Stent redilation in canine models of congenital heart disease: Pulmonary artery stenosis and coarctation of the aorta

In a canine puppy model, pulmonary artery stenosis was created by banding the left pulmonary artery to 30–40% of its original diameter. Animals underwent right heart catheterization and angiography 1–2 mo later, and Palmaz P308 stents were implanted. Stent redilation was performed 3–5 mo later. One mo postredilation, the animals were restudied and sacrificed. Coarctations of the aorta were created by transverse aortic incision and longitudinal repair. P308 stent implantation was performed 2–3 mo later. Stent redilation was performed after 6–10 mo, and the animals were restudied and sacrificed 1–2 mo later. Stent implantation was performed in 6 puppies with pulmonary artery stenosis, as 2 animals developed postoperative pulmonary arterial hypoplasia, precluding stenting. The stenosis diameter increased from 4.8 ± 0.5 mm to 7.4 ± 0.6 mm (mean ± SE) following stenting (P = 0.005), and increased further to 9.2 ± 0.7 mm following redilation (P < 0.001). There were no significant vessel tears or ruptures. Coarctation stenting was performed in 8 animals. The coarctation was dilated from 5.8 ± 0.9 mm to 9.8 ± 0.6 mm (P < 0.001), and to 13.5 ± 0.5 mm at redilation (P = 0.002). Redilation could not be performed in 1 animal. Aortic rupture and death occurred in 2 of 7 animals at redilation. Stent implantation and redilation in experimental pulmonary artery stenosis appears safe and effective. Though stent implantation for coarctation of the aorta appears safe, there was a 28% aortic rupture rate at stent redilation in this model. © 1996 Wiley‐Liss, Inc.