Trends in Endovascular Reperfusion Therapy for Acute Stroke after Introduction of Mechanical Thrombectomy Devices: Japanese Registry of NeuroEndovascular Therapy (JR-NET)3

In Japan, the era of thrombectomy for acute stroke started when the Merci retriever was approved in 2010 and the Penumbra system in 2011. New-generation Penumbra catheters (MAX series) and stent retrievers were introduced in 2013 and 2014, respectively. The aim of this study was to clarify the general status and trends in endovascular reperfusion therapy for stroke in Japan from 2010 to 2014. We extracted a total of 3705 patients (72.1 ± 12.2 years, 1482 women) from a nationwide study of patients receiving any neuroendovascular treatment, the Japanese Registry of NeuroEndovascular Therapy 3. Reperfusion therapy resulted in a successful reperfusion rate of 59%, and 31% of patients achieved a favorable outcome at 30 days of onset. The frequency of Merci-including procedures increased to 52% in the first half of 2011, but conversely decreased to 1% in the second half of 2014. The frequency of Penumbra-including procedures increased from 18% in the second half of 2011 to 67% in the first half of 2014, decreasing to 38% in the second half of 2014. The reperfusion rate and 30-day clinical outcomes remained almost unchanged until June 2013, and started to improve thereafter, coincident with the introduction and spread of newer-generation devices. The rate of successful reperfusion reached 71–76%, and 36–38% of patients achieved a favorable outcome in 2014. After multivariate adjustment for preprocedure variables, the calendar period from 2013 to 2014 was significantly associated with improvement in reperfusion rates and clinical outcomes.