Patients beyond the 6-hour invasive stroke treatment window benefitted from endovascular treatment of proximal MCA or ICA occlusion up to 16 hours from onset if there was a large ischemic penumbra on perfusion imaging that had not yet infarcted.
Why does this matter?
We just read another article, the DAWN trial, about this topic last month. In DAWN, endovascular treatment was offered up to 24 hours from onset when clinical deficits of stroke were greater than expected based on infarct volume. DEFUSE 3 based invasive treatment on perfusion imaging criteria rather than clinical criteria, which allowed 40% more patients to be eligible for thrombectomy. The results of the DAWN trial prompted an early interim analysis and consequently early cessation of this trial for clear benefit.
Yank that clot outta there
This open-label RCT was stopped early after enrolling 90 patients to usual treatment and 92 to endovascular treatment. Most did not get tPA, given the late presentation. To be included, the infarct volume had to be 70mL or less with an ischemic penumbra at least 1.8 times the infarct volume based on perfusion imaging (see image). 90-day disability on modified Rankin score was markedly better in the endovascular group: 45% vs. 17% functionally independent, NNT = 4. Also mortality was 14% in the endovascular treatment arm vs 26% in the usual treatment group, NNT = 9. Significant intracranial bleeding and serious adverse outcomes were no different in each group, though the trial was stopped early and may have not recruited enough patients to detect a statistical difference. These two recent studies are practice changing. We need to involve neurology and neurointerventionalists in select patients with proximal stroke, even those who present after 6 hours.
Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med. 2018 Jan 24. doi: 10.1056/NEJMoa1713973. [Epub ahead of print]
Peer reviewed by Thomas Davis, MD.