Anesthesia Management in Endovascular Therapy for Ischemic Stroke (AMETIS)

Since 2015, the management of anterior acute ischemic stroke (AIS) involves endovascular treatment with mechanical thrombectomy (MT). This urgent, difficult and uncomfortable procedure in frail patients requires multidisciplinary care ideally involving neurologists, interventional neuroradiologists and anesthesiologists.

Two anesthetic strategies are currently used: pharmacologic sedation in spontaneous ventilation or general anesthesia with tracheal intubation. General anesthesia provides strict immobility, protects the airway and avoids emergency intubation in case of severe procedural complication (notably vomiting and aspiration). Sedation is a frequently used alternative because of (1) a rapid execution which could reduce delay to reperfusion, (2) a lower risk of blood pressure drop that may compromise cerebral blood flow in the penumbra area, (3) the theoretical capacity to assess neurological status during the procedure and (4) the supposed risk of complications associated with mechanical ventilation and intravenous anesthestics on brain metabolism. Nevertheless, sedation exposes to dramatic complications in case of patient agitation and movements.

The choice of the ideal anesthesic management is still lacking. Old retrospective studies seemed to favor sedation with worst neurological outcome associated with general anesthesia. Nevertheless, these datas suffered methodological issues with selection bias: more severe patients based on NIHSS score were rather treated with general anesthesia and blood pressure was not controlled. Recent studies that demonstrated the benefit of MT did not include a specific anesthetic protocol and none of the studies currently available included a blood pressure management protocol that appears to be an essential component of cerebral perfusion. A subgroup analysis of the MR Clean study, including patients with an identical initial NIHSS score, did not find benefit from MT in patients with general anesthesia compared to those receiving sedation. Finally, authors concluded that performing a MT under general anesthesia would significantly lengthen the reperfusion delay and nullify the benefit of MT.

The prospective, randomized, single-center SIESTA trial, conducted in 150 patients with an anterior circulation AIS, found no difference in the early neurological improvement (primary endpoint), assessed on the change in NIHSS score between admission and the 24th hour, between the conscious sedation group and the general anesthesia group. There were a tendency for a better 3-month neurological outcome in the general anesthesia group (37% vs 18% of patients with a Modified Rankin score of 0-2 in the general anesthesia and conscious sedation groups respectively), but it was not possible to conclude due to a lack of statistical power.

Due to the increasing number of patients eligible for endovascular MT and the potential implication of these two anesthetic management on the functional outcome, a study comparing general anesthesia and sedation during a MT seems essential as specified in the recent updated American Stroke Association guidelines.

The objective of this study is to assess whether sedation or general anesthesia during endovascular treatment with mechanical thrombectomy is associated with a difference in morbidity (neurological outcome and peri-procedural complications), in anterior circulation AIS.