Abstract 164: Early Infarct Growth Correlates With Both Collateral Status and Clinical Outcomes After Thrombecomy

Abstract

Background: We assessed the correlation between early infarct growth rate (EIGR), collaterals and clinical outcomes following endovascular thrombectomy (EVT). Methods: In a prospective multicenter cohort study of imaging selection for EVT (SELECT), consecutive patients with large vessel occlusion (ICA, M1, M2) presenting up to 24 hr from last known well (LKW) were enrolled at 9 centers. CT perfusion was obtained prior to EVT. EIGR was defined as CTP ischemic core volume (rCBF<30%) divided by the time from LKW to baseline CTP. The optimal EIGR cutoff was identified by maximizing the sum of the sensitivity and specificity to predict favorable outcome (90 day mRS 0-2). Slow progressors were defined as having an EIGR below the cutoff. Good collaterals were defined on CTP as a hypoperfusion intensity ratio (HIR) <0.4 and on CTA as collateral score > 2. Results: Of 445 enrolled, 284 received EVT. The optimal EIGR was <10 ml/hr; 199 were slow and 85 fast progressors. Fast progressors had higher median NIHSS (19 vs. 15, P< 0.001), earlier median LKW to puncture 180 vs. 266 min, P< 0.001,. Slow progressors had better collaterals on both CTP and CTAs: HIR aOR 4.97 (2.3-10.7), p<0.001; CTA collaterals 3.02 (1.6-5.7), p=0.001. EIGR was an independent predictor of good outcome after adjusting for age NIHSS, LKW to puncture, mTICI and tPA aOR 0.73 (95% CI 0.61-0.89, p=0.001). Slow progressors were 3.5 times more likely to achieve mRS 0-2 after EVT aOR 3.51 (95% CI 1.8-6.7, p<0.001). Fast progressors had substantially worse clinical outcomes both in early and late time window (Table 1). The odds of good outcome decreased by 14% for each 5 ml/hour increase in EIGR, OR:0.87(0.80-0.94), p<0.001 and the probability of good outcome declined more rapidly in fast progressors (Figure 1). Conclusion: The early infarct growth strongly correlates with both collateral status and clinical outcomes after EVT. Fast progressors have a much more rapid decline in favorable outcomes at late treatment times.