Hemodynamic parameter measurements and lung histochemistry.

RV pressure and RV hypertrophy were measured as described previously (21). Intrapulmonary vessels were visualized by hematoxylin-eosin staining on 5-μm-thick formalin-fixed paraffin-embedded lung cross sections. Pulmonary vascular remodeling, indicated by the thickening of the smooth muscle layer of distal small PA, was measured using Aperio software.