What is a normal peak pulmonary artery pressure?

Normal Peak Pulmonary Artery Pressure

The normal peak (systolic) pulmonary artery pressure ranges from approximately 15-30 mmHg, with a mean pulmonary arterial pressure at rest of 14 ± 3 mmHg and an upper limit of normal of approximately 20 mmHg. 1

Normal Pulmonary Pressure Values

Pulmonary arterial pressure has several components that are important to understand:

• Mean Pulmonary Arterial Pressure (mPAP): 14 ± 3 mmHg at rest 1, 2
• Upper limit of normal for mPAP: approximately 20 mmHg 1
• Pulmonary Capillary Wedge Pressure (PCWP): ≤15 mmHg in normal individuals 1

Diagnostic Thresholds for Pulmonary Hypertension

It's important to distinguish between normal values and diagnostic thresholds for pulmonary hypertension:

• Pulmonary Hypertension Definition: mPAP ≥25 mmHg at rest as assessed by right heart catheterization 3, 1, 4
• Borderline Values: mPAP between 21-24 mmHg are of uncertain clinical significance but warrant close follow-up, especially in patients at risk for developing pulmonary arterial hypertension 1

Measurement Considerations

• Gold Standard: Right heart catheterization remains the gold standard for accurate measurement of pulmonary pressures 1, 5
• Standardization: Proper measurement requires standardization, including uniformity of the pressure transducer zero level at the midthoracic line 5
• Non-invasive Assessment: Echocardiography can provide estimates of pulmonary artery pressure but has limitations compared to direct measurement 6

Age-Related Considerations

• Normal values of pulmonary artery pressure during exercise are influenced by age 7
• In individuals younger than 50 years, mPAP increases in parallel with cardiac output during exercise
• In those 50 years and older, the increase in mPAP during exercise is steeper, likely due to diastolic dysfunction of the left ventricle 7

Clinical Implications

• The conventional definition of pulmonary arterial hypertension (PAH) used in clinical studies includes an mPAP >25 mm Hg at rest with a normal pulmonary arterial wedge pressure ≤15 mm Hg and a pulmonary vascular resistance >3 Wood units 3
• When interpreting pulmonary pressure values, it's essential to consider the clinical context, including the presence of left heart disease, lung disease, and other potential causes of pulmonary hypertension 1

Common Pitfalls

• Relying solely on echocardiography for definitive diagnosis of pulmonary hypertension
• Failing to consider age-related changes in normal pulmonary pressures, especially during exercise
• Not distinguishing between pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH), which are not synonymous terms 3
• Overlooking the importance of proper zeroing of pressure transducers during catheterization, which can lead to measurement errors

Remember that while non-invasive methods like echocardiography are useful screening tools, right heart catheterization remains essential for accurate measurement of pulmonary artery pressures and definitive diagnosis of pulmonary hypertension.