Abstract TP73: Lower Prehospital Blood Pressure Is Not Associated with Larger Infarct Volumes in Non-lacunar Ischemic Stroke Patients
Bibliographic record
Abstract
Background: Although prehospital blood pressure (BP)-lowering trials in acute stroke have begun, concerns persist that hypotension may exacerbate hypoperfusion and increase infarct volumes, particularly in non-lacunar stroke. We tested the hypothesis that lower prehospital BP is associated with larger infarct volumes in non-lacunar ischemic stroke. Methods: We conducted a retrospective study of consecutive patients with suspected stroke transported by Emergency Medical Services (EMS) during an 18-month period. Serial prehospital BP data were obtained from a centralized EMS database. Hospital charts and neuroimaging were reviewed. Stroke etiology was classified using TOAST criteria. Infarct volumes were measured on follow-up MRI or CT using semi-automated thresholding planimetric techniques by two independent raters, blinded to prehospital BP. Results: Of a total 960 patients transported by EMS, 367 had a final diagnosis of ischemic stroke. Stroke etiology was large artery disease in 51 patients, cardioembolic in 140, lacunar in 44, other determined etiology in 22, and cryptogenic in 110 patients. Follow-up imaging was available in 315 patients (163 MR, 152 CT) at a median (IQR) 1(1) days. The overall median non-lacunar infarct volume was 16.5 (49.6) ml, median NIHSS was 7(10), and mean prehospital SBP was 153 ± 25 mmHg. Mean prehospital SBP was lower in patients with other determined etiology (133.2 ± 26.1 mmHg, p<0.01) than cardioembolic (150.9 ± 25.5 mmHg), large artery disease (157.1 ± 26.1 mmHg) and cryptogenic stroke (157.7 ± 22.9 mmHg). Median infarct volume was similar across categories of stroke etiology (large artery disease (16.3 (60.3) ml), cardioembolic (19.9 (76.2) ml), other determined etiology (23.9 (33.6) ml), and cryptogenic stroke (11.5 (35.9) ml), p=0.12). There was no correlation between mean prehospital SBP and mean infarct volume (r =-0.06, p=0.33). NIHSS score was correlated with mean infarct volume (r=0.6, p<0.001), but not mean prehospital SBP (r=-0.07, p=0.24). Conclusion: These data provide no evidence to suggest that lower prehospital BP is associated with larger infarct volumes in patients with non-lacunar ischemic stroke. The effect of BP reduction on infarct volumes should be assessed as part of randomized trials.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".