Bilateral dynamic cerebral autoregulation assessment during endovascular treatment in large-vessel occlusion stroke

Recanalization by endovascular treatment (EVT) is effective in acute ischaemic stroke caused by large-vessel occlusion. Better understanding of the pathophysiology could possibly identify targets for improving peri-procedural management and thereby patient outcome. Dynamic cerebral autoregulation (dCA), which maintains cerebral blood flow despite changes in arterial blood pressure (ABP), is reportedly impaired after EVT. Blood pressure thresholds after EVT have previously been individualized by accounting for dCA, which could improve outcome. The conventional method to estimate dCA requires transcranial Doppler, which is difficult to use during EVT. Instead, we investigated dCA during EVT by near-infrared spectroscopy (NIRS) which is more feasible. NIRS and ABP were measured continuously before recanalization, immediately after recanalization, and after general anaesthesia termination for subsequent transfer function analysis yielding the dCA measure of phase shift (0.07-0.2 Hz). Phase shift did not differ between the ischaemic and contralateral hemisphere but the sensitivity to end-tidal CO₂ was increased in the ischaemic hemisphere immediately after recanalization. Phase shift over time interacted with 90-day functional outcome including independence and mortality. Hence, patients with good long-term outcome showed increased phase shift during and after EVT, while phase shift decreased in poor outcome patients. In conclusion, dCA did not differ between hemispheres during EVT but was more sensitive to end-tidal CO₂ in the ischaemic compared to the contralateral hemisphere and dCA evolved differently in patients with good and poor outcome. Our findings of individual dCA differences during EVT suggest benefit of individualized blood pressure management, which should be addressed in future studies.