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How regional stroke systems improve LVO stroke care

A paradigm shift for EMS in the era of large vessel occlusion stroke draws on success of prehospital STEMI assessment and care


By Robert Dickson, MD; Michael Aiken, EMT-P; Kevin Crocker, LP; Casey Patrick, MD and Catherine Bissell, RN

Time-sensitive emergencies is a recurrent theme in discussions about where the most impact can be made in improving prehospital patient outcomes. EMS, since its humble beginnings in 1966 with publication of the EMS White Paper; "Accidental Death and Disability: The Neglected Disease of Modern Society [1]," EMS has evolved into the largest sub-specialty of emergency medicine.

What started with recognition of the poor care for trauma patients has evolved to include the time critical importance of prehospital assessment, treatment and transportation destination decisions for STEMI and stroke. Now the specialized subtype of ischemic stroke, large vessel occlusion (LVO), is being added to the list of time sensitive emergencies where EMS actions can improve patient survival and quality of life.

Each region has its own unique challenges to timely care of patients with suspected stroke syndromes. (Photo/Allied Academies)
Each region has its own unique challenges to timely care of patients with suspected stroke syndromes. (Photo/Allied Academies)

Where we are today in developing systems of care for LVO resembles where we were with STEMI 20 years ago. Twenty years ago we began busting a few myths that existed in STEMI. Those myths were:

  • First, EMS could never be trained to perform 12 lead ECG.
  • Second, paramedics could not possibly interpret ECG’s to diagnose STEMI.
  • Lastly, no hospital would take patients directly to a cath lab on our pre-hospital diagnosis.

Now most would agree that what seemed impossible to some medical directors and service directors, is now routine and standard of care in EMS systems around the world. Just as EMS evolved in the way we treat patients with suspected ischemic chest pain we also have to revamp how we approach patients with suspected stroke to obtain the best possible outcomes for our patients.

Prehospital stroke care

Tissue Plasminogen Activator (TPA) FDA approved in 1996 was the only approved therapy for acute ischemic stroke until 2015. There is mounting evidence that in addition to TPA, mechanical embolectomy is beneficial for patients with LVO strokes.  

Five landmark trials, published in 2015, demonstrated the effectiveness of endovascular therapy with a number needed- to-treat of two to four patients to have one survive with minimal to no disability. These studies also highlight the time dependent nature of mechanical embolectomy with those receiving therapy sooner having improved odds of good outcome [2-6].

The 2015 American Stroke Association guidelines recommend endovascular therapy in addition to TPA for patients with LVO of the internal carotid artery or proximal portion of the middle cerebral artery who present less than six hours from onset of symptoms and have a National Institutes of Health Stroke Score of >6. Further recommendations include developing regional systems of care to facilitate proper diagnosis and destination dispositions for patients with suspected LVO strokes [7].

Prehospital care for LVO stroke

In 2016, the SouthEast Texas Regional Advisory Council (SETRAC) Stroke Committee and the Montgomery County Hospital District (MCHD) EMS department began a collaboration to:

  1. Validate an optimal stroke diagnostic algorithm,
  2. Evaluate the best severity criteria to predict LVO strokes, and
  3. Develop a regional stroke toolkit to address LVO stroke.

The process began at MCHD with a 2016 quality improvement analysis that revealed that a low percentage of our severe stoke patients were being transported to a comprehensive stoke centers [8]. Those findings informed an education and improvement plan.

All personnel completed a mandatory four-hour continuing education course on stroke in April, 2016. This session included presentations on stroke including the burden of disease, vascular anatomy, pathophysiology of stroke and EMS diagnosis including teaching the rapid arterial occlusion evaluation (RACE) score (figure 1).

RACE was added to the existing stroke diagnostic tool the SouthEast Texas Assessment and Transport Stroke (STATS) tool (figure 2)[8].

