Zeenat Safdar et al. JCHF 2014;2:412-421 Levels of Circulating Collagen Biomarkers in Patients With PAH and Healthy Controls Levels of (A) PIIINP, (B) CITP, (C) MMP-9, and (D) TIMP-1 were elevated in patients with PAH as compared with healthy controls (CTL) (p < 0.001 for all). Data are presented as medians with 5th and 95th percentiles. CITP = carboxy-terminal telopeptide of type I collagen; MMP = matrix metalloproteinase; PAH = pulmonary arterial hypertension; PIIINP = N-terminal pro-peptide of type III procollagen; TIMP = tissue inhibitor of metalloproteinase. Zeenat Safdar et al. JCHF 2014;2:412-421 American College of Cardiology Foundation