What is the pathophysiology of pulmonary arterial hypertension (PAH)?

Updated: Apr 25, 2018
  • Author: Kristin E Schwab, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Increased pulmonary vascular resistance is the main pathogenic mechanism in pulmonary arterial hypertension (PAH). This is typically due to vasoconstriction, remodeling, and thrombosis of the small pulmonary arteries and arterioles. [3]  

On pathology, patients with PAH are found to have hyperplasia and hypertrophy of the intima, media, and adventitia of the pulmonary arterial vasculature. On the molecular level, this is related to endothelial dysfunction, which leads to disorganized endothelial cell proliferation, decreased production of vasodilators such as prostacyclin and nitric oxide, and overexpression of vasoconstrictors like endothelin. These pathophysiologic mechanisms are particularly important as they guide the therapeutic targets of pharmacotherapies for advanced PAH disease.

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