SELECT2 RCT – Endovascular Thrombectomy for Large Ischemic Strokes 

April 3, 2023

Written by Jason Lesnick

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Thrombectomy plus usual medical care in patients with a proximal large vessel occlusion (LVO), a large ischemic core, and last known well <24 hours from presentation improves functional outcomes compared to medical care alone.

Why does this matter?
Thrombectomy has been shown to be more effective than medical therapy alone in selected patients with ischemic stroke due to LVO, but patients with large strokes on noncontrast CT or perfusion imaging have been underrepresented in thrombectomy trials. The safety and efficacy of thrombectomy in patients with a larger ischemic burden have not been well established.

I choose you, SELECT2!
This was a prospective, randomized, open-label, international (North America, Europe, Australia, New Zealand) trial of 352 patients with stroke due to occlusion of the internal carotid artery or first segment of the middle cerebral artery within 24 hours of symptom onset.

Patients were assigned 1:1 to either endovascular thrombectomy plus medical care or medical care alone. The primary outcome was modified Rankin Scale (mRS) at 90 days, with secondary outcomes of functional independence (defined as mRS 0 to 2) at 90 days, independent ambulation (mRS score of 0 to 3) at 90 days, procedural complications, successful reperfusion, discharge location, early neurologic improvement (decrease of ≥ 8 points in NIHSS score from baseline to 24 hours), and quality of life using Neuro-QoL measures. Notably, mRS scores of 6 (death) and 5 (patient bedridden, constant care needed) were merged for their analysis to avoid considering a shift of 6 to 5 as a substantial improvement in functional status. 

Safety outcomes included symptomatic ICH, death, neurologic worsening (increase of ≥ 4 points in NIHSS score within 24 hours of presentation), and procedural complications. 

Median NIHSS was 19; median time from last known well 9.31 hours. 28.6% of patients awoke with symptoms of stroke; IV thrombolysis was given in 20.8% of the thrombectomy group and 17.3% in the medical care group.

This trial was stopped early for efficacy by the data and safety monitoring board at a secondary interim analysis after 300 patients had been enrolled. The median mRS score was 4 in the thrombectomy group and 5 in the medical care group, with generalized odds ratio favoring endovascular thrombectomy of 1.51 (95%CI 1.20 to 1.89). Functional independence was observed in 20.0% of patients in the thrombectomy group and 7.0% of patients in the medical care group. Independent ambulation was present in 37.9% of the thrombectomy patients and 18.7% in the medical-care group. 

Symptomatic ICH occurred in 1 patient (0.6%) in the thrombectomy group and 2 patients (1.1%) in the medical-care group. Procedural complications occurred in 18.5% of patients, including arterial access site (3%), 4% vessel perforation, and 6% vascular dissection.

If a patient is a candidate for thrombectomy, it appears as though there is a meaningful benefit in function for these sick patients relative to the risks and complications. 

Source
Trial of Endovascular Thrombectomy for Large Ischemic Strokes. N Engl J Med. 2023 Feb 10. doi: 10.1056/NEJMoa2214403. Online ahead of print.