NPPB and stage 5 chronic kidney disease: A1AG, Alpha-1 acid glycoprotein; CRP, C-reactive protein; eGFR, estimated glomerular filtration rate; ESRD, end-stage renal disease; IVC, inferior vena cava; MHD, maintenance hemodialysis; pro-BNP, Pro-brain natriuretic peptide; PH, pulmonary hypertension.