Abstract 051: Utilization of CT Perfusion to Optimize Selection Of Elderly Patients For Thrombectomy: A Retrospective analysis
Authors: Singh Romil , Abdullah Hassan , Kaur Harsimran , Cerejo Russell , Saini Harneel , Williamson Richard , Hackett Christopher 
Published: March 2024

Introduction
CT perfusion (CTP) has been utilized to appropriately select patients with large vessel occlusion (LVO) for endovascular thrombectomy (EVT). Elderly patients and patients with fast‐growing ischemic cores have been shown to have worse outcomes after EVT. There is limited data on elderly patients aged ≥90 years old and ischemic core growth related to outcomes. We aimed to examine age, ischemic core growth, and outcomes in patients with LVO treated with EVT [1].

Methods
This is a retrospective study using prospectively collected data from a large academic medical center. Patients with LVO and treated with EVT between December 2017 and December 2022 were included in this study. Patients without CTP completed prior to EVT, patients with missing baseline or 90‐day modified Rankin Scale scores (mRS), and patients in which CTP was completed but failed were excluded from this study. Early infarct growth rate (relative cerebral blood flow < 30% / last known well to CTP) was used to determine if ischemic core growth was fast (≥10ml/h) or slow (<10ml/h). We compared nonagenarians to younger patients (<90 years old) and examined outcomes. Primary outcome was 90‐day mRS, which we evaluated using a proportional odds ordinal regression model adjusted for baseline mRS, NIHSS, and confounding variables identified in univariate analyses. Secondary outcome was excellent reperfusion (TICI ≥2C), which was analyzed using hierarchical binomial logistic regression and adjusted for potential confounding variables. Subgroup analysis compared 90‐day mRS and reperfusion rates in octogenarians and nonagenarians [2].

Results
Among 353 patients selected for EVT using CTP during the study, 325 patients were included in this study. Mean age ±SD was 74.61 ±14.49 years [133 (40.9%) ≥80 years old; 63 (19.4%) ≥90 years old] with initial NIHSS of 12 (IQR, 5 – 18) and 176 (54.2%) were female. Fewer nonagenarians selected for EVT with CTP were identified as fast progressors compared to younger patients, 7 (11.1%) compared to 65 (24.8%), respectively, Odds Ratio (OR) = 0.38 [95% Confidence Interval (CI), 0.16 – 0.87], p = 0.019. Nonagenarians who were fast progressors were more likely to experience worse 90‐day mRS (shift to next worse level) than younger patients and nonagenarians with slow progressing ischemic cores, median (IQR) mRS, 6 (5,6) versus 3 (1,6), adjusted OR (aOR) = 6.79 [95%CI, 1.14 – 40.29], p = 0.035. None of the nonagenarians with fast‐progressing ischemic cores achieved a 90‐day mRS of 0 – 2 or returned to baseline function. Patients aged ≥80 years, who were fast progressors, were more likely to shift to a worse 90‐day outcome than younger patients, aOR = 3.74 [95%CI, 1.43 – 9.75], p = .007. Comparable 90‐day mRS were found between octogenarians and nonagenarians, p = 0.55. Similar proportions of excellent reperfusion rates were seen in all patients, all p > 0.38.

Conclusion
Excellent reperfusion rates were not affected by age or ischemic core growth rate. Despite this, elderly patients with fast ischemic core growth were more likely to experience worse 90 day functional outcomes compared to younger patients and patients with slower core growth prior to EVT.