Balloon-Expandable Stent Treatment of Experimental Coarctation of the Aorta: Early Hemodynamic and Pathological Evaluation

The present study was intended to evaluate the acute and short‐term hemodynamic, angiographic, and pathological response to balloon‐expandable stent treatment of experimental coarctation of the aorta. A discrete thoracic coarctation was surgically created in six mongrel dogs (two adults, four puppies). Two months postoperatively all six dogs (8.9–30 kg) underwent left heart catheterization and coarctation stenting performed through a femoral artery cutdown. A Palmaz PS‐30 stent was advanced to the coarctation through a 10French sheath, and expanded with an angioplasty balloon chosen to equal the diameter of the proximal aorta (9–12 mm). Stent implantation was successful in each dog. The systolic pressure gradient decreased from 26.3 ± 9.1 mmHg (mean ± SE) to 0.5 ± 0.5 mmHg (P = 0.04), and the coarctation diameter improved from 50 ± 6% to 82 ± 6% of the diameter of the proximal descending aorta (P < 0.01). Follow‐up catheterization 4–7 weeks after stenting documented no stent migration, early restenosis, thrombosis, obstruction of arterial side branches, or aneurysm formation. Pathological evaluation of the explanted segments of stented aorta documented that by 6–7 weeks the stents are covered by a neointima composed of intimal proliferation and fibrosis with an endothelial cell surface. These data suggest that balloon‐expandable stainless steel stents provide excellent acute and short‐term relief of coarctation in this experimental model. Larger and longer‐term studies are needed to better assess the incidence of restenosis or aneurysm formation following stenting of coarctation of the aorta.