Session report ESOC 2025: Acute reperfusion treatment

In the evening of Day 1 at ESOC 2025 here in Helsinki, Finland, Götz Thomalla (Hamburg, Germany) and Bertrand Lapergue (Suresnes, France) chaired this first debate session “Acute reperfusion treatment – exploring the margins”.

Pooja Kathri (Cincinnati, USA) kicked off the session with a talk arguing in favor of “Intravenous thrombolysis should be used in large core stroke!” The tenure of the audience was balanced between pro and con for intravenous thrombolysis (IVT) in large core stroke (ASPECT 0-5). She took the audience down the memory line of IVT in acute ischemic stroke showing data from the ECASS and IST-3 trials. The extent of early ischemic changes did not modify the treatment effect in ECASS-I, IST-3 and NINDS trials, but some hypodensity in NINDS indicated harm, also ASPECTS did not modify the treatment effect though only a small number of patients had an ASPECTS 0-2 in the NINDS trial. She argues that not all large cores and early ischemic changes are the same and that all data combined show that the extent of early ischemic changes on CT per se should not deter treatment with alteplase. She concludes that if otherwise eligible (<4.5 hours) we should treat patients regardless of the extent of early ischemic changes. Jesse Dawson from Glasgow, UK tried to convince the auditorium with arguments against the use of IVT in large core stroke. He showed data from IST-3 where only a small rate of patients was in the low ASPECTS group. Next, data regarding the extended time window showed a clear benefit of IVT, but also an increased risk for sICH. Also, he argues that regarding the use IVT in large cores before endovascular treatment (EVT), data from Germany and Switzerland showed signals of increased sICH in lower ASPECTS score patients. Furthermore, in the late time window, he argues that data do not support the use of IVT if EVT is planned, because only a small amount of patients received IVT in the late window in the trials and he argues that these patients might have received IVT before the core evolved to a large core, and in these patients, the outcome was left unchanged, except for the bleeding risk - which was increased. After these two presentations, the debate-vote shifted and the speakers convinced the auditorium to roughly 65% against a general IVT-use in large core ischemic stroke. The next debate was titled “After the large core trials – Mechanical thrombectomy (MT) should be used irrespective of ASPECTS!”. The vote was quite balanced before the talks. Caroline Arquizan from Montpellier, France argued in favor of MT. She summarised the large core MT trials and the meta-analysis by Liu et al. 2025. Sub-analyses showed no differences in treatment effect between ASPECTS 0-2 vs 3-5. Also, regarding infarct volumes with cut-offs of 100 or 150 ml, no difference in treatment effect was observed. She argued that ischemia is a heterogenous phenomenon inside the core which is not fully understood by CT or MRI. She mentioned that there are no data from large core trials supporting an infarct size threshold for MT efficacy, at least in the early time window. She argues that using ASPECTS as a treatment cut-off excludes salvageable patients and that advanced imaging is not entirely necessary for patient selection. Also, she argues that a less restrictive patient selection leads to a treatment benefit and that the benefit of MT in large cores comes from recanalisation itself. Nevertheless, large core remains a strong prognostic factor for poor outcome but not a treatment effect modifier. Obviously, we cannot generalise all patients because of the lack of subgroup data. Other trials and meta-analyses of individual patients are needed e.g. patients with ASPECTS 0-2 in the late time window. Greg Albers from Stanford, USA showed arguments against the use of MT and shows data on various studies including studies reporting net water uptake as surrogate for severe hypodensity and a study using a Hounsfield unit cut-off for early ischemic changes. He partly disagrees and argues that size does in fact matter, the trials had very low rates of patients for very large cores, ANGEL-ASPECTS had only 2 patients with a core >150 ml, SELECT2 had only 21 patients with a core >150 ml. He emphasises on the “large core paradox”, which will be published in an article soon. In short, he mentions that the benefit of MT in large core LVO patients is consistent with the established and validated core/penumbra model. However, further mechanisms, such as salvage of scattered “mini-penumbras” and prevention of additional edema might also contribute to the efficacy of MT in large core ischemic stroke. All in all, he argues that we have to establish the outer limits for MT efficacy in the future. The speakers induced a shift of the vote and now 64% of the auditorium voted against the general use of MT in large core ischemic stroke irrespective of ASPECTS.

The final debate of the evening was about add-on antithrombotics in patients receiving reperfusion therapy. The question to the auditorium was “Will add-on antithrombotics (in addition to IVT/EVT) improve outcomes in patients receiving reperfusion therapy? The majority (52%) voted “yes”, “no” and “undecided” were quite balanced. Octavio Marques Pontes-Neto (Sao Paulo, Brazil) presented arguments in favor of add-on antithrombotics. He showed various trials including agents like tirofiban, eptifibatide, and argatroban. He showed an outlook to the arriving era of nanomedicines, which possibly will change the landscape of acute ischemic stroke treatment in the future.

He concludes that the benefits of add-on antithrombotics in stroke reperfusion therapy must be tailored to stroke etiology and timing. While aggressive antithrombotic strategies are well established in myocardial infarction, stroke care must balance efficacy with bleeding risk. Tirofiban may improve functional outcomes and is promising in selected populations, but broader use needs further validation. Future research should focus on individualised approaches, based on clot composition, etiology, and timing. In patients with atherothrombotic stroke, early deterioration, tandem occlusions or stenting, the targeted use of add-on antithrombotics is likely to improve outcomes and should be implemented selectively.

Else Charlotte Sandset from Oslo, Norway showed convincing evidence against the use of add-on antithrombotics. She showed data from the ARTIS (no effect of aspirin after IVT), ARAIS (no effect of argatroban on mRS after IVT), and the MOST trial (higher mortality). The ASSET-IT trial, which was presented earlier this morning, showed promising results but the rate of sICH was very low in the intervention group and no hemorrhage was detected in the control group. Furthermore, the MR CLEAN MED study showed an elevated risk of sICH. Overall and generally speaking, the current evidence suggests danger using add-on antithrombotics on a broad basis. Other trials are currently underway for the use of add-on antithrombotics in various situations. The debate vote shifted after the talks and the auditorium seemed to opt for a more cautious regime regarding add-on antithrombotic use in reperfusion therapy.

This first debate session was very exciting and engaged all the stroke enthusiasts in the auditorium who did not regret staying until the end of day 1 here at ESOC 2025 in Helsinki, Finland.