'Magic window' opening wider?
Imaging study may redefine conventional treatment time frame for stroke
CHARLESTON -- Practitioners who treat stroke patients now have proof that perfusion imaging can better determine who is and who isn't beyond the "magic window" to restore blood flow to the brain. Lead study author Aquilla Turk, D.O., MUSC Interventional Neuroradiology co-director and neurosciences and radiology professor, described the study as a landmark turn in providing patients with treatments they may not have had otherwise. Currently, the standard of care most providers use as a treatment criterion is the four-hour "magic window."
"This study definitively shows that perfusion imaging as a patient selection criterion for endovascular therapy is a successful evaluation tool, whether patients are presenting at three hours out from their stroke or 11 hours," Turk said. "Broadly speaking, these results could transform our approach to patient selection and ultimately may mean that we will be able to treat significantly more patients and reduce the devastating burden of this disease on individuals and families."
Study results show that patients with ischemic stroke may be successfully treated with endovascular therapy well beyond the 4.5 hour treatment window today considered standard by most neurointerventional practitioners. The multi-center study evaluated the use of computed tomography (CT) perfusion imaging, regardless of time from symptom onset, in selecting patients for endovascular treatment, a technique which utilizes devices or clot-busting drugs directly at the problem site in the brain to dispel clots and restore blood flow. CT perfusion imaging is used in combination with other imaging techniques to determine which areas of the brain are irreversibly injured from a stroke, and which areas are still alive, but at great risk. From there, practitioners can better decide who is still a candidate for treatment.
According to Neurosciences clinical chairman and neurosurgery professor Sunil Patel, M.D., South Carolina had one of the highest mortality rates from stroke in the country about five years ago. Patel applauded the strides the department made to recruit and retain some of the nation's top stroke experts while bringing the infrastructure of the program up to speed. "Within this short period, we have come to offer unparalleled stroke care in this state, and now have one of the most comprehensive stroke programs in the country. South Carolinians are finally seeing greatly reduced stroke mortality rates and significantly improved outcomes after treatment," he said.
Study data collected from the Medical University of South Carolina (MUSC) in Charleston, Swedish Medical Center in Denver, Co., and the University of Florida in Gainesville, showed that out of 247 patients for whom perfusion imaging was used, 42.5 percent demonstrated good functional outcomes, which is comparable to results from all other significant trials to date which evaluated endovascular therapy conducted under eight hours. Notably, this latest study showed no significant difference in treatment outcome between patients treated less than eight hours (42.8 percent) and those treated over eight hours (41.9 percent). Additionally, immediately following treatment, restoration of blood flow was accomplished in 76 percent of patients, with a higher success rate in those treated over eight hours (81.1 percent) as opposed to those treated under eight hours (71.7 percent). All study subjects underwent mechanical thrombectomy, or treatment utilizing devices to restore blood flow.
According to the American Stroke Association, approximately 795,000 Americans suffer a new or recurrent stroke annually. Of that total, 137,000 individuals die each year from stroke, making it the fourth leading cause of death. In 2010, Americans paid approximately $73.7 billion for stroke-related medical costs and disability.