Conscious sedation non-superior to general anesthesia for endovascular therapy in patients with posterior circulation stroke: CANVAS II randomized controlled trial

1. The CANVAS II randomized controlled trial demonstrated similar functional outcomes between general anesthesia and conscious sedation among patients with posterior circulation acute ischemic stroke undergoing endovascular therapy.

2. Secondary outcomes, including successful reperfusion rates, length of hospital stay, length of neurological intensive care unit stay, and 90-day mortality, were similar between those who received general anesthesia and those who received conscious sedation. 

Evidence Rating Level: 1 (Excellent)

Study Rundown: Acute ischemic stroke (AIS) is a common cause of morbidity and mortality. Endovascular therapy (EVT) to treat anterior AIS has been shown to be effective, and functional outcomes under general anesthesia (GA) were better than or similar to those under conscious sedation (CS). However, based on previous studies, functional outcomes of GA vs CS for patients undergoing EVT remain unclear. The CANVAS II dual center, randomized controlled trial investigated whether CS is an effective and safe alternative to GA for EVT for patients with posterior AIS. Adult patients (n= 93) with an acute posterior circulation stroke (PCS) were randomized 1:1 for EVT with GA or CS between March 2018 and June 2021; patients were followed up for 3 months. The primary outcome was functional independence using a modified Rankin scale (mRS) score of 2 or lower at 90-days. Successful reperfusion was a secondary outcome measured using the modified treatment in cerebral infarction (mTICI) score. At 90-days, both cohorts demonstrated similar rates of mRS score between 0-2 (OR: 0.91 [95% CI: 0.37-2.22), representing functional independence. Complications after EVT, mortality (at 30- and 90-days), length of hospital stay, and length of stay in the neurological intensive care unit were not significantly different between groups. Successful reperfusion, measured using the mTICI score, was also similar between cohorts (OR: 5.86 [95% CI: 1.16-29.53]). Overall, the CANVAS II trial, the first trial comparing anesthetic methods for EVT for patients with acute PCS, demonstrated similar functional and safety outcomes between those who underwent GA versus those who received CS. This study may be limited by its generalizability, given its small sample size and data from only two centers in China.

Click to read the study in JAMA Neurology

Relevant Reading: Effect of conscious sedation vs general anesthesia on early neurological improvement among patients with ischemic stroke undergoing endovascular thrombectomy

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