Imaging triage of acute stroke patients for endovascular clot retrieval: Effect of increased therapeutic window on the utilization of CT perfusion

Introduction: Recent randomized trials showing improved outcomes for later-presenting acute ischaemic stroke (AIS) patients with large vessel occlusion (LVO) treated with endovascular clot retrieval (ECR) may result in substantial increases in CTP utilization. This 3-hospital, single-institution cohort study aimed to compare 2017 and 2018 patient cohorts for the following: CTP use in AIS. Prevalence of LVO in all patients having CTP. Number and clinical characteristics of patients triaged to ECR. Number of patients receiving CTP relative to similar-acuity total ED presentations. Methods: Inclusion criteria: Consecutive adult emergency (ED) patients receiving CTP for suspected AIS. Study period 1:1 January–30 June 2017; Period 2:1 January–30 June 2018. Data collection: age, gender, triage category, NIHSS (National Institute of Health Stroke Score), symptoms/signs, time elapsed since last seen well (TESLSW) to triage, disposition (home/other). Results: A 38.7 % increase in CTP (512 in 2017, 710 in 2018) occurred with 39/512 (7.6%) and 72/710 (10.1%) having intended ECR. CTPs per intended ECR declined from 13.1 to 9.9. 36/512 (7.0%) and 58/710 (8.2%) patients had ECR (61.1% increase) and 22/36 (61.1%) and 25/58 (43.1%) of these were discharged home in 2017 and 2018, respectively, an increase of 3/22(14%). Conclusion: Despite a 38.7% increase in CTP utilization, we experienced a reduction in the number of CTPs performed/patient triaged to ECR. This did not reflect higher LVO prevalence among later presenters but may reflect changed selection criteria for CTP and/or decision making about suitability for ECR.