Broadly implementing stroke embolectomy faces hurdles

Another issue is volume. “Telemedicine may allow broader use of [more sophisticated] imaging, but if a place is only doing 20 endovascular procedures a year, they won’t have the best outcomes. Most small hospitals that today give patients TPA see 20 cases or fewer a year, and perhaps 5 patients will have a large-vessel occlusion,” Dr. Derdeyn said.

Before the new reports documenting the safety and efficacy of endovascular treatment, “we did not have the justification to bypass primary stroke centers and take patients directly to comprehensive stroke centers,” Dr. Khatri said. Now, “there is clear evidence that patients with severe strokes should not go to the nearby primary stroke center” but instead head directly for the centers capable of performing embolectomy. But Dr. Khatri also acknowledged that a complex calculation is needed to balance the trade off: Is it better to take a stroke patient more quickly to a nearby hospital that can only start TPA and perhaps later forward the patient to an embolectomy-ready hospital, or to transport the patient somewhat further to a facility able to deliver both TPA and embolectomy?

Dr. Khatri said that, in the Cincinnati area, “we have scheduled a retreat for March to start to plan how this will happen.” Her region includes just one comprehensive stroke center that already performs endovascular treatments for stroke, at the University of Cincinnati, which sits amid 16 other hospitals that perform acute stroke care and can administer TPA. “Ambulance-based triage will be a big issue,” she predicted.

Other aspects of improved triage will be training ambulance personal to better identify the more severe stroke patients who will most likely need endovascular treatment and improving communication between ambulance crews and receiving hospitals to further speed up a process that depends on quick treatment to get the best outcomes.

The ideal is “having paramedics call and tell us what is happening [in their ambulance] and give us as much information as possible so we can start planning for the patient’s arrival. Most hospitals don’t do this now; relatively few have their system well organized,” Dr. Goyal said in an interview. A finely orchestrated emergency transport system and hospital-based stroke team was part of the program developed at the University of Calgary by Dr. Goyal and his associates and which they credited with contributing to the successful embolectomy trial they led, called ESCAPE (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times)(N. Engl. J. Med. 2015 Feb. 11 [doi:10.1056/NEJMoa1414905]). Dr. Goyal said that he is now visiting hospitals around the world to assist them in setting up stroke-response systems that mimic what was successful in Calgary and the other centers that participated in ESCAPE.

Improving triage with better screening

A key to improved ambulance triage will be identifying a simple, evidence-based method for assessing stroke severity that ambulance personnel can use to determine what sort of care a patient needs and where the patient needs to go to. Although a couple of U.S. sites have begun pilot studies of field-based CT units that allow stroke patients to undergo imaging-based assessment in the field, clinical evaluation remains the main tool used in the ambulance.

One possible tool is the Los Angeles Motor Scale (LAMS), a stroke-assessment scoring system developed by Dr. Saver and his associates for ambulance use about a decade ago (Prehosp. Emerg. Care 2004;8:46-50). “A LAMS score of 4 or 5 [on a scale of 0-5] is a good starting point, and with time it might improve,” Dr. Goyal said.

The National Institutes of Health Stroke Scale (NIHSS) is a clinical assessment tool not designed for prehospital use, but a new analysis reported at the meeting showed value in using the NIHSS to identify stroke patients who are good candidates for endovascular treatment, further suggesting that a simple screening tool could potentially work in the ambulance to identify patients who probably need embolectomy.

The new analysis combined data from two randomized trials: The IMS (Interventional Management of Stroke) III trial, the results of which, published in early 2013, showed no incremental benefit of endovascular therapy plus TPA over TPA alone for patients with acute ischemic stroke (N. Engl. J. Med. 2013;368:893-903); and the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) trial, the results of which, published in January, showed a significant incremental benefit from endovascular treatment – it was the first of the four studies recently reported to show this benefit (N. Engl. J. Med. 2015;372:11-20).