Introduction/Purpose Successful revascularization following endovascular therapies for acute stroke has been defined inconsistently across studies. Technical success has been noted by angiography, although methods have varied considerably. Local site readings rather than core labs have been used, employing different scales, divergent definitions, and unqualified thresholds to ascribe success. Most importantly, revascularization success is rarely complemented by correlation with symptomatic intracranial hemorrhage (SICH) or clinical outcomes. Recent introduction of stentriever devices and potentially improved revascularization rates draws greater attention to specific definitions of such revascularization metrics. The Trevo® System utilizing Stentriever Technology is a novel device for thrombus removal recently reported in TREVO (Thrombectomy REvascularization of large Vessel Occlusions in acute ischemic stroke) Study. We tested a broad array of revascularization success definitions in TREVO to illustrate these distinct measures.

Materials and Methods TREVO was a multicenter, prospective, single-arm trial evaluating mechanical thrombectomy with the Trevo System across seven European sites, enrolling subjects aged 18–85 with NIHSS of 8–30 and treatment within 8 h from symptom onset. TREVO primary endpoint was target vessel revascularization, defined as TICI≥2a, read by the independent angiography and imaging core lab. Central angiography measures of target lesion location and TICI were compared to local readings. A battery of core lab measures were also analyzed, including SICH and clinical outcome endpoints of mRS 0–2 at 90 days, independently adjudicated.

Results TREVO enrolled 60 subjects (median age 65 years and median NIHSS 18). TICI was measured post-device and at procedure end (final). Post-device, site and core lab agreed exactly in 46.7% (45.0% at final), while the site reported better scores than core lab in 36.7% post-device (50.0% at final), and lower scores than core lab in 16.7% (3.3% at final). Greatest discrepancy resulted from cases with site readings of TICI 3 and corresponding core lab readings of TICI 2b. Overall, good agreement between site and core lab occurred with designation in location of target occlusion (90%), with core lab using a more distal reference in 5 and a more proximal reference in 1. Revascularization post-device (TICI≥2a) was 76.7% by site and 90.0% by core lab, with final success of 90.0% by site and 91.7% by core. Success defined by core TICI≥2b was 72% after device use and 78% final. The core lab also graded TIMI revascularization with success obtained in 74.1% post-device and 79.3% final. Final revascularization success without SICH defined by core lab was achieved in 83.3% (TICI≥2a) and 70% (TICI≥2b), with 72.4% for TIMI 2/3. Good clinical outcomes (day 90 mRS 0-2) occurred in 62.3% with core lab TICI≥2a final success and 60.0% with core lab TICI≥2b final success. Correlation between revascularization measures and clinical outcomes was good for all angiographic measures, yet strongest for final TIMI 2/3 (63.4%).

Conclusion TREVO demonstrates the high rates of revascularization success with novel Stentriever technology, substantiated by a broad range of metrics. Discrepancies in the definition of revascularization success illustrated by these measures should prompt similar analyses of recent and ongoing multicenter studies.

Competing interests D Liebeskind: NIH-NINDS. Concentric Medical, CoAxia. O Jansen: Concentric Medical. G Walker: Concentric Medical. J Macho: None. M Killer: None. N Wahlgren: Concentric Medical.