Thrombectomy Outcomes With General vs Nongeneral Anesthesia: A Pooled Patient-Level Analysis From the EXTEND-IA Trials and SELECT Study

Abstract

Background and objectives: The effect of anesthesia choice on endovascular thrombectomy (EVT) outcomes is unclear. Collateral status on perfusion imaging may help identify the optimal anesthesia choice.

Methods: In a pooled patient-level analysis of EXTEND-IA, EXTEND-IA TNK, EXTEND-IA TNK part II, and SELECT, EVT functional outcomes (modified Rankin Scale score distribution) were compared between general anesthesia (GA) vs non-GA in a propensity-matched sample. Furthermore, we evaluated the association of collateral flow on perfusion imaging, assessed by hypoperfusion intensity ratio (HIR) - Tmax > 10 seconds/Tmax > 6 seconds (good collaterals - HIR < 0.4, poor collaterals - HIR ≥ 0.4) on the association between anesthesia type and EVT outcomes.

Results: Of 725 treated with EVT, 299 (41%) received GA and 426 (59%) non-GA. The baseline characteristics differed in presentation National Institutes of Health Stroke Scale score (median [interquartile range] GA: 18 [13-22], non-GA: 16 [11-20], p < 0.001) and ischemic core volume (GA: 15.0 mL [3.2-38.0] vs non-GA: 9.0 mL [0.0-31.0], p < 0.001). In addition, GA was associated with longer last known well to arterial access (203 minutes [157-267] vs 186 minutes [138-252], p = 0.002), but similar procedural time (35.5 minutes [23-59] vs 34 minutes [22-54], p = 0.51). Of 182 matched pairs using propensity scores, baseline characteristics were similar. In the propensity score-matched pairs, GA was independently associated with worse functional outcomes (adjusted common odds ratio [adj. cOR]: 0.64, 95% CI: 0.44-0.93, p = 0.021) and higher neurologic worsening (GA: 14.9% vs non-GA: 8.9%, aOR: 2.10, 95% CI: 1.02-4.33, p = 0.045). Patients with poor collaterals had worse functional outcomes with GA (adj. cOR: 0.47, 95% CI: 0.29-0.76, p = 0.002), whereas no difference was observed in those with good collaterals (adj. cOR: 0.93, 95% CI: 0.50-1.74, p = 0.82), p _interaction: 0.07. No difference was observed in infarct growth overall and in patients with good collaterals, whereas patients with poor collaterals demonstrated larger infarct growth with GA with a significant interaction between collaterals and anesthesia type on infarct growth rate (p _interaction: 0.020).

Discussion: GA was associated with worse functional outcomes after EVT, particularly in patients with poor collaterals in a propensity score-matched analysis from a pooled patient-level cohort from 3 randomized trials and 1 prospective cohort study. The confounding by indication may persist despite the doubly robust nature of the analysis. These findings have implications for randomized trials of GA vs non-GA and may be of utility for clinicians when making anesthesia type choice.

Classification of evidence: This study provides Class III evidence that use of GA is associated with worse functional outcome in patients undergoing EVT.

Trial registration information: EXTEND-IA: ClinicalTrials.gov (NCT01492725); EXTEND-IA TNK: ClinicalTrials.gov (NCT02388061); EXTEND-IA TNK part II: ClinicalTrials.gov (NCT03340493); and SELECT: ClinicalTrials.gov (NCT02446587).

Figure 1. Illustrative Cases for Good and Poor Collaterals and Study Flowchart

(A) Illustrative cases for good and poor collaterals on perfusion imaging. Patient 1 demonstrated Tmax >10 seconds volume of 7.0 mL and Tmax > 6 seconds volume of 71.3 mL, resulting in an HIR of 0.09, which is considered a marker for good collaterals, whereas patient 2 demonstrated Tmax > 10 seconds volume of 59.0 mL and Tmax > 6 seconds volume of 68.9 mL, resulting in an HIR of 0.86, which is considered a marker for poor collaterals. (B) Study flowchart. HIR = hypoperfusion intensity ratio.

Figure 2. Distribution of Functional Outcomes by 90-Day mRS Score in the Propensity-Matched Cohort

(A) Illustrates EVT outcomes in patients based on their anesthesia type, demonstrating an overall shift toward better functional outcomes in patients treated with non-GA. (B) Illustrates EVT outcomes in patients based on their anesthesia type in patients with HIR < 0.4. (C) Illustrates EVT outcomes in patients based on their anesthesia type in patients with HIR ≥ 0.4. Patients with poor collaterals (HIR ≥ 0.4) demonstrated a clear shift in the functional outcomes with non-GA, whereas the distribution of functional outcomes was similar for GA and non-GA approaches for patients with good collaterals (HIR < 0.4). EVT = endovascular thrombectomy; GA = general anesthesia; HIR = hypoperfusion intensity ratio; mRS = modified Rankin Scale.