SESSION TITLE: Pulmonary Vascular Disease Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: The benefit of anticoagulant use in pulmonary arterial hypertension (PAH) patients remains unclear. Multiple studies have shown conflicting results regarding the utility of anticoagulation in PAH. Moreover, other points of controversies include selection of specific anticoagulant agent, intensity of anticoagulation, and patient selection based on PAH subtype. This study aims to evaluate the practice habits of physicians caring for patients with PAH in the United States of America (USA). METHODS: A seven-question web-based survey regarding anticoagulation management in patients with PAH in the USA was distributed by email to clinicians with experience treating patients with pulmonary hypertension and are registered members of the Pulmonary Hypertension Association (PHA). RESULTS: We received a total of 56 responses, predominantly from academic, non-profit institutions (82.14%, n=46); by PHA members serving as non-trainee physicians (98.21%, n=55). The majority of respondents (53.57%, n=31) rarely start anticoagulation in patients with WHO group 1 PAH. In idiopathic PAH (IPAH) subtype, providers mainly start in severe disease (22.82%, n=12) or for other coexisting indications (e.g., an indwelling catheter, underlying thrombogenic disorder, prior clots). Nearly all (86%, n=50) respondents rarely start anticoagulation in connective tissue disease related PAH (CTD-PAH). While the majority of respondents do not routinely use anticoagulation in general, those who do, use warfarin (46.3%, n=25) and target a lower range of INR (1.5–2). Few providers (18.18%, n=10) reported using direct oral anticoagulants. CONCLUSIONS: Despite the presence of limited evidence showing that the use of anticoagulation in patients with PAH may be associated with survival benefit—specifically in the idiopathic PAH subtype—the majority of clinicians who care for these patients believe that the risks outweigh the benefits unless there is a coexisting indication. Prospective and randomized studies are warranted for further evaluation. CLINICAL IMPLICATIONS: This study highlights the uncertainty among clinicians about the benefit of anticoagulation in patients with WHO group 1 PAH and the need for randomized trials. DISCLOSURES: No relevant relationships by Noura Alturaif, source=Web Response No relevant relationships by Jamie Kennedy, source=Web Response No relevant relationships by Sula Mazimba, source=Web Response Clinical Trial support relationship with Complexa, Inc Please note: $1001 - $5000 Added 04/02/2020 by Andrew Mihalek, source=Web Response, value=Grant/Research Support