Pre-Hospital Start of IV Thrombolysis Might Result in Improved Functional Outcome in Stroke Patients. Interview with:
Dr Alexander Kunz MD
Department of Neurology
Charité-University Medicine Berlin
Berlin, Germany What is the background for this study?

Response: Systemic thrombolysis with tissue plasminogen activator (tPA) in acute ischemic stroke has been an approved therapy for over 20 years now. To date, tPA can be administered to eligible patients within a 4.5 hours time window after the onset of symptoms. Results from large thrombolysis trials and meta-analyses have shown, that the beneficial effects of tPA are inversely correlated with the delay from symptoms onset to start of tPA treatment. This relationship is frequently summarized in the slogan “Time is brain!”

Currently, several research groups are evaluating the concept of pre-hospital thrombolysis using a mobile stroke treatment unit (MSTU) in order to achieve significant reductions in onset-to-treatment delays. MSTU are specialized ambulances equipped with a CT scanner and a mini-laboratory.

In Berlin, Germany, we have been operating an MSTU (stroke emergency mobile vehicle, STEMO) since 2011. Previous studies had shown that start of tPA treatment was 25min earlier when patients were cared by STEMO than within conventional care, i.e. admission to hospital by regular ambulance and in-hospital tPA treatment. However, these studies did not prove, that earlier treatment in STEMO is associated with better outcome. Therefore, the aim of the current study was to compare 3-month functional outcome after tPA in patients with acute ischemic stroke who received STEMO care vs conventional care. What are the main findings?

Response: Our main findings are:
• Mean onset-to-treatment time was now 33 min shorter in patients of the STEMO group than in patients with conventional care.
• Ten time more patients in the STEMO cohort received tPA within 60 min of symptoms onset.
• In unadjusted analysis, the difference in primary outcome (i.e. no or minor functional deficit after three months) between treatment groups (STEMO care vs conventional care) was not significant. However, the secondary outcomes (i.e. survival without severe disability and mortality) were more favorable for patients in the STEMO group.
• After adjusting for co-variables, STEMO care had a higher probability of survival without or with minor deficit (primary outcome) after 3 months but this result did not reach the predefined level of significance (p=0.052). Secondary outcomes such as survival without severe disability (p<0.01), mortality (p=0.052) or functional outcome across the entire mRS range (p<0.01) were also favoring STEMO treatment.
• Safety outcomes did not differ significantly between patients in the STEMO group and those in the conventional care group neither for intracranial hemorrhage nor for 7-day mortality.

In summary, our results suggest that pre-hospital start of intravenous thrombolysis might result in improved functional outcome in patients. What should readers take away from your report?

Response: The data of our study are in strong support of published data from large randomized controlled tPA trials and from meta-analyses showing that the earlier tPA is administered to eligible patients the better the outcome. Even though the time window for tPA treatment is 4.5 hours after symptoms onset, all efforts should be made to minimize treatment delays. Mobile stroke treatment units (MSTU) are adequate tools to implement significant reductions in onset-to-treatment times. Using the MSTU concept allows us to treat approximately one third of patients within the ‘Golden Hour of ischemic stroke’ (i.e. within 60min after onset). What recommendations do you have for future research as a result of this study?

Response: Our study has several limitations, that are mainly related to the methodology of registry-based comparisons. Nevertheless, these are the best outcome data on pre-hospital thrombolysis available to date. The validity of our outcome results has to be proven in large randomized controlled trials. Future trials on pre-hospital stroke care should therefore additionally analyze long-term outcomes of stroke patients who are eligible for invasive treatment such as mechanical thrombectomy or hematoma evacuation. Faster diagnosis in MSTU helps to deliver patients to appropriate hospitals with corresponding treatment facilities and avoids unnecessary time delays. Is there anything else you would like to add?

Response: In addition to the apparent benefits, the MSTU concept promises to serve as an ideal research platform for new diagnostics or new treatment options in human acute stroke. This is because patients with acute stroke access the MSTU at a very early stage of their disease and a specialized team is always aboard. Thank you for your contribution to the community.


Functional outcomes of pre-hospital thrombolysis in a mobile stroke treatment unit compared with conventional care: an observational registry study
Kunz, Alexander et al.
The Lancet Neurology , Volume 15 , Issue 10 , 1035 – 1043

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on August 24, 2016 by Marie Benz MD FAAD