Written by Clay Smith
Endovascular therapy (EVT) for acute ischemic stroke can dramatically improve outcome in select patients. This review helps us makes sense of the trials on this topic.
Why does this matter?
So many trials came out in such a short space of time that it can be difficult to keep them all straight in our minds. This is an incredible review that brings all this information together in one place.
Pull the clot out
The early trials of EVT for stroke showed no benefit over tPA. Subsequent trials focused on proximal clots and used stent retrievers, which proved much more effective. This is great, but most patients don’t benefit. Only select stroke patients with distal intracranial ICA, proximal MCA, or proximal ACA clots and brain that is ischemic but still viable can benefit from EVT. Most trials removed the clot within 6 hours. But in DAWN and DEFUSE 3, perfusion-guided imaging (or exam worse than expected based on MRI) allowed the window to be expanded from 6-24 hours, assuming a large ischemic penumbra and small infarct core.
Here is a list of the key trials that includes of all the major EVT trials (extracted from this article, Table 3). I have added links to PubMed for easy reference.
Trials of Endovascular Therapy For Acute Stroke
(Study: Year; N; Hours to intervention; Disability benefit; NNT)
IMS–III: 2013; N = 658; 3-hour window; No difference; N/A
MR RESCUE: 2013, N = 118, 8-hour window, No difference; N/A
SYNTHESIS: 2013; N = 181; 6-hour window; No difference; N/A
MR CLEAN: 2015; N = 500; 6-hour window; 13.5% benefit; NNT = 7
ESCAPE: 2015 N = 316; 12-hour window; 23.7% benefit; NNT = 4
EXTEND IA: 2015; N = 70; 4.5-hour window; 31% benefit; NNT = 3
SWIFT PRIME: 2015; N = 196; 6-hour window; 25% benefit; NNT = 12
REVASCAT: 2015; N = 206; 8-hour window; 15.5% benefit; NNT = 7
THRACE: 2016; N = 414; 5-hour window; 11% benefit; NNT = 9
THERAPY: 2016; N = 108; 4.5-hour window; No difference; N/A
DAWN: 2017; N = 206; 24-hour window; 36% benefit; NNT = 3
DEFUSE 3: 2018; N = 182; 16-hour window; 28% benefit; NNT = 4
The authors proposed a stroke workup algorithm that takes EVT into account.
A New Paradigm Shift in Acute Ischemic Stroke, Large Vessel Occlusions, and Endovascular Therapy. J Emerg Med. 2018 Dec 7. pii: S0736-4679(18)31048-5. doi: 10.1016/j.jemermed.2018.10.022. [Epub ahead of print]
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