SESSION TITLE: Pulmonary Vascular Disease 1 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2018 01:00 PM - 02:00 PM PURPOSE: Pulmonary endarterectomy (PEA) is the definitive treatment for chronic thromboembolic pulmonary hypertension (CTEPH). However, not all patients are surgical candidates and some may be left with residual pulmonary hypertension after PEA. Treatment options for such patients are limited. The microvasculopathy of CTEPH and pulmonary arterial hypertension (PAH) are similar. A few randomized controlled trials (RCTs) have reported on the use of PAH specific therapy in CTEPH but not all have shown improvement in exercise capacity and/or pulmonary hemodynamics. METHODS: PUBMED was searched for articles published between January 1996 and February 2018, using the term “chronic thromboembolic pulmonary hypertension” and applying the filters: English language, Humans and Clinical Trials. Studies were included if they met the following criteria: randomized, placebo controlled, clinical trial AND pulmonary hypertension (PH) confirmed by right heart catheterization, AND baseline and follow up six minute walk distance (6MWD) AND baseline and follow up pulmonary hemodynamic data. RevMan 5.3 was used to perform the meta-analysis. RESULTS: Five RCTs met our inclusion criteria. There was a total of 293 patients treated for 12-16 weeks with placebo or one of the three drug classes of PAH specific therapy: Riociguat (n= 173), Endothelin receptor antagonist (n= 118), and Phosphodiesterase 5 inhibitor (n= 9). The majority of the cases was inoperable CTEPH. Overall, the placebo corrected mean change in 6MWD was 24.73 meters (95%CI 14.24, 35.21). The mean change in mean pulmonary artery pressure was -4.78 mm Hg (95%CI-6.42, -3.14), in pulmonary vascular resistance -194 dynes.sec/cm5 (95%CI -233.30, -155.09) and in cardiac index 0.39 L/min/m2 (95%CI 0.16, 0.61). CONCLUSIONS: The use of PAH specific therapy in patients with CTEPH results in significant improvement in 6MWD and pulmonary hemodynamics. CLINICAL IMPLICATIONS: PAH specific therapy is beneficial in patients with inoperable CTEPH or persistent CTEPH following PEA. DISCLOSURES: No relevant relationships by Jason Filopei, source=Web Response No relevant relationships by Adil Shujaat, source=Web Response No relevant relationships by David Steiger, source=Web Response