The pulmonary valve is a tricuspid, semilunar valve that is similar in construction and size to the aortic valve. The valve has a right (R) -, a left (L) and an anterior cusp (A). The pulmonary valve has a slightly more left, anterior and superior position to the aortic valve.
Pulmonary regurgitation (PR) is a volume load for the RV. Important regurgitation will lead to RV dilation. Due to this volume load the RV will endure long but eventually will fail.
Quantification of pulmonary regurgitation
|Grading the severity of PR|
|PR severity classes||Mild||Moderate||Severe|
|Colour flow PR jet width 𝛼||Small, usually <10mm in length with a narrow origin||Intermediate||Large, with a wide origin; may be brief in duration|
|Reversal flow in pulmonary artery branches||Absent||Absent||Present|
|CW signal of PR jet 𝛽||Faint/Slow deceleration||Dense/variable||Dense/steep deceleration, early termination od diastolic flow|
|Pulmonic vs aortic flow by PW||Normal or slightly increased||Intermediate||Greatly increased|
|VC width (mm)||Not defined||Not defined||Not defined|
|Deceleration time of PR (ms)||Not defined||Not defined||<260|
|Pressure half-time (ms) 𝛾||Not defined||Not defined||<100|
|Jet width/annulus ratio (%)||Not defined||Not defined||>65|
|PR index 𝛿||Not defined||Not defined||<0,77|
|EROA (mm²)||Not defined||Not defined||Not defined|
|R Vol (mL)||Not defined||Not defined||Not defined|
|RV size 𝜀||Usually normal||Normal or dilated||Usually dilated|
|CW, continuous wave; EROA, effective regurgitant orifice area; PR, pulmonic regurgitation; RV right ventricle; PW, pulsed wave; R Vol regurgitant volume; VC, vena contracta.
𝛼 At Nyquist limit of 50-60 cm/s.
𝛽 Steep deceleration is not specific for severe PR
𝛾 Pressure half time is shortened with increasing RV diastolic pressure.
𝛿 PR index ratio of PR duration by CW Doppler to total diastolic time.
𝜀 Unless for other reasons, the RV size is usually normal in patients with mild PR. In acute severe PR, the RV size is often normal. Accepted cut-off values for non-significant RV enlargement (measurements obtained from the apical 4-chamber view): Mid RV dimension ≦33mm, RV end-diastolic area ≦ 28cm², RV end-systolic area ≦16cm². RV fractional area change >32%, maximal.
Causes of pulmonary regurgitation
|PR is found in 40-80% of people||incorrectly constructed valve cusp(s)||As a result of pulmonary hypertension.|
|Absence or partial absense of a valve cusp||By balloon dilatation of the PV in correction of pulmonary stenosis|
Pulmonary stenosis is very rare.
Quantification of pulmonary stenosis
|PGmax (mmHg)||< 36||36 - 64||> 64|
|Vmax (m/s)||< 3||3 - 4||> 4|
Causes of pulmonary stenosis
|Tetralogy van Fallot||Rheumatic fever|