With good early results and superior to balloon dilation only, stents have found its place in interventions in children with a congenital heart disease, but solutions are needed to cover early infancy and the neonatal period.
Under compassionate care regulations we implanted absorbable metals stents (AMS, Biotronik, Berlin, Germany) in three patients (bodyweight 1,7 kg, 7 kg, 2 kg) with severe pulmonary vessel obstructions and critical clinical conditions. The AMS was made of an alloy of over 90% of magnesium and some rare earth elements. Projected degradation time was 4 to 8 weeks after implantation; intravascular stability of the stent was 1 to 3 weeks. All stents and the implantation procedures were well tolerated and follow-up was not noticeably influenced by the stent degradation. All three children recovered and could be dismissed home from the hospital.
After 4 weeks all stents had lost its stability and gave room to further procedures. One patient died 5 months after implantation due to pneumonia not related to the stent. Autopsy and histopathology revealed a patent vessel at the stented area, with the stent dissolved completely.
Biodegradable metal stents offer new strategies in the therapy of congenital heart diseases especially for newborns and small infants. Depending on the implantation site stent diameters of 6 mm and larger are needed. A prolonged degradation time may help to avoid early reintervention. To evaluate the possible domain of biodegradable metal stents in children with congenital heart diseases is an important challenge to come.