“Many stroke patients have a sudden blockage in a major artery that cannot be eliminated by clot-busting medication alone,” said interventional neurologist Dileep R. Yavagal, M.D., associate professor of clinical neurology and neurological surgery, and director of interventional neurology at the Miller School of Medicine. “Unless the clot can be removed from the blood vessel within a few hours after a stroke, the patient may survive but have a long-term disability.”
Using the Solitaire™ stent retriever, together with clot-busting intravenous tissue plasminogen activator (IVtPA) was so safe and effective that the clinical trial was halted early in February, added Yavagal, who is also co-director of endovascular neurology at the Miller School and who was the principal investigator for the University of Miami/Jackson Memorial Hospital site and served on the study steering committee for the 39-center study.
“The mounting evidence from this landmark trial and others are game changers for treating acute stroke patients,” said Ralph L. Sacco, M.D., M.S., Professor and Chairman of Neurology, and Olemberg Family Chair in Neurological Disorders.
New treatments are needed for stroke, which is a leading cause of adult disability in the United States, according to Jose G. Romano, M.D., professor of clinical neurology, and Chief of the Stroke Division. Noting that nearly 800,000 patients experience a stroke each year, Romano said clot-busting medications have been effective in preventing immediate injury when administered within 4.5 hours after a stroke. “However, clot-busting medications such as Alteplase have limited impact in those with large vessel occlusion,” he added.
The study, “Stent Retriever Thrombectomy After Intravenous tPA vs tPA Alone In Stroke,” reported the results of a phase III clinical trial of the Solitaire With the Intention For Thrombectomy as PRIMary Endovascular treatment (SWIFT PRIME) stent retrieval device, which is made by Medtronic.
The SWIFT PRIME study involved 196 patients; half were given the medication alone, and half were treated with the medication and the Solitaire device, which is a self-expanding stent typically introduced through the groin artery and navigated to the blocked artery in the brain, where it captures and retrieves the large blood clot and restores blood flow. The researchers found that a Solitaire stent retriever neurovascular thrombectomy within six hours of stroke onset was significantly better in improving patients’ functional outcomes at 90 days.
“Our early findings showed highly positive results after enrolling less than 50 percent of the planned patients,” Yavagal said. “The number needed to treat (NNT), an indicator of the effectiveness of a medical intervention, was a stunningly low four patients. That means one of every four treated patients would have a positive outcome of independence.”
SWIFT PRIME was among several concurrent trials launched worldwide to test the latest generation of devices used in the emergency treatment of clots suddenly blocking arteries in the brain (thrombectomy). “These devices can open the blood vessel much more quickly, reducing damage to the brain from lack of blood flow,” said Yavagal.
The SWIFT PRIME study was distinctive in several respects, including enrolling clinical trial participants in centers in multiple countries and health systems, including UHealth/Jackson. “As the lead clinical coordinator on this trial, it was an incredibly humbling experience to witness first-hand the reshaping of acute stroke care worldwide,” said Kevin N. Ramdas, M.D., M.P.H. (candidate), senior clinical research coordinator in the Neuroendovascular Division of the Department of Neurology.
Yavagal said the UM/Jackson team has participated in all the major clinical trials of the combination strategy, and has treated more than 300 acute stroke patients with endovascular devices since 2008. “We have been pioneers in bringing this treatment to South Florida, and have seen great outcomes in our patients,” he said. “This trial and other recent studies will allow us to expand this revolutionary treatment to larger numbers of stroke patients and help them retain independence without long-term disability.”
University of Miami