Abstract
We examined the rabbit aortic injury induced by passage of a balloon catheter (4F) and neointimal thickening. Balloon catheterization was performed at three different inflation pressures (400, 600, or 800mmHg). For comparative studies, rabbit aortas were subjected to intimal injury by insertion of a polyethylene tubing (PESO) for 24hrs. Aortic injury by passage of the balloon catheter at 600 or 800mmHg caused both endothelial denudation and varying degrees of medial damage such as interruption of the elastic lamina and necrosis of medial smooth muscle cells, furthermore, significant loss of DNA content was detected in these injured aortas. While balloon catheterization at 400mmHg and insertion of the polyethylene tubing induced only endothelial denudation. The neointimal thickening developed following each aortic injury. However, the neointimal thickening and the frequency of intimal smooth muscle cell proliferation following balloon catheterization at 800mmHg was rather mild. Norepinephrine-induced vascular constriction was significantly reduced in the aortic rings injured by balloon catheter at 600 and 800mmHg compared with those of uninjured and injured ones at 400mmHg.
These results demonstrate that a denuding injury by passage of a balloon catheter causes varying degrees of medial damage dependent on the inflation pressure in contrast with that by insertion of a polyethylene tubing.
