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← Section II · Valvular Heart Disease
II.G

Pulmonic Valve

7 cards

Notes

Anatomy and imaging

  • Three semilunar cusps (anterior, right, left) - hardest of the four valves to image on TTE.
  • Best views: PSAX of the aortic valve (RV outflow), parasternal RVOT view, subcostal short-axis.
  • TEE: main PA and right PA seen well; left PA is often obscured by air.

Pulmonic stenosis (PS) - severity

  • Mild: peak velocity < 3 m/s (peak gradient < 36 mmHg).
  • Moderate: peak velocity 3–4 m/s (peak gradient 36–64 mmHg).
  • Severe: peak velocity > 4 m/s (peak gradient > 64 mmHg).

Causes of PS

  • Congenital: bicuspid or dysplastic PV (Noonan syndrome), tetralogy of Fallot, subvalvular (infundibular) stenosis, supravalvular / peripheral PS (Williams syndrome, rubella), branch PA stenosis.
  • Acquired: rheumatic (rare), carcinoid, prior surgical repair, mass extrinsic compression.

Pulmonic regurgitation (PR)

  • Trace/mild PR nearly universal on echo.
  • Causes: pulmonary hypertension (annular dilation), congenital absent valve syndrome, post-repair TOF (RVOT patch → free PR), carcinoid, endocarditis.

Severe PR - echo features

  • Dense CW envelope with steep deceleration slope (PR pressure half-time < 100 ms).
  • Wide vena contracta (> 50 % of the PV annulus width by color).
  • Holodiastolic reversal in the pulmonary artery (below the pulmonic valve).
  • RV dilation (chronic).
  • Pulmonary regurgitation index (PRi) = PR duration / diastolic duration; < 0.77 → severe PR.

Pulmonary hypertension and PV M-mode

  • Severe PAH signs on PV M-mode: diminutive or absent 'a'-wave, prolonged pre-ejection period, mid-systolic notching ('flying-W sign'), from transient reversal of the RVOT–PA gradient due to poor PA compliance.
  • Pulmonic stenosis M-mode: exaggerated prominent 'a'-wave, NO mid-systolic notching.

PA acceleration time (AT) and PAP

  • Normal PA AT ≥ 130 ms (measured from onset of pulmonary ejection to peak on PW Doppler in RVOT).
  • AT ≤ 100 ms → elevated mean PAP; roughly:
    • Mean PAP (mmHg) ≈ 79 − 0.45 × AT (ms) (Mahan formula).
  • Mid-systolic notching of the PA velocity envelope → severe PAH.

Cards

  • basicII.G-001
    State the peak velocity/gradient thresholds for MILD, MODERATE, and SEVERE pulmonic stenosis.
    → Mild: peak velocity < 3 m/s (peak gradient < 36 mmHg). Moderate: 3–4 m/s (36–64 mmHg). Severe: > 4 m/s (> 64 mmHg).
  • basicII.G-002
    Congenital syndromes associated with pulmonic stenosis?
    → Noonan syndrome (dysplastic PV), Williams syndrome (supravalvular PS + peripheral PS), congenital rubella (peripheral PS), tetralogy of Fallot (infundibular PS).
  • basicII.G-003
    Give three echo criteria for SEVERE pulmonic regurgitation.
    → Steep CW deceleration slope (PR pressure half-time < 100 ms); vena contracta > 50% of PV annulus width by color; holodiastolic flow reversal in the pulmonary artery; RV dilation (chronic).
  • basicII.G-004
    Most common cause of severe PR in adults?
    → Post-surgical repair of tetralogy of Fallot with a transannular RVOT patch — creates chronic free PR. Also PAH-related annular dilation.
  • basicII.G-005
    State the Mahan formula relating PA acceleration time to mean PA pressure.
    → Mean PAP (mmHg) ≈ 79 − 0.45 × AT (ms), where AT is the pulmonary flow acceleration time in the RVOT.
  • basicII.G-006
    What pulmonary acceleration time indicates elevated mean PAP?
    → AT ≤ 100 ms suggests elevated mean PAP. Normal AT ≥ 130 ms. AT is measured from the onset of pulmonary ejection to peak velocity on PW Doppler in the RVOT.
  • basicII.G-007
    Compare pulmonic valve M-mode findings in pulmonic stenosis vs severe pulmonary hypertension.
    → PS: exaggerated prominent 'a'-wave, NO mid-systolic notching. Severe PAH: diminutive/absent 'a'-wave WITH mid-systolic notching ('flying-W sign'), from transient reversal of the RVOT–PA gradient due to poor PA compliance.