Researchers have upped the ante on the “golden hour” concept in stroke with their finding that ultra-early stroke intervention is a reachable target.
The FAST-MAG trial, originally designed to test magnesium as a neuroprotective agent, had 12.1% of 1,680 stroke patients treated by paramedics within 30 minutes of the time they were last known to be well, according to Fatima Pariona-Vargas, MD, of Peru’s National University of Cajamarca School of Medicine, and colleagues.
Magnesium administration within this “platinum half-hour” did not result in better 3-month functional outcomes. “However, once a beneficial therapy able to be started in ambulances becomes available, platinum half hour treatment is likely to be associated with maximal intervention benefit,” the authors argued in their paper in Stroke.
Given the precious minutes spent waiting for EMS to arrive on the scene and transport the patient, prehospital treatment is probably the only practical way to employ stroke interventions within the platinum half-hour, the researchers acknowledged.
The 12.1% rate of treatment within 30 minutes by the FAST-MAG paramedics is “very impressive,” said James Grotta, MD, a vascular neurologist at Memorial Hermann Health System and director of the Houston Mobile Stroke Unit.
“The study underscores the importance and potential value of moving treatment into the prehospital setting,” he said MedPage Today.
Neuroprotective agents would theoretically fit the bill for safe, ultra-early prehospital treatment of hemorrhagic and ischemic strokes alike. The hope is that the agents would allow regular ambulances to skip the imaging required to distinguish between the two when applying intravenous (IV) thrombolysis and other treatments.
A good neuroprotectant might buy rescuers more time for other therapies once they confirm that the patient has a hemorrhagic or ischemic stroke, said stroke neurologist Tudor Jovin, MD, of Cooper Medical School of Rowan University in Camden, New Jersey, in an interview.
Yet researchers have failed, time and time againto identify a good agent.
NA-1 is one neuroprotectant still currently under investigation in the FRONTIER trial.
Although FAST-MAG had failed to show efficacy for prehospital IV magnesium ≤2 hours of stroke onset, magnesium, being a glutamate antagonist, might still have neuroprotective effects revealed if administered very early and studied in a larger sample, Grotta suggested.
As for speedy reperfusion therapy, he said that tenecteplase (TNKase) shows promise for fast administration – perhaps feasible in the first 30 minutes.
“I think that in acute stroke treatment, we’re entering a new era where these kinds of approaches are becoming feasible,” Jovin said.
He noted that besides prehospital therapies, there also needs to be faster detection of stroke in the field. To that end, devices are being developed to detect strokes when they happen. “That’s something we used to think was science fiction. It looks more and more like reality – not yet in wide use, but hopefully soon,” he said.
Pariona-Vargas and colleagues had conducted an exploratory analysis of the phase III FAST-MAG trial.
Study participants had a median age of 69 years, and the group included approximately 45% women. Patients scored a median 4 on the prehospital Los Angeles Motor Scale and 8 on early-hospital NIH Stroke Scale deficits.
In FAST-MAG, certain patients were more likely to be treated in the platinum half-hour:
- Acute cerebral ischemia: those with severe motor deficits on first prehospital assessment and younger age
- Intracranial cranial hemorrhage: women, non-Hispanic people, and people with more severe motor deficits
Jovin highlighted the paramedics’ high rate of correct diagnosis of vascular emergency, as only 2.5% of FAST-MAG patients turned out to be stroke mimics.
The study authors acknowledged that they lacked routine early vessel imaging results after hospital arrival and follow-up imaging. This prevented them from assessing the impact of large vessel occlusion on early presentation, and also left them in the dark regarding post-arrival infarct growth and hematoma expansion.
“These data set the stage for future clinical trials to test the type of prehospital treatments that will be required to reach stroke patients during this crucial platinum time window,” maintained Anthony Kim, MD, MAS, medical director of the University of California San Francisco Comprehensive Stroke Center.
He said that in the meantime, EMS agencies and emergency medicine departments are already using other strategies – from improving public awareness of stroke symptoms to revamping prehospital triage and routing protocols – to cut down time to treatment for stroke patients.
“The bottom line is one would expect better outcomes with earlier treatment,” Grotta said.
FAST-MAG had been funded by an NIH grant.
Study co-authors disclosed relationships with Cerenovus, Medtronic, BrainsGate, BrainQ, Rapid Medical, Genentech, and Stryker.
Pariona-Vargas, Jovin, and Kim had no relevant disclosures.
Grotta reported consulting for companies that make mobile stroke units.