Figure 3. Histologic Pulmonary Vascular Remodeling in Pulmonary Hypertension due to Left Heart Disease.

Left panel: Comparison of pulmonary arteries, veins, and indeterminate vessels among healthy controls, PH-HFrEF, PH-HFpEF, and PVOD patients. Representative vessels with remodeling approximating the median values for medial and intimal thickening of arteries, veins, and indeterminate vessels in each group are shown. Right, top panel: There is progressive severity of medial and intimal thickening in pulmonary arteries and veins from healthy controls (normal) to PH-HFrEF to PH-HFpEF to PVOD (most severely abnormal). Right, bottom panel: increases in medial and intimal thickening in the pulmonary arteries and veins correlates with increased severity of pulmonary hypertension (increased PASP). The solid line represents the estimated PASP via linear regression based on medial/intimal thickening, and the dotted lines represent the 95% confidence interval. HF, heart failure; HFpEF, HF with preserved ejection fraction; HFrEF, HF with reduced ejection fraction; %IT, percent intimal thickness; %MT, percent medial thickness; PH, pulmonary hypertension; PVOD, pulmonary veno-occlusive disease; IV, indeterminate vessels; PASP, pulmonary artery systolic pressure. Reproduced with permission from Fayyaz et al., Circulation 2018..; and PVOD, pulmonary veno-occlusive disease. Reproduced with permission from Fayyaz et al., Circulation 2018.