Abstract Background and aims Subacute lesion growth after acute ischemic stroke is associated with worsening of functional outcome. Lesion severity can be assessed with Net Water Uptake (NWU). This study determines how associations between NWU and functional outcome vary with time starting at baseline to 1 week post-stroke. Methods We included anterior circulation large vessel occlusion patients who are treated with endovascular treatment from the MRCLEAN NO-IV trial. NWU was calculated as the ratio of infarcted tissue density to its contralateral homolog. Logistic regression models were made to assess associations between NWU measured at different imaging times (baseline, 24 hours, 1 week) and functional independence. To evaluate temporal infarct evolution, ΔNWU was calculated at intervals between imaging times, and its association with outcome was analyzed using analogous regression models. Results One hundred and fifteen patients were included. The median NWU evolved from 4.3% (IQR: 2.1-6.8%) at baseline to 9.0% (IQR: 3.0-13%) at 24 hours and 15% (IQR: 11-19%) at 1 week. The median NWU increase (ΔNWU) from baseline to 1 week was 10% (IQR: 5.3-16%). Only NWU measured at 1 week was significantly associated with functional dependence (aOR: 0.7095% CI=0.50-0.90 per five-percentage-point NWU increase). Also increase in ΔNWU1wk-BL was significantly associated with functional dependence (aOR: 0.7095% CI=0.56-0.90 per five-percentage-point ΔNWU1wk-BL increase). Conclusions In our population, only NWU measured at 1 week was associated with functional independence, indicating that the cumulative burden of edema expansion is clinically relevant for functional outcome. This supports further investigation of secondary interventions targeting edema expansion in the early post-stroke period. Conflict of interest W. Olszewski is funded by GEMINI (www.dth-gemini.eu): a European Union’s Horizon research and innovation program (Grant Agreement Number: 101136438); F. Cavalcante: nothing to disclose; L. van Poppel: nothing to disclose; L. Beenen: nothing to disclose; B. Emmer: Grants by Dutch Science foundation on behalf of Healthcare evaluation, Health Holland topsector Lifesciences and Nicolab, all paid to institution; I. van den Wijngaard: nothing to disclose; R. Lemmens: nothing to disclose; Y. Roos: nothing to disclose; H. Marquering is cofounder and shareholder of Nico.lab, Trianect, and inSteps B.V.; P. Konduri is a cofounder and shareholder of inSteps BV, received funds from European Union’s Horizon research and innovation program (Grant Agreement Number: 101136438) and is currently funded by NIH/NINDS (grant nr R01NS075209); C. Majoie reports grants from European Commission (related and paid to institution) and CVON/Dutch Heart Foundation, Stryker, TWIN Foundation, and Health Evaluation Netherlands (outside the submitted work and paid to institution); and is shareholder of Nico.lab. Figure 1 - belongs to Methods Figure 2 - belongs to Results
Olszewski et al. (Fri,) studied this question.