SESSION TITLE: Pulmonary Hypertension: Causes and Outcomes SESSION TYPE: Original Investigation Slide PRESENTED ON: Monday, October 30, 2017 at 04:30 PM - 05:30 PM PURPOSE: Fibrosing mediastinitis (FM) can present with complex cardiovascular and pulmonary issues that pose diagnostic and therapeutic challenges. As part of a larger review of patients with fibrosing mediastinitis at our institution, we sought to better characterize mechanisms of pulmonary hypertension (PH) in patients with FM. METHODS: We queried and retrospectively reviewed medical records at the Mayo Clinic, MN of patients with FM-related PH (1998-2016). RESULTS: 56 FM patients - 34 females (median age 42; range (14-76)) and 22 males (median age 47; range (29-74)) were diagnosed with PH based on echo and/or right-heart catheterization (RHC). Average duration of in-person follow-up was 188 days, with a median f/u period of 580 days (range: 1-6099 days). 7 patients had RHC-confirmed PH at outside institutions; 23 patients underwent RHC at Mayo Clinic. Most RHCs were performed as part of planned vascular diagnostic procedures or inteventions, for example, selective angiography with or without dilatation or stenting of occluded vessels. 5 patients were found to have positive vasodilator response on RHC. On retrospective review, PH in FM patients was mainly attributed to FM alone (41 cases), FM in combination with other cardiopulmonary causes (14) and from valvular disease (1). Pulmonary arterial involvement was confirmed in 36 cases and pulmonary venous involvement was noted in 34 patients based on data from CT studies, angiograms, catheterization, ventilation-perfusion scans and documentation on outside records. Venous and arterial involvement was not assessed in all patients. Review of vena caval involvement, though frequent was not assessed for this review. Vascular interventions including dilatation of native vessels, in-stent stenosis and stent placement were performed in 23 cases. Death in 2 patients within a week of such interventions was likely attributable to procedure-related complications. CONCLUSIONS: Patients with FM span both sexes and all age groups. This orphan disease can present late and with complex cardio-pulmonary involvement. Our institution has cared for hundreds of FM patients with the aid of expert multi-disciplinary consultation and intervention often providing the only feasible options of palliative intervention. Our institution has previously reported on outcomes of Rituximab in FM, airway stents and vascular interventions in FM. As part of our efforts to analyze this cohort of patients, the data presented here is the largest review of PH in FM thus far. We hope to further analyze our cohort for date regarding outcomes of pharmacologic and non-pharmacologic interventions in FM. Other pertinent issues noted on our review were a high incidence of predominantly right-sided involvement, supraventricular tachycardias, friable and congested airways, chest pain and “hemi-autoppneumonectomy” on perfusion imaging without development of significant PH. We encourage the establishment of registries and collaboration within and between institution to help generate valuable and much-needed outcome data. CLINICAL IMPLICATIONS: PH is not uncommon in FM and can result from both arterial and venous involvement. A multidisciplinary and thoughtful approach is necessary in the management of these often complex patients with severe disease. DISCLOSURE: The following authors have nothing to disclose: Shireen Mirza, Tobias Peikert No Product/Research Disclosure Information