Cerebral vessel recanalization therapy, either intravenous thrombolysis or mechanical thrombectomy, is the main treatment that can significantly improve clinical outcomes after acute ischemic stroke. The degree of recanalization and cerebral reperfusion of the ischemic penumbra are dependent on cerebral hemodynamics. Currently, the main imaging modalities to assess reperfusion are MRI and CT perfusion. However, these imaging techniques cannot predict reperfusion‐associated complications and are not readily available in many centers. It is also not feasible to repeat them frequently for sequential assessments, which is important because of the changing nature of cerebral hemodynamics following stroke. Transcranial Doppler sonography (TCD) is a valid, safe, and inexpensive technique that can assess recanalized vessels and reperfused tissue in real‐time at the bedside. Post thrombectomy reocclusion, hyperperfusion syndrome, distal embolization, and remote infarction result in poor outcomes after mechanical or intravenous reperfusion therapy. Managing blood pressure following these endovascular treatments can also be a dilemma. TCD has an important role, with major clinical implications, in evaluating cerebral hemodynamics and collateral vessel status, guiding clinicians in making individualized decisions based on cerebral blood flow during acute stroke care. This review summarizes the most relevant literature on the role of TCD in evaluating patients after reperfusion therapy. We also discuss the importance of performing TCD in the first few hours following thrombolytic therapy in identifying hyperperfusion syndrome and embolic signals, predicting recurrent stroke, and detecting reocclusions, all of which may help improve patient prognosis. We recommend TCD during the hyperacute phase of stroke in comprehensive stroke centers.

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BACKGROUND Recent advances in endovascular therapy (EVT) have led to significant improvements in functional outcomes of patients with stroke. However, early neurological deterioration after EVT has remained a concerning issue. This cohort study was designed to assess the feasibility of early transcranial Doppler (TCD) after EVT and to identify associations between TCD findings and early neurological deterioration. METHODS Between October 16, 2020, and March 28, 2021, we recruited 20 patients with acute ischemic stroke with large‐vessel occlusion who underwent EVT. Five patients were excluded because of a poor temporal window; 2 had an unsuccessful intervention. Using TCD, we measured peak systolic velocity, end‐diastolic velocity, mean flow velocity, and pulsatility index for all selected arteries before and within 60 minutes after EVT. We also examined the association between active leptomeningeal collateral flow after EVT and early neurological deterioration. Patients were followed for 3 months, and disability was measured using the modified Rankin scale. RESULTS Two patients had early neurological deterioration with elevated blood pressure and active leptomeningeal flow despite successful EVT. Most patients with poststroke disability (modified Rankin scale>2) had either flow diversion or active leptomeningeal collateral flow in the presence of elevated blood pressure (≥170/93 mm Hg). In cases without early neurological deterioration and in those with a modified Rankin scale<2, we did not observe any flow diversion or active leptomeningeal collateral. They also had a blood pressure of ≤155/85 mm Hg after EVT. All patients with hemorrhagic transformation had evidence of hyperemia on TCD. CONCLUSIONS Early TCD is a feasible and safe approach to evaluate cerebral blood flow before and after EVT and identify those at risk of early neurological deterioration. For the next phase of this study, we plan to manage blood pressures based on individualized cerebral flow and the presence of active collateral arteries after EVT.