Introduction: Endovascular thrombectomy predominantly with the Solitaire stent retriever results in better outcomes among ischemic stroke patients with proximal, anterior circulation occlusions. The overall effect size and benefit in important subgroups are best estimated using pooled, individual participant-level data meta-analysis.
Methods: The SEER consortium pooled individual patient-level data from the 4 major randomized trials in which Solitaire retrievable stents were the predominant endovascular device, ESCAPE, SWIFT-PRIME, REVASCAT, and EXTEND-IA. A formal statistical analysis plan was pre-specified. The primary outcome is the modified Rankin Score at 90 days. Secondary outcomes include functional independence (mRS 0-2) and mortality at 90 days. Clinical sub-groups assessed are age, sex, NIHSS score, and target occlusion location. Full results will be presented at the meeting.
Results: Among 777 patients randomized (400 intervention, 377 control), mean age was 68 (sd 13), 51% were female, pretreatment NIHSS was median 17 (iqr 7), median ASPECTS score was 8 (iqr 2). More favorable outcomes over the entire mRS were observed with thrombectomy, CMH test p <0.001. Treatment benefit was homogenous across all subgroups of age, sex, baseline NIHSS, and target occlusion location. The rate of functional independence (mRS 0-2) at 90d was 55.0% endovascular vs. 31.5% control (RR = 1.7 CI95 1.4-2.1). The risk of death trended lower in the endovascular group (RR = 0.75 CI95 0.5-1.1). Among 128 patients ≥ 80 years of age, 37.8% (endovascular) vs. 18.5% (control) achieved an independent outcome (RR 2.0 CI95 1.1-3.8). Among 206 subjects with ICA occlusion, 45.9% (endovascular) vs. 18.9% (control) achieved an independent outcome (RR 2.4 CI95 1.5-3.8). Among 561 with MCA occlusions, 58.6% (endovascular) and 38.9% (control) achieved an independent outcome (RR 1.6 CI95 1.3-2.0).
Conclusions: Endovascular treatment for anterior circulation, large vessel occlusion ischemic stroke is a robust therapy in old and young, men and women, more and less severe deficits, and both ICA and MCA occlusions. The magnitude of benefit is large and consistent across trials; overall, 1 of every 4 treated patients achieves functional independence as a result of therapy.