Endovascular thrombectomy for ischemic stroke 6 to 16 hours after a patient was last known to be well plus standard medical therapy resulted in better functional outcomes than standard medical therapy alone among patients with proximal middle-cerebral-artery or internal-carotid-artery occlusion and a region of tissue that was ischemic but not yet infarcted. This according to a randomized, open-label trial of thrombectomy patients in 38 US centers. Among the details:
- The trial was terminated early for efficacy after 182 patients had undergone randomization (92 to the endovascular-therapy group and 90 to the medical-therapy group).
- Endovascular therapy plus medical therapy was associated with a favorable shift in the distribution of functional outcomes at 90 days and a higher percentage of patients who were functionally independent, when compared with medical therapy alone.
- Specifically, a higher percentage of patients who were functionally independent, defined as a score on the modified Rankin scale of 0 to 2, in the endovascular therapy group vs medical therapy alone (45% vs 17%, P<0.001).
- 90-day mortality rate was 14% in the endovascular-therapy group and 26% in the medical-therapy group, with no significant between-group differences in frequency of symptomatic intracranial hemorrhage or of serious adverse events.
Albers GW, Marks MP, Kemp S, et al. Thrombectomy for stroke at 6 to 16 hours with selection by perfusion imaging. [Published online ahead of print January 24, 2018]. N Engl J Med. doi:10.1056/NEJMoa1713973.
In the recent guidelines on early management of stroke, IV alteplase is recommended for selected patients who may be treated within 3 hours (level of evidence ‒ A) and 3-4.5 hours (level of evidence – B) of ischemic stroke symptom onset or last known well or at baseline state. The guidelines go on to state that IV alteplase should be administered even if endovascular therapy is being considered. The guidelines then go on to give criteria for using endovascular therapy within 6 hours if patients meet the inclusion criteria. In discussing the study above, the guidelines state, “In selected patients with acute ischemic stroke within 6 to 16 hours of last known normal who have large vessel obstruction in the anterior circulation and meet eligibility criteria, mechanical thrombectomy is recommended.”1 The improvement in functional outcome in this study is probably the result of careful patient selection for patients with significant amounts of remaining ischemic brain tissue that was not yet infarcted. This selection was achieved through strict eligibility criteria that assessed the volume of partially ischemic tissue to infarcted tissue and required a minimum absolute volume of potentially reversible ischemic tissue. Estimates of the volume of the ischemic core and the partially ischemic at-risk regions were derived from CT perfusion or MRI diffusion and perfusion scans. The important take-home for primary care is that for selected patients in centers with the availability of mechanical thrombectomy, patients may derive substantial benefit up to 16 hours after clinical onset of stroke. — Neil Skolnik, MD
- Powers WJ, Rabinstein AA, Ackerson T, et al; on behalf of the American Heart Association Stroke Council. 2018 Guidelines for the early management of patients with acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. [Published online ahead of print January 24, 2018]. Stroke. doi:10.1161/STR.0000000000000158.