Abstract Body: Introduction: CT perfusion maps (CTP) can estimate the ischemic core in acute ischemic stroke based on distinctive cerebral blood flow (CBF) thresholds. However, metabolic factors beyond perfusion influence the tissue tolerance to ischemia and the infarct growth rate.
Hypothesis: We hypothesize that patients with lower hemoglobin and higher blood glucose levels exhibit reduced cerebral tissue resilience to hypoperfusion and will show larger ischemic core underestimation volume (ICuV) compared to other patients with normal hemoglobin and blood glucose levels.
Methods: Large vessel occlusion stroke patients investigated with baseline CTP undergoing thrombectomy with near-complete reperfusion and without parenchymal hemorrhage from the ESCAPE-NA1 trial were included. Patients were subdivided into anemic (Hgb <130g/L for men and <120g/L for women) and non-anemic groups, and hyperglycemic (blood glucose level >7mmol/L) and normoglycemic groups. The primary outcome was the presence of “perfusion scotoma” defined as ICuV ≥10mL. The presence of “perfusion scotoma” and median ICuV were compared between anemic vs. non-anemic and hyperglycemic vs. normoglycemic patients using non-parametric tests and multivariable binary logistic regression with adjustment for baseline variables.
Results: One-hundred-sixty-two/1105 (15%) patients were included (Figure 1). The median ICuV was 7.26mL (IQR=0-25.63). Seventy-eight (48%) patients demonstrated perfusion scotoma. Forty-two (25.7%) patients were anemic, and 65 (40.1%) were hyperglycemic. In univariable analysis, the hyperglycemic group had a higher prevalence of perfusion scotoma (65% [n=40] vs. 39% [n=38], p=0.006) and larger ICuV (17.79 mL [IQR=1.57-42.75] vs. 6 mL [-0.31, 12.51], p=0.003) compared to normoglycemic patients (Figure 2). No significant ICuV differences between patients with and without anemia were seen. Multivariable regression analysis revealed an association between perfusion scotoma and hyperglycemia, adjusted odds ratio (OR) 2.37 (95%CI=1.22-4.61), and between perfusion scotoma and blood glucose levels, adjusted OR 1.19 (95%CI= 1.02-1.37) per 1 mmol/L increase (Figure 3).
Conclusion: In our study, CTP-based ischemic core underestimation was common and associated with higher baseline blood glucose levels. Individual metabolic factors beyond perfusion that critically influence the infarct growth rate should be considered when interpreting baseline CTP estimations of the ischemic core volume.