Mean pulmonary arterial pressure
Mean pulmonary arterial pressure (mPAP or MPAP) can be estimated by echocardiography, although the gold standard remains measurements taken directly during right heart catheterization. It is calculated by the formula:
(PASystolic pressure +2 PADiastolic pressure) / 3
The pulmonary arterial systolic pressure (PASP) is derived (using the simplified Bernoulli equation) from the peak velocity of the tricuspid regurgitant jet, as measured by continuous wave Doppler, and the PA diastolic pressure from the end diastolic velocity of the pulmonary regurgitant (PR) jet. Alternative methods of estimating the mean PA pressure include:
- mPAP = (0.61 x PASP) + 2
- mPAP = 4 x (PR peak velocity) + right atrial pressure (RAP)
- mPAP = 90 - (0.62 x RVOT acceleration time)
- mPAP = (mean RA-RV pressure gradient) + RAP
- derived from the velocity-time integral of the TR jet
Normal MPAP is less than 20 mmHg and considered elevated when it exceeds 25 mmHg at rest or 30 mmHg with exertion.
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