Background and Aims Neonatal Intra-Cardiac Thrombosis (ICT) is a life-threatening complication of extreme prematurity. Current management is controversial. We aimed to review cases of ICT on our neonatal unit and evaluate use of tissue plasminogen activator (t-PA) for thrombolysis.

Methods Retrospective study of cases of ICT and response to t-PA treatment in our neonatal unit in the 2-year period 2006–2007.

Results Four infants had ICT (birth gestations and weights ranged from 24.3–28.0 weeks and 695–985 g), an incidence of 4/153 (2.6%) in infants ⩽28 weeks’ gestation. All were asymptomatic and ICT was coincidentally found on echocardiography at median 19 days (range 13–26) postnatal. The ICT was located within the right atrium (n = 2) or originating from the IVC-right atrial junction (n = 2). All had an associated PDA, and had an indwelling central venous catheter for parenteral nutrition infusion at or within 7 days prior to diagnosis. In 3 infants t-PA treatment commenced immediately at 20 μg/kg/hr, gradually increasing to maximum dose 400 μg/kg/hr. Resolution of ICT occurred within 2–6 days. In 1 infant with liver disease, thrombocytopaenia, and mucosal bleeding treatment was deferred until coagulation status improved, but stopped after 2 days before complete resolution because of low fibrinogen levels (ICT subsequently resolved with heparin therapy). All infants had daily platelet counts, fibrinogen levels and echocardiograms during treatment. No infant suffered clinical bleeding or intracranial haemorrhage due to treatment with t-PA.

Conclusion In our experience t-PA may safely and effectively treat ICT in high-risk neonates.