Cerebral small vessel disease impairs dynamic cerebral autoregulation and mediates outcomes after stroke thrombectomy.

BACKGROUND

Cerebral small vessel disease (CSVD) is associated with poor outcomes after endovascular thrombectomy (EVT), but the underlying mechanism remains unclear. Impaired dynamic cerebral autoregulation (dCA), a fundamental function of cerebral microvasculature, has been proposed as a potential mediator but has not been systematically investigated.

OBJECTIVES

To determine whether CSVD burden influences functional outcomes through alterations in dCA.

DESIGN

Observational-cohort-study.

METHODS

We included 107 patients with anterior circulation large-vessel occlusion and successful EVT (expanded Thrombolysis in Cerebral Infarction ⩾2b). CSVD burden was assessed using standardised neuroimaging markers and dichotomised as none-to-mild (score 0-1) versus moderate-to-severe (score 2-3). dCA was assessed at two time points: early phase (T1, around 24 h post-EVT) and early subacute phase (T2, around 4-5 days post-EVT). Mediation analysis was performed to assess whether dCA changes mediated the association between CSVD burden and functional independence (modified Rankin Scale (mRS) score 0-2) at 90 days.

RESULTS

Patients with moderate-to-severe CSVD (n = 38) demonstrated distinct dCA recovery patterns compared with those with none-to-mild CSVD (n = 69). While patients with none-to-mild CSVD exhibited 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 = -20.06, 95% confidence interval (CI): -37.78 to -0.90, p = 0.040). 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 0.25, 95% CI 0.09-0.74, p = 0.012). 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).

CONCLUSION

Higher CSVD burden was associated with worse functional outcomes after EVT, partially explained by impaired dCA. Patients with moderate-to-severe CSVD exhibited deteriorating dCA, whereas those with none-to-mild CSVD showed progressive improvement. Larger powerful studies are warranted to validate these findings and elucidate underlying mechanisms.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT06361017.