ICAT: A simple score predicting critical care needs after thrombolysis in stroke patients

Background: Patients receiving intravenous thrombolysis (IVT) for acute ischemic stroke are at risk of developing complications, commonly necessitating admission to an intensive care unit (ICU). At present, most IVT is administered in the Emergency Department or in dedicated stroke units, but no evidence-based criteria exist that allow for early identification of patients at increased risk of developing ICU needs. The present study describes a novel prediction score aiming to identify a subpopulation of post-IVT patients at high risk for critical care interventions. Methods: We retrospectively analyzed data from 301 patients undergoing IVT at our institutions during a 5-year period. Two hundred and ninety patients met inclusion criteria. The sample was randomly divided into a development and a validation cohort. Logistic regression was used to develop a risk score by weighting predictors of critical care needs based on strength of association. Results: Seventy-two patients (24.8%) required critical care interventions. Black race (odds ratio [OR] 3.81, p=0.006), male sex (OR 3.79, p=0.008), systolic blood pressure (SBP; OR 1.45 per 10mm Hg increase in SBP, p<0.001), and NIH stroke scale (NIHSS; OR 1.09 per 1 point increase in NIHSS, p=0.071) were independent predictors of critical care needs. The optimal model for score development, predicting critical care needs, achieved an AUC of 0.782 in the validation group. The score was named the ICAT (Intensive Care After Thrombolysis) score, assigning the following points: black race (1 point), male sex (1 point), SBP (2 points if 160-200mm Hg; 4 points if >200mm Hg), and NIHSS (1 point if 7-12; 2 points if >12). Each 1-point increase in the score was associated with 2.22-fold increased odds for critical care needs (95% CI 1.78-2.76, p<0.001). A score ≥2 was associated with over 13 times higher odds of critical care needs compared to a score <2 (OR 13.60, 95% CI 3.23-57.19), predicting critical care with 97.2% sensitivity and 28.0% specificity. Conclusion: The ICAT score, combining information about race, sex, SBP, and NIHSS, predicts critical care needs in post-IVT patients and may be helpful when triaging post-IVT patients to the appropriate monitoring environment.