NPPB and Tricuspid regurgitation: The serum ANGP-1 concentration was not significantly correlated with modified Medical Research Council (mMRC) dyspnea scale (Fig. 2a; ρ = 0.091, p = 0.625), 6-min walk distance (6MWD; Fig. 2b; r = 0.157, p = 0.547), the percent predicted diffusion lung capacity for carbon monoxide (%DLCO; Fig. 2c; r = − 0.257, p = 0.336), NT-ProBNP concentration (Fig. 2d; r = − 0.182, p = 0.456), or tricuspid regurgitation peak gradient (TRPG, Fig. 2e; r = 0.028, p = 0.895) and right ventricular diameter (RVD, Fig. 2f; r = − 0.148, p = 0.613), which were evaluated by echocardiography.