Biodegradation of tungsten embolisation coils used in children

Background: It has been suggested that tungsten coils (TCs) may corrode 30 months after transcatheter embolisation (TCE) The aim of this study was to follow up children after TCE of aorto-pulmonary collaterals (APCs) with TCs. Materials and methods: Successful TCE of 99 APCs was performed in children using 152 TCs. Chest radiographs were obtained on the day after the procedure, after 3-6 months and 9-12 months, and yearly thereafter. Results: Mean follow-up was 39.3 months. After 9-12 months, radiographs revealed a decrease in radio-opacity and reduction of coil width in 29 (37.6%) of 77 APCs. After a mean of 25 months (range 13-51 months), there was loss of visibility in 44 (57.2%) of 77 TCs and a reduction in 29 (37.6%) of 77. After a mean of 39.3 months, all TCs showed decrease or loss of radio-opacity. Exponential function predicts complete biodegradation of 95% of TCs within 10 years after TCE (r2 = 0.923). After a mean of 28.4 months, repeat catheterisation was performed in 24 APCs with TCs with decreased or lost radio-opacity. Recanalisation had occurred in 58.3%. Conclusions: Dissolution occurred in 57.2% of TCs within a mean of 25 months, and within 39.3 months all TCs showed decrease or loss of radio-opacity. Recanalisation of closed APCs occurred in 58.3%.