O-032 Outcomes of M1 vs M2 thrombectomy for acute ischemic stroke patients with low ASPECTS – an international multicenter investigation
Bibliographic record
Abstract
Background Recent landmark trials have demonstrated the efficacy and safety of endovascular thrombectomy (EVT) for stroke patients with proximal large vessel occlusions and large areas of ischemic territory as evidenced by low Alberta Stroke Program Early CT scores (ASPECTS). However, the effectiveness of EVT for low-ASPECTS stroke patients with occlusion of the second segment of the middle cerebral artery (M2) is unclear. Methods We conducted an international multi-center retrospective cohort study of the Stroke Thrombectomy and Aneurysm Registry. Patients with isolated M1 or M2 occlusions and low ASPECTS (5 or lower) who underwent successful EVT revascularization from 2013 to 2023 were identified. Patient demographics, medical history, and stroke characteristics were captured. Primary outcome was futile revascularization (90-day modified Rankin scale [mRS] 5 or 6). Secondary outcomes include ordinal 90-day mRS outcomes, acceptable 90-day outcomes (mRS 0–3), intracranial hemorrhage (ICH), and sICH. Multivariable binary and ordinal logistic regression analyses were used to adjust for confounders. Results 173 patients were included; 138 patients had an M1 occlusion, and 35 patients had an M2 occlusion. Overall, M2 patients experienced higher rates of futile revascularization compared to M1 patients (mRS 5–6, 50.0% vs. 29.9%, respectively; p=0.029). We observed similar rates of ICH (47.1% vs. 40.7%, p=0.51) and sICH (11.8% vs. 8.9%, p=0.61) for M2 and M1 patients, respectively. After multivariable adjustments for age, NIH stroke scale, pre-stroke mRS, treatment time window, ASPECTS, prior intravenous thrombolysis, front-line EVT technique, and ICH, M2 patients had significantly higher odds of futile revascularization compared to M1 patients (OR 5.48 [95%CI 1.91 to 15.7], p=0.002), lower odds of acceptable outcomes (OR 0.33 [95%CI 0.12 to 0.89], p=0.028), and worse 90-day mRS outcomes (common OR 3.05 [95%CI 1.33 to 7.01], p=0.009). Conclusions EVT for low-ASPECTS M2 occlusions was significantly associated with worse outcomes compared to EVT for low-ASPECTS M1 occlusions, independent of baseline characteristics and ICH. These findings suggest that providers should take caution in extrapolating the positive findings of recent low ASPECTS EVT trials to patients with M2 occlusions. Disclosures H. Chen: None. M. Colasurdo: None. H. Matsukawa: None. C. Cunningham: None. I. Maier: None. P. Jabbour: None. J. Kim: None. S. Wolfe: None. A. Rai: None. R. Starke: None. M. Psychogios: None. A. Shaban: None. N. Goyal: None. S. Yoshimura: None. H. Cuellar: None. B. Howard: None. A. Alawieh: None. A. Alaraj: None. M. Ezzeldin: None. D. Romano: None. O. Tanweer: None. J. Mascitelli: None. I. Fragata: None. A. Polifka: None. F. Siddiqui: None. J. Osbun: None. R. Grandhi: None. R. Crosa: None. C. Matouk: None. M. Park: None. M. Levitt: None. W. Brinjikji: None. M. Moss: None. E. Daglioglu: None. R. Williamson: None. P. Navia: None. R. De Leacy: None. S. Chowdhry: None. D. Altschul: None. A. Spiotta: 2; C; Penumbra, Terumo, RapidAI, Cerenovus. P. Kan: 1; C; Medtronic, Siemens, NIH (1U18EB029353–01). 2; C; Imperative Care, Stryker Neurovascular. 4; C; Vena Medical.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".