• Cerebrovascular Disease
• Nursing Clinical Trials

A novel and innovative neuroprotective stroke treatment trial is underway in Los Angeles County that could impact 50% of the 600,000 patients diagnosed with ischemic stroke each year in the United States. The aim of the study is to demonstrate that paramedic initiation of intravenous magnesium sulfate (MgSO₄) within 2 hours of symptom onset improves the long-term functional outcome of hyperacute stroke patients. Jeffrey L. Saver, MD, David Geffen School of Medicine, Los Angeles, CA, presented the initial findings of the Field Administration of Stroke Therapy-Magnesium (FAST-MAG; NCT00059332) Phase III Trial. The results that were discussed in this poster involved 719 (55.3%) of the 1,298 planned patient enrollment into the multicenter, randomized, double-blind, placebo-controlled trial.

If given early enough, MgSO₄ reduces infarct volume, inhibits neuronal death, and attenuates motor impairment in animal models of cerebral ischemia [Enomoto T et al. Clin Calcium 2004]. A previous proof-of-concept study that involved 20 patients showed that field initiation of MgSO₄ to ischemic or hemorrhagic stroke patients is feasible and safe. Good functional outcome at 3 months (Rankin Scale Score ≤2) occurred in 60% of the treated patients [Saver JL et al. Stroke 2004]. However, early initiation of neuroprotective agents after stroke onset is crucial to success.

In the present study, suspected strokes were identified by the Los Angeles Prehospital Stroke Screen (LAPSS) method. Stroke severity was measured using the Los Angeles Motor Scale (LAMS), a 5-point prehospital deficit scale that characterizes pretreatment stroke severity. Patients were included in the study if they were aged 40 to 95 years, symptom onset occurred within 2 hours of treatment initiation, and a deficit was present at ≥15 minutes. Patients who were in a coma or who had rapidly improving neurologic deficits, pre-existing neurologic conditions and/or psychiatric or advanced systemic disease were excluded from the study. All patients were ambulance-transported. Prehospital explicit informed consent was obtained by cell phone. Paramedics administered an intravenous loading dose of MgSO₄ or matched placebo in the field at 4 grams over 15 minutes. In the emergency department, a maintenance infusion of 16 grams MgSO₄ or matched placebo was given over 24 hours. Patient demographics and baseline characteristics are shown in Table 1.

The median time to study drug initiation from stroke onset was 46 minutes, the mean time of paramedic arrival to drug initiation was 30 minutes, and mean time from paramedic arrival and the patient's arrival in the emergency department was 35 minutes. Treatment was initiated within 1 hour of stroke onset in 73% and between 1 to 2 hours in 25% of patients. The primary study endpoint is the modified Rankin Scale (mRS) score, assessed 3 months poststroke. The Cochran-Mantel-Haenszel test will be used to compare outcomes between the MgSO₄ and placebo treatment groups. These results will be presented in a future report.

Dr. Saver concluded that prehospital administration of neuroprotective agents substantially reduces on-scene-to-needle time. He listed a number of innovative firsts for the FAST-MAG trial: first “golden” hour (<1 hour) stroke treatment trial; first acute (<3 hr) neuroprotective stroke treatment trial; first trial of neuroprotective drugs before recanalization therapies; first prehospital stroke RCT; and first prehospital RCT for any condition that employed physician-elicited informed consent.

• © 2009 MD Conference Express