Five clinical trials have been designed to establish which is the treatment window and the best method to select patients for the endovascular therapy.There is a consensus that it is effective if it is started within six hours of the episode and the baseline collateral flow predicts the final treatment outcome.But there are still several unanswered questions that have been recently reviewed in a seminal paper that discusses the ongoing clinical trials.
Is thrombectomy useful if it’s implemented at more than 6 hours from onset?
The DEFUSE 3 clinical trial was designed to study the premise that this intervention might be able to salvage the brain tissue 6 hours after the event; the goal is to identify potential candidates by imaging techniques in order to use treatment protocols approved by the Federal Drug Administration (FDA)
The eligible candidates have an occlusion of the Internal Carotid artery or an MI occlusion and a target mismatch profile; those with contraindications for CT or MRI scans and a baseline NIH Stroke Scale (NIHSS) were excluded form the trial. The patients are triaged either for the thrombectomy plus the traditional therapy or that medical therapy alone. The treatment is delivered within 16 hours with a Solitaire device or a Penumbra aspiration system.
Is the Trevo thrombectomy plus medical management better after 90 days?
The DAWN trial will study the outcomes of the endovascular therapy when it is administered 6 to 24 hours after the onset of the event; the participants, randomized in a 1:1 ratio in 50 sites, will be studied at 90 days. Unlike the DEFUSE 3 study some patients will have a clinical-imaging mismatch.
Do stroke patients ineligible for t-PA benefit from the endovascular therapy?
The POSITIVE trial will study those patients that undergo a thrombectomy compared to medical therapy alone at 6 to 12 hours after the event. Patients that do not have in the imaging studies an associated large penumbra—an area that might be functionally compromised—will be excluded from it.
Is thrombectomy better for patients with moderate to good collateral flow?
The MR CLEAN LATE trial will study those eligible patients that undergo the procedure after 6 to 12 hours after the event and will enrol 500 patients. The RACECAT trial in Catalonia will determine which triage method is more effective; after the emergency responders contact the neurologists, the patients will be quickly referred to either a stroke or a thrombectomy unit.
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