B60-28 Severe Pulmonary Hypertension in an Adolescent Patient With Sickle Cell Disease and Chronic Pulmonary Emboli

Abstract Introduction Pulmonary hypertension (PH) is a recognized complication of sickle cell disease (SCD), arising from various underlying mechanisms. We present a 17-year-old female with SCD, identified to have chronic thromboemboli as a key contributor to her severe PH. Description A 17-year-old female with homozygous SCD on chronic red blood cell transfusions via central venous catheter (CVC) for severe pain events presented to an outside hospital (OSH) with fatigue, dyspnea, cough, chest pain, nausea, and diarrhea. She was febrile, tachycardic, tachypneic, and hypoxemic to 80% on room air. Examination revealed scleral icterus, increased work of breathing, and hepatomegaly. Laboratory testing showed leukocytosis, hyperbilirubinemia, and transaminitis. Hemoglobin S level was 35%, consistent with chronic transfusion therapy. Chest radiograph demonstrated cardiomegaly without pulmonary infiltrate. Transthoracic echocardiogram (TTE) showed severe PH with right ventricular dysfunction (RVD) and enlargement. Chest computed tomography angiography (CTA) revealed cardiomegaly and mosaic attenuation without large pulmonary embolism. Admitted to the OSH, cardiac catheterization demonstrated severe precapillary PH with a mean pulmonary artery pressure (mPAP) of 47mmHg, pulmonary vascular resistance index (PVRi) of 17WU⋅m2, and left ventricular end-diastolic pressure (LVEDP) of 9mmHg. She was transferred to our tertiary care center on inhaled nitric oxide (iNO) via high-flow nasal cannula for evaluation; rheumatologic, infectious, and coagulation studies were unremarkable. Serial TTEs showed persistent RVD, and B-type natriuretic peptide reduced from 1,140 to 74pg/mL with supportive therapy. Lung perfusion scan revealed no significant perfusion defects, though CTA demonstrated small chronic filling defects consistent with thromboembolic disease (Figure). She initiated anticoagulation, sildenafil, and bosentan. Repeat cardiac catheterization two-weeks later revealed improved PH (mPAP of 29mmHg, PVRi of 7.8WU⋅m2, and LVEDP of 9mmHg) prompting pulmonary balloon angioplasty and mechanical thrombectomy with modest angiographic improvement. She successfully weaned off iNO, CVC removed, and discharged on enoxaparin, tadalafil, ambrisentan, and supplemental oxygen. At her two-month follow-up, severe RVD persisted. She initiated subcutaneous treprostinil with significant improvement in dyspnea, activity intolerance, and from functional class III to II. Repeat CTA at six-months demonstrated vascular thinning but resolution of emboli. Discussion Few cases have described chronic thromboembolic pulmonary hypertension (CTEPH) in pediatric SCD and may be underrecognized in this population as an inciting factor of severe PH. This case illustrates the diagnostic and therapeutic challenges of CTEPH in a pediatric patient with SCD. The complexities of early recognition and multidisciplinary management—including anticoagulation, vasodilator therapy, and interventional evaluation—are essential given the poor prognosis this severe complication portends. This abstract is funded by: None