BCEN CFRN Practice Question

Pulmonary arterial hypertension (PAH) is characterized by progressive narrowing, remodeling, and obliteration of the small pulmonary arteries. Endothelial and smooth-muscle proliferation, medial hypertrophy, and in-situ thrombosis raise pulmonary vascular resistance, so the right ventricle must generate higher pressures to maintain flow. Elevated left-atrial pressure from left-sided heart failure (Group 2) and hypoxic vasoconstriction from chronic lung disease (Group 3) are leading causes of other forms of pulmonary hypertension, while infectious upper-airway processes do not directly elevate pulmonary artery pressures.