Transcranial Doppler ultrasound to evaluate the risk of hyperperfusion after endovascular stroke thrombectomy

BACKGROUND AND PURPOSE: Hemorrhagic transformation (HT) has been reported in up to 50% of acute ischemic stroke (AIS) patients with a large vessel occlusion (LVO) treated with endovascular thrombectomy (EVT). HT may be driven by postrecanalization hyperperfusion injury and is independently associated with worse functional outcomes. Strategies to identify patients at risk for HT may assist in developing preventive therapies. METHODS: We prospectively included adult AIS patients with an anterior circulation LVO achieving successful recanalization after EVT. Consenting participants received transcranial Doppler ultrasound (TCD) within 18 hours of procedure completion. We compared flow velocities according to the presence of HT on the computed tomography scan performed within the first 24±12 hours from the end of EVT. We also evaluated the association of flow velocities with systemic blood pressure (BP) readings at the time of insonation. RESULTS: A total of 48 patients consented to participate in the study. Six (12%) were excluded due to the absence of temporal windows. HT was detected in 20 participants (48%). Those with HT had higher peak systolic velocities on the middle cerebral arteries compared to those without HT for both the symptomatic (107±42 vs. 82±25 cm/second, p = .024) and asymptomatic (97±21 vs. 81±25 cm/second, p = .040) sides. No correlation of flow velocities on either the symptomatic or asymptomatic side and BP measurements at the time of insonation was detected. CONCLUSION: TCD can identify patients at risk of HT following successful EVT. TCD could serve as an inexpensive ancillary test to guide participant selection for clinical trials targeting postprocedural reperfusion injury.