The preoperative assessment of stroke risk in lesions involving the internal carotid artery.

Patients with vascular or tumourous lesions involving the internal carotid artery are at risk of damage or occlusion of this vessel during surgical or endovascular procedures. To assess the stroke risk transcranial Doppler aided carotid compression tests were performed in 82 patients. Based on changes of blood flow velocity (BFV), pulsatility index, systolic/diastolic ratio and length of transient hyperaemic response three groups could be differentiated. Patients in group A (31%) showed only a slight reaction of BFV and were at minimal risk in case of carotid occlusion. Patients in group B (52%) underwent a distinct decrease of Doppler readings with partial improvement and were considered to have moderate to high stroke risk. In group C patients (17%) trial occlusion caused a dramatic reduction of BFV with no recovery (p < 0.01), which denotes a very high stroke risk. Transcranial Doppler aided carotid occlusion manoeuvres provide useful information on cerebrovascular collateral capacity and prognosis of stroke risk.