Mean Pulmonary Arterial Pressure Calculator

Mean Pulmonary Arterial Pressure Explained

MPAP is a pulmonary and cardiovascular parameter derived from the relationship between systolic and diastolic pressures from the pulmonary artery, with specific use in the diagnosis of pulmonary hypertension (PAH).

Mean Pulmonary Arterial Pressure (MPAP) = (SPPA + 2 x DPPA ) / 3

Where:

• SP_PA – Pulmonary Artery Systolic Pressure – derived from peak velocity of the tricuspid regurgitant jet, as measured by continuous wave Doppler;
• DP_PA– Pulmonary Artery Diastolic Pressure – derived from the end diastolic velocity of the pulmonary regurgitant (PR) jet.

Normal MPAP is less than 20 mmHg. Values between 20 and 25 mmHg are considered elevated. Pulmonary arterial hypertension (PAH) is diagnosed when MPAP exceeds 25 mmHg at rest or 30 mmHg during exercise.

Other MPAP Formulas

• MPAP (Chemla formula) = (0.61 x SPPA ) + 2 mmHg

• MPAP = 4 x PR peak velocity2 + right atrial pressure (RAP)
• MPAP = 90 – (0.62 x RVOT acceleration time)

Pulmonary Hypertension

PAH is defined as high blood pressure in the heart-lung circulatory system that delivers oxygenated blood from the lungs to the heart and returns oxygen-depleted blood back to the lungs.

Pulmonary arterial pressure is normally 20% of systemic arterial pressure and pulmonary vascular resistance is approximately 10% of systemic vascular resistance (SVR usually 900-1,500 dynes-sec/cm⁵, PVR usually 90 – 120 dynes-sec/cm⁵).

Pulmonary hypertension is due to either an increased PVR or a hyperdynamic cardiac state that increases SP_PA (e.g. abnormal cardiac physiology) despite a normal PVR.

Increased PVR is associated with damaged pulmonary parenchyma, damage to pulmonary blood vessels (both arteriolar and capillary level). PAH can occur when the arteries in the lungs become narrowed and thicken, slowing the flow of blood through the pulmonary arteries from the heart to the lungs.

Known causes of PAH include chronic obstructive pulmonary disease (COPD) and interstitial lung disease, as well as cardiac disease that lead to an increased left atrial pressure (e.g. ischemic heart disease, mitral stenosis, dilated cardiomyopathy).

Degrees of PAH (when MPAP >25mmHg at rest or >30 mmHg at exercse) may be classified according to SP_PA :

Early symptoms of PAH include shortness of breath, fatigue, chest pain, pain in upper right side of abdomen, whilst later symptoms include feeling light-headed (especially during physical activity), fainting, swelling in the ankles or legs and bluish lips or skin.

The World Health Organization has established five groups of pulmonary hypertension:

References

Chemla D, Castelain V, Provencher S, Humbert M, Simonneau G, Hervé P. Evaluation of various empirical formulas for estimating mean pulmonary artery pressure by using systolic pulmonary artery pressure in adults. Chest. 2009; 135(3):760-768.

Chemla D et al. Systolic and Mean Pulmonary Artery Pressures. Chest, Volume 147, Issue 4, 943 - 950.

Montani D et al. Pulmonary arterial hypertension. Orphanet J Rare Dis. 2013; 8:97.

Parasuraman S, Walker S, Loudon BL, Gollop ND, Wilson AM, Lowery C, Frenneaux MP. Assessment of pulmonary artery pressure by echocardiography-A comprehensive review. Int J Cardiol Heart Vasc. 2016; 12:45-51.

Simonneau G, Gatzoulis MA, Adatia I, et al. Updated clinical classification of pulmonary hypertension [published correction appears in J Am Coll Cardiol. 2014; 63(7):746] [published correction appears in J Am Coll Cardiol. 2014 Feb 25;63(7):746]