Diagnostic Performance of the Resistance Index (RI) for Assessing Cerebral Vasoreactivity Using Transcranial Doppler in Patients with Carotid Artery Stenosis or Occlusion

What this Trial Is About

Researchers are investigating a simpler way to assess cerebral vasoreactivity in patients with carotid artery stenosis or occlusion. While routine revascularization for asymptomatic carotid stenosis is uncertain due to reduced stroke risk from optimal medical therapy, identifying high-risk patients who may still benefit from revascularization is important. Current cerebral vasoreactivity testing using transcranial Doppler ultrasound is complex, requires specialized equipment and trained personnel, and is not widely available. This study evaluates the resistance index (RI), a routine measure from transcranial echo-Doppler, as a potential predictor of cerebral vasoreactivity. The goal is to use the RI to quickly identify patients with normal vasoreactivity who do not need the full pharmacological cerebral vasoreactivity test, which is time-consuming. Patients will undergo measurement of the RI on the middle cerebral artery, with randomization of test order between RI measurement and the reference vasoreactivity test. Participants will provide informed consent before enrollment and must meet specific criteria related to carotid artery stenosis or occlusion and temporal bone window suitability. Researchers will measure the difference in average resistance index between arteries on both sides of the brain on Day 1 and assess its accuracy in detecting normal vasoreactivity. Secondary measures include sensitivity and specificity of additional Doppler indices and their correlation with vasoreactivity. The study is observational and led by Centre Hospitalier Universitaire de Nîmes, with patient participation lasting a single study day.

Diagnostic Performance of the Resistance Index (RI) for the Assessment of Cerebral Vasoreactivity in Transcranial Doppler