“The value of experience is not in seeing much, but in seeing wisely.”
― Sir William Osler

 

Deciphering signal from noise as it relates to modern stroke care can be challenging and conflicting, especially as it pertains to the out of hospital environment. In this podcast, we brought the knowledge and experience of Dr. Ben Newman: a neurosurgeon and endovascular therapy expert to discuss advances, challenges, and strategies in caring for our stroke patients.

When to Bypass

Perhaps the most challenging decision to make when presented with a patient experiencing an acute stroke is the transport decision. Should we transport them to a Comprehensive Stroke Center (CSC), or to a "thrombolytic capable center"? 

The 2018 AHA/ASA Stroke Guidelines state that:

When several IV alteplase–capable hospital options exist within a defined geographic region, the benefit of bypassing the closest to bring the patient to one that offers a higher level of stroke care, including mechanical thrombectomy, is uncertain. Further research is needed.

They also state that the  Mission: Lifeline Severity–based Stroke Triage Algorithm for EMS may be reasonable in some circumstances. This algorithm recommends, in some circumstances, transporting the patient to a comprehensive center only if the transport time is "<15 additional minutes compared with the travel time to the closest primary stroke center or acute stroke-ready hospital." In the podcast, Dr. Newman believes that the travel time past a "lytic" capable center should be limited to 20, maybe even 30 minutes. 

Where you transport stroke patients to should be determined by your local protocols and Medical Director in coordination with local experts. Here are a few considerations:

• Patients with contraindications to thrombolytics may still be candidates for thrombectomy. 
• Last Known Well (LKW) isn't much of a factor in thrombectomy decision making. Patients with a "wake up stroke" may still be thrombectomy candidates depending upon the results of CTA and perfusion imaging.
• Comprehensive Stroke Centers typically see a high volume of stroke patients and have a well established work flow that results in above average door to needle times. Transporting the patient further might result in an overall shorter time to thrombolytic administration. 
• Most patients with LVO, although candidates for thrombolytics, are less likely to respond, and may be at increased risk for intra-cerebral hemorrhage. 

When to Suspect LVO

It should be noted that the prevalence of LVO varies greatly in the literature, ranging anywhere from 5 to 50%, meaning that very There are multiple stroke severity algorithms of which even less consensus exists! Essentially, these scales that were originally developed and validated to recognize strokes have been adapted by adding percentage points to determine severity.  So, most of your stroke "screening" tools now have an associated "severity" tool. 

The bottom line is, pick one screening tool for your department, preferably the one you currently use, and use the "sister" severity tool and get really good at it, then evaluate for over or under triage. 

Our (Curbside to Bedsides) recommendation is that if your department doesn't have a standardized severity tool patients who are having classic, unequivocal stroke symptoms (dominant hemisphere deficits, gaze deviations, flaccidity, speech deficits, etc.), are likely experiencing a LVO. 

 

 

References

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