Clinical question: Does endovascular thrombectomy improve clinical outcomes in patients presenting with acute ischemic stroke?
Bottom line: High-quality evidence shows that endovascular therapy using mechanical thrombectomy for the treatment of acute ischemic stroke leads to improved functional outcomes as compared with standard medical therapy with intravenous tissue plasminogen activator (tPA). You would have to treat 8 patients with endovascular therapy to achieve functional independence for 1 patient. (LOE = 1a)
Reference: Badhiwala JH, Nassiri F, Alhazzani W, et al. Endovascular thrombectomy for acute ischemic stroke: a meta-analysis. JAMA 2015;314(17):1832–1843.
Study design: Meta-analysis (randomized controlled trials)
Funding source: Unknown/not stated
Setting: Inpatient (any location)
Synopsis: These investigators searched multiple databases including MEDLINE, EMBASE, Google Scholar, and the Cochrane Library to find randomized clinical trials that compared endovascular mechanical thrombectomy with tPA for the treatment of acute ischemic stroke. Three reviewers independently evaluated the studies for eligibility, extracted data from the included studies, and assessed study quality using the Cochrane Collaboration's tool for risk of bias. Ultimately, 8 studies with a total of 2423 patients were included in the review. Most studies used a time window of 6 hours from stroke onset for time to endovascular therapy. The primary outcome was the modified Rankin Scale (mRS) score, which measures the degree of functional disability (a scale of 0 to 6, where 0 = no symptoms, 1 = symptoms but no disability, 5 = severe disability, and 6 = death).
Endovascular thrombectomy led to reduced disability at 90 days (odds ratio = 1.56; 95% CI 1.14-2.13; P = .005). Furthermore, those who received endovascular thrombectomy were more likely to be functionally independent (mRS score of 0, 1, or 2) than those who received tPA (45% vs 32%; P = .005; number needed to treat = 8). There were no significant differences detected in mortality, symptomatic intracranial bleeds, or in-hospital medical complications. Given the high degree of heterogeneity noted in the primary end point, subgroup and sensitivity analyses were performed that showed better functional outcomes in patients with confirmed proximal arterial occlusion, those who received combined tPA and endovascular interventions, and those who had the newer retrievable stent devices used for thrombectomy. More recent studies, as compared with earlier studies, were also more likely to favor endovascular thrombectomy.
Dr. Kulkarni is an assistant professor of hospital medicine at Northwestern University in Chicago.