Case studyPrediction of favorable outcome by percent improvement in patients with acute ischemic stroke treated with endovascular stent thrombectomy

- Percent improvement after EST is a useful marker for predicting good outcome.
- RNI, defined as a percent improvement ⩾30%, can predict good outcome after EST.
- Good collaterals and short ORT were independent predictors of RNI.

Our objective was to investigate a method for assessing early improvement and its predictive value for 3-month functional outcome in patients treated with EST. A total of 97 consecutive AIS patients undergoing EST were prospectively collected and retrospective reviewed. Data on demographics, vascular risk factors, admission National Institutes of Health Stroke Scale (NIHSS) score, 24-h NIHSS score, reperfusion and collateral formation were collected. Percent improvement was defined as ([baseline NIHSS score − 24-h NIHSS score]/baseline NIHSS score × 100%), while absolute improvement was calculated by the difference between scores (baseline NIHSS score − 24-h NIHSS score). A 3-month functional outcome was assessed using the modified Rankin Scale (mRS). Favorable outcome was defined as a mRS score of 0-2. Areas under the receiver-operating characteristic (ROC) curve (AUC) for percent improvement and absolute improvement in predicting favorable outcome was compared. Finally, we investigated the independent predictors of improvement at 24 h after EST and its relationship with favorable outcome. Pairwise comparison of ROC curves revealed that percent improvement had larger AUC than absolute improvement (p = 0.004). Rapid neurological improvement (RNI), defined as percent improvement ⩾30%, was a powerful predictor of favorable outcome (odds ratio [OR] 7.63, confidence interval [CI]: 2.65-21.96; p < 0.001). Good collaterals (OR 2.86; 95% CI: 1.11-7.38; p = 0.030) and short onset-to-reperfusion time (ORT) (OR 3.02, 95% CI: 1.17-7.80; p = 0.022) were independent predictors of RNI. RNI predicted 3-month favorable outcome in AIS patients treated with EST. Good collaterals and short ORT are independent predictors of RNI.