Experimental model of symptomatic vasospasm in rabbits.

The common carotid arteries were ligated bilaterally 2 weeks before induction of subarachnoid hemorrhage in rabbits. The rabbits were observed closely for clinical symptoms, and angiographic and pathologic investigations were performed. Thirteen experimental rabbits showed a progressing neurologic deficit that was worst on the fourth or fifth day after the subarachnoid hemorrhage. This symptomatic change did not occur in five rabbits without previous carotid ligation. Presumably, the rabbits with carotid ligation became symptomatic because they no longer had a collateral blood flow to compensate for the reduced blood flow in the basilar artery after subarachnoid hemorrhage. Our model of symptomatic vasospasm after subarachnoid hemorrhage may be beneficial for future studies.