Objective: Identification of predictors of intracerebral haemorrhage after carotid endarterectomy.
Design: Retrospective comparison of patients who developed intracerebral haemorrhage and patients who did not, with special attention to intraoperative transcranial Doppler monitoring of the ipsilateral middle cerebral artery and postoperative signs and symptoms of hypoperfusion.
Subjects and materials: Two-hundred and thirty-three patients were studied with regard to the increase of peak blood flow velocities and pulsatility indices after endarterectomy and to the occurrence of unilateral throbbing headache or hypertension.
Results: Intracerebral haemorrhage occurred in five cases. Seventeen patients complained of headache or showed hypertension, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, 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 < 10(-5); one-way ANOVA). When cut-off levels for the increase of peak blood flow velocities and pulsatility indices were set to 175 and 100%, respectively, the positive predictive value of intraoperative transcranial Doppler was 100% (diagnostic gain 98%). The negative predictive value, the sensitivity and specificity were 99, 80 and 100%, respectively.
Conclusion: An increase of peak blood flow velocity > or = 100% or pulsatility index > or = 100% after declamping predicts intracerebral haemorrhage more accurately than the occurrence of headache or hypertension. 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.