From the Journals

Mobile stroke unit had clinical impact on EVT



In its first year of operation, a mobile stroke unit in Melbourne demonstrated substantial savings in time to commencement of both thrombolysis and endovascular thrombectomy (EVT), results from a prospective study showed.

“While previously published data from MSU [mobile stroke unit] services in Europe and North America show substantial reductions in time to thrombolysis of approximately 30-45 minutes, little is known about the clinical impact on EVT,” first author Henry Zhao, MBBS, and colleagues wrote in a study published in Stroke.

Launched in November 2017, the Melbourne MSU is based at a large comprehensive stroke center and operates with a 20-km radius, servicing about 1.7 million people within the city of Melbourne. It is staffed with an onboard neurologist or senior stroke fellow who provides primary assessment and treatment decisions, a stroke advanced practice nurse who provides clinical support and treatment administration, a clinician who provides CT imaging, and advanced life support and mobile intensive care paramedics who provide transport logistics and paramedicine support. For the current analysis, MSU patients who received reperfusion therapy were compared with control patients presenting to metropolitan Melbourne stroke units via standard ambulance within MSU operating hours. The primary outcome was median time difference in first ambulance dispatch to treatment, which the researchers used quantile regression analysis to determine. Time savings were subsequently converted to disability-adjusted life years (DALY) avoiding using published estimates.

Dr. Zhao of the Melbourne Brain Centre and department of neurology at Royal Melbourne Hospital and his colleagues reported that, in its first year of operation, the Melbourne MSU administered prehospital thrombolysis to 100 patients with a mean age of nearly 74 years. More than half of the patients (62%) were male. Compared with controls, the median time savings per MSU patient was 26 minutes for dispatch to hospital arrival and 15 minutes for hospital arrival to thrombolysis (P less than .0010 for both associations). The calculated overall time saving from dispatch to thrombolysis was 42.5 minutes.

Over the same time period, 41 MSU patients with a mean age of 76 years received EVT dispatch-to-treatment time saving of 51 minutes (P less than 0.001). This included a median time saving of 17 minutes for EVT hospital arrival to arterial puncture for MSU patients (P = .001). Overall estimated median DALYs saved through earlier provision of reperfusion therapies were 20.9 for thrombolysis and 24.6 for EVT.

“The benefit in EVT patients was primarily driven by prehospital MSU diagnosis of large vessel occlusion, which enabled bypass of a local non-EVT center directly to a comprehensive stroke center in almost 50% of patients with large vessel occlusion,” the researchers wrote. “Even when patients were located close to an EVT center, MSU pre-notification and facilitated workflows achieved a reduction in hospital arrival to arterial puncture by one-third. Furthermore, the time saving was seen despite the majority of EVT patients receiving repeat imaging in hospital to visualize the extracranial circulation.”

The study is scheduled to be presented at the International Stroke Conference on Feb. 20.

The Melbourne MSU received funding from the Australian Commonwealth Government, Victorian State Government, Royal Melbourne Hospital Neurosciences Foundation, Stroke Foundation, the Florey Institute of Neurosciences and Mental Health, the University of Melbourne, Boehringer Ingelheim, and private donation. Dr. Zhao disclosed that he has received grants from the Australian Commonwealth Government and the University of Melbourne and personal fees from Boehringer Ingelheim.

SOURCE: Zhao H et al. Stroke. 2020 Feb 12. doi: 10.1161/strokeaha.119.027843.

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