CONGENITAL HEART DISEASE Various reasons for repeat dilatation of stented pulmonary arteries in paediatric patients

Objective: To evaluate the reasons for repeat intervention in patients treated with balloon expandable stents for pulmonary artery stenoses, with particular analysis of the time intervals between interventions. Design: A retrospective observational study. Setting: A single paediatric cardiology centre. Patients: 38 patients, mean age 6.9 years, range 6 days to 34 years (one adult patient); mean weight 19.7 kg, range 2.5–75 kg. Intervention: Implantation of balloon expandable stents in 46 cases of main pulmonary artery stenosis, right pulmonary artery stenosis, left pulmonary artery stenosis, or right ventricle to pulmonary artery conduits. Main outcome measures: Adaptation of stent diameter to patient growth; development of pulmonary arteries; pressure gradient in the right ventricle. Results: 56 stents were implanted in 46 lesions. During a mean follow up time of 2.2 years, 40 repeat dilatations were performed on 28 of 42 reinvestigated stents. A second repeat dilatation was performed on eight stents, and a third on four stents. The mean time period between implantation and repeat dilatations was 15.5 months. Conclusions: Repeat dilatation of stented pulmonary arteries was done mainly to adapt the stent diameter to the patient’s growth. However, repeat dilatations were also performed to relieve stent obstruction caused by intimal proliferation (17.5%), or to overcome progressive external compression (25%). While most repeat interventions in adult patients are for intimal hyperplasia, in paediatric patients they are needed for a variety of reasons.