Prehospital Telestroke vs Paramedic Scores to Accurately Identify Stroke Reperfusion Candidates: A Cluster Randomized Controlled Trial

Abstract

Background and objective: Stroke reperfusion therapy is time critical. Improving prehospital diagnostic accuracy including the likelihood of large vessel occlusion can aid with efficient and appropriate diversion decisions to optimize onset-to-treatment time. In this study, we investigated whether prehospital telestroke improves diagnostic accuracy when compared with paramedic assessments and assessed feasibility.

Methods: We conducted a pragmatic, community-based, cluster randomized controlled trial comparing the diagnostic accuracy of telestroke assessments inside the ambulance with a modified Los Angeles Motor Scale (PASTA score). The primary outcome was the accuracy of predicting reperfusion candidates; secondary outcomes were accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of either approach to identify IV thrombolysis (IVT) and endovascular thrombectomy (EVT) candidates and true stroke patients by study group. The accuracy of telestroke and PASTA assessments was compared against in-person assessment in the emergency department and with the final diagnosis/intervention for the patient. We also monitored for technical challenges.

Results: We recruited 76 patients (35 telestroke and 41 PASTA) between August 2019 and September 2020. The mean age was 72.2 (±14.6) years. Telestroke was 100% (95% CI 90%-100%) and PASTA 70.7% (54.5%-83.9%) accurate in predicting reperfusion candidates compared with preimaging emergency department neurologist assessment (p < 0.001). When compared with actual reperfusion therapy administered, the predictive accuracy was 80% (63.1%-91.6%) and 60.1% (44.5%-75.8%) for telestroke and PASTA, respectively (p < 0.001). In predicting the administration of IVT, telestroke was 80% (63.1-91.6) and PASTA was 56.1% (39.8-71.5) accurate (p < 0.001). In predicting intervention with EVT, telestroke was 88.6% (73.3-96.8) and PASTA 56.1% (39.8-71.5) accurate (p = 0.005). The service model proved technically feasible and was acceptable to neurologists.

Discussion: Prehospital telestroke assessment is feasible, accurate, and superior to the PASTA score in predicting acute reperfusion therapies, presenting an effective option to guide prehospital diversion decisions.

Trial registration: The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12619001678189).anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378655&isReview=true.

Classification of evidence: This study provides Class I evidence that intra-ambulance telestroke evaluation has a greater diagnostic accuracy compared with the PASTA score performed by paramedics in distinguishing hyperacute stroke patients who are candidates for reperfusion therapy.