PB2437 THROMBOLYTIC THERAPY IN PEDIATRIC PATIENTS; OUTCOME AND COMPLICATIONS OF TISSUE PLASMINOGEN ACTIVATOR

Background: Although tissue plasminogen activator (tPA), is not indicated in patients under 18 years, off‐label administration is increasingly reported in life or limb‐threatening thrombi. Aims: To present experience with tPA administration in pediatric patients. Methods: Between March 2012 and January 2018, hospital records of patients who received thrombolytic therapy were reviewed. Written informed consent forms signed by legal guardians of the patients for off‐lable use of tPA were present in patients’ hospital files. Major bleeding was defined as any intracranial or retroperitoneal bleeding, or bleeding requiring prolonged admission, transfusion or bleeding leading to death. All other bleeding events were classified as minor. Dose modifications were performed with monitorization of clinical findings, imaging studies and bleeding complications. Results: Seven children, 1 day‐17 years underwent thrombolysis with tPA. First patient had acute lymphoblastic leukemia, fungal pneumonia; she had also central venous catheter and developed superior vena cava syndrome due to right juguler vein thrombosis. Second patient had nephrotic syndrome and diffuse pulmonary thrombosis causing hypoxia. Third patient with Kawasaki disease had coronary aneurism and thrombosis. Fourth patient was a newborn with 37 week‐gestation born with left arm cyanosis and had subclavian artery thrombosis. This baby had methylen tethra hydropholate reductase plus phrothrombin 20210 heterozygous mutations. Fifth patient with homozygous antithrombin deficiency had adolescent pregnancy and vaginal delivery; she presented on the post‐partum 10 th day with left renal vein, artery and vena cava inferior (VCI) thrombosis. Sixth patient had hypertension and right kidney atrophy developed left renal artery thrombosis. Seventh patient had Behçet's disease and developed right atrium, pulmonary arteries, VCI, vena‐porta, vena hepatica, bilateral iliac vein thrombosis. Administration of tPA was started median 2 days (1‐12) after onset of symptoms. Median initial tPA dose was 0.1 mg/g/h (0.03‐0.4) and the median maximum dose was 0.15 mg/kg/h (0.06‐0.4). Dose escalation or de‐escalation was performed according to monitorization by imaging findings, resolution of clinical findings, and bleeding complication. Median tPA duration was 46 h (12‐72 h). Concomitant heparin was administered in all patients except patient 2 and 3. Outcome was complete resolution was achieved in patients 1,2,6,7, partial resolution in patient 3 and no resolution in patients 4 and 5. There was one organ (kidney in patient 4) and one limp loss (patient 5). There was one major bleeding in patient 7; he had melena, hematemesis, epistaxis that required transfusion and withdrawal of concomitant heparin. Three of the patients had minor bleedings (epistaxis, gingival bleeding, venipuncture site bleeding) that could be easily controlled. Summary/Conclusion: Thrombolysis with tPA seems safe and effective in pediatric patients. A dose between 0.06‐0.1 mg/kg/h seems safer regarding bleeding complications. Doses between‐ 0.15‐0.4 mg/kg/h may be used if necessary with close monitorization.