Clinical question: Does the use of stent retrievers in conjunction with tissue plasminogen activator improve outcomes in patients with acute ischemic stroke?
Bottom line: The use of stent retriever devices in addition to tissue plasminogen activator (tPA) in patients with anterior circulation acute ischemic stroke results in more patients with functional independence at 90 days. Based on data from the studies included in this review, the American Heart Association/American Stroke Association guidelines now strongly recommend the use of stent retrievers with class 1a level of evidence. (LOE = 1a)
Reference: Touma L, Filion KB, Sterling LH, Atallah R, Windle SB, Eisenberg MJ. Stent retrievers for the treatment of acute ischemic stroke. JAMA Neurol 2016;73(3):275-281.
Study design: Meta-analysis (randomized controlled trials)
Funding source: Unknown/not stated
Setting: Inpatient (any location) with outpatient follow-up
Synopsis: Intra-arterial therapy using stent retriever devices for thrombectomy added to standard therapy with tPA is a promising treatment for acute ischemic stroke. Four recent randomized controlled trials examining the effectiveness of stent retrievers have been terminated early because of the strong benefit seen with this therapy.
In this study, investigators searched MEDLINE, EMBASE, and the Cochrane Library, as well as trial registries and references of included studies, to find randomized controlled trials that compared stent retrievers plus tPA with tPA alone. Two authors independently extracted data from the 5 included studies (N = 1287) and assessed study quality using the Cochrane Collaboration Risk of Bias Tool.
All studies included patients with imaging-confirmed anterior circulation strokes and used the modified Rankin Scale (mRS) to assess for improvement in functional status at 90 days. Four of the 5 studies only included patients with excellent pre-stroke functional independence. Additionally, 4 of the 5 studies restricted stent retriever therapy to patients who presented within 6 hours of onset of stroke symptoms. The studies had a low risk of bias overall.
The pooled 90-day outcomes showed that patients who received stent retriever therapy plus tPA were more likely to achieve greater functional independence, defined as an mRS score of 0 to 2, than patients who received tPA alone (relative risk 1.72; 95% CI 1.38 - 1.99). You would need to treat 6 patients with stent retriever therapy to have one patient achieve functional independence. There were no significant differences detected in mortality or in the rates of intracranial bleeds or parenchymal hematomas.
Dr. Kulkarni is an assistant professor of hospital medicine at Northwestern University in Chicago.