Endovascular thrombectomy has been shown to be more effective in reducing disability than medical treatment alone in selected patients with ischemic stroke due to large cerebral vessel occlusion. However, patients with large strokes on computed tomography (CT) scan have been underrepresented in thrombectomy trials, even though such strokes account for approximately one-fifth of large vessel occlusion strokes.
Consequently, the safety and effectiveness of thrombectomy in patients with a higher ischemic burden have not been well established. These patients generally have poor neurological outcomes, including progression of stroke symptoms, cerebral edema, and death. Results from a trial conducted in Japan, post hoc analyzes of previous trials, and a prospective cohort study have suggested that endovascular thrombectomy may improve functional outcomes in patients with large strokes.
The estimated extent of ischemic change in acute stroke differs depending on the imaging method used to measure the volume of infarcted tissue. Ischemic changes on non-contrast CT appear as areas of hypodensity and are evaluated with the use of the semiquantitative measure of Alberta Stroke Program Early Computed Tomography Score (ASPECTS). Perfusion imaging identifies quantitative brain volume with critically reduced blood flow that is considered irreversibly damaged, while diffusion-weighted magnetic resonance imaging (MRI) detects the volume of brain tissue affected by cytotoxic edema.
In a randomized controlled trial involving patients with acute ischemic stroke with a large ischemic central volume, we aimed to evaluate whether endovascular thrombectomy within 24 hours of stroke onset (defined as the last time knew the patient was well) leads to better functional outcomes than standard medical care alone. We used several imaging methods to determine central infarct size.
Background
Efficacy and safety trials of endovascular thrombectomy in patients with large ischemic strokes have been conducted in limited populations.
Methods
We conducted a prospective, randomized, open-label, adaptive international trial involving patients with stroke due to occlusion of the internal carotid artery or the first segment of the middle cerebral artery to evaluate endovascular thrombectomy within 24 hours of onset.
Patients had a large ischemic central volume, defined as an Alberta Stroke Program Early CT Scan Score of 3 to 5 (range, 0 to 10, with lower scores indicating a larger infarct) or a large ischemic central volume. of at least 50 mL in diffusion-weighted CT or MRI perfusion.
Patients were assigned in a 1:1 ratio to endovascular thrombectomy plus medical care or medical care alone. The primary outcome was the modified Rankin Scale score at 90 days (range, 0 to 6, with higher scores indicating greater disability). Functional independence was a secondary outcome.
Results
The trial was stopped early due to its effectiveness ; 178 patients had been assigned to the thrombectomy group and 174 to the medical care group.
The generalized odds ratio for a change in the distribution of modified Rankin scale scores toward better outcomes in favor of thrombectomy was 1.51 (95% confidence interval [CI], 1.20 to 1. 89; P < 0.001).
Twenty percent of patients in the thrombectomy group and 7% in the medical care group had functional independence (relative risk, 2.97; 95% CI, 1.60 to 5.51). Mortality was similar in the two groups.
In the thrombectomy group, arterial access site complications occurred in 5 patients, dissection in 10, cerebral vessel perforation in 7, and transient vasospasm in 11. Symptomatic intracranial hemorrhage occurred in 1 patient in the thrombectomy group and in 2 in the medical care group.
Figure : Distribution of scores on the modified Rankin scale at 90 days (intention-to-treat population). A score of 0 on the modified Rankin scale indicates no symptoms; a score of 1, no clinically significant disability (patients can perform usual work, leisure, and school activities); a score of 2, mild disability (patients are able to take care of their own affairs without assistance, but cannot perform all of the above activities); a score of 3, moderate disability (patients require some assistance but can walk without assistance); a score of 4, moderately severe disability; a score of 5, severe disability (patients are bedridden and require constant care); and a score of 6, death. Percentages may not add up to 100 due to rounding.
Conclusions
Among patients with large ischemic strokes, endovascular thrombectomy produced better functional outcomes than medical care, but was associated with vascular complications. Brain hemorrhages were rare in both groups.
Final message Among patients in North America, Europe, Australia, and New Zealand with acute ischemic stroke due to proximal large vessel occlusion and with a large ischemic core, endovascular thrombectomy in addition to standard medical care resulted in improved functional outcomes. than medical care alone. Thrombectomy was associated with vascular complications of the procedure. |
(Funded by Stryker Neurovascular; SELECT2 ClinicalTrials.gov number, NCT03876457. opens in new tab.)
