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

Abstract

To assess the safety and efficacy of redilation of central venous stents in a growing animal model. 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. 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. Palmaz stents can be redilated safely and effectively in an animal model of growing central veins.