DEFUSE 3 Shows Effectiveness of Stroke Thrombectomy to 16 Hours, Utility of Perfusion Imaging
January 24, 2018—The National Institutes of Health (NIH) announced that the results of the DEFUSE 3 trial were presented at the International Stroke Conference 2018, held January 24–26 in Los Angeles, California and published online by Gregory W. Albers, MD, et al in The New England Journal of Medicine.
The large study conducted at 38 centers across the United States was funded by NIH's National Institute of Neurological Disorders and Stroke (NINDS StrokeNet, which is a network of hospitals providing research infrastructure for multisite clinical trials.
According to NIH, DEFUSE 3 demonstrated that thrombectomy up to 16 hours after symptom onset in selected patients led to improved outcomes compared with standard medical therapy. NIH ended the study early on the recommendation of the independent Data and Safety and Monitoring Board because of overwhelming evidence of the benefit from the clot removal procedure.
Walter Koroshetz, MD, Director of NINDS, commented in the NIH announcement, "These striking results will have an immediate impact and save people from life-long disability or death. I really cannot overstate the size of this effect. The study shows that one out of three stroke patients who present with at-risk brain tissue on their scans improve, and some may walk out of the hospital saved from what would otherwise have been a devastating brain injury."
In the study, perfusion MRI or CT scans were analyzed using RAPID, an automated analysis software. The DEFUSE 3 investigators identified patients thought to have salvageable tissue up to 16 hours after stroke onset. Patients were randomized to either receive endovascular thrombectomy plus standard medical therapy or medical therapy alone.
As NIH noted, endovascular thrombectomy is currently approved for use up to 6 hours after onset of stroke symptoms.
The DEFUSE 3 investigators found that this intervention can be effective up to 16 hours after symptoms begin in this select group of patients. The patients in the thrombectomy group had substantially better outcomes 90 days after treatment compared with those in the control group. For example, 45% of the patients treated with the clot removal procedure achieved functional independence compared with 17% in the control group.
In addition, thrombectomy was associated with improved survival: 14% of the treated group died within 90 days of the study, compared with 26% in the control group.
In the NIH's announcement, Dr. Albers commented, "Although stroke is a medical emergency that should be treated as soon as possible, DEFUSE 3 opens the door to treatment even for some patients who wake up with a stroke or arrive at the hospital many hours after their initial symptoms." Dr. Albers is Professor of Neurology and Neurological Sciences at Stanford University School of Medicine and Director of the Stanford Stroke Center in Stanford, California.
NIH noted that DEFUSE 3 builds on results from the two earlier DEFUSE studies as well as the DAWN trial, which used perfusion imaging technology to identify patients most likely to benefit from interventions such as thrombectomy. Those studies suggested that the advanced brain imaging could identify which patients could benefit from restoring blood flow in an extended treatment window.
In an interview with Endovascular Today, DEFUSE 3 investigator Scott E. Kasner, MD, commented, "The incredibly impressive results of DEFUSE 3 along with the recent results of DAWN are already changing practice and benefitting patients around the world. The extended time window for acute stroke therapy is the biggest advance in decades. The big challenge for us all is figuring out how to get stroke patients to comprehensive stroke centers in time to deliver this intervention." Dr. Kasner is a neurologist with the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, Pennsylvania.