Background: Severe neonatal aortic thrombosis is rare but can lead to significant morbidity or death if inadequately treated. Thrombolytic therapy is indicated for thrombi which are life-threatening, organ-threatening, or limb-threatening, but dosing consensus has not been established.Observation: We report a case of a 700 g preterm neonate with spontaneous intestinal perforation who developed an occlusive aortic thrombus with signs of limb ischemia. He was treated successfully with tissue plasminogen activator without hemorrhagic complications. He was started at a dose of 0.06 mg/kg/h and received a maximum dose of 0.3 mg/kg/h. Long-term follow-up at 3 years and 3 months showed no negative sequelae. Conclusion:Alteplase may be considered in premature, extremely low-birth weight infants with careful assessment of risk and benefits, along with frequent surveillance and supportive care.

on behalf of the Thrombosis, Hemostasis in Newborns (THiN) Group Among children, neonates have the highest incidence of thrombosis. Thrombolytic agents are used for the management of life and/or organ-threatening thrombosis. Literature on the efficacy and safety of thrombolytic agents in neonates is limited. We reviewed the evidence on dosing, administration, monitoring and treatment duration of tissue plasminogen activator (tPA), streptokinase and urokinase (URK) in neonates (< -28days). A systematic literature search was conducted of current databases from inception until 31 March 2021. The initial search yielded 6881 articles and 18 were retained for review. tPA, streptokinase and URK was utilized in 12, seven and four studies on 115, 51 and 16 patients, respectively. The dose range for tPA, streptokinase and URK was 0.01 -0.6 mg/kg/h, 50-2000 and 1000-0 000 units/kg/h, respectively, and treatment duration ranged from 30 min to 30 days. This is the first study to objectively summarize the efficacy and safety of thrombolytic agents in neonates. Overall, thrombolysis was associated with 87.9% complete or partial thrombus resolution and 7.4% recurrence risk. The bleeding risk associated with thrombolytic agents was 23.1% on pooled analysis, which is higher than other anticoagulants. Larger prospective studies are required to determine effective dosing regimens of these therapeutic drugs and further clarify their efficacy and safety.