A novel P-32 deployable balloon system inhibits formation of neointima in porcine coronary arteries after balloon-overstretching injury

Background Intracoronary radiation has shown the potential to reduce format ion of neointima in porcine models of restenosis. Objective To investigate the feasibility, safety, and efficacy of a new 'de ployable-balloon' device with radioisotope P-32 integrated into the balloon material. Methods Ten swine were subjected to balloon-overstretching injury in 20 cor onary arteries and were randomly allocated to receive a radiation dose of 0 , 15, or 20 Gy prescribed to 1 mm from the surface of the radioactive ballo on material. The animals were killed 4 weeks after the procedure. Their cor onaries were perfusion fixed and stained. Vessel parameters (area of intima and length of fracture) and area of thrombus area were analyzed by compute r-aided histomorphometry. Results Radiation treatment with the new P-32 balloon device was performed without complications. The lengths of fracture for the three groups were si milar (NS). Formation of neointima after balloon injury was less in members of the radiated groups than it was in controls (area of intima/length of f racture was 0.70 +/- 0.12 mm for controls, 0.08 +/- 0.13 mm with 15 Gy, and 0.07 +/- 0.17 mm with 20 Gy; P < 0.001). Vessels treated with 20 Gy had a greater total area of thrombus (0.00 +/- 0.00 versus 0.51 +/- 0.98 mm(2), P < 0.01). Conclusions Intracoronary radiation therapy using a new P-32 deployable-bal loon system is feasible and safe. A radiation dose of 15 Gy was sufficient to inhibit neointimal response in the porcine coronary-balloon-injury model . Coron Artery Dis 12:317-322 (C) 2001 Lippincott Williams & Wilkins.