Thrombectomy’s success treating strokes prompts rethinking of selection criteria



– CT or magnetic resonance brain imaging of acute ischemic stroke patients was the key triage tool in two groundbreaking thrombectomy trials, DAWN and DEFUSE; results from both showed that patients found by imaging to have limited infarcted cores could safely benefit from endovascular thrombectomy, even when they are more than 6 hours out from their stroke onset, breaking the 6-hour barrier created 3 years ago by the first wave of thrombectomy trials.

But some stroke neurologists studying thrombectomy are now convinced that imaging is not needed and may actually harm acute ischemic stroke patients early on by introducing an unnecessary time delay when they present within the first 6 hours after stroke onset.

This new thinking on how to best use brain imaging in acute ischemic stroke patients is part of the rapid evolution of acute stroke management as experts process new data and refine their approach both within 6 hours of stroke onset and during the new treatment window of 6-24 hours post onset. The dramatic success achieved with thrombectomy in highly selected late-window patients prompted researchers to promote pushing the boundaries further to find less-selected late patients who could also potentially benefit from thrombectomy.

The downside of early imaging

Dr. Tudor G. Jovin Mitchel L. Zoler/Frontline Medical News

Dr. Tudor G. Jovin

“The fundamental way to frame the issue is to look at fast and slow progressors,” a characterization based on the speed at which a patient’s brain infarct grows, Tudor G. Jovin, MD, said at the International Stroke Conference, sponsored by the American Heart Association. Once a large vessel occlusion blocks cerebral blood flow, the rate at which the hypoperfused ischemic tissue, the penumbra, becomes infarcted primarily depends on the amount of collateral flow that reaches the hypoperfused region. The greater the collateral flow, the slower the infarct will grow, with the amount of collateral flow very individualized in each patient.


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