Article Figures & Data
Figures
- Figure 1
Flow chart of the study population and process. AIS, acute ischaemic stroke; CTA, CT angiography; NIHSS, National Institutes of Health Stroke Scale; TOF-MRA, time of flight MR angiography.
- Figure 2
Illustration of features contributing to identification of LVO by Gini importance values. Gini importance is a measurement of the feature importance in the model, the higher the value of Gini importance is, the more important the feature is. LOC, level of consciousness; NIHSS, National Institutes of Health Stroke Scale.
Tables
- Table 1
Comparison of clinical characteristics between cohort of the training set and test set
Cohort of the training set (n=15 365) Cohort of the test set
(n=4215)P value Female, n (%) 5868 (38.2) 1518 (36.0) 0.010 Age, year, median (IQR) 70 (60–79) 71 (60–79) 0.012 Atrial fibrillation, n (%) 3274 (21.3) 804 (19.1) 0.002 Congestive heart failure, n (%) 338 (2.2) 75 (1.8) 0.104 Coronary heart disease, n (%) 1283 (8.4) 303 (7.2) 0.015 Family history of cardiovascular disease, n (%) 174 (1.1) 25 (0.6) 0.002 Smoking, n (%) 4637 (30.2) 1181 (28.0) 0.007 Hyperlipidaemia, n (%) 890 (5.8) 199 (4.7) 0.008 Diabetes mellitus, n (%) 2497 (16.3) 702 (16.7) 0.526 Hypertension, n (%) 9815 (63.9) 2624 (62.3) 0.053 History of stroke/TIA, n (%) 1968 (12.8) 560 (13.3) 0.422 Hyperhomocysteinaemia, n (%) 1011 (6.6) 237 (5.6) 0.026 Prior anticoagulation therapy, n (%) 338 (2.2) 83 (2.0) 0.400 Prior antiplatelet therapy, n (%) 2191 (14.3) 558 (13.2) 0.094 LVO, n (%) 4417 (28.7) 1279 (30.3) 0.044 Systolic blood pressure, mm Hg, median (IQR) 154 (139–168) 153 (139–167) 0.450 Diastolic blood pressure, mm Hg, median (IQR) 85 (76–94) 84 (76–94) 0.065 NIHSS sum, median (IQR) 6 (3–13) 5 (2–12) <0.001 NIHSS items LOC, median (IQR) 0 (0–0) 0 (0–0) 0.288 LOC questions, median (IQR) 0 (0–1) 0 (0–0) 0.064 LOC commands, median (IQR) 0 (0–0) 0 (0–0) 0.020 Gaze deviation, median (IQR) 0 (0–0) 0 (0–0) 0.001 Visual field test, median (IQR) 0 (0–0) 0 (0–0) 0.341 Facial palsy, median (IQR) 1 (0–1) 1 (0–1) 0.003 Motor left arm, median (IQR) 0 (0–2) 0 (0–2) <0.001 Motor right arm, median (IQR) 0 (0–2) 0 (0–2) 0.258 Motor left leg, median (IQR) 0 (0–2) 0 (0–2) <0.001 Motor right leg, median (IQR) 0 (0–2) 0 (0–2) 0.063 Limb ataxia, median (IQR) 0 (0–0) 0 (0–0) 0.002 Sensory, median (IQR) 1 (0–1) 1 (0–1) 0.003 Aphasia, median (IQR) 0 (0–2) 0 (0–2) 0.003 Dysarthria, median (IQR) 1 (0–1) 1 (0–1) 0.014 Extinction and inattention, median (IQR) 0 (0–0) 0 (0–0) 0.678 LOC, level of consciousness; LVO, large vessel occlusion; NIHSS, National Institutes of Health Stroke Scale; TIA, transient ischaemic attack.
- Table 2
Comparison of eight models to predict LVO in the test set
AUC (95% CI) SEN SPE Accuracy RF 0.831 (0.819 to 0.843) 0.721 0.827 0.772 GBM 0.831 (0.820 to 0.843) 0.721 0.825 0.772 XGBoost 0.831 (0.820 to 0.844) 0.715 0.825 0.770 LightGBM 0.828 (0.816 to 0.840) 0.721 0.826 0.774 Ada boosting 0.828 (0.817 to 0.841) 0.704 0.824 0.765 ANN 0.819 (0.817 to 0.842) 0.740 0.781 0.761 LR 0.790 (0.778 to 0.804) 0.735 0.746 0.740 KNN 0.774 (0.762 to 0.789) 0.685 0.769 0.727 ANN, artificial neural network; AUC, area under the curve; GBM, gradient boosting machine; KNN, K-Nearest Neighbour; LR, logistic regression; LVO, large vessel occlusion stroke; RF, random forests; SEN, sensitivity; SPE, specificity; XGBoost, extreme gradient boosting.
- Table 3
Comparison of various published clinical scales with RF model to predict LVO in the test set
Cut-off AUC (95% CI) SEN SPE Accuracy RF — 0.831 (0.819 to 0.843) 0.721 0.827 0.772 mNIHSS ≥7 0.809 (0.795 to 0.824) 0.760 0.755 0.769 sNIHSS-EMS ≥6 0.809 (0.795 to 0.824) 0.722 0.788 0.764 NIHSS ≥6 0.806 (0.792 to 0.820) 0.727 0.792 0.708 RACE ≥5 0.806 (0.791 to 0.821) 0.712 0.793 0.764 CPSSS ≥2 0.804 (0.789 to 0.819) 0.658 0.826 0.761 FAST-ED ≥4 0.804 (0.790 to 0.819) 0.611 0.850 0.760 s-NIHSS-5 ≥4 0.804 (0.790 to 0.819) 0.738 0.763 0.760 3I-SS ≥4 0.798 (0.782 to 0.813) 0.641 0.852 0.759 LAMS ≥4 0.779 (0.764 to 0.795) 0.652 0.808 0.746 PASS ≥2 0.778 (0.763 to 0.794) 0.660 0.823 0.751 s-NIHSS-1 ≥2 0.773 (0.757 to 0.789) 0.698 0.761 0.695 FPSS ≥5 0.762 (0.746 to 0.778) 0.781 0.620 0.711 G-FAST ≥3 0.755 (0.740 to 0.771) 0.763 0.653 0.697 VAN ≥2 0.732 (0.715 to 0.748) 0.847 0.534 0.650 ROSIER ≥4 0.730 (0.714 to 0.746) 0.886 0.467 0.694 FAST ≥3 0.706 (0.690 to 0.723) 0.682 0.681 0.685 aNIHSS ≥1 0.689 (0.672 to 0.706) 0.542 0.751 0.416 aNIHSS, abbreviated NIHSS; AUC, area under the curve; CPSSS, Cincinnati Pre-hospital Stroke Severity scale; EMS, emergency medical services; FAST-ED, Field Assessment Stroke Triage for Emergency Destination scale; FPSS, Finnish Prehospital Stroke Scale; G-FAST, gaze–face–arm–speech–time test; 3I-SS, three-item Stroke Scale; LAMS, Los Angeles Motor Scale; LVO, large vessel occlusion stroke; mNIHSS, modified NIHSS; NIHSS, National Institutes of Health Stroke Scale; PASS, Pre-hospital Acute Stroke Severity scale; RACE, Rapid Arterial Occlusion Evaluation Scale; RF, random forests; ROSIER, Recognition of Stroke in the Emergency Room; SEN, sensitivity; sNIHSS, shortened versions of the NIHSS; SPE, specificity; VAN, stroke vision, aphasia, neglect assessment.
