Background and purpose Hemorrhagic transformation (HT) is a complication that may cause neurological deterioration in patients with acute ischemic stroke. Various radiological subtypes of HT can be distinguished. Their influence on functional outcome is currently unclear. The purpose of this study was to assess the associations between HT subtypes and functional outcome in acute ischemic stroke patients with proven large vessel occlusion included in the MR CLEAN trial (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic stroke in The Netherlands).
Methods All patients with follow-up imaging were included. HT was classified on follow-up CT scans according to the European Cooperative Acute Stroke Study II classification. Functional outcome was assessed using the modified Rankin Scale (mRS) 90 days after stroke onset. Ordinal logistic regression analysis with adjustment for potential confounders was used to determine the association of HT subtypes with functional outcome.
Results Of 478 patients, 222 had HT. Of these, 76 (16%) patients were classified as hemorrhagic infarction type 1, 71 (15%) as hemorrhagic infarction type 2, 36 (8%) as parenchymal hematoma type 1, and 39 (8%) as parenchymal hematoma type 2. Hemorrhagic infarction type 2 (adjusted common OR (acOR) 0.54, 95% CI: 0.32 to 0.89) and parenchymal hematoma type 2 (acOR 0.37, 95% CI 0.17 to 0.78) were significantly associated with a worse functional outcome. Hemorrhagic infarction type 1 and parenchymal hematoma type 1 were not significantly associated, although their point estimates pointed in the direction of worse outcome.
Conclusion This study suggests that parenchymal hematoma type 2 is relevant for functional outcome after an acute ischemic stroke, and smaller HTs might also influence long term functional outcome.
Trail registration number ISRCTN10888758.
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Contributors The MR CLEAN trial was designed by WHvZ, AvdL, RJvO, DWJD, YBWEMR, and CBLMM. OAB collected and prepared the data for the trial. OAB, AMMB, KMT, and KRvK prepared the data for this study. KRvK and KMT conducted the statistical analysis, interpreted the results, and drafted the paper. HAM assisted with the statistical analysis, interpretation of the results, and drafting the paper. AMMB, OAB, LAvdB, VC, HFL, WHvZ, AvdL, RJvO, DWJD, YBWEMR, and CBLMM critically revised the paper. All authors approved the version to be published.
Funding The MR CLEAN trial was partly funded by the Dutch Heart Foundation, grant No 2008T30, and by unrestricted grants from AngioCare BV, Medtronic/Covidien/EV3, MEDAC Gmbh/LAMEPRO, Penumbra Inc, Stryker, and Top Medical/Concentric.
Competing interests Academic Medical Center Amsterdam received funds from Stryker for consultations by CBLMM, YBWEMR, and OAB. CBLMM received research grants from CVON/Dutch Heart Foundation, European Commission, and Twin Foundation. HAM, AMMB, and CBLMM are shareholders of Nico.lab, a company that focuses on the use of artificial intelligence for medical image analysis. Erasmus MC received funds from Stryker for consultations by DWJD and AvdL, and Bracco Imaging for consultations by DWJD. Maastricht University Medical Center received funds from Stryker for consultations by WHvZ. WHvZ had speaking engagements with Stryker and Cerenovus.
Patient consent Obtained.
Ethics approval A central medical ethics committee and the research boards of all participating centers accepted the MR CLEAN trial.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Because of the sensitive nature of the data collected for this study, requests to access the data set may be sent to the MR CLEAN executive committee (https://www.mrclean-trial.org/).