From the Guidelines
Normal pulmonary arterial pressure as measured by right heart catheterization (RHC) is defined as a mean pulmonary arterial pressure (mPAP) less than 20 mmHg at rest. This definition is based on the most recent guidelines and studies, including the 2022 update from the American College of Radiology 1. The normal values for pulmonary arterial pressure include a systolic pressure of 15-30 mmHg, diastolic pressure of 4-12 mmHg, and mean pressure of 9-18 mmHg.
Importance of Normal Pulmonary Arterial Pressure
Right heart catheterization is considered the gold standard for measuring pulmonary pressures as it provides direct measurement rather than estimates from non-invasive methods like echocardiography 1. During the procedure, a catheter is inserted through a vein (typically in the neck, arm, or groin) and advanced into the right side of the heart and pulmonary arteries to measure pressures directly.
Clinical Significance
Normal pulmonary arterial pressure is important because elevated pressures (pulmonary hypertension) can indicate various cardiopulmonary conditions that may require treatment, such as left heart disease, lung disease, pulmonary arterial hypertension, or chronic thromboembolic disease 1. Maintaining normal pulmonary pressures is essential for proper heart function and oxygen delivery throughout the body. The diagnosis of pulmonary hypertension and its classification have evolved over time, with the most recent updates providing clear criteria for precapillary, isolated postcapillary, and combined pre- and postcapillary pulmonary hypertension 1.
Key Points
- Normal pulmonary arterial pressure is less than 20 mmHg at rest.
- Right heart catheterization is the gold standard for measuring pulmonary pressures.
- Elevated pulmonary pressures can indicate various cardiopulmonary conditions.
- Maintaining normal pulmonary pressures is essential for proper heart function and oxygen delivery. The most recent and highest quality study, the 2022 update from the American College of Radiology 1, provides the basis for the definition and clinical significance of normal pulmonary arterial pressure.
From the FDA Drug Label
CLINICAL PHARMACOLOGY 12. 1 Mechanism of Action Sildenafil is an inhibitor of cGMP specific phosphodiesterase type-5 (PDE-5) in the smooth muscle of the pulmonary vasculature, where PDE-5 is responsible for degradation of cGMP. The FDA drug label does not answer the question.
From the Research
Normal Pulmonary Arterial Pressure by RHC
- The normal pulmonary arterial pressure is typically considered to be less than 20 mmHg, as stated in a study published in 2022 2.
- However, the European Society of Cardiology guidelines require a mean pulmonary arterial pressure of ≥ 25 mm Hg to confirm the diagnosis of pulmonary hypertension (PH) 3.
- Right heart catheterization (RHC) is the gold standard for assessing pulmonary hemodynamics and diagnosing PH 3, 4, 2, 5.
- RHC provides valuable information about the differential diagnosis and severity of PH, and helps determine the patient's prognosis 3.
Diagnosis of Pulmonary Hypertension
- A mean pulmonary artery pressure (mPAP) of >20 mmHg is considered above normal and is associated with clinical events, including mortality 6.
- Pulmonary vascular resistance (PVR) of 2.2 to 3.0 WU, previously considered normal, appears to associate with elevated clinical risk 6.
- A revised approach to classifying PH patients as pre-capillary, isolated post-capillary, or combined pre-/post-capillary PH guides point-of-care diagnosis, risk stratification, and treatment 6.
Importance of Accurate Hemodynamic Assessment
- Accurate hemodynamic assessment is critical for the diagnosis and treatment of PH 6.
- Errors in assessing the correct pulmonary artery wedge pressure (PAWP) can significantly affect accurate classification of patients with pulmonary hypertension, and lead to potentially deleterious treatment decisions 5.
- Best practices in RHC performance, emphasizing practical and pathophysiologic principles, are essential to obtain the most accurate results 5.