Extravascular perivenous fibrin support leads to aneurysmal degeneration and intimal hyperplasia in arterialized vein grafts in the rat

BACKGROUND AND AIMS: External support of vein grafts by fibrin glue possibly prevents overdistension, vascular remodeling, and neointimal hyperplasia. Previous animal models of neointimal hyperplasia showed conflicting results. Here, long-term effects of external fibrin glue support were studied in a new rat model of jugular vein to abdominal aorta transposition. MATERIALS AND METHODS AND METHODS: In male Wistar rats (250-300 g) right jugular vein (1.0-1.5 cm) was transposed to the infrarenal aorta. Fibrin glue (0.25 ml) covered the vein before releasing the vascular clamps (n = 6). Control vein grafts were exposed directly to blood pressure. After 16 weeks vein grafts were pressure-fixed for histology. Intima thickness, luminal and intimal area were measured by planimetry and elastic fibers demonstrated by Elastica van Giesson staining. RESULTS: Intimal thickness (74.04 +/- 6.7 microm vs 1245 +/- 187 microm, control vs fibrin treatment; p < 0.001), intimal area (2517.16 +/- 355 mm(2) vs 18424 +/- 4927 mm(2), control vs fibrin treatment; p < 0.05) and luminal area (2184.75 +/- 347 mm(2) vs 7231.85 +/- 1782 mm(2), control vs fibrin treatment; p < 0.05) were significantly increased, elastic fibers in the vessel wall were diminished and the vessel wall infiltrated by mononuclear cells in fibrin glue supported veins. CONCLUSION: External support of vein grafts by fibrin glue leads to aneurysmal degeneration and intimal hyperplasia, thereby possibly jeopardizing long-term graft patency.