Netherlands: A new study conducted in the Netherlands has found that endovascular treatment for anterior circulation ischaemic stroke is effective and safe within a 6 to 24-hour window, according to research published in The Lancet.
The study, called MR CLEAN-LATE, aimed to assess the efficacy and safety of endovascular treatment for patients treated in the late window, between 6 and 24 hours from symptom onset or last seen well, selected based on the presence of collateral flow on CT angiography (CTA).

The study was a multicentre, open-label, blinded-endpoint, randomized, controlled, phase 3 trial conducted in 18 stroke intervention centers in the Netherlands. Patients aged 18 years or older with ischaemic stroke, presenting in the late window with an anterior circulation large-vessel occlusion and collateral flow on CTA, and a neurological deficit score of at atleast 2 on the National Institutes of Health Stroke Scale were included.
Patients were randomly assigned (1:1) to receive endovascular treatment or no endovascular treatment (control), in addition to best medical treatment. The primary outcome was the modified Rankin Scale (mRS) score at 90 days after randomization.
The study concluded with following clinical findings:
1. The median mRS score at 90 days was lower in the endovascular treatment group than in the control group.
2. There was a shift towards better outcomes on the mRS for the endovascular treatment group.
3. All-cause mortality did not differ significantly between groups.
4. Symptomatic intracranial hemorrhage occurred more often in the endovascular treatment group than in the control group.
The study also suggests that selection of patients for endovascular treatment in the late window could be primarily based on the presence of collateral flow. The results of this study could have a significant impact on the treatment of stroke patients and improve patient outcomes.
“While all-cause mortality did not differ significantly between groups, symptomatic intracranial hemorrhage occurred more often in the endovascular treatment group than in the control group. Therefore, careful consideration is needed when selecting patients for this treatment.” added the researchers of the study.
Reference:
H Olthuis, S. G., V Pirson, F. A., E Pinckaers, F. M., Hinsenveld, W. H., Nieboer, D., Ceulemans, A., M M Knapen, R. R., Quirien Robbe, M. M., Berkhemer, O. A., A van Walderveen, M. A., Lycklama à Nijeholt, G. J., Uyttenboogaart, M., Schonewille, W. J., van der Sluijs, P. M., Wolff, L., Voorst, H. V., Postma, A. A., Roosendaal, S. D., der Hoorn, A. V., . . . van Oostenbrugge, R. J. (2023, March 29). Endovascular treatment versus no endovascular treatment after 6–24 h in patients with ischaemic stroke and collateral flow on CT angiography (MR CLEAN-LATE) in the Netherlands: a multicentre, open-label, blinded-endpoint, randomised, controlled, phase 3 trial. The Lancet. https://doi.org/10.1016/S0140-6736(23)00575-5