Expanding thrombectomy 6-24 hours after stroke onset
While Dr. Jovin and Dr. Nogueira called for more aggressive and less selective use of thrombectomy in patients who present within 6 hours of their stroke onset, they acknowledged that for patients who present during the 6- to 24-hour window, selection for thrombectomy should follow the rules applied in DAWN and in the more inclusive Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke (DEFUSE 3) trial (N Engl J Med. 2018 Feb 22;378:708-18). That means using imaging to confirm that the patient’s infarcted core is within the enrollment ceiling, but both neurologists also downplayed the need for the more sophisticated imaging approaches that were often used in both trials as well as in current routine practice at comprehensive stroke centers. They agreed that noncontrast CT, a widely available method, seems adequate for patient selection, based on the admittedly limited data available right now.
Dr. Nogueira cited data from the Trevo stent retriever registry, collected from nearly 1,000 U.S. acute ischemic stroke patients who underwent thrombectomy with this device. (Researchers at the conference reported updated registry data with nearly 2,000 patients with findings similar to what Dr. Nogueira referenced.) Although these patients underwent treatment before results of DAWN and DEFUSE 3 came out and before release of the new U.S. acute stroke management guidelines (Stroke. 2018 Jan 24; doi: 10.1161/STR.0000000000000158) that endorsed targeted thrombectomy for patients 6-24 hours out from their stroke onset, 278 (28%) of the registry patients underwent thrombectomy treatment during the 6- to 24-hour time window. In this subgroup, 34 patients underwent noncontrast CT to assess their infarcted core prior to thrombectomy, while the other patients underwent perfusion CT, MRI, or both. The noncontrast CT patients had recanalization rates, adverse event rates, and 90-day modified Rankin Scale (mRS) scores comparable with those of patients assessed with more advanced imaging.
Based on this, “just looking at CT only seems reasonable. Noncontrast CT is a pretty valid way to select patients,” Dr. Nogueira said.
“This is the direction we should follow to simplify the paradigm for treating beyond 6 hours,” agreed Dr. Jovin, who also called for further advances in patient selection to expand the pool of patients who qualify for thrombectomy during the 6- to 24-hour postonset period.