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Article History

Received: 28 May 2026

Revised: 17 July 2026

Accepted: 20 July 2026

First Online: 19 August 2026

Declarations

Conflicts of interest: The author(s) would like to disclose the following. The authors have completed the ICMJE uniform disclosure form. R.J. Koopmans reports no disclosures relevant to the manuscript; M.A. Tjerkstra reports a speakers fee and an Amsterdam Neurosciences POC Grant; M.R. Germans reports no disclosures relevant to the manuscript; M.D.I. Vergouwen reports no disclosures relevant to the manuscript; K. Jellema reports no disclosures relevant to the manuscript; R.W. Koot reports no disclosures relevant to the manuscript; N.D. Kruyt reports no disclosures relevant to the manuscript; J.F.C. Wolfs reports consulting fees from NuVasive Netherlands, Silony Medical and Bolt Circinus Medical Consultancy outside the submitted work; H. Kieft reports no disclosures relevant to the manuscript; D. Nanda reports no disclosures relevant to the manuscript; B. van der Pol reports no disclosures relevant to the manuscript; G. Roks reports no disclosures relevant to the manuscript; F. de Beer reports no disclosures relevant to the manuscript; L.J.A. Reichman reports no disclosures relevant to the manuscript; P.J.A.M. Brouwers reports no disclosures relevant to the manuscript; V.I.H. Kwa reports a grant from ZonMw (The Netherlands) project number 843004122; T.C. van der Ree reports no disclosures relevant to the manuscript; H.P. Bienfait reports no disclosures relevant to the manuscript; H.D. Boogaarts reports consulting fees paid to the Department of Neurosurgery, Radboud University Medical Center Nijmegen from Stryker neurovascular; C.J.M. Klijn reports grants from Promising Care funding scheme of the National Health Care Institute and ZonMw (2021038368), Penumbra Inc. and the Dutch Heart Foundation outside the submitted work, consulting fees from Alnylam, advisory committee for the setup of this study. In addition, C.J.M. Klijn reports to be a member of the DSMB of ENCHANTED2 (NCT04140110), MOSES (NCT NCT03961334), OPTIMAS (NCT03759938), ENRICH-AF (NCT03950076), chair of the DSMB of EMITT (NCT05318612) and ELAPSE (NCT05976685), participant in the ESO ICH (guideline) committee, and participant in a consensus panel meeting (May 2023) organized by EMCREG-International, a global educational consortium; this meeting was funded through an unrestricted educational grant from AstraZeneca.; R. van den Berg reports consulting fees for unrelated research and teaching activities from Cerenovus Neurovascular; B.A. Coert reports no disclosures relevant to the manuscript; J. Horn reports no disclosures relevant to the manuscript; C.B.L.M. Majoie reports grants from Stryker, Boehringer-Ingelheim, European Union, CVON/Dutch Heart Foundation and Healthcare Evaluation Netherlands outside the submitted work and is a Shareholder of Nico-Lab, a company that focuses on the use of artificial intelligence for medical image analysis; G.J.E. Rinkel reports no disclosures relevant to the manuscript; Y.B.W.E.M. Roos is a minor stockholder of Nico-Lab; W.P. Vandertop reports no disclosures relevant to the manuscript; R. Post reports no disclosures relevant to the manuscript; D. Verbaan reports funding of Fonds NutsOhra.

Reporting checklist: The authors have used the CONSORT checklist as a reporting checklist for this article.

Ethical approval: The ethics committee of the Amsterdam University Medical Center (Amsterdam UMC, Amsterdam, the Netherlands) approved the trial protocol (2012_160#2012370).

Informed consent: Because of the necessity of urgent administration of tranexamic acid and incapability of the vast majority of patients with subarachnoid hemorrhage to provide informed consent at short notice, the trial was done using deferred consent, under the exception from informed consent requirements for emergency research. As soon as the informed consent dialogue no longer interfered with proper and rapid diagnosis and aneurysm treatment, patients or their legally authorized representatives were notified about enrollment into the trial by the research team and asked to provide written informed consent for continued tranexamic acid treatment (if applicable) and data collection until the end of the trial.

Consent for publication: This manuscript has not been published elsewhere and is not under consideration by another journal. The manuscript complies with instructions to authors. Authorship requirements have been met and the final manuscript was approved by all authors.