Assessing Predictive Factors for Thrombectomy Necessity in Acute Ischemic Stroke: Insights From the Direct to Angio Suite Protocol

BACKGROUND: Endovascular thrombectomy (EVT) has emerged as an effective treatment option. Unfortunately, interfacility transfers to thrombectomy-capable centers often delay treatment time. The direct to angio suite (DTA) pathway reduces interfacility transfer time by foregoing the emergency department at the thrombectomy-capable center and directing patients immediately to the angio suite. Up to 22% of patients transferred under the DTA pathway will not have a large vessel occlusion on cerebral angiography or will experience significant neurological improvement, obviating the need for EVT. This study evaluated predictive factors associated with EVT under the DTA protocol. METHODS: A retrospective review was conducted on 2590 patients transferred to 2 comprehensive stroke centers from January 2015 to December 2020. Data from 407 patients transferred under the DTA protocol were analyzed to identify factors associated with undergoing EVT using multivariable logistic regression adjusted for age, sex, National Institutes of Health Stroke Scale (NIHSS) score on arrival at the comprehensive stroke center, Alberta Stroke Program Early Computed Tomography Score, decrease in NIHSS score from initial presentation to arrival at the comprehensive stroke center by ≥5 points (change in NIHSS score from referring hospital to comprehensive stroke center), intravenous thrombolytics, and computed tomography angiography–confirmed large vessel occlusion. Statistical analysis included the Mann-Whitney U test, the Fisher exact test, the Pearson χ 2 test, and the logistic regression analysis. RESULTS: Of the 407 patients transferred under the DTA protocol (median age, 73 interquartile range, 63–82 years; 50% female), 355 underwent EVT, while 52 did not. Among patients who did not undergo EVT, 12 demonstrated significant neurological improvement on arrival, obviating the need for intervention. Among the remaining 40 patients, diagnostic cerebral angiography demonstrated distal clot migration or patent vessels, precluding thrombectomy. Factors associated with EVT included comprehensive stroke center NIHSS score, large vessel occlusion on computed tomography angiography at the satellite hospital, change in NIHSS score from referring hospital to comprehensive stroke center score, intravenous thrombolytics, and Alberta Stroke Program Early Computed Tomography Score. Comprehensive stroke center NIHSS score ≥8 (odds ratio, 5.99) and large vessel occlusion on computed tomography angiography (odds ratio, 5.36) were associated with higher odds of EVT. In contrast, change in NIHSS score from referring hospital to comprehensive stroke center score (odds ratio, 0.38), intravenous thrombolytics (odds ratio, 0.41), and Alberta Stroke Program Early Computed Tomography Score ≥9 (odds ratio, 0.22) were associated with lower odds of EVT. Tenfold cross-validation demonstrated a sensitivity of 96.65%, positive predictive value of 89.15%, and negative predictive value of 65.22%. The full model demonstrated strong discrimination (area under the curve, 0.84). CONCLUSIONS: The study identifies key predictors of EVT under the DTA protocol, highlighting the role of initial clinical assessment and neuroimaging in optimizing patient selection and reducing unnecessary interventions.