PREDICTION OF INTRACEREBRAL HEMORRHAGE AFTER CAROTID ENDARTERECTOMY BY CLINICAL-CRITERIA AND INTRAOPERATIVE TRANSCRANIAL DOPPLER MONITORING

Intracerebral haemorrhage is a serious complication after carotid endarterectomy. We tried to identify predictors of this event. Two-hundred-and-thirty-three operations were selected from a total of 280 because of reliable intraoperative trascranial Doppler data with regards to the increase of peak blood flow velocities and pulsatility indices in the ipsilateral middle cerebral artery after release of the internal carotid artery cross-clamp. We also recorded the occurrence of unilateral throbbing headache or hypertension after the operation. Five patients developed an intracerebral haemorrhage after the operation. Seventeen patients developed headache or hypertension after surgery, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, for intracerebral haemorrhage was 24% (diagnostic gain 22%). The negative predictive value, sensitivity and specificity were 99, 80 and 94%, respectively. The increase of peak blood flow velocities and pulsatility indices in patients who developed intracerebral haemorrhage was significantly higher than in patients who did not (p < 105; one-way ANOVA). With appropriate cut-off levels for the increase of peak blood flow velocities (≥175% increase) or pulsatility indices (≥100% increase) after release of the cross-clamps, the positive predictive value of intraoperative transcranial Doppler for intracerebral haemorrhage was 100% (diagnostic gain 98%). The negative predictive value, sensitivity and specificity were 99, 80 and 100%, respectively. An increase of peak blood flow velocity ≥175% or pulsatility index ≥100% after unclamping the internal carotid artery predicts postoperative intracerebral haemorrhage more accurately than the occurrence of headache or hypertension after the operation. Transcranial Doppler monitoring can be used to identify patients at risk for intracerebral haemorrhage, in whom control of blood pressure and modest degrees of anticoagulation may be appropriate. © 1994 W. B. Saunders Company Ltd.