Early clinical surrogates for outcome prediction after stroke thrombectomy in daily clinical practice

Background and purpose To investigate early clinical surrogates for long-term independency of patients treated with thrombectomy for large vessel occlusion stroke in daily clinical routine. Methods All patients with anterior circulation stroke enrolled in the German Stroke Registry-Endovascular Treatment from 07/2015 to 04/2018 were analysed. National Institute of Health Stroke Scale (NIHSS) on admission, NIHSS percentage change, NIHSS delta and NIHSS at 24 hours as well as existing binary definitions of early neurological improvement (ENI; improvement of 8 (major ENI)/10 (dramatic ENI) NIHSS points or reaching 0/1 were compared for predicting functional outcome at 90 days using the modified Rankin Scale (mRS). Excellent and favourable outcome were defined as 0–1 and 0–2, respectively. Results Among 2262 endovasculary treated patients with acute ischaemic anterior circulation stroke, NIHSS at 24 hours had the highest discriminative ability to predict excellent (receiver operator characteristics (ROC) NIHSS 24 hours area under the curve (AUC) 0.86 (0.84–0.88)) and favourable long-term functional outcome (ROC NIHSS 24 hours AUC 0.86 (0.85–0.88)) in comparison to NIHSS percentage change (ROC % change AUC mRS ≤1: 0.81 (0.78–0.83) mRS ≤2: 0.81 (0.79–0.83)), NIHSS delta change (ROC Δ change AUC mRS ≤1: 0.74 (0.72–0.77), mRS ≤2: 0.77 (0.74–0.79)) and NIHSS admission (ROC Adm AUC mRS ≤1: 0.70 (0.68–0.73), mRS ≤2: 0.67 (0.68–0.71)). Advanced age was the only independent predictor (adjusted OR 1.05, 95% CI 1.03 to 1.07, p<0.001) for turning the outcome prognosis from favourable (mRS ≤2) to poor (mRS ≥4) at 90 days. Conclusion The NIHSS at 24 hours postintervention with a threshold of ≤8 points serves best as a surrogate for long-term functional outcome after thrombectomy for anterior circulation stroke in daily clinical practice. Only advanced age significantly decreases its predictive value.