An open, prospective, blinded evaluation, international, multicentre, controlled study of safety and efficacy of thrombectomy and standard stroke care in clinical routine treatment of acute occlusive stroke compared to standard stroke care only.

Status: Initiated
Type of study: An international, multicentre controlled study of safety and efficacy of thrombectomy in acute occlusive stroke
Location: Global


Thrombectomy (TBY) was not accepted in guidelines as evidence based therapy until end of 2015. At the end of 2014 and beginning of 2015 several RCTs had shown favourable functional outcome compared to stand alone treatment with IVT and this resulted in new recommendations (International Journal of stroke, consensus statement Karolinska stroke update).


A metaanalysis of all randomised trials on TBY included in a subsequent publication of this consensus statement (International Journal of Stroke)(21) showed significant improvement of the Odds Ratio (OR) for functional independence for patients treated with thrombectomy.  There was no difference in OR for symptomatic haemorrhage and mortality, although, for mortality there was a trend to a favourable outcome.


For the trials published during 2014/2015, TBY was associated with absolute improvement of functional independence between 14 and 31% absolute improvement of functional independence, compared to standard treatment (which in general included intravenous thrombolysis) (21), and pooled analyses of 5 randomised controlled trials, HERMES.

Considering the benefit of recanalization according to  published studies, and the ongoing implementation of this technique in clinical practice, a study comparing thrombectomy combined with and without intravenous thrombolysis in routine settings is needed.

Primary Study Objective

To determine the benefit and safety of TBY in clinical routine practice by selected stent retrievers or other selected novel devices in addition to standard care in patients with major cerebral artery occlusion as compared to standard care only. Standard care may include IVT in accordance with current guidelines.


Trial design

Prospective, open, blinded evaluation, international, multicentre, controlled study of thrombectomy compared to standard treatment only, based on SITS clinical trial platform, of consecutively enrolled ischaemic stroke patients with confirmed occlusion of a major cerebral artery who will be considered eligible for thrombectomy in agreement with routine clinical criteria. Standard care may include IVT in accordance with current guidelines.  

Patient inclusion

Highlights from inclusion criteria:

·      Patients with acute stroke after exclusion of intracranial haemorrhage on CT/MRI scan.

·      Confirmed diagnosis on CTA of persisting occlusion of the terminal Internal Carotid Artery (Car-T), proximal Middle Cerebral Artery (MCA, M1), proximal part of the insular segment of MCA (M2), proximal part of the anterior cerebral artery (A1), Basilar Artery (BA) or proximal part of the posterior cerebral artery (P1), consistent with the clinical symptoms. For inclusion in the study, CTA must not be performed later than 15 minutes after IVT start if given. For patients not treated with IVT, CTA should preferably be performed within 15 minutes of completion of the non-contrast CT but must be performed within 6 hours after stroke onset.

·      Baseline NIHSS Score at initiation of IVT is recommended between 7 and 25 for anterior circulation stroke and ≥7 without upper limit for posterior circulation stroke (baseline NIHSS score should be assessed by an NIHSS-certified physician), but patients may also be included beyond these scores if thrombectomy would still be of benefit for the patient as judged by the investigator.

Eligible patients for IVT are treated according to clinical guidelines (Attachment 1), and IVT, if given, initiated within 4.5 h 


Primary outcome is the categorical shift in mRS score at 3 months. Key secondary outcome and safety variables are proportion of patients with functional independence (mRS score 0-2), proportion of patients with excellent recovery (mRS score 0-1), symptomatic intracranial hemorrhage (SICH), degree of recanalisation, and mortality at 3 months after stroke onset.

Related documents and links

Study protocol
Project plan
Inclusion & exclusion criterias
Imaging procedures manual
Imaging – Short instructions guidance
Transmittal sheet - CT/MRI
Transmittal sheet - DSA
mRS Guidance
mRS Camera usage and video recording
Link to mRS certificate
Study guidance
Link to NIHSS certificate
eCRF users guide
Test patient instruction - Active centres
Test patient instruction - Control centres
Delegation log
Enrolment log
Physician´s verification form
Presentation/slides – Initiation