麻豆传媒

SAN DIEGO -- A magnesium drip in the ambulance on the way to the hospital didn't improve stroke outcomes in a randomized trial, though the demonstration of feasibility for pivotal trials in that setting was seen as a victory.

Disability at 3 months came out the same with magnesium as with placebo, with a mean modified Rankin score of 2.7 in both groups (P=0.28), , of the University of California Los Angeles, and colleagues found.

Nor did any subgroup appear to benefit in the FAST-MAG trial, the researchers reported at the International Stroke Conference.

Magnesium dilates cerebral blood vessels to increase flow, and has been neuroprotective in randomized trials of other conditions, like preterm birth and cardiac arrest, while pre-clinical models supported use in stroke.

However, this trial definitively settled any questions that magnesium hadn't been given early enough to be effective, commented , director of acute stroke services at Massachusetts General Hospital in Boston.

"Put it back on the shelf," he told 麻豆传媒. "There's no future for magnesium in acute stroke neuroprotection."

Nevertheless, the trial was a key demonstration that pivotal phase III field trials are feasible, he and Saver agreed.

FAST-MAG was the first pre-hospital, randomized controlled trial for any condition employing physician-elicited informed consent (delivered when paramedics called from a cellphone on the scene for stroke diagnosis review) and the first phase III "golden hour" stroke trial.

In it, 74% of the 1,700 randomized patients started the study drug within 60 minutes of stroke onset.

The study procedures for stroke diagnosis, consent, and starting patients on a rate-limiting infusion of 4 grams of magnesium (continued in the hospital for 24 hours) didn't slow down paramedics at all.

In fact, the time from their arrival on the scene to the hospital door averaged 33 minutes, beating the historical average of 35 minutes for the Los Angeles area.

That achievement was despite including 40 emergency medical services provider agencies, thousands of paramedics, and 60 receiving hospitals in Los Angeles and adjacent Orange County.

"The methods developed in this trial and the patient data from this trial are going to be made publicly available so the techniques in the trial can be used to test other promising agents in the pipeline," Saver told reporters at a press conference.

The strategies can't be employed for pre-hospital thrombolytic therapy at this point, but there are starting to be trials moving in that direction, he noted, pointing to another trial presented at the conference and at the European Stroke Conference last year.

In that prospective German PHANTOM-S trial, an ambulance outfitted with a CT scanner and a neurologist trained in emergency medicine cut time to treatment by 25 minutes.

And the mobile stroke unit boosted use of clot-busting medication to 33% compared with 21% among patients who got conventional care when the specialty ambulance wasn't available (P<0.01).

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