Advances may make time window less important in stroke treatment


Patients presenting with ischaemic stroke may be successfully treated with endovascular therapy well beyond the 8-hour treatment window today considered standard by most neurointerventional practitioners. According to a study presented at the Society of NeuroInterventional Surgery (SNIS) 9th Annual Meeting (San Diego, USA, 23–27 July).

The multicentre study evaluated the use of computed tomography (CT) perfusion imaging, regardless of time from symptom onset, in selecting patients for endovascular treatment with devices or clot-busting drugs used directly at the problem site in the brain. 
Study data collected from the Medical University of South Carolina (MUSC) in Charleston, Swedish Medical Center in Denver, Colorado and the University of Florida in Gainesville, show that out of 247 patients for whom perfusion imaging was used, 42.5% showed a 90-day modified Rankin Scale score (a measure of the degree of disability in people who have suffered a stroke) of 0 – 2% (considered a good functional outcome), 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 outcomes between patients treated under eight hours (42.8%) and those treated over eight hours (41.9%).  Additionally, immediately following treatment, restoration of blood flow was accomplished in 76% of patients, with a higher success rate in those treated over eight hours (81.1%) as opposed to those treated under eight hours (71.7%). All study subjects underwent mechanical thrombectomy, or treatment utilising devices to re-open the affected vessel.

“This is truly a landmark study in that it definitively shows that perfusion imaging as a patient selection criteria for endovascular therapy is a successful evaluation tool, whether patients are presenting at three hours out from their stroke or 11 hours,” said Aquilla Turk, professor of Radiology and Neurosurgery, director of Neurointerventional Surgery of MUSC. “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 data was collected from 2007 to 2011 from patients with a mean age of 65.9 presenting with an average score of 18 on the NIH Stroke Scale (NIHSS), a standardised measure used to clinically evaluate the degree of impairment of a stroke in such areas as consciousness vision, speech, movement, language and sensation. Anyone with an NIHSS score of less than 8 was excluded from the study. The overall mean time from symptom onset to treatment start was 8 hours, with an average time to treat of 4.8 hours in the group of patients treated under 8 hours, and 16.4 hours in the group treated over eight hours. The 90-day mortality rate for study subjects was 23%. The safety and efficacy data showed that utilising an imaging based approach to patient selection is comparable to benchmark data established in all of the time-based clinical stroke trials to date.