LOW CEREBRAL BLOOD-FLOW AND PERFUSION RESERVE INDUCE HYPERPERFUSION AFTER SURGICAL REVASCULARIZATION - CASE-REPORTS AND ANALYSIS OF CEREBRAL HEMODYNAMICS

BACKGROUND Hyperperfusion syndrome after surgical revascularization is a rare complication and there has not been any systematic study on fa ctors that induce hyperperfusion after surgery. In this paper, we retr ospectively analyzed the factors related to this syndrome. PATIENTS AN D METHODS We performed 46 cases of surgical revascularization includin g 33 cases of carotid endarterectomy (CEA) and 13 cases of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis during t he past 5 years. Among these, we encountered three cases of hyperperfu sion syndrome despite well-controlled blood pressure postoperatively. To evaluate factors related to the occurrence of hyperperfusion syndro me, we examined four parameters: (1) regional cerebral blood flow (rCB F), (2) the increase in the ratio of the postoperative rCBF compared t o the preoperative rCBF (increase ratio), (3) cerebral perfusion reser ve presented by the increase of rCBF after acetazolamide administratio n (Delta rCBF), and (4) the difference in mean blood pressure between the preoperative and postoperative state (Delta BP). RESULTS Preoperat ive rCBF was significantly lower in cases of hyperperfusion syndrome t han the control cases (p < 0.01 Mann-Whitney U-test). Moreover Delta r CBF was evidently lower in the hyperperfusion cases than the control ( p < 0.05 Fisher's exact method). However, there was no significant dif ference in the Delta BP between the hyperperfusion cases and the contr ol cases. CONCLUSION In cases of marked low perfusion (low rCBF) with poor perfusion reserve (low Delta rCBF), hyperperfusion after surgical revascularization can occur even if blood pressure is adequately cont rolled. (C) 1997 by Elsevier Science Inc.