NPPB and chronic obstructive pulmonary disease: We report here on a cohort of PH-COPD patients with significant improvement in their six-minute walk distance (6MWD) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) with concordant RV morphometric improvements by echocardiography (TTE) on iTRE therapy phenotyped for a baseline right ventricular (RV)-dependent circulatory limitation by TTE and right heart catheterization (RHC).