NPPB and pulmonary arterial hypertension: In a study that compared serum levels of NT-proBNP, NT-proANP, and cTnI in eight control dogs with respiratory disease but without pulmonary hypertension (PH) and 12 dogs with precapillary PH, Kellihan et al. [61] found higher mean NT-proBNP levels in dogs with PH (2,011 pmol/L, in the 274-7713 pmol/L interval) than in the control group (744 pmol/L, 531-2710 pmol/L).