Trivial/mild pul regurg is common in ventilated patients.
Regurgitation jets can be used to estimate MPAP and PADP.
Assessment:
2D assessment as for pulmonary stenosis.
Colour:
Jet width.
Mild pulmonary regurg the jet width is narrow and increases in size with severity.
There may be rapid equalisation of PA and RV diastolic pressures causing a brief colour jet which is challenging to assess.
CW:
Attempt to align with colour jet.
Visual assessment for density and deceleration rate.
If mild regurg the deceleration will be slow. Deceleration slow steepens with increased severity.
Peak velocity used to calculate PA diastolic pressure. End diastolic velocity used to measure MPAP.
PW:
Measure RVOT VTI.
Compare the ratio of RVOT VTI to LVOT VTI measured in A5C view.
Regurgitation fraction and volume:
Measure tricuspid annulus diameter in cm then use this to calculate the CSA of tricuspid valve in cm^2:
CSAtv = 0.785 x tricuspid annulus diameter^2
VTI of tricuspid inflow in A4C using PW doppler to give TV VTI in cm. Place sample volume at valve leaflet tips.
Calculate stroke volume of TV in ml/beat which can be calculated from:
SVtv = CSA RVOT x TV VTI
In PSAX – measure diameter of RVOT at level of PV annulus (RVOT2) in cm then calculate CSA:
CSA RVOT = 0.785 x RVOT diameter^2
Measure VTI of RVOT outflow with PW doppler.
SV RVOT can be calculated from:
SV RVOT = RVOT CSA x RVOT VTI
PR volume can therefore be calculated from:
RV = SV RVOT – SV TV
Pulmonary regurgitant fraction can be calculated from:
RF = RV / SV TV (x 100 to express as percentage)
This measurement is not valid if there is significant tricuspid regurgitation or any error in measurement of TV annulus/RVOT can have large impact on result.
Severity is determined by all of the above variables.