By Matthew E. Fink, MD
Louis and Gertrude Feil Professor and Chair, Department of Neurology, Associate Dean for Clinical Affairs, New York Presbyterian/Weill Cornell Medical College
SOURCE: Li Q, Abdalkader M, Siegler JE, et al. Mechanical thrombectomy for large ischemic stroke: A systematic review and meta-analysis. Neurology 2023; Jun 5. doi:10.1212/WNL.0000000000207536. [Online ahead of print].
Endovascular thrombectomy (EVT) has been rapidly adopted throughout the world for the treatment of patients with acute ischemic stroke and large vessel occlusion. This approach has achieved strong recommendations in stroke guidelines. However, the trials that form the basis of the recommendations have strict imaging recruitment criteria, including an Alberta Stroke Program Early CT Score (ASPECTS) greater than 5 on non-contrast computed tomography (CT) or infarct core volume < 70 mL on CT perfusion imaging. Patients with large infarct cores have been thought to be less likely to benefit from thrombectomy with an increased risk of reperfusion injury or symptomatic intracranial hemorrhage. The efficacy of EVT in patients with large core infarct has not been well studied.
These investigators undertook a systematic review and meta-analysis to provide a detailed and updated summary of all published clinical trial data around endovascular thrombectomy. They combined the pooled results of three major randomized clinical trials (RESCUE-Japan LIMIT, SELECT2, and ANGEL-ASPECT), as well as observational cohort studies, to investigate the efficacy of EVT in patients with large core ischemic strokes. The inclusion criteria for this review were patients with ASPECTS ≤ 5 or infarct core volume ≥ 50 mL, a randomized controlled trial or observational study, and interventional arm with both EVT and medical management, reporting a modified Rankin Scale score of 0-3 at three months, 90-day mortality, and rate of symptomatic intracerebral hemorrhage. Randomized trials with fewer than 100 patients were excluded. The primary outcome was independent ambulation, defined as a modified Rankin Scale score of 0-3 at 90 days. Secondary outcomes were functional independence and the rate of decompressive craniectomy. Safety outcomes were the rate of symptomatic intracerebral hemorrhage and mortality at 90 days.
The randomized clinical trials included 1,010 patients, of whom 509 were treated with EVT. The cohort studies included 1,851 patients, of whom 859 were treated with EVT. Across all three clinical trials, EVT improved the primary outcome of independent ambulation in patients with large ischemic core (risk ratio [RR], 1.78; P < 0.001). The same findings were found from the 10 observational cohort studies (RR, 2.33; P < 0.001). Analysis of secondary outcomes showed that EVT improved the likelihood of functional independence in both the randomized clinical trials as well as the cohort studies. In the randomized clinical trials, there was a higher rate of symptomatic intracerebral hemorrhage in the EVT group compared to the medical management group, 4.7% vs. 2.6%, respectively. However, the differences were not statistically significant. The rate of symptomatic intracerebral hemorrhage was similar between EVT and medical management in the patients analyzed from the cohort studies. There was no difference in the rate of decompressive hemicraniectomy between patients treated with EVT vs. medical management. There was no difference in mortality between the two groups as well.
In this well-done systematic review and meta-analysis, the investigators demonstrated that from the analysis of three pooled randomized clinical trials, patients who underwent EVT had a nearly twofold higher chance of independent ambulation at 90 days, a higher probability of achieving 90-day functional independence, a numerically higher rate of symptomatic intracranial hemorrhage, and a comparable mortality rate when compared with medical management alone. These effects were concordant with what also was found in the 10 observational studies. In conclusion, a less restrictive patient selection protocol should be considered in patients with large core ischemic strokes. It is likely that this will lead to treatment benefit.
