The first hour after a stroke occurs is termed the “Golden Hour” because this is the window in which a stroke victim has the best chance to not only survive but also avoid incapacitating, long-term neurological damage. Often, the first individual that attends to a stroke victim is a paramedic who usually arrive on the scene within the one hour window. UCLA researchers presented the results of an eight-year study, termed the FAST-MAG trial, which evaluated the benefits of prompt administration of intravenous (IV) magnesium. The findings were presented on February 13 at the American Stroke Association’s International Stroke Conference in San Diego.
Unfortunately, the researchers found that giving stroke patients IV magnesium within an hour of symptom onset does not improve stroke outcomes; however, the study found that, by working with paramedics in the field, IV medications can be given to stroke patients within the “golden hour.” That finding is a “game changer,” note study co-principal investigator Dr. Jeffrey Saver, director of the UCLA Stroke Center and professor of neurology at the David Geffen School of Medicine at UCLA. He added, “Stroke is a true emergency condition. For every minute that goes by without restoration of blood flow, two million nerve cells are lost. Since time lost is brain lost, we wanted to develop a method that let us get potentially brain-saving drugs to the patient in the earliest moments of onset of the stroke. If these patients don’t get protective drugs until two, three or four hours later, irreversible brain damage has already occurred.”
Rather than grumbling about the failure of the FAST-MAG trial, the investigators are now searching for new drugs and treatments that can be administered in the field to improve long-term outcomes. Dr. Saver explained that the infrastructure to treat patients quickly was created by the study and is in place; thus, it marks a major accomplishment.
The study, which was conducted from 2005 through 2013, involved collaboration between 315 ambulances, 40 emergency medical service agencies, 60 receiving hospitals and 2,988 paramedics. It found that 74% of the 1,700 study patients in Los Angeles and Orange counties were treated within the first hour, with the magnesium administered within an average time of 45 minutes. “With this study, we were able to reach the threatened brain faster than ever before,” explained co-principal investigator Dr. Sidney Starkman, co-director of the UCLA Stroke Center and professor of emergency medicine and neurology at the David Geffen School of Medicine at UCLA. He added, “The study has really opened up opportunities to treat patients in the pre-hospital setting in the earliest minutes after symptoms appear.” He noted that the study would not have been possible without the approval and confidence of the California and local emergency medical service agencies as well as the administrations of the participating hospitals.
Currently, the only immediate treatment for strokes caused by blockage of blood vessels is tissue plasminogen activator (tPA), which can dissolve clots. However, the drug cannot be given until the patient arrive at the hospital and undergoes a CT scan to rule out bleeding in the brain. Dr. Saver explained that the administration of tPA in an ambulance without a CT scan first is not an option because it could harm patients whose strokes are caused by brain bleed. (Strokes causes by blood vessel blockage are known as ischemic strokes; stokes caused by bleeding in the brain are known as hemorrhagic strokes.) He noted, however, that neuroprotective drugs can be administered in the field because they are safe for both ischemic and hemorrhagic strokes..
Magnesium was chosen for the FAST-MAG trial because it dilated blood vessels in the brain in animal studies; thus, increasing blood flow. In addition, it counteracted the damaging calcium build up that occurs in cells deprived of oxygen. Before the study began, magnesium had been approved for the treatment of medical conditions in people because it had a good safety profile.
Dr. Saver said that the FAST-MAG researchers were extremely grateful for the almost 3,000 paramedics involved in the study, as well as the emergency medicine physicians, neurologists, neurosurgeons, and nurses who participated. He said, “Now we are tasked with finding a different agent or combination of agents that can improve stroke outcomes within that golden hour. We developed a treatment platform that works and can be used around the world to test promising agents. FAST-MAG has opened a new, earlier-than-ever window for treatment that has the potential to significantly improve outcomes for the hundreds of thousands of people each year who suffer a stroke.”
Stroke is the fourth leading cause of death in the US and is a major cause of adult disability. Approximately 800,000 Americans suffer a stroke each year. On average, one American dies from a stroke every four minutes.