Abstract
Background:
Serial ASPECTS of ischemic stroke lesion evolution from baseline to 24-hours has been established as an effective surrogate endpoint in endovascular therapy. The use of this imaging shift has not been implemented beyond thrombectomy trials to estimate impact of endovascular therapy in large-scale registry data.
Methods:
The STRATIS Imaging Core Lab, blind to all clinical data, independently determined ASPECTS scores on baseline and 24-hour studies. ASPECTS regional involvement and resulting total scores were analyzed in anterior circulation occlusions in STRATIS. Statistical analyses calculated the proportion of subjects with 0 ASPECTS score shift and separately, those with shifts >4, 5, 6 points. Clinical predictors of ASPECTS shift and regional involvement were determined.
Results:
Baseline ASPECTS (n=517) was 8.2 ± 1.59 (median 8.0 (2, 10)) and 24-hour ASPECTS (n=547) was 6.0 ± 2.92 (median 7.0 (0, 10)). Serial ASPECTS (n=487) revealed change of -2.1 ± 2.41 (median-1.0 (-10, 3)). Absolutely no change in ASPECTS, or 0 shift from baseline to 24 hours, occurred in 157/487 (32%). Substantial ASPECTS decline of ≥4 occurred in 117/487 (24%), with ≥5 in 76/487 (16%) and ≥6 in 51/487 (10%). ASPECTS decline was linked with baseline collaterals (ASITN 4 (n=19; -0.9 ± 1.05); 3 (n=117; -0.8 ± 1.21); 2 (n=140; -2.6 ± 2.27); 1 (n=29; -3.6 ± 2.34); 0 (n=10; -4.2 ± 3.08)) and the degree of subsequent reperfusion (oTICI 3 (n=63; -1.1 ± 1.94); 2B (n=282; -1.9 ± 2.32); 2A (n=103; -3.4 ± 2.38); 1 (n=2; -3.0 ± 1.41); 0 (n=10; -4.0 ± 2.75)). Baseline predictors of ≥6 ASPECTS decline included previous TIA (OR 3.10 (95%CI 1.32, 7.31), diabetes (OR 2.23 (95%CI 1.22, 4.07)) and baseline NIHSS (OR 1.10 (95%CI 1.03, 1.16).
Conclusions:
Frozen ASPECTS or 0 shift from baseline to 24 hours occurs in about 1/3 of all cases treated with endovascular therapy in a large-scale registry. Poor collaterals, prior TIA, diabetes and elevated baseline NIHSS may be important predictors of those likely to experience infarct evolution despite reperfusion, identifying optimal candidates for neuroprotection with endovascular therapy.