Local photodynamic therapy reduces tissue hyperplasia after stenting in an experimental restenosis model

Local photodynamic therapy was used to prevent neointimal hyperplasia after stenting. Slotted tube stents were placed with 16 atmospheres in porcine femoral arteries with the external diameter to match the diameter at 10 atmospheres. Animals were randomly allocated to Group 1 (stenting only); or Group 2 with stenting, local drug delivery of a photosensitizer (5 mg Photofrin) and subsequent exposure to light (photodynamic therapy, 100 J). Fourteen days later, all vessels were excised, fixed and processed for histology. Tissue hyperplasia was observed after stenting in vessels from Group 1. In Group 2 with photodynamic therapy, the myoproliferative response was significantly reduced. Tissue hyperplasia after stenting was effectively suppressed by photodynamic therapy.