Abstract A032: Pragmatic Transcranial Doppler Metrics Predict Parenchymal Hemorrhage Following Successful Endovascular Thrombectomy in Anterior Large Vessel Occlusion Stroke

Introduction: Parenchymal hemorrhage (PH) remains a significant complication following successful endovascular thrombectomy (EVT). We aimed to define bedside transcranial doppler (TCD) measures associated with PH. Method: We reviewed 162 patients with MCA-M1 or ICA terminus occlusion who underwent successful recanalization (TICI≥2b) and TCD within 24-72 hours post EVT. MCA mean flow velocity (MFV), peak-systolic velocity (PSV), end-diastolic velocity (EDV), and pulsatility index (PI) were measured in the ipsilateral (EVT) and contralateral (control) sides. EVT-to-control side ratios (MFV-R, PSV-R, EDV-R and PI-R) were calculated. Dynamic Flow Index (DFI), defined as MFV ÷ PI, was used to explore microvascular conductance as previously validated. PH was classified as <30% (PH1) or ≥30% (PH2) of infarct bed by blinded review of imaging post EVT. Multivariable logistic regression assessed the relationship between TCD parameters and PH1/2, adjusting for baseline NIHSS, diastolic blood pressure, heart rate, atrial fibrillation, cervical ICA tandem lesion, and angiographic collaterals; a second model also included final infarct size. Result: Compared with patients without PH, those with PH1/2 had lower MFV-R (PH:0.93 95% CI 0.84–1.03 vs No-PH:1.07 0.92–1.29, p=0.0035), lower PSV-R (PH:0.94 0.83–1.10 vs No-PH:1.08 0.92–1.29, p=0.0347), lower EDV-R (PH:0.87 0.79–1.00 vs No-PH:1.08 0.93–1.36, p=0.0006), and lower ipsilateral DFI (PH: 45.0 28.9–53.5 vs no PH: 59.8 41.9–80.3, p=0.0019). PI-R was higher in PH (PH: 1.07 1.01–1.18 vs no PH: 0.97 0.89–1.06, p=0.0002). In adjusted models, MFV-R (OR 0.153 95% CI 0.027–0.875, p=0.035), PI-R (OR 30.63 2.25–417.58, p=0.010), EDV-R (OR 0.112 0.023–0.547, p=0.007), and ipsilateral DFI (per 1-unit increase: OR 0.972 0.948–0.996, p=0.022) were associated with PH. In the second model including infarct size, PI-R (OR 84.65 3.15–2273.83, p=0.008) and EDV-R (OR 0.124 0.020–0.759, p=0.024) remained significant. Conclusion: Elevated PI-R and reduced EDV-R on post-EVT TCD (increased microvascular resistance) are positively associated with PH, whereas increased MVF-R and DFI (increased microvascular conductance) may be protective. Incorporating pragmatic TCD ratios into patient management post EVT may improve risk stratification for hemorrhagic transformation and help individualize blood pressure management. Prospective studies are needed to confirm these findings.