Futile reperfusion and predicted therapeutic benefits after successful endovascular treatment according to initial stroke severity

BACKGROUND: Futile reperfusion (poor functional status despite successful reperfusion) was observed in up to 67% of patients enrolled in recent endovascular treatment (EVT) clinical trials. We investigated the impact of baseline stroke severity on both futile reperfusion and therapeutic benefit of successful EVT. METHODS: Using a prospective multicenter stroke registry, we identified consecutive ischemic stroke patients with anterior circulation large artery occlusion, who were reperfused successfully by EVT (Thrombolysis in Cerebral Infarction grade 2b-3). The rate of futile reperfusion was assessed across the initial National Institutes of Health Stroke Scale (NIHSS) scores. The frequency of poor outcomes (modified Rankin scale [mRS] 3-6) according to NIHSS scores was compared between patients revascularized successfully by EVT and those who did not receive EVT, after standardizing for age. RESULTS: Among 21,591 patients with ischemic stroke, 972 (4.5%) received EVT within 12 h of onset, including 440 who met study eligibility criteria. Futile reperfusion was observed in 226 of the 440 study-eligible patients (51.4%) and was associated with stroke severity: 20.9% in NIHSS scores ≤5, 34.6% in 6-10, 58.9% in 11-20, and 63.8% in > 20 (p < 0.001). Nonetheless, the therapeutic benefit of EVT also increased with increasing stroke severity (p for interaction < 0.001): 0.1% in NIHSS ≤5, 18.6% in 6-10, 28.7% in 11-20, and 34.3% in > 20. CONCLUSIONS: EVT is more beneficial with increasing stroke severity, although futile reperfusion also increases with higher stroke severity.