LITFL | Critical Care Compendium | Pulmonary Hypertension Echocardiography
Pulmonary Hypertension Echocardiography
OVERVIEW
TOE better than TTE
Normal pulmonary arterial pressure in a person living at sea level has a mean value of 12-16 mm Hg.
Pulmonary hypertension is present when mean pulmonary artery pressure exceeds 25 mm Hg at rest or 30 mm Hg with exercise.
MEASUREMENT OF PULMONARY ARTERY PRESSURE
Doppler Echo can approximate pulmonary artery systolic pressure (PASP) using
— tricuspid valve velocity (4v2 = TV pressure gradient)
— estimated CVP (=RA pressure)
— Bernoulli equation
PASP = RVSP (in the absence of RVOTO or pulmonic stenosis)
RVSP = 4v2 + CVP
Mean PAP can be approximated because mPAP = 0.61•sPAP + 2.
A systolic PAP of 40 mm Hg typically implies a mean PAP more than 25 mm Hg = pulmonary hypertension
Severity of pulmonary hypertension (mPAP)
Mild = 25-40mmHg
Moderate = 41-55mmHg
Severe = > 55mmHg
The mean and end diastolic pressures in the pulmonary artery are directly assessed by measuring peak and end-diastolic velocities of the pulmonary regurgitant jet
Diastolic PA pressure (dPAP) = PR end diastolic pressure gradient + RA pressure
Mean PA pressure (mPAP) = PR peak pressure gradient + RA pressure
Mean pulmonary arterial pressure can also be calculated from the acceleration time of the RVOT VTI.
OTHER ECHOCARGRAPHIC FINDINGS
dilated PA
— greater calibre than aorta
RA dilation
— distension
— rounding
— RV to LV ratio > 0.6 in the four chamber view
bulging of septum into the LV cavity causing diastolic dysfunction
presence of at least a trivial tricuspid regurgitant jet is almost universal – increases with severity of pulmonary hypertension
Cause may be identified:
LV failure
mitral or aortic valve disease
shunts
PE