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

Abstract

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. 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. External support of vein grafts by fibrin glue leads to aneurysmal degeneration and intimal hyperplasia, thereby possibly jeopardizing long-term graft patency.