Collateral arterial capacity following acute iliac occlusion in the rat

The development of collateral circulation after ligation of the left iliac artery was studied in 46 rats by means of microsphere distribution in muscles of both lower limbs. The radioactive microspheres were injected into the aortic root in the hyperemic phase after 5 min of cuff-induced ischemia of the lower extremities. The hyperemic response to cuff-induced ischemia as well as microsphere distribution between both lower limbs in control animals were studied separately in 23 rats. The largest hyperemic response occurred 15-30 s after cuff-induced ischemia. After iliac artery ligation, flow in the thigh increased from 43% of control value 20 min after ligation to 70% after 26 days of recovery. Flow in calf muscles increased correspondingly from 4% to 33%. This study quantifies the capacity of collateral formation following acute iliac artery occlusion.