Progress toward Approval of Stents in Coarctation of the Aorta

Since the first successful surgical repair was performed in 1944 by Crafoord, 2) various methods including operative and transcatheter approaches have been developed with excellent outcomes. Neonates with severe CoA present with heart failure and shock after closure of the ductus arteriosus and deteriorate rapidly if left untreated. However, patients with less severe CoA may not be diagnosed until late childhood or adulthood. Hypertension is the most common presentation for these patients. Transcatheter balloon angioplasty has been used as an alternative option to surgical repair, especially for recurrent CoA. In 1982, balloon angioplasty was introduced by Lock et al. 3) for native CoA. Despite the high success rate of balloon angioplasty, high rates of re-coarctation and aortic wall injury compared to surgery remain a concern. A 15% rate of re-coarctation for balloon angioplasty of native CoA has been reported 4) and aortic aneurysm developed in 35% on long-term follow-up. 5) Balloon angioplasty alone is not currently recommended for treatment of CoA in adults. Endovascular stents were first reported as a new option for treatment of CoA in 1991. 6) Endovascular stents provide structural support and prevent over-dilation, which can otherwise lead to aortic wall injury and restenosis. Several studies reported high success rates and lower complication rates in endovascular stent placement compared to balloon angioplasty or surgery. However, no endovascular stent has been approved by US Food and Drug Administration (FDA) for use in the aorta thus far. NuMed Inc. (Hopkinton, NY, USA) developed the Cheatham-Platinum (CP) stent for use in the aorta and The Coarctation of the Aorta Stent Trial (COAST) was conducted in 2007. 7) The COAST showed procedural success in all but one case, and no acute adverse events occurred. Two years after stent implantation, no surgical re-interventions were needed but transcatheter re-interventions in 19 (21%) patients were performed successfully due to aortic wall injury or stent re-stenosis. A covered endovascular stent was first used for CoA in 1999 for the purpose of reducing aortic wall complications. Covered stents may be used not only as a rescue therapy, but also as an initial therapy, especially in elderly patients with friable and calcified aortic tissue. For patients with very severe or complex CoA at high risk of aortic wall injury during balloon dilatation or bare metal stent implantation, covered stent implantation should be implemented. However, significant aortic branch occlusion needs to be avoided. A randomized trial comparing bare …