Study Results Show That Minimally Invasive Therapy is Successful for Over Two-Thirds of Stroke Patients Treated Outside the Standard Eight-Hour Window
Findings May Potentially Lead to New Approach to Stroke Treatment
BOCA RATON, Fla., July 30 /PRNewswire-USNewswire/ — When minimally invasive endovascular (through the vessel) therapy made its debut two decades ago, stroke care underwent a major shift as the “window of treatment” for patients suffering a stroke was expanded to eight hours within symptom onset, rather than the standard three-hour window required by the FDA-approved intravenous tPA therapy. Now, a new retrospective, multi-center study shows that endovascular therapy beyond the eight-hour window restored blood flow in the brain in approximately 74 percent of patients suffering ischemic (caused by a clot) stroke. Presented today at the Society of NeuroInterventional Surgery (SNIS) 6th Annual Meeting in Boca Raton, FL, the data suggests that this treatment is safe and potentially leads to improved outcomes for a select number of late-presenting patients, including those who awake with stroke symptoms.
According to lead author Raul Nogueira, M.D., Assistant in Neurology and Radiology at Massachusetts General Hospital — Harvard Medical School, presentation beyond eight hours of symptom onset has traditionally been the single most important factor in excluding patients from stroke treatment. Thus, continued Nogueira, when brain imaging studies revealed that a significant number of late-presenting stroke patients showed evidence of salvageable brain tissue in the area of the stroke, it was an important avenue to pursue. This meant that endovascular therapy (performed by neurointerventional specialists who use drugs or mechanical devices inserted through a catheter or narrow tube that is threaded up through the vessels directly to the problem site to dispel the clot) could potentially be utilized successfully in these patients.
“As we considered the possibilities, it became an exciting proposition to pursue our hypothesis,” said Nogueira. “Traditionally, these patients had been deemed untreatable. But if the therapeutic window could be expanded, these findings could make a significant impact on the future of stroke treatment.”
The study included a consecutive case series of 237 patients whose first angiography (a diagnostic test that infuses the blood vessels with dye in order to clearly visualize the vessel structures) confirming a clot in the brain was performed later than eight hours from the last time the patient was seen well. All patients were identified from prospectively acquire databases at 10 high volume academic stroke centers across the United States.
Of the 237 study participants, 49 percent were males and 51 percent were females, with a mean (or average) age of 64 years and whose mean time from last seen well to t reatment was 15 hours. On the standard National Institute of Health Stroke Scale (NIHSS) — a test that uses baseline data to determine severity of a stroke and projected outcome — participants registered a mean score of 15 (any score over 10 is associated with a serious stroke). Various endovascular treatments were used, including: clot-dissolving drugs in 46 percent of the cases; the MERCI Retriever, a clot-removal device, in 62 percent of cases; and other mechanical instruments, including the recently FDA-approved Penumbra Device, in 36 percent of cases.
Beyond the immediate results that showed an overwhelming success in restoring blood flow, follow-up at 90 days in 198 patients indicate that 93 (47 percent) patients registered good outcomes (meaning patients could be functionally independent) and 123 (62 percent) patients reflected acceptable outcomes. Approximately nine percent suffered a symptomatic brain hemorrhage and the overall mortality rate was 22 percent. When analyzing what factors were most closely associated with favorable outcomes, successful restoration of blood flow, younger age, lower stroke severity (as indicated by the NIHSS), and male gender were identified.
According to Nogueira, the study serves as preliminary data for DAWN, a prospective randomized trial designed to assess the benefit of this approach as compared to standard medical therapy. “We look forward to exploring this preliminary data more in-depth in order to bring more clarity to the treatment of late-presenting stroke patients. The possibilities are exciting, as these findings could very well mean that thousands of patients who would not have been previous candidates for treatment could benefit from therapies that could restore their quality of life.”
Stroke is the third leading cause of death in the United States, Canada, Europe and Japan. According to the American Stroke Association, approximately 800,000 Americans each year suffer a new or recurrent stroke. Americans will pay close to $68.9 billion in 2009 for stroke-related medical costs and disability.
SNIS members are neurointerventional practitioners with backgrounds in neuroradiology, neurosurgery and neurology that come together in the shared discipline of neurointerventional surgery. Our practitioners specialize in minimally invasive and endovascular procedures to treat stroke, aneurysms, carotid stenosis and spine fractures. Over the past two decades, our physicians have made numerous contributions to the neurosciences including: advancing stroke treatment through catheter based therapy; innovating endovascular coiling for aneurysms; pioneering interventional procedures to treat fractures in the spine; and initiating the first-ever stroke registry to track procedural success in the treatment of acute stroke. More information on SNIS and our members’ treatment specialties may be found at www.snisonline.org.
SOURCE Society of NeuroInterventional Surgery