ABSTRACT NUMBER: ESOC2026A290 CEREBRAL SMALL VESSEL DISEASE IMPAIRS DYNAMIC CEREBRAL AUTOREGULATION RECOVERY AND PARTIALLY MEDIATES FUNCTIONAL OUTCOME FOLLOWING STROKE THROMBECTOMY

Abstract Background and aims Cerebral small vessel disease (CSVD) is associated with poor outcomes after endovascular thrombectomy (EVT), but the underlying mechanism remains unclear. We aimed to determine whether CSVD burden influences functional outcomes through alterations in dynamic cerebral autoregulation (dCA). Methods We included 107 patients with anterior circulation large-vessel occlusion and successful EVT (eTICI ≥2b). CSVD burden was dichotomised as none-to-mild (score 0-1) versus moderate-to-severe (score 2-3). dCA was assessed at T1 (~24h post-EVT) and T2 (~4-5d post-EVT). Mediation analysis examined whether dCA changes mediated the CSVD-functional independence (mRS 0-2) association at 90 days. Results Patients with moderate-to-severe CSVD (n=38) demonstrated distinct dCA recovery patterns versus none-to-mild CSVD (n=69). None-to-mild CSVD patients showed improved very low frequency (VLF, 0.02-0.07 Hz) phase differences from T1 to T2 (+7.67° [-9.73, 35.53]), those with moderate-to-severe CSVD exhibited deterioration (-7.17° [-25.03, -0.74], P=0.004), which remained significant after multivariable adjustment (β=15.63, 95% CI, 3.92-27.35, P=0.009). Functional independence was achieved in 73.9% of patients with none-to-mild CSVD versus 52.6% in those with moderate-to-severe CSVD (adjusted OR 0.37, 95% CI, 0.16–0.86, P=0.022). Mediation analysis revealed that VLF phase changes in the affected side mediated 24.48% of the association between CSVD burden and functional outcome (average causal mediation effect: -7%, P<0.001; total effect: -29%, P=0.020). Conclusions Higher CSVD burden was associated with worse functional outcomes after EVT, partially mediated by impaired dCA. Moderate-to-severe CSVD patients exhibited deteriorating dCA, whereas none-to-mild CSVD patients showed progressive improvement. Larger studies are warranted to validate these findings. Conflict of interest Yue Qiao: nothing to disclose.