LAUSR

Dr. Scott and colleagues conducted a community-based, single-center, cluster randomized controlled trial in Wellington, New Zealand, comparing the diagnostic accuracy of prehospital telestroke assessments (inside the ambulance) with a modified Los Angeles Motor Scale (PASTA score) for identifying candidates for reperfusion therapies in a sample of 76 patients. They found that prehospital telestroke assessment had an accuracy of 80% compared with 60.1% for the PASTA score for identifying patients who went on to receive reperfusion therapies and concluded that such assessments present an effective option to guide prehospital diversion decisions. In response, Dr. Barber notes that whereas the paramedics in the study were instructed to transport PASTA-positive patients to the most appropriate stroke hospital, a positive PASTA score was originally intended to trigger a telephone discussion between paramedics and the on-call stroke neurologist before a decision is made to transport a patient to a thrombectomy-capable comprehensive stroke center. Responding to this comment, the authors argue that PASTA has been used in other parts of New Zealand without phone calls to neurologists, a model that is also more widely generalizable to emergency medical services around the world using other prehospital scores such as the Los Angeles Motor Scale. They note that in their study, PASTA missed 28.6% of thrombolysis recipients identified using the FAST assessment, suggesting insufficient sensitivity to reliably identify such patients, and counter that adding a telephone call after a positive PASTA assessment would only improve specificity and not sensitivity. On the other hand, PASTA showed excellent sensitivity in predicting thrombectomy use. This exchange highlights the complexities involved in the implementation and evaluation of prehospital scores in stroke systems, and the limitations that arise when scores such as PASTA are expected to identify patients eligible for any reperfusion therapy as opposed to thrombectomy alone.