Abstract 130: SWIFT! Early Presentation is Associated with Better Collaterals, Smaller Established Infarcts, and Better Clinical Outcomes from Endovascular Recanalization

Abstract

Background: Increasing time from symptom onset to presentation may incur greater ischemic injury and decreased likelihood of successful outcomes after acute stroke therapy. The impact of time may be assessed physiologically by degree of accumulated ischemic injury on baseline imaging and status of collateral vessels at angiography; and clinically by final functional outcome. Methods: The SWIFT trial dataset was analyzed with respect to ASPECTS scores, angiographic collaterals, clinical outcome, and time to presentation (defined as stroke onset to hospital arrival). Known determinants of successful angiographic and clinical outcomes were considered as covariates, with main analyses defining the interaction of time to presentation on ASPECTS score, collateral grade, reperfusion and related clinical outcome. Results: 137 patients (mean age 67±12 years, 52% female, median pretreatment NIHSS 18 (range 8-28)) with full data were studied. Time to presentation was median 180 min (IQR 95-250) and was < 3 hours in 51% and > 3 hours in 49%. Time to presentation was unrelated to age, gender, most risk factors (except atrial fibrillation (present < 3 hours in 41.4% vs. > 3 hours in 64.2%, p=0.010), NIHSS, glucose or BP. Pre-stroke mRS 0, however, was associated with presentation < 3 hours, (82.8% vs. 63.8%, p=0.035). Worse collateral scores were noted with longer times to presentation: collateral grade 0-1 (n=32) mean 232±84 min; 2 (n=48) 164±99 min; 3 (n=35) 155±104 min; 4 (n=4) 54±16 min; p<0.001. Later presentation was associated with more extensive ischemic injury at baseline (median ASPECTS 8 (IQR 7-9) beyond 3 hours vs. 9 (IQR 8-10) within 3 hours, p=0.015). Multivariate analyses identified presentation > 3 hours as the sole independent predictor of extensive baseline infarct (ASPECTS ≤ 7), p=0.003. Time to presentation was unrelated with likelihood of successful angiographic reperfusion (p=NS), yet earlier presentation demonstrated a strong influence with better Day 90 mRS outcomes (p<0.001). Conclusions: Time was a critical factor in successful clinical outcomes in SWIFT. Shorter times to presentation were associated with better collaterals, smaller established infarcts and better clinical outcome after revascularization.