Selection of patients for intra-arterial treatment for acute ischaemic stroke: development and validation of a clinical decision tool in two randomised trials

Abstract

Objective To improve the selection of patients with acute ischaemic stroke for intra-arterial treatment using a clinical decision tool to predict individual treatment benefit. Design Multivariable regression modelling with data from two randomised controlled clinical trials. Setting 16 hospitals in the Netherlands (derivation cohort) and 58 hospitals in the United States, Canada, Australia, and Europe (validation cohort). Participants 500 patients from the Multicenter Randomised Clinical Trial of Endovascular Treatment for Acute Ischaemic Stroke in the Netherlands trial (derivation cohort) and 260 patients with intracranial occlusion from the Interventional Management of Stroke III trial (validation cohort). Main outcome measures The primary outcome was the modified Rankin Scale (mRS) score at 90 days after stroke. We constructed an ordinal logistic regression model to predict outcome and treatment benefit, defined as the difference between the predicted probability of good functional outcome (mRS score 0-2) with and without intra-arterial treatment. Results 11 baseline clinical and radiological characteristics were included in the model. The externally validated C statistic was 0.69 (95% confidence interval 0.64 to 0.73) for the ordinal model and 0.73 (0.67 to 0.79) for the prediction of good functional outcome, indicating moderate discriminative ability. The mean predicted treatment benefit varied between patients in the combined derivation and validation cohort from −2.3% to 24.3%. There was benefit of intra-arterial treatment predicted for some individual patients from groups in which no treatment effect was found in previous subgroup analyses, such as those with no or poor collaterals. Conclusion The proposed clinical decision tool combines multiple baseline clinical and radiological characteristics and shows large variations in treatment benefit between patients. The tool is clinically useful as it aids in distinguishing between individual patients who may experience benefit from intra-arterial treatment for acute ischaemic stroke and those who will not. Trial registration clinicaltrials.gov NCT00359424 (IMS III) and isrctn.com ISRCTN10888758 (MR CLEAN).

Importance of Reperfusion Status after Intra-Arterial Thrombectomy for Prediction of Outcome in Anterior Circulation Large Vessel Stroke

“…With regards to radiological predictors, baseline CT ASPECTS was a significant predictor of outcome in univariate analysis, as demonstrated before [8, 9, 12-14, 17, 29]. However, in multivariate analysis, CT ASPECTS was not an independent predictor of outcome.…”

“…Some studies found that collateral status was not an independent predictor of outcome when other variables were taken into account [14, 38]. Our results suggest that CT/CTA findings at presentation are of limited value for predicting clinical outcome and should be interpreted with caution [8, 42]. …”

“…However, exceptions could be made at the physician’s discretion and therefore the time from stroke onset to treatment was not used as an exclusion criterion. Based on findings from previous prediction models for IVT and IAT [8-24], the following variables were extracted from the registry: age, prestroke mRS, National Institutes of Health Stroke Scale (NIHSS) at presentation, Alberta Stroke Program Early CT Score (ASPECTS) for early ischemic changes [12], the Tan score for collateral supply [15], treatment with IVT, time from symptom onset to the end of IAT (i.e., sheath from groin), reperfusion status assessed with the eTICI score, and functional outcome. The eTICI score ranges from grade 0 (no reperfusion) to grade 3 (complete reperfusion) and was assessed after intervention by digital subtraction angiography.…”

“…Information on prognosis is crucial to both patients and their family, and aids in determining appropriate rehabilitation programs. However, predicting outcome after ischemic stroke remains difficult due to its heterogeneous nature and the various factors affecting the disease course [8-18]. …”

“…Patient selection for IAT has been studied extensively [2, 6-8], whereas prognostication after IAT is relatively understudied [8-11]. Previous studies designed prediction models for outcome after ischemic stroke; however, the degree of reperfusion status was often not accounted for [19-23].…”