Rajbeer Singh Sangha, MD 

van den Berg LA, Koelman DLH, Berkhemer OA, Rozeman AD, Fransen PSS, Beumer D, et al. Type of Anesthesia and Differences in Clinical Outcome After Intra-Arterial Treatment for Ischemic Stroke. Stroke. 2015

With the recent trials publishing favorable data for the use of intra-arterial therapy during acute ischemic stroke, the methods utilized during these procedures will come under further scrutiny.  One of the factors that has thought to be associated with changes in outcome and hotly debated is the use of general anesthesia during endovascular therapy.  Previous studies have suggested that patients who do not receive GA have better clinical outcomes.  Some of the factors that have been postulated with the poor outcomes include induction and recovery phases in GA which are stressful and could lead to cardiac arrhythmias and cardiac ischemia. Furthermore inhaled and intravenous (IV) anesthetic agents are known to alter blood carbon dioxide (CO2) and can cause blood pressure shifts that could lead to changes in cerebral autoregulation with decreased cerebral perfusion.  The authors of the MR CLEAN study hypothesize that patients undergoing endovascular therapy will do better without general anesthesia and use the data from the study to conduct a post-hoc analysis.

They conduct a retrospective cohort study in patients from the pre-trial cohort of the Multicenter Randomized Clinical Trial of Endovascular treatment for acute ischemic stroke in the Netherlands (MR CLEAN), which consists of all consecutive patients with AIS treated with IAT in 16 stroke centers in The Netherlands. Out of the 369 patients that were in the registry, 21 were excluded and 348 patients were used for the analysis; 278 patients were treated without GA and 70 patients with GAA total of 82 (82/348(24%)) patients were functionally independent (mRS 0-2) at discharge. Good clinical outcome was seen in 26% (72 /278) of patients in the non-GA group and in 14% (10/70) of patients in the GA group. A higher mortality rate was seen in the GA group (15/70( 21%)) as compared to the non-GA group (46/278 (17%)), however this difference was not statistically significant.  In unadjusted logistic regression analysis, non-GA was significantly associated with good clinical outcome (OR: 2.1, 95% CI 1.02-4.31). After adjusting for pre-specified prognostic factors, the point estimate remained positive, however did not reach statistically significance (OR: 1.9, 95 % CI: 0.89-4.24). 

This retrospective analysis of the MR CLEAN cohort of patients suggests that patients with AIS of the anterior circulation undergoing IAT without general anesthesia have a higher probability of good clinical outcome compared to patients treated with general anesthesia.  These results did not however reach statistical significance and still leaves a lot of room for debate.  Until a randomized clinical trial is not conducted which compares the two modalities we will not have a conclusive answer.  In light of the recent trials and the importance of anesthesia, a multicenter trial should be conducted addressing this question.  It will be also interesting to see the post hoc analysis of the other interventional trials and see if they reach similar conclusions.