used in significant TR.
    • Table 11-3 summarizes findings of significant TS; its content is not provided in the source text.
Q8 What are the mechanisms and etiologies of tricuspid regurgitation? ▾
  • General:
    • A small degree of TR is normally present in most people.
    • Important to grade abnormal TR and determine its mechanism.
  • Secondary (functional) TR:
    • Most common cause of significant TR.
    • Due to:
      • Annular dilatation secondary to RV or RA dilatation
      • Apical tethering of leaflets due to RV remodeling
      • Or both
  • Primary TR — acquired:
    • Myxomatous degeneration: most common cause of primary TR.
      • May be associated with prolapse, defined as excessive billowing into the right atrium.
      • If prolapse is present, TR jet is eccentric and opposite in direction to the prolapsed leaflet.
    • Chest trauma: causes torn or flail leaflet.
    • RV endomyocardial biopsy
    • Pacemaker lead that interferes with TV closure
    • Endocarditis
    • Rheumatic
    • Carcinoid: causes frozen immobile valve with retracted leaflets.
  • Primary TR — congenital:
    • Ebstein’s anomaly
    • TV tethering in perimembranous VSD
    • Repaired tetralogy of Fallot
    • Congenitally corrected transposition of great vessels where the tricuspid valve is the systemic atrioventricular valve.
Q9 How is TR assessed using right heart chamber findings and Doppler parameters such as jet area, vena contracta, PISA, CW Doppler, and hepatic vein flow? ▾
  • Right heart chambers:
    • Significant TR causes volume overload on RV and RA → both become dilated.
    • Interventricular septum is usually flattened at end-diastole.
    • If TR is caused by or associated with pulmonary hypertension, septal flattening occurs during systole and diastole, indicating pressure and volume overload.
    • If the TV is normal and RV function is abnormal, TR is likely the result, not the cause, of RV dysfunction.
  • Doppler acquisition:
    • Obtain signal in the view showing maximum TR and best angle alignment for spectral Doppler.
  • Jet area:
    • Limitations similar to MR.
    • Eccentric wall-impinging jets appear smaller than central jets with the same regurgitant volume.
    • Pulmonary hypertension increases TR velocity and momentum, making the jet appear more severe.
    • In wide-open TR, jet velocity may be very low, no aliasing occurs, and the jet may not be visible.
    • TR jet area > 10 cm² is consistent with severe TR.
  • Vena contracta:
    • 2D vena contracta width > 0.7 cm is consistent with severe TR.
    • 3D vena contracta area (VCA) correlates well with EROA.
    • VCA > 0.4 cm² is consistent with severe TR.
  • PISA:
    • Not as validated as in MR and has the same limitations.
    • Regurgitant orifice in TR is usually non-circular.
    • PISA radius can be used for severity estimation.
    • PISA can quantify EROA and regurgitant volume.
    • Because of lower TR velocity and non-circular orifice, the cutoff for PISA-derived regurgitant volume is lower than for MR.
    • Volumetric measurement of regurgitant volume across the TV is not feasible due to the non-circular TV annulus; PISA is the only echocardiographic method for its estimation.
  • CW Doppler:
    • Mild TR: soft, parabolic jet.
    • Severe TR: dense, triangular jet with early peaking due to rapid RV-RA equilibrium.
  • Hepatic vein PW Doppler:
    • Normal: systolic dominance of forward flow.
    • Increasing TR severity: systolic blunting.
    • Severe TR: systolic flow reversal.
    • Hepatic vein systolic reversal with no other explanation is specific for severe TR.
    • Other causes of hepatic vein systolic reversal:
      • A-V desynchrony in atrial fibrillation, complete heart block, ventricular paced rhythm.
      • These usually do not cause systolic reversal in every beat; reversal occurs only with some beats.
    • With decreased RA/RV compliance and elevated RA pressure, moderate TR can still produce hepatic vein systolic reversal, particularly with inspiration.
Q10 Summarize the comprehensive TR severity grading parameters and 3D TV orientation, and list the references. ▾
  • General approach:
    • Mild TR is common in healthy individuals.
    • In more than mild TR, the mechanism should be identified.
    • A comprehensive approach including all parameters is essential for accurate grading.
Parameter Mild Moderate Severe
TV morphology Normal Moderately abnormal Severe valve lesion
RV and RA size Usually normal Normal/dilated Dilated
IVC diameter < 2 cm Normal or mildly dilated 2.1–2.5 cm Dilated > 2.5 cm
Color flow jet area Small, narrow, central Moderate Large central or eccentric wall impinging jet
Flow convergence zone Not visible, transient or small Intermediate Large throughout systole
CW Doppler Faint/partial/parabolic Dense, parabolic or triangular Dense, triangular
Color flow jet area at Nyquist 50–70 cm/sec — — > 10 cm²
Vena contracta width at Nyquist 50–70 cm/sec < 0.3 cm 0.3–0.6 cm ≥ 0.7 cm
PISA radius at Nyquist 28 cm/sec Slightly increased Intermediate Greatly increased
Hepatic vein flow Systolic dominance Systolic blunting Systolic flow reversal
Tricuspid inflow A-wave dominance Variable E-wave > 1 m/sec
EROA (cm²) < 0.20 0.20–0.39 ≥ 0.40
Regurgitant volume by 2D PISA (ml) < 30 30–44 ≥ 45
  • 3D TV views:
    • When viewing the TV by 3D echocardiography, the interventricular septum and interatrial septum should always be positioned inferiorly, whether viewed from the RV or RA perspective.
    • Leaflets can then be identified accordingly.
  • References:
    • Baumgartner H et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009;22(5):442.
    • Zoghbi WA et al. Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation. J Am Soc Echocardiogr. 2017;30(4):303–371.