Structural changes of the intradural arteries following subarachnoid hemorrhage.

Abstract

✓ The histology of the intradural arteries was studied in 12 consecutive autopsy cases of patients dying 1 day to 15 months after their initial spontaneous subarachnoid hemorrhage. In all patients surviving 4 weeks or more and in one surviving 4 days, the lumina of the intracranial arteries were narrowed by subendothelial granulation tissue which thickened the intima. In all seven cases with structural changes in the intracranial arteries, vessels near the site of hemorrhage were involved; in four cases vessels remote from the site of hemorrhage were also involved. Changes were usually restricted to large arteries with a prominent muscular layer and confined to the subarachnoid space. The presence and degree of intimal thickening correlated with the distribution and amount of subarachnoid blood or its breakdown products. This process apparently does not represent an obliterative endarteritis involving vessels exclusively supplying infarcted brain, but is probably a reaction to mechanical or anoxic damage to the intima following vasoconstriction. It is suggested that this arterial structural change might be confused with delayed or prolonged “vasopasm.”