MRI after removal of central venous access device reveals a high number of asymptomatic thromboses in children with haemophilia.

Central venous access devices (CVADs) are often required in children with haemophilia to secure venous access for prophylactic treatment or immune tolerance therapy. Complications of CVADs include infections, thrombosis and mechanical problems. This study sought to determine the outcome of the vessels by magnetic resonance imaging (MRI) in children with haemophilia and to assess risk factors for development of catheter-related deep venous thrombosis (DVT). After the removal of CVAD an MRI of the chest and neck was performed to 20 boys with haemophilia who each had 1-3 (total number 27) CVADs placed. MRI revealed DVT in five children (25%). As their CVADs were functional at the time of the removal, the DVTs were clinically silent. However, there had been suspicion of DVT leading to replacement of the CVAD in one case. All the children with DVT had their CVADs inserted initially below the age of 1 year. The clinical signs of mild post-thrombotic syndrome (PTS) were common: dilated chest wall veins were observed in 11 (55%) children and were associated with DVT in three cases. Arm circumference discrepancy was observed in one child with DVT. No correlation between the duration or number of CVADs and DVT was detected. None of the patients had subjective symptoms of PTS. Silent DVT is a common complication of CVAD. Catheter insertion at a young age seems to predispose to thrombosis. The long-term consequences of the DVTs remain unknown.