Abstract DP345: Transcranial Doppler Pulsatility Index Predicts Worsening Reperfusion Injury on Dual-Energy CT After EVT

Background: Dual-energy CT (DECT) is used to differentiate contrast staining (blood-brain-barrier disruption) versus hemorrhage, which represent a spectrum of reperfusion injury after endovascular therapy (EVT). Transcranial Doppler (TCD) hemodynamic measures have been associated with long-term outcomes post-EVT. We tested whether key TCD metrics predict tissue injury severity on DECT after EVT. Methods: Single-center retrospective analysis of a prospective registry of patients with MCA or intracranial ICA occlusion who underwent early TCD and DECT after successful EVT (eTICI ≥2b50) from 8/2023-3/2025. Key DECT outcomes: no staining (NS=1), contrast staining (CS=2), or hemorrhage (HT=3). Key TCD predictors: mean flow velocity (MFV), peak systolic velocity (PSV), end-diastolic velocity (EDV), and pulsatility index (PI). Clinical, procedural and TCD characteristics were compared amongst DECT groups 1-3. Ordinal logistic regression measured association of TCD predictors and DECT outcome grades 1-3. Covariates included: baseline NIHSS, last-known-well-to-arrival (LKWA), ASPECTS, MCA-M1 occlusion, angiographic collaterals (good/moderate vs poor) and eTICI grade. Results: Of 88 patients, DECT grades were: NS 33 (38%), CS 36 (41%), HT 19 (22%). Ipsilateral PI (iPI) increased across grades [NS 0.97 (0.84-1.19), CS 1.19 (0.94-1.39), HT 1.16 (1.06-1.31); p=0.026], while ipsilateral MFV/PSV/EDV did not differ (all p≥0.2). Longer LKWA tracked with higher grade [3.7 h (2.1-8.9), 6.9 h (3.3-14.2), 12.1 h (5.2-19.3); p=0.006]. DBP and MAP varied by grade [DBP: 68.8, 63.3, 66.0; p=0.021; MAP: 89.5, 84.3, 89.0; p=0.036]. Discharge mRS worsened with grade [4 (2-4), 4 (3-4), 4 (4-5); p=0.019]. MCA-M1 occlusion was more frequent in NS than CS/HT [84.9% vs 55.6%/57.9%; p=0.022]. Good collaterals were less common in CS/HT vs NS [13.9%/21.1% vs 39.4%; p=0.046]. Adjusted models: iPI independently predicted higher DECT grade (aOR 6.13, 95% CI 1.39-27.05; p=0.017) and LKWA per hour remained significant (aOR 1.04, 1.01-1.08; p=0.011); ASPECTS showed a protective trend (aOR 0.84, 0.67-1.05; p=0.12). Conclusions: Post-EVT iPI, but not velocity indices (ipsilateral MFV/PSV/EDV), predict reperfusion injury grade on DECT. This supports the notion that increased microvascular resistance rather than focal hyperemia may serve as a biomarker to ischemic reperfusion injury. These findings may help individualize blood pressure management after EVT and need to be tested in future studies.