- Design
- Secondary analysis of a randomised controlled trial
- Population
- 198 patients with large-core ischaemic stroke in the TENSION trial
- Primary outcome
- Ordinal modified Rankin Scale at 12 months
- Effect
- Baseline NWU acOR 1.10 per point (1.05–1.16); NWU × thrombectomy interaction acOR 1.17 (1.06–1.30)
A secondary analysis of the TENSION randomised trial, which tested thrombectomy in large-core ischaemic stroke, measured lesion net water uptake on admission non-contrast CT in 198 patients, and again at 24 hours in 168. Outcome was the modified Rankin Scale at 12 months.
At 12 months, 23% had a modified Rankin score of 0–3 and 56% had died. Each percentage-point rise in baseline water uptake was associated with worse outcome (adjusted common OR 1.10, 95% CI 1.05–1.16), discriminated better than ASPECTS, and modified the effect of thrombectomy (interaction OR 1.17). Water uptake at 24 hours was the strongest single imaging predictor (AUC 0.78 for a good outcome) and predicted late death in 90-day survivors.
Net water uptake is a quantitative CT measure that some software already provides. This analysis suggests it captures how much of the core is already irreversibly injured. It is a secondary analysis and should not yet be used to deny thrombectomy, but it is worth reporting where the tools exist.
- Consider reporting net water uptake alongside ASPECTS where your stroke software provides it.
- Do not exclude a large-core patient from thrombectomy on water uptake alone; this is not yet validated for selection.
- Use 24-hour water uptake, where measured, as an aid to prognosis discussions with families.
- Note that large-core outcomes remain poor: over half of these patients had died by 12 months.
Why it matters
It offers a measure of tissue already lost that may explain why large-core thrombectomy helps some patients and not others.
Don't overread it
A secondary analysis — water uptake has not been tested as a selection criterion for thrombectomy.
The statistics, in plain English
An odds ratio of 1.10 per percentage point adds up: a lesion with 10 points more water uptake carries substantially higher odds of a worse outcome. The interaction term suggests thrombectomy helps less as water uptake rises, but interactions in secondary analyses are hypothesis-generating.
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