Abstract TP175: Older Age is Associated With Smaller Ischemic Core Volume and Slower Infarct Progression Despite High Clinical Severity in Anterior Circulation Large Vessel Occlusion Stroke

Abstract

Background: Older patients with acute stroke due to anterior circulation large vessel occlusion (ACLVO) experience worse clinical outcomes. Fast progressors typically present early with high stroke severity and larger ischemic core volumes. However, the relationship between aging and early infarct growth rate is unknown. We examined the association between older age, baseline ischemic core volumes and fast or slow infarct growth during ACLVO. Methods: Retrospective study of patients with acute ICA or MCA occlusion across two academic centers in 2014-2019. Patients were included if they had baseline CTP or MRI within 24 hours after estimated stroke onset. Infarct growth rate (IGR) was calculated as ischemic core volume (ml) / stroke onset to imaging time (h). Fast or Slow progressor status was defined by IGR ≥ or < 10 ml/h. Univariate comparisons were made across age tertiles. Multivariable linear and logistic regression analysis examined the association of age tertile with ischemic core volume and slow progressor status adjusting for sex, vascular co-morbidities and NIHSS. Results: We included 312 patients (57% female; age tertiles [T1-T3]: 33—66, 67—81, and 82—102). Older age was associated with decreasing ischemic core volume (median [range] ml: T1, 29 [0-253]; T2, 12 [0-406]; T3, 6 [0-244]; p<0.001) and lower IGR (median [range] ml/h: T1, 5.8 [0-153]; T2, 2.6 [0-122.5]; T3, 0.6 [0-248]; p<0.001). The frequency of slow progressors increased with age (N (%): T1, 65/107 (61); T2, 76/105 (72); T3, 78/100 (78); p=0.02). However, baseline NIHSS was numerically higher with older age (median [range]: T1, 16 [1-30]; T2, 17 [2-38]; T3, 18 [1-33]; p=0.22). In multivariable models, age tertile (T3 vs T1) and NIHSS were associated with: 1. ischemic core volume (age coefficient [95% CI], -18.9 [-36.1, -1.7], p=0.03; NIHSS coefficient [95% CI], 3.2[2.3, 4.1], p<0.001); and 2. slow progressor status (age OR 2.63 [1.27, 5.43], p=0.009); NIHSS OR 0.91 [0.87, 0.95], p<0.001). Conclusions: Older age was paradoxically associated with lower baseline core volumes and slow progressor status, despite high stroke severity during acute ACLVO, suggesting older patients may be more vulnerable to even slow infarct growth. Future studies are needed to confirm and extend the findings.