In order to bring you the best possible user experience, this site uses Javascript. If you are seeing this message, it is likely that the Javascript option in your browser is disabled. For optimal viewing of this site, please ensure that Javascript is enabled for your browser.
Did you know that your browser is out of date? To get the best experience using our website we recommend that you upgrade to a newer version. Learn more.

Retrieval of larger thrombi associated with improved neurological recovery after stroke

London, UK – 31 Aug 2015: Retrieval of larger thrombi during intra arterial treatment (IAT) is associated with improved neurological recovery after acute ischaemic stroke, according to a sub study of the MR CLEAN trial presented at ESC Congress today by Dr Anouchska Autar, PhD candidate at the Erasmus Medical Centre in Rotterdam, the Netherlands.1

Coronary Artery Disease, Acute Coronary Syndromes, Acute Cardiac Care
Diseases of the Aorta, Peripheral Vascular Disease, Stroke

EMBARGO : 31 August 2015 at 13:00 BST

“Acute ischaemic strokes occur when a blood clot, also called a thrombus, embolises to the brain where it restricts the flow of blood,” said Dr Autar. “MR CLEAN was the first trial to show the benefit of IAT to remove blood clots within six hours after a stroke.2 IAT, which was given against a background of standard care including intravenous tissue plasminogen activator3 if indicated, led to better restoration of blood flow and improved functional outcome when compared to no IAT.”

 Thrombi retrieved during the MR CLEAN trial were collected for the current sub study to investigate the relationship between the macroscopic appearance of thrombi retrieved during IAT, cause of stroke, and clinical outcome. Measures of macroscopic appearance included length, width, area and numbers of particles the thrombus had broken into.
Neurological recovery was assessed using the National Institutes of Health Stroke Severity Scale (NIHSS).

 The study included 35 collections of thrombi from 35 patients who had undergone IAT after an acute ischaemic stroke. Most of the patients had a severe stroke, of which 49% were of cardiac origin and 20% were due to atherosclerosis.

 The researchers found that patients whose stroke was caused by atherosclerosis had significantly longer and larger thrombi (p=0.0035 and p=0.045, respectively) than those with stroke from other causes. “This could be because patients with atherosclerosis have more diseased arteries and this may influence thrombus size,” said Dr Autar.

 They also found that patients from whom longer and wider thrombi were retrieved had significantly improved neurological recovery at discharge after IAT compared to those with smaller thrombi (p=0.03 and p=0.04, respectively). “This finding is particularly important because it indicates that the larger the pieces that you retrieve, the better this is for your patient,” said Dr Autar.

 Interestingly, an increased number of particles retrieved during IAT showed a trend towards a worse neurological recovery at discharge, although the association was not significant (p=0.079). Dr Autar said: “Together, this suggests that some emboli are more likely to disintegrate and the smaller particles may embolise and obstruct the microvasculature of the brain, leading to incomplete recovery.”

 She concluded: “Our study shows that retrieval of larger thrombi during IAT is associated with improved neurological recovery at discharge in patients with acute ischaemic stroke. The findings indicate that a simple parameter such as thrombus size might influence the decision to give or refrain from additional thrombolysis. This needs to be verified of course in larger trials.”



1Dr Autar will present the abstract ‘Thrombectomy for acute ischemic stroke: retrieval of larger thrombi is associated with improved neurological recovery’ during:
•    The press conference ‘Life Threatening Scenarios’ on Monday 31 August at 13 :00
•    Poster session 6: Stroke on Tuesday 1 September at 8:30 in the Poster Area
2Berkhemer OA, Fransen PSS, Beumer D et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015;372:11-20. DOI: 10.1056/NEJMoa1411587
3Tissue plasminogen activator is a drug that helps dissolve a blood clot quickly and restore blood flow to the brain.

Notes to editor

SOURCES OF FUNDING: The study was sponsored by The Netherlands Heart Foundation.



ESC Press Office
For background information or assistance, please contact the ESC Press Office.
For independent comment on site or interviews, please contact the ESC spokesperson coordinator: +44 7785 467 947

About the European Society of Cardiology
The European Society of Cardiology (ESC) represents more than 90 000 cardiology professionals across Europe and worldwide. Its mission is to reduce the burden of cardiovascular disease in Europe.
About ESC Congress 2015
ESC Congress is the world’s largest and most influential cardiovascular event contributing to global awareness of the latest clinical trials and breakthrough discoveries. ESC Congress 2015 takes place 29 August to 2 September at ExCel London in London, UK. Access the scientific programme. More information is available from the ESC Press Office at

To access all the scientific resources from the sessions during the congress, visit ESC Congress 365.  

This press release accompanies both a presentation and an ESC press conference at the ESC Congress 2015. Edited by the ESC from material supplied by the investigators themselves, this press release does not necessarily reflect the opinion of the European Society of Cardiology. The content of the press release has been approved by the presenter.