Clinical Trial of the New Stent Retriever Tron FX for both Proximal and Distal Intracranial Large Vessel Occlusions

•We report a clinical trial of the Tron FX stent retriever, including the smallest size of 2/15 mm for distal intracranial LVO.•The Tron FX were used as the first-line device.•The overall rate of mTICI grade 2a–3 was 80.0% (86.7% with 2/15 mm), and a 90-day mRS ≤ 2 or improvement of NIHSS ≥ 10 was achieved in 66.7% of cases (80.0% with 2/15 mm).•The overall 90-day mortality rate was 8.0%, and symptomatic intracranial hemorrhage occurred in 2.0% of cases. In all of randomized controlled trials of mechanical thrombectomy, the target vessels were proximal. Herein we report a clinical trial of the Tron FX stent retriever, including the smallest size of 2/15 mm for distal intracranial large vessel occlusion (LVO). Eligible patients presented within 8 h of onset with proximal or distal LVOs, and the Tron FX 4/20 mm or 2/15 mm were used as the first-line device. The primary endpoints were rate of modified Thrombolysis in Cerebral Infarction (mTICI) grade 2a–3 immediately after using Tron FX only, and mortality rate 90 d. We compared the outcomes between sizes 4/20 and 2/15 mm. The clinical trial was conducted in 50 cases, of which 44% presented with distal LVO and 15 cases were treated using only Tron FX 2/15 mm. The overall rate of mTICI grade 2a–3 was 80.0% (75.8% with Tron FX 4/20 mm, and 86.7% with 2/15 mm), and a 90-day modified Rankin Scale ≤ 2 or improvement of National Institute of Health Stroke Scale after thrombectomy ≥ 10 was achieved in 66.7% of cases (61.3% with Tron FX 4/20 mm, and 80.0% with 2/15 mm). The overall 90-day mortality rate was 8.0%, and symptomatic intracranial hemorrhage within 24 h occurred in 2.0% of cases. In this clinical trial using the Tron FX, which included the size of 2/15 mm for distal LVO, its efficacy was similar and its safety was superior compared with previous studies.