Biomarkers for the prognosis of pulmonary arterial hypertension: Holy Grail or flying circus?

Despite recent and major progresses in the field of pulmonary vascular diseases pulmonary arterial hypertension (PAH) outcome still needs improvement. In parallel, several changes are observed in a disease that is no longer described as typically affecting young women. This is outlined in the most recent reports from PAH registries, where increasing age at the time of diagnosis is constantly described. Regardless the cause of this changing face, the quest for the perfect prognostic factor in PAH is ongoing. Among the numerous variables of interest, biomarkers are particularly attractive, as they do not require expertise or invasive procedure. This is the case for brain natriuretic peptide (BNP) and the inactive N-terminal cleavage product of its pro-hormone (NT-proBNP), which have proven to be reliable. This might also be the case for endothelin-1 (ET-1), a potent vasoactive peptide involved in the endothelin pathway and its biologically stable surrogate, carboxy-terminal pro-endothelin-1 (CT-proET1) that could independently predict 1-year event-free survival in PAH. Of course, further research is warranted to confirm these results. Yet, even if there are probably few chances, if any, to discover the "Holy Grail", researcher's efforts must continue. The combination of pertinent parameters in composite scores is indeed promising and emphasized in the most recent PAH guidelines. Clinicians would probably need to use a subtle combination of several biomarkers and clinical, functional, hemodynamic and right ventricular parameter criteria to drive the most ambitious treatment goals in a complex and life threatening disease.