Prospective performance data was collected and suggested modifications were needed in the STATS diagnostic and severity guidelines (figure 3).

A stroke toolkit was produced that emphasized recommended best practices for stroke assessment and treatment, based on the American Stroke Association 2015 guidelines [7].

These care algorithms are easily modified for individual systems and follow the five R’s method of stroke evaluation developed by the MCHD clinical services team (figure 4a-d). This method follows a standard algorithm for:

  • Recognition of stroke symptoms,
  • Rule out mimics,
  • Rank for severity to determine optimal destination (primary or comprehensive),
  • Report (activate appropriate resources) and
  • Roll-out (begin treatment with minimal scene times similar to severe trauma cases).  

In the coming year our group aims to roll out a regional education plan for LVO stroke diagnosis and regional care for all of our advanced life support agencies and first responder personnel in the southeast Texas region. This training will consist of train-the-trainer sessions focusing on disease burden of stroke, stroke sub-types, LVO pathophysiology, time sensitive nature of endovascular and medical thrombolysis therapy for stroke along with the stroke diagnostic and severity criteria. The educational materials will be free open access online along with skills cards to practice assessment tools and follow up test material to assess knowledge retention. 

Improved clinical guideline compliance

Just like the challenges of STEMI diagnosis and destination determination 20 years ago, the evolution in therapy for LVO will challenge EMS providers to step up and assist in regional plans to care for these patients. After completion of training to MCHD EMS personnel we observed a steady increase in compliance with clinical guidelines on patient destination based on severity scoring.

Each region has its own unique challenges to timely care of patients with suspected stroke syndromes. The MCHD-SETRAC stroke diagnostic and therapy algorithms were designed to be easily adapted to various service delivery models. In remote systems, these tools may be useful to develop bypass or rapid transfer guidelines to ensure prompt therapy for patients with suspected LVO.

References

  1. Division of Medical Sciences, Committee on Trauma and Committee on Shock (September 1966), Accidental Death and Disability: The Neglected Disease of Modern Society, Washington, D.C.: National Academy of Sciences-National Research Council
  2. Berkhemer OA, Fransen PSS, Beumer D, et al. A Randomized Trial of Intraarterial Treatment for Acute Ischemic Stroke. New England Journal of Medicine. 2015;372(4):394-394.
  3. Mayank Goyal, M.D., Andrew M. Demchuk, M.D., Bijoy K. Menon, M.D et al. Randomized Assessment of Rapid Endovascular Treatment of Ischemic Stroke. N Engl J Med 2015; 372:1019-1030
  4. Bruce C.V. Campbell, M.D., Peter J. Mitchell, M.D., Timothy J. Kleinig, M.D et al. Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging Selection. N Engl J Med 2015; 372:1009-1018
  5. Saver JL, Goyal M, Bonafe A, et al. Stent-Retriever Thrombectomy after Intravenous t-PA vs. t-PA Alone in Stroke. New England Journal of Medicine. 2015;372(24):2285-2295.
  6. Tudor G. Jovin, M.D., Angel Chamorro, M.D., Erik Cobo, Ph.D et al. Thrombectomy within 8 Hours after Symptom Onset in Ischemic Stroke. N Engl J Med 2015; 372:2296-2306
  7. 2015 AHA/ASA Focused Update of the 2013 Guidelines for the Early Management of Patients with Acute Ischemic Stroke Regarding Endovascular Treatment
  8. Dickson, R MD, Gleisberg, G  MBA, NREMT-B, Gillum,L MPH, LP. A Paradigm Shift in EMS Evaluation of Stroke: Current Practice & the Way Forward in an Era of Novel Endovascular Therapy for Large Vessel Occlusion (LVO) Strokes. Journal of Emergency Medical Services August 2016

About the author
Robert Dickson, MD, FAAEM, FACEP, FACEM, is assistant professor of Emergency Medicine, Baylor College of Medicine; and medical director, MCHD-EMS.

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