Abstract • 128

Increasing numbers of children are successfully cured of primary diseases that cause serious morbidity and mortality. Clinically important secondary complications are occurring, of which thromboembolic events (TEs), are amongst the most frequent and serious.

Venous TEs (VTE) : The age distribution shows a predominance of small infants less than 1 year of age. Over 95% of children with VTEs have serious underlying diseases of which cancer (CA), and congenital heart disease (CHD) are the most common. The presence of central venous lines (CVLs) is the single most important risk factor for VTE while the contribution of congenital disorders is uncertain. The majority of VTEs are located in the upper venous system which reflects the placement of CVLs. Ultrasound is the most frequently used diagnostic test but has not been validated against venography in children. The current standard of care for VTE in children is standard heparin (SH) followed by either oral anticoagulants (OAs). The role of low molecular weight heparins are unknown. Recurrent VTE, and post phlebitic syndrome occur in approximately 10% of children with a 3 year follow up.

Arterial TEs: The vast majority of arterial TEs in children are secondary to arterial catheters and can be considered in three main groups: umbilical arterial catheters (UACs), cardiac catheterizations (CCs), and peripheral catheters (PACs). Several RCTs have shown that SH has a role in preventing catheter related thrombosis in all circumstances.

Future: Determination of the optimal prevention and treatment of TEs during childhood will require multi-centre participation in RCTs.