STEMO (Stroke Emergency Mobile Unit) delivery of tPA reduces call-to-needle time in acute stroke patients

Key study points:

  1. Use of STEMO (stroke emergency mobile unit) in administering tPA (tissue plasminogen activator) to subjects with acute ischemic stroke reduces mean call-to-needle time in comparison to in-hospital treatment (62 minutes and 98 minutes, respectively).
  2. STEMO can deliver tPA with few safety concerns including hemorrhages.
  3. Currently, a controlled prospective study is taking place to further evaluate safety

Primer: Stroke is an acute injury of the neurologic system, caused either by ischemia or hemorrhage. Ischemic strokes account for ~87% of all strokes and their subtypes include thrombosis, embolism, and hypoperfusion. Symptoms can vary from abrupt and maximal at onset to fluctuating, or diffuse, non-focal. The use of tPA (tissue plasminogen activator) in thrombolytic therapy for acute ischemic stroke patients has been recommended in the window 3 hours of since symptom onset. Unfortunately, many patients do not receive tPA within the optimal time frame and thus risk decreased effectiveness of this therapy once in-hospital.

The PHANTOM-S (Pre-Hospital Acute Neurological Therapy and Optimization of Medical care in Stroke patients) study introduced an ambulance containing a CT (Computed Tomography) scanner, point-of-care laboratory, tele-radiology via mobile technology, and an emergency-trained neurologist on board, termed as the “STEMO (stroke emergency mobile unit)”. The aim was to reduce such delays in therapy by providing therapy in pre-hospital settings.

Background reading:

1. Intravenous fibrinolytic (thrombolytic) therapy in acute ischemic stroke: Therapeutic use.

2. Clinical diagnosis of stroke subtypes.

3. Tissue Plasminogen Activator For Acute Ischemic Stroke.

This [prospective study]:  This pilot study portion of the prospective PHANTOM-S study was conducted in the emergency medical services system in Berlin, Germany during February to April 2011. STEMO was deployed to 208 suspected stroke emergencies determined via a pre-existing interview algorithm.

Of the 77 patients who gave informed consent to treatment with t-PA, a total of 53 patients (87%) had in-hospital confirmed diagnoses of stroke. Of the 45 patients (58%) whose prehospital diagnoses of acute stroke were confirmed in-hospital, 23 (51%) received tPA. Mean call-to-needle time was 62 minutes. Two patients (8%) treated with tPA developed intracranial hemorrhages within the first 7 days after stroke onset. No other adverse events were reported during the 7 days following.

In sum: The PHANTOM-S study demonstrates that stroke management in pre-hospital settings is more time-efficient (onset-to-needle time <90 minutes in 48% of patients vs. 11% of patients treated in 3 hour time window from the International Stroke Thrombolysis Registry) with minimal risk of adverse. Because this study was intended to examine feasibility and only treated a small group of patients, a controlled study with a larger sample size comparing STEMO and conventional in-hospital stroke management is ongoing. In addition, the resources and costs involved in this type of care will be compared to that of the pre-existing system. The data from such studies will contribute towards shifting the paradigm of care to pre-hospital settings, providing critical thrombolytic therapy in the earliest window possible.

Click to read the study in Neurology

By [EP] and [MS]

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