INTRACRANIAL HEMORRHAGE FOLLOWING SURGICAL REVASCULARIZATION FOR TREATMENT OF ACUTE STROKES.

I N THE evaluation of the results of vascular reconstructive operations for cerebral vascular insufficiency it becomes necessary to divide the clinical syndromes of cerebral insufficiency into two broad categories. The category of patients for whom revascularization seems most helpful is represented by those individuals whose totally or partially occlusive lesions produce transient ischemic attacks or chronic lowgrade insufficiency in the apparent absence of cerebral infarction. In this category, when occlusive lesions are present in operable extracranial arteries, improvement in cerebral function following successful operations ordinarily is subject to clear evaluation on the basis of definable changes in neurologic symptoms or findings. An early unfavorable neurologic result may be considered to be caused largely by an error in performance of operation. The other category is represented by those patients whose occlusive lesions have caused frank cerebral infarction resulting in a fixed or progressive neurologic deficit. The numerous variations in the natural history of recovery of cerebral function in this group make it difficult to define the extent of improvement that properly may be credited to a successful arterial operation, particularly when operation is performed a few hours or days after the onset of a stroke. When improvement follows operation upon a patient with a recent acute stroke it may be difficult to determine whether this result represents a natural phase of recovery or whether it has occurred because of increased arterial flow to partially ischemic brain tissue at the periphery of the infarcted zone. Conversely,