Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits

Venous diseases like iliofemoral deep vein thrombosis and valvular dysfunction induce venous hypertension. To know the effects of the hypertension on venous mechanics, blood pressure in the left femoral vein in the rabbit was chronically elevated by the constriction of the left external iliac vein. Wall dimensions and biomechanical properties of the femoral vein were studied in vitro at 1, 2, or 4 wk after surgery. Blood pressure measured immediately before the animal was killed was significantly higher in the left femoral vein than in the sham-operated, contralateral vein. Wall thickness was increased by blood pressure elevation even at 1 wk, which restored circumferential wall stress to a control level. The stress was kept at normal up to 4 wk. Vascular tone and vascular contractility were increased by the elevation of blood pressure; however, wall elasticity and compliance were kept at a normal level. These results are very similar to those observed in hypertensive arteries, indicating that not only arteries but veins optimally operate against blood pressure elevation.