What defines pulmonary hypertension in terms of mean PA pressure?

Pulmonary hypertension is defined by a mean pulmonary artery pressure (PA pressure) greater than 25 mmHg at rest, according to current clinical guidelines. This threshold is significant because it indicates increased pressure in the pulmonary arteries, which can lead to various complications, including right heart failure and reduced oxygenation due to decreased pulmonary blood flow. The condition is diagnosed through invasive measurement during right heart catheterization, which allows for a direct assessment of the pressures within the pulmonary circulation.

The importance of this definition lies in its utility for diagnosis and management of patients with suspected pulmonary hypertension. Identifying pressures above this level allows healthcare providers to determine appropriate treatment strategies and to monitor disease progression.