Timing of periarterial blood removal for the prevention of vasonecrosis

In an attempt to provide some data on the time interval during which surgical removal of subarachnoid blood would be beneficial for the prevention of the vasospasm-vasonecrosis syndrome, we have performed experiments on the femoral arteries of rabbits. Blood was allowed to clot around the exposed femoral artery and then removed at 24, 36, 48, and 72 hours. These experiments reveal that after 24 hours of blood contact the arteries appear normal, whereas after 36 hours or more of blood contact a definite pathologic reaction is present. On the basis of these animal experiments, we recommend that if an attempt is to be made at the prevention of delayed neurologic deterioration by surgical removal of clotted blood from around the cerebral arteries, the surgery should be performed within 36 hours or as soon thereafter as possible.