Predicting the emergence of malignant brain oedema in acute ischaemic stroke: a prospective multicentre study with development and validation of predictive modelling.

Background: We aimed to develop and validate a prognostic model for predicting malignant brain oedema in patients with acute ischaemic stroke in a real-world setting of practice. Methods: A prospective multicentre study enrolled adult patients with acute ischaemic stroke with brain CT < 24 h of onset of symptoms admitted to nine tertiary-level hospitals in China between September 2017 and December 2019. Malignant brain oedema was defined as any patient who had decompressive craniectomy, discharge in coma, or in-hospital death attributed to symptomatic brain swelling. The derivation cohort was a consecutive cohort of patients from one centre and the validation cohort was non-consecutive patients from the other centres. Multivariable logistic regression was used to define independent predictors from baseline clinical characteristics, imaging features, complications, and management. A web-based nomogram and a risk score were developed based on the final model. Model performance was assessed for discrimination and calibration in both derivation and validation cohorts. The study is registered, NCT03222024. Findings: Based on the derivation cohort (n = 1627), the model was developed with seven variables including large infarct (adjusted odds ratio [OR] 40.90, 95% CI 20.20-82.80), National Institutes of Health Stroke Scale (NIHSS) score (OR 1.09, 1.06-1.12), thrombolysis (OR 2.11, 1.18-3.78), endovascular treatment (OR 2.87, 1.47-5.59), pneumonia (OR 2.47, 1.53-3.97), brain atrophy (OR 0.57, 0.37-0.86), and recanalisation (OR 0.36, 0.17-0.75). The classification threshold of a predicted probability ≥0.14 showed good discrimination and calibration in both derivation cohort (area under the receiver-operating curve [AUC] 0.90, 0.87-0.92; sensitivity 0.95, 0.92-0.98) and validation cohort (n = 556, AUC 0.88, 0.82-0.95; sensitivity 0.84, 0.73-0.95). The risk score based on this model had a total point that ranged from -1 to 20, with an optimal score of ≥10 showing good discrimination and calibration in both derivation (AUC 0.89, 0.87-0.92; sensitivity 0.95, 0.92-0.98) and validation (AUC 0.88, 0.82-0.95; sensitivity 0.84, 0.73-0.95) cohorts. Interpretation: The INTEP-AR model (i.e. large Infarct, NIHSS score, Thrombolysis, Endovascular treatment, Pneumonia, brain Atrophy, and Recanalisation) incorporating multiple clinical and radiological characteristics has shown good prognostic value for predicting malignant brain oedema after acute ischaemic stroke. Funding: National Natural Science Foundation of China; Science and Technology Department of Sichuan Province; West China Hospital.