The risk profile change in patients with severe chronic thromboembolic pulmonary hypertension treated with subcutaneous treprostinil.

Chronic thromboembolic pulmonary hypertension (CTEPH) is successfully treatable with pulmonary endarterectomy (PEA), balloon pulmonary angioplasty, and medical therapy. Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management risk score (RRS) is able to predict long-term outcome in inoperable patients or in patients with residual PH after surgery. We performed a post hoc analysis of RRS in patients who were enrolled in the CTREPH study (NCT01416636), a randomized, double-blind clinical trial comparing high-dose and low-dose subcutaneous (SC) treprostinil in patients with severe CTEPH that was classified by an interdisciplinary CTEPH team as nonoperable, or as persistent or recurrent pulmonary hypertension after PEA. Baseline mean RRS was similar in both treatment groups (8.7 in high-dose arm vs. 8.6 in low-dose arm), but mean RRS change from baseline to Week 24 was greater in the high-dose treprostinil group than in the low-dose treprostinil group (-0.88 vs. -0.17). The difference in RRS change from baseline to Week 24 between high dose versus low dose was statistically significant with mean difference of -0.70 (95% confidence interval: -1.36 to -0.05,  = 0.0352), and was driven mainly by improvement of World Health Organization functional class and N-terminal pro-brain natriuretic peptide concentration. SC treprostinil therapy administered in standard dose had positive effect on the risk profile measured by RRS in patients with inoperable or persistent/recurrent severe CTEPH. Although our study was limited by the small sample size and post hoc nature, assessment of risk profile is of great importance to this particular patient population with very poor prognosis.