Abstract 058: General anesthesia versus conscious sedation during endovascular thrombectomy for distal vessel occlusions
Authors: Mehta Amol , Kellner Christopher , Shigematsu Tomoyoshi , Shoirah Hazem , Caton Michael T. , Oxley Thomas J. , DeLeacy Reade , Mocco J. , Fifi Johanna , Majidi Shahram 
Published: March 2024

Introduction
Choice of anesthesia for endovascular thrombectomy in large vessel occlusion of the anterior circulation has been well studied, although practice patterns may still be variable. Anesthesia choice for distal vessel occlusions (DVO) presents unique challenges, however. General anesthesia (GA) may offer advantages over conscious sedation (CS) due to reduced patient movement facilitating catheter navigation, but concerns persist about potential delays and hypotension impacting collateral circulation. In our study, we aim to explore this question further.

Methods
In our prospectively maintained stroke registry from December 2014 to July 2023, we identified patients with DMVO defined as M2, M3, M4 occlusion, ACA occlusion, and PCA occlusion, who underwent MT for AIS. We compared patients who received CS to those who GA. Our primary outcome measures were length of procedure defined as time from entering angiography suite until final recanalization, access time to recanalization, CS to GA conversion rate, number of passes to reach TICI2b or better and first pass effect. Our secondary outcomes were length of stay, and modified Rankin Scale (mRS) at 5 days, 30 days, and 90 days.

Results
Total of 290 patients with DVO were identified, the median age was 73 (IQR 19). Of these, 86 patients (29.7%) underwent GA, and 200 (69.0%) received CS. CS to GA conversion was required in 36 patients (12.4%). Females accounted for 47.5% of the CS group and 38.4% of the GA group. No significant differences were found between the two groups in the racial and gender composition (p>0.1). The mean admission NIHSS was significantly higher in the GA group (16.86) compared to the CS group (12.44) as was the rate of IV thrombolysis in the CS (36.2%) group compared to GA (31.4%) group (p<0.01). The type of anesthesia used was not influenced by the laterality of the stroke in the middle cerebral artery territory (left vs right) (χ²=0.39, p=0.53). After adjusting for age, sex, IV thrombolysis, and admission NIHSS, CS usage did not result in an increase in procedural time (β=1.3, p=0.83). Furthermore, CS had no significant effect on the total number of passes (β=‐0.15, p=0.53), nor did it influence the likelihood of achieving first‐pass recanalization (β=0.28, p=0.48). No associations were found between CS use and the modified Rankin Scale (mRS) at 5 days (β=0.17, p=0.65), 30 days (β=0.22, p=0.75), or 90 days (β=0.15, p=0.67). Likewise, the length of stay in the hospital (β=1.71, p=0.77) was not significantly affected by the use of CS.

Conclusion
In our analysis of DMVO, the use of CS during thrombectomy appeared to be safe and feasible and comparable to GA with regards to procedural length, number of passes, and rate of first pass recanalization. Similarly, the type of anesthesia did not have an impact on clinical outcome. Further studies are needed to build on these findings and inform optimal management strategies.