GASS
General Anesthesia versus Sedation, Both with Hemodynamic Control, during Intraarterial Treatment for Stroke: The GASS Randomized Trial
Clinical Question
To determine if conscious sedation is associated with a better functional outcome at 3 months compared to general anesthesia in patients undergoing endovascular therapy for acute ischemic stroke due to a large vessel occlusion in the anterior circulation.
Bottom Line
In this trial, standardized general anesthesia and standardized conscious sedation during endovascular treatment for stroke resulted in similar functional outcomes at 3 months. The choice of anesthetic strategy did not significantly impact the primary outcome, suggesting clinicians can use either approach.
Major Points
- GASS was a multicenter, single-blind, randomized controlled trial that enrolled 345 patients with large vessel occlusion stroke at four centers in France.
- Patients undergoing endovascular therapy were randomized 1:1 to receive either a standardized conscious sedation protocol or a standardized general anesthesia protocol.
- A key feature of the trial was that both groups had a standardized protocol for intraoperative blood pressure control.
- The primary outcome, a favorable functional outcome (modified Rankin Scale [mRS] score of 2 or less) at 3 months, was not significantly different between groups: 36% in the conscious sedation group versus 40% in the general anesthesia group (P=0.474).
- Patients in the general anesthesia group had a significantly higher rate of successful recanalization (85% vs. 75%; P=0.021) but also experienced longer times from arrival to groin puncture.
- The incidence of symptomatic intracranial hemorrhage and 3-month mortality was similar in both groups.
Design
Study Type: Investigator-initiated, prospective, multicenter, parallel-group, single-blind, randomized, controlled, superiority trial
Randomization: 1
Blinding: Single-blind (patients, nonmedical research staff, the statistician, and the data and safety monitoring committee were blinded; outcome assessors were blinded).
Enrollment Period: September 2016 to June 2020
Follow-up Duration: 3 months
Centers: 4
Countries: France
Sample Size: 345
Analysis: Intention-to-treat analysis. The primary endpoint was compared between groups using the chi-square test.
Inclusion Criteria
- Age older than 18 years
- Admitted to a participating center for occlusion of a large vessel in the anterior cerebral circulation
- Admitted for endovascular therapy
Exclusion Criteria
- Already intubated and mechanically ventilated before inclusion
- Intracerebral hemorrhage associated with the ischemic stroke
- Contraindicated for conscious sedation (eg, Glasgow Coma Scale less than 8, severe agitation)
- Contraindicated for succinylcholine (used in the general anesthesia protocol)
- Inability to walk prior to the current event or history of a previous stroke
Arms
| Field | Control | Conscious Sedation |
|---|---|---|
| Intervention | Standardized general anesthesia protocol using etomidate, target-controlled infusion of propofol and remifentanil, and succinylcholine, with standardized hemodynamic control (systolic blood pressure 140-185 mmHg). | Standardized conscious sedation protocol using target-controlled infusion of remifentanil (maximum target, 2 ng/ml) and local anesthesia, with standardized hemodynamic control (systolic blood pressure 140-185 mmHg). |
| Duration | Duration of the endovascular procedure | Duration of the endovascular procedure |
Outcomes
| Outcome | Type | Control | Intervention | HR / OR / RR | P-value |
|---|---|---|---|---|---|
| Favorable neurologic outcome, defined as a modified Rankin Scale (mRS) score of 2 or less, assessed at 3 months (range 2 to 6 months) after treatment. | Primary | 40% (66/169) | 36% (63/176) | 3.26% | 0.474 |
| Successful recanalization (modified Thrombolysis in Cerebral Ischemia grade 2b-3) | Secondary | 85% (144/169) | 75% (131/174) | 0.021 | |
| Time from stroke onset to groin puncture, min (mean±SD) | Secondary | 269±85 | 248±92 | 0.040 | |
| Mortality at 3 months | Secondary | 19% (31/166) | 16% (28/175) | 0.514 | |
| Symptomatic intracranial hemorrhage | Adverse | 22% (37/169) | 24% (42/176) | 0.642 | |
| Technical failure of endovascular treatment | Adverse | 2.3% (4/169) | 7.3% (13/176) | 0.044 |
Subgroup Analysis
Analyses adjusted for baseline NIHSS score and administration of IV thrombolysis did not change the result for the primary outcome.
Criticisms
- The primary outcome was assessed in a wider time-frame (2 to 6 months) than the planned 3 months for logistical reasons.
- A systematic post-procedural scan at day 1 to assess infarct volume (eg, ASPECTS) was not performed as it was not standard practice at the time of study design.
- The study population had a lower rate of good functional outcome and a higher mortality rate compared to some other stroke trials, which may be related to the older age of the cohort.
Funding
French Ministry of Health
Based on: GASS (ANESTHESIOLOGY, 2022)
Authors: Axelle Maurice, M.D., François Eugène, ..., for the GASS (General Anesthesia versus Sedation for Acute Stroke Treatment) Study Group and the French Society of Anesthesiologists (SFAR) Research Network
Citation: ANESTHESIOLOGY 2022; 136:567-76
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