Through a metabolomics approach, Harbaum et al investigated lipoprotein profiles in patients with idiopathic and heritable PAH, and demonstrated that high-density lipoprotein apolipoprotein A-1(HDL-4-Apo A-1), HDL-4-Apo A-2, and HDL-4-phospholipids were predictors of survival, independent of established outcome measures, including NT-proBNP and 6MWD.56 Here, NPPB is linked to pulmonary arterial hypertension.