What is the normal pulmonary artery pressure at rest?

Normal Pulmonary Artery Pressure at Rest

Normal mean pulmonary artery pressure (mPAP) at rest is 14 ± 3 mmHg, with an upper limit of normal of approximately 20 mmHg. 1, 2, 3

Hemodynamic Reference Values

Mean Pulmonary Artery Pressure

• The normal mPAP at rest is 14 ± 3 mmHg (mean ± standard deviation), establishing a physiologic baseline measured by right heart catheterization. 1
• The upper limit of normal is approximately 20 mmHg, representing mean plus two standard deviations from the population norm. 1, 2, 3
• Values between 21-24 mmHg fall into a "gray zone" with uncertain clinical significance, though emerging data associate even this mild elevation with increased mortality risk. 1, 4

Systolic Pulmonary Artery Pressure

• Normal pulmonary artery systolic pressure (PASP) measured invasively averages 21 ± 4 mmHg. 2, 3
• The upper limit of normal for PASP is approximately 30 mmHg. 2, 3
• On echocardiography, estimated PASP (ePASP) >30 mmHg is generally outside the normal range in healthy individuals. 2

Diagnostic Threshold for Pulmonary Hypertension

• Pulmonary hypertension is formally defined as mPAP ≥25 mmHg at rest as assessed by right heart catheterization, the threshold used in all randomized controlled trials and registries. 1, 5
• Recent guidelines have proposed lowering this threshold to mPAP >20 mmHg based on the upper limit of normal, though the 25 mmHg cutoff remains the established clinical standard. 1, 6, 2

Clinical Significance of Borderline Elevations

Even mild elevations in pulmonary pressure carry prognostic weight. Classification and regression tree analysis identifies prognostic thresholds at 17 mmHg and 26 mmHg, with values between 20-25 mmHg representing an independent predictor of poor survival after adjusting for age and comorbidities. 4

• Patients with mPAP 20-24 mmHg demonstrate increased mortality compared to those with lower-normal pressures. 6, 2, 4
• ePASP >30 mmHg on echocardiography is associated with 25-40% five-year mortality, with risk rising approximately 40% for every 10 mmHg increase. 2, 3

Measurement Considerations

Gold Standard Assessment

• Right heart catheterization remains the gold standard for measuring pulmonary artery pressure, with the pressure transducer zero level standardized at the midthoracic line (level of the left atrium). 5
• All hemodynamic values are measured at rest in stable clinical conditions. 1

Echocardiographic Estimation

• Doppler echocardiography estimates PASP by measuring tricuspid regurgitation jet velocity using the modified Bernoulli equation, adding estimated right atrial pressure. 7, 8
• The optimal sPAP cutoff for detecting PH (mPAP ≥25 mmHg) is 41 mmHg (sensitivity 92%, specificity 91%), while the optimal tricuspid regurgitation pressure gradient cutoff is 36 mmHg (sensitivity 90%, specificity 93%). 7
• Echocardiography alone is insufficient to support treatment decisions for specific pulmonary hypertension therapy; invasive confirmation is mandatory. 6, 3, 5

Common Pitfalls

• Do not diagnose pulmonary hypertension based solely on echocardiography—right heart catheterization is required for definitive diagnosis and to guide PAH-specific therapy. 6, 3, 5
• Exercise-induced PH cannot be defined with current evidence; the previous threshold of mPAP >30 mmHg with exercise is not supported by data, as healthy individuals can reach much higher values during exertion. 1
• Absence of measurable tricuspid regurgitation on echocardiography does not exclude elevated pulmonary artery pressure. 2