The relationship of lumen diameter and neointimal hyperplasia with inflation pressure.

BACKGROUND: The mechanical stretch injury imposed by the intravascular intervention contributes to neointimal hyperplasia. Lessening of this damage without the compromise of luminal dilation could be an alternative way to alleviate restenosis.

OBJECTIVE: We aimed to assess the relationship of lumen diameter and neointimal hyperplasia with inflation pressure using color Doppler ultrasound-guided balloon dilation.

METHODS: The anteroposterior diameter of the given aortic segment in rabbits was measured by ultrasonography to ensure the similar original diameter. Then they were assigned into three groups with the inflation force at 1, 5, 10 atmosphere pressure (atm), respectively. Balloon dilation and injury of the given aortic segment were performed. Two weeks later, all rabbits were euthanized for histologic evaluation.

RESULTS: After operation, the lumen diameter of each group enlarged significantly (P< 0.05) with a similar rate of change. However, neointimal area, circumference and hepatocyte growth factor (HGF) positive cells in group with 1 atm were significantly less than those of the other two (P< 0.05). Maximal neointima thickness increased significantly with the elevation of the inflation pressure (P< 0.05).

CONCLUSIONS: Based on sufficient dilation of the balloon, the balloon inflated with the less pressure caused the similar increase in lumen diameter as the higher pressure but the less neointimal hyperplasia and HGF positive cells.