This article is a collaboration between 鶹ý and:
Reduced disability with mechanical clot removal for large-vessel ischemic strokes -- as consistently seen across recent trials -- gave a clear mandate for use but also re-emphasized the need for speed.
"It's all about timing," said , director of the stroke program at Cedars-Sinai in Los Angeles.
Those trials -- MR CLEAN, SWIFT PRIME, ESCAPE, EXTEND-IA, and REVASCAT -- were positive whereas the prior spate -- , , and -- had been neutral in large part for that reason, facilitated by newer, easier devices that allow quicker treatment, Lyden told 鶹ý. He chaired the data safety monitoring board of the largest of the prior failed endovascular thrombectomy trials.
A workflow analysis of SWIFT PRIME, presented last week at the European Stroke Organization conference in Glasgow, Scotland, highlighted the fast times.
Door-to-groin puncture averaged 90 minutes in the trial compared with the guideline-recommended 120 minutes; and the imaging-to-puncture time was 57 minutes on average across the 29 sites in seven countries.
Groin puncture within 3 hours of onset is tough to do in real-life, routine practice, , director of the stroke program at the University of Vermont in Burlington, told 鶹ý.
, director of the UCLA Comprehensive Stroke Center in Los Angeles and principal investigator for SWIFT PRIME, offered the following tips on how to get there.
Enhance Prehospital Notification
Most regions are already on-board with calling ahead from the ambulance to prime the hospital's stroke response. The next step is to report severity, which is a key clue to strokes appropriate for thrombectomy, Saver suggested.
A score of 4 or 5 on the Los Angeles Motor Scale (LAMS) as a simple characterization of hand, arm, and facial weakness has been shown to strongly that stand to benefit from thrombectomy.
While that scale is already embedded in the Los Angeles Prehospital Stroke Screen (LAPSS) used by many paramedic systems, additional data and guidelines will likely be necessary before ambulance routing systems take the LAMS score into account in sending these patients straight to thrombectomy-capable hospitals, Saver suggested.
The initial validation of another similar prehospital scale to predict stroke severity, the was presented at the European stroke conference and online in Stroke.
While still in the early phase, Lyden noted that there's already an infrastructure in place, unlike at the start of thrombolytic clot busting decades ago.
"The only key is organization and willingness to work out a plan [for transfer to thrombectomy centers]," he said.
Commit to Speed
With that prehospital notification, the interventional team needs to be primed to come in to the hospital as soon as a possible patient is identified; not waiting until the workup confirms an appropriate candidate, Saver recommended.
Some of the trials used perfusion CT imaging to measure salvageable brain, whereas others kept to noncontrast CT and CT angiography. No clear mandate has emerged for one over the other, although the trials have suggested avoiding MRI for timeliness's sake.
The key is to commit to a set algorithm for the chosen imaging strategy and have agreed-upon milestones in evaluation of the patient for when to head to the cath lab, Saver suggested.
Some data from the MR CLEAN trial suggested general anesthesia might be a disadvantage in thrombectomy, which some suggested was due to the delays it introduced.
But in SWIFT PRIME, hospitals with a policy of doing general anesthesia for the procedure were as efficient as those with a policy of conscious sedation in all cases, Saver noted.
"General anesthesia -- if the hospital is committed to do it quickly and rapidly -- is acceptable," he said. "But once you've established your policy, then whether you're going to do conscious sedation or general anesthesia, all members of the anesthesia team must understand that time is of the essence and the patient has to get to the cath lab as fast as possible."
Feedback on how a center is doing with its times can also help, he added.
Bundle Up
Precious minutes can also be saved by keeping bundled kits in the interventional suite with all of the devices and materials needed for stent retriever use instead of spending time collecting materials, Saver pointed out.
Each 5 minutes of delay eliminated benefit for one person out of every 100 treated with thrombectomy, analysis of SWIFT PRIME showed.
MR CLEAN showed nearly an absolute 7% drop in the advantage of mechanical clot removal in achieving good functional outcome versus medical therapy alone for each additional hour from stroke onset to reperfusion.
"The importance of the message that 'time is brain' is even stronger in the thrombectomy era," Saver noted. "We have to bring all of our emergency medicine, prehospital, interventional suite, and neurology colleagues together to wring every last minute out of our systems of care."
From the American Heart Association: