Liver fibrosis marker, 7S domain of collagen type IV, in patients with pre-capillary pulmonary hypertension

Pulmonary hypertension (PH) causes right ventricular dysfunction and central venous congestion, and may lead to congestive hepatopathy. The serum 7S domain of collagen type IV (P4NP 7S) is an established marker of liver fibrosis in chronic liver disease. We aimed to determine whether P4NP 7S is related to hemodynamic parameters, and assessed the potential values of P4NP 7S to predict mortality.Consecutive 76 pre-capillary PH patients were divided into tertiles based on their serum P4NP 7S levels. We compared right-heart catheterization, echocardiographic findings, and mortality among the tertiles, and compared P4NP 7S with other known biomarkers of mortality.Cardiac index, mean pulmonary arterial pressure, pulmonary vascular resistance, and right ventricular fractional area change did not differ among the three groups. In contrast, compared to 1st and 2nd tertiles, the 3rd tertile had higher levels of right atrial pressure, right atrial area, and right ventricular area (P0.05, respectively). In the Kaplan-Meier analysis, mortality progressively increased from the 1st to 2nd and 3rd tertiles (log-rank, P=0.002). In the Cox proportional hazard analysis, P4NP 7S was a predictor of mortality. ROC analysis demonstrated that a P4NP 7S concentration of 4.75ng/ml predicted mortality (AUC 0.85, 95% CI 0.75-0.94; P0.001), and that the prognostic value of P4NP 7S was comparable or superior to that of other biomarkers (total bilirubin, creatinine, uric acid, C-reactive protein, B-type natriuretic peptide, and troponin I).Serum P4NP 7S is associated with higher central venous pressure, right-sided volume overload, and mortality in PH patients.