Abstract WP283: High Rates of ASPECTS Decay Leading to Ineligibility for Thrombectomy in Patients Transferred to a Comprehensive Stroke Center Covering a Large Geographic Area
Bibliographic record
Abstract
Introduction: Endovascular therapy has revolutionized acute stroke management associated with large vessel occlusion (LVO). The province of Saskatchewan currently has 8 primary stroke centers (PSC) and 1 comprehensive stroke center (CSC) spread over a large geographical area. Seventy three percent of the population lives outside the Saskatoon metropolitan area, which houses the province’s single comprehensive stroke centre. Geography remains a significant barrier to providing endovascular therapy in a timely manner to eligible patients, knowing that the time to recanalization is a vital variable in clinical outcome. We aim to quantify the distance and time to transfer of patients to the CSC, and determine factors associated with clinically significant evolution of infarct during transfer. Methods: We completed a retrospective analysis of all acute stroke patients with LVOs who were transferred from PSCs to the CSC for possible endovascular therapy in Saskatchewan from July 2016 - July 2018. Along with patient, imaging, and outcome specific factors, detailed transfer data including modality, time, and distance were collected. Results: Sixty-nine LVO patients were transferred from PSCs to the CSC with intention to treat with mechanical thrombectomy. Upon reassessment at the CSC, 32 patients (46%) no longer qualified for thrombectomy, due to progression of stroke with ASPECTS score decay. Inter-facility deterioration risk factors were assessed using transfer metrics, patient characteristics, and initial imaging findings at the PSC to understand this patient population better. Distance to the PSC and distance from PSC to CSC were the most significant contributors to ASPECTS decay. Conclusions: Almost half of the patients transferred to the CSC with intention to treat with endovascular thrombectomy became ineligible during transfer. Since the large geographic area covered by the CSC leads to a significant cost burden associated with transfers, we aim to optimize transfer protocols to better serve the outlying areas.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".