Palmaz stent in the treatment of central venous stenosis: safety and efficacy of redilation.

PURPOSE: To assess the safety and efficacy of redilation of central venous stents in a growing animal model. MATERIALS AND METHODS: Palmaz stents were placed in the inferior vena cava (IVC) in 18 newborn lambs. After 5 months, vena cavography was performed. Those animals in which growth of the IVC adjacent to the stent and/or neointimal hyperplasia had resulted in a stenosis were considered candidates for redilation. Repeat vena cavography, intravascular ultrasound, and histologic examination were performed at 2 or 6 months. RESULTS: A stenosis of > 20% was demonstrated in 13 animals. Redilation was performed, and a 50% mean increase in stent diameter was achieved. There were no immediate complications. Late complications included nonocclusive laminar clot (n = 2), and a bar of tissue dividing but not occluding the caval lumen (n = 1). Moderate neointimal hyperplasia occurred in all stents. Stent compression (unrelated to redilation) occurred in seven animals. CONCLUSION: Palmaz stents can be redilated sa...