Abstract WP269: Association of the Compensation Index, Delayed Perfusion Index, Hypoperfusion Intensity Ratio, and Cerebral Blood Volume Index with 90-day Functional Independence After Endovascular Thrombectomy

Background: Computed tomography perfusion (CTP) estimates the volume of brain tissue that is infarcted and salvageable, in addition to providing quantifiable measures of collateral circulation. Recently, a novel CTP parameter, the compensation index (COMPI; ratio of 4-second delayed perfusion to 6-second delayed perfusion), was shown to correlate more strongly with digital subtraction angiography collaterals than the cerebral blood volume index (CBVI) and hypoperfusion intensity ratio (HIR). However, the relationship between COMPI and functional outcomes is unknown. Methods: From a prospectively maintained code stroke registry, we retrospectively analyzed all anterior circulation large vessel occlusion patients treated at 2 thrombectomy centers from 1/1/2024-12/31/2024 to determine the relationship between COMPI, the delayed perfusion index (DPI; ratio of 4-second delayed perfusion to 10-second delayed perfusion), CBVI, HIR, and functional outcomes. The primary outcome was 90-day modified Rankin Scale (mRS) score 0-2. A univariable logistic regression analysis was performed to assess the association between each CTP parameter and 90-day functional independence in the full cohort and in those achieving endovascular reperfusion (modified treatment in cerebral ischemia 2b-3). Multivariable logistic regression was performed to determine factors independently associated with the primary outcome. Results: 323 subjects (median age 69 [57-78] years, 52.6% male, median NIHSS 15 [10-19.5]) were included, of whom 146/302 (48.3%) with available outcome data were functionally independent at 90 days. COMPI was not associated with the primary outcome in the univariate analysis (odds ratio [OR] 0.987, 95% confidence interval [CI] 0.902-1.081, p=0.783). CBVI was the only candidate CTP parameter that was independently associated with 90-day mRS 0-2 in the full cohort (per 0.1-point increase, OR 1.349, 95% CI 1.099-1.655, p=0.004) and in those achieving endovascular reperfusion (per 0.1-point increase, OR 1.340, 95% CI 1.094-1.614, p=0.005). Conclusion: The compensation index was not associated with 90-day functional independence in this multicenter, retrospective study of patients treated with endovascular thrombectomy. CBVI was independently associated with good functional outcomes in the full cohort and in those who achieved reperfusion. Future investigations of CBVI in alternate cohorts and as a potential prognosticator after endovascular thrombectomy are required.