Regionwide Retrospective Survey of Acute Mechanical Thrombectomy in Tama, Suburban Tokyo: A Preliminary Report

Background and Purpose: To improve results of acute thrombectomy, the time from stroke onset to efficient recanalization must be minimized. Studies have confirmed the importance of rapid treatment, workflow, and efficient team-based care for acute thrombectomy in large vessel occlusion. This study examined the challenges facing mechanical thrombectomy in the Tama area (population, 4.3 million), a densely populated urban area of Tokyo, Japan, and analyzed retrospective data from the Tama-REgistry of Acute endovascular Thrombectomy. Methods: This study was a retrospective observational study using data from Tama-REgistry of Acute endovascular Thrombectomy, a multicenter registry of mechanical thrombectomy for acute ischemic stroke in the Tama area of Tokyo. The survey covered 396 patients with large vessel occlusion who underwent acute thrombectomy between January 2015 and March 2017. Participating facilities are 12 of the 13 recanalization therapy-capable stroke centers. Results: We analyzed 326 cases for which modified Rankin Scale score at 90 days was available, of which 264 cases were directly admitted, and 62 cases were transferred from other stroke centers. Median time from stroke onset to hospital arrival was 111 minutes, and from arrival to efficient recanalization was 135 minutes. Efficient recanalization was achieved in 257 cases (78.8%), symptomatic hemorrhage developed in 19 cases (5.8%), and modified Rankin Scale 0-2 at 90 days was seen in 129 cases (39.6%). The vast majority of patients (n = 299, 94.3%) were transferred within 10 km to the enrolling hospital. Conclusions: These results provide useful information about the emergent transfer system for patients with large vessel occlusion in a densely populated urban area.