Abstract 84: Collaterals Drive Reperfusion in Stratis

Abstract

Background: Collateral circulation to the ischemic territory is a pivotal factor in outcomes after acute ischemic stroke. Extent of angiographic collaterals prior to endovascular therapy has been linked with reperfusion in previous trials, yet the mechanism remains unclear. We analyzed whether downstream collateral grade influences the pace and degree of ultimate reperfusion. Methods: The angiography dataset collated by the STRATIS Core Lab was analyzed to relate the grade of collateral circulation (ASITN) with adjudicated procedural time metrics to exact time of first TICI ≥ 2A and with the final eTICI score, delineating reperfusion into 7 distinct categories. Results: Collateral grade on routine angiography injections was available in 574/984 (58%) of STRATIS subjects (age 67.5 ± 15.1, 47% women, baseline NIHSS 16.8 ± 5.5). Collaterals included 203/574 (35.4%) with ASITN 3-4, 291/574 (50.7%) ASITN 2 and 80/574 (13.9%) ASITN 0-1. TICI ≥ 2A was achieved at 32.4 ± 23.5 minutes from angiography start and 26.4 ± 18.6 minutes from visualization of the arterial occlusion. The eTICI included 78 TICI 3 (13.6%), 140 TICI 2C (24.4%), 226 TICI o2B (39.3%), 68 TICI m2B (11.8%), 44 TICI 2A (7.7%), 4 TICI 1 (0.7%) and 14 TICI 0 (2.4%). More robust collateral grade was strongly associated with lower NIHSS (15.9 ± 5.4 (ASITN 3-4); 16.7 ± 5.5 (ASITN 2); 19.6 ± 5.1 (ASITN 0-1); p<0.001). Intervals from angiography start, visualization of the arterial occlusion and first device pass to TICI ≥ 2A were all shorter in ASITN 3-4 versus 0-2, with time from first device pass to TICI ≥ 2A reaching statistical significance (p=0.034). Better collaterals were also strongly linked with more extensive reperfusion (Figure). Collaterals and reperfusion were linked at all occlusion sites (ICA, M1, M2, BA). Conclusions: Collaterals on routinely available angiography prior to thrombectomy in STRATIS were strikingly tied to both the speed and degree of final reperfusion, across every site of arterial occlusion.