Intravascular stent prosthesis for right ventricular outflow obstruction

Objectives. This study was designed to assess the impact of implantation of balloon-expandable stents on right ventricular outflow obstruction in children with congenital heart disease. Background. Intravascular stenting has been established as a useful treatment in adults with coronary and peripheral vascular disease. Its application in the treatment of infants and children with pulmonary, systemic and right ventricular conduit obstruction resistant to balloon angioplasty is limited. Methods. A total of 24 stainless steel stents were implanted in 17 patients. Five stents were placed within right ventricular to pulmonary artery conduits, 17 in branch pulmonary arteries and 1 in an aortopulmonary collateral vessel. Follow-up time has ranged from 1 to 14 months, with 6 patients having hemodynamic and angiographic studies >1 year after stent placement. The mean age at implantation was 7.4 ± 5.6 years and the mean weight 33 ± 16 kg. Results. Optimal stent position was obtained in 22 of 24 implantations. In one patient the stent slipped from the delivery balloon and was left positioned in the inferior vena cava. No embolization or thrombotic event has been documented. Among patients with right ventricular to pulmonary artery conduit obstruction, the gradient was immediately reduced from 85 ± 30 mm Hg to 35 ± 20 mm Hg after stent implantation; however, three patients required conduit replacement because of persistent obstruction with elevated right ventricular pressures (82 ± 16 mm Hg). In 10 of 11 patients with pulmonary artery stenosis, clinical improvement was noted in association with enlargement of vessel diameter by 92% ± 90% (range 17% to 355%) and the gradient reduction of 22 ± 24 mm Hg to 3 ± 4 mm Hg. Conclusions. These data support the view that intravascular stenting will become an important adjunct in the management of children with congenital heart disease.