Predictive Value Of ASL,DTI,and HRV For Cerebral Edema In Patient With Acute Ischemic Stroke After Successful Recanalization With Endovascular Therapy

BackgroundThe occurrence of cerebral edema after acute ischemic stroke(AIS)considerably diminishes the clinical benefit of endovascular therapy(EVT).Existing predictors of cerebral edema are not uniform and have low predictive efficiency,and there is an urgent need to explore novel and more efficient indicators.Arterial spin labeling(ASL)reflects cerebral perfusion,diffusion tensor image analysis along the perivascular space(DTI-ALPS)assesses the glymphatic system(GS)function,and heart rate variability(HRV)measures the activity of the autonomic nervous system(ANS).Previous studies have suggested a potential link between cerebral perfusion,GS,ANS,and the development of post-stroke cerebral edema.ObjectiveTo investigate the predictive value of ASL,DTI,and HRV for cerebral edema in patients with AIS after successful recanalization with EVT.MethodsThe retrospective study was conducted in three parts.The study populations were screened from a prospective cohort of screening for biomarkers related to neurological outcomes in patients treated EVT for AIS that were enrolled consecutively from 2019 to 2022 in the Intensive Care Unit of the Department of Neurology,Nan Fang Hospital.The first part enrolled 157 AIS patients who completed ASL examination before EVT and the visually discernible high signal(HS)on ASL images was classified as Class ⅠHS located within the lesion area and Class Ⅱ HS located around the lesion area,according to their distribution.The second part enrolled 18 AIS patients who completed DTI examination within 24 h after EVT and the DTI-ALPS index of their bilateral cerebral hemispheres was calculated.The third part enrolled 127 AIS patients who completed dynamic electrocardiogram examination within 48 h after EVT and the HRV time-domain and frequency-domain indicators were automatically obtained from 24hour Holter recordings.The development and severity of post-stroke cerebral edema was assessed based on clinical and imaging data within three days after EVT,including malignant brain edema(MBE),cerebral edema(CED)image typing,hemorrhagic transformation(HT),and net water uptake(NWU).Univariate analysis,stepwise logistic regression analysis,and the receiver operator characteristic(ROC)curves were utilized.Results(1)ASL HS had a good inter-observer agreement(κ=0.763,95%confidence interval(CI)0.618-0.908).The proportion of containing Class Ⅱ HS(namely Class ⅡHS and Class Ⅰ+Ⅱ HS)was higher in the CED 1 type group than the CED 2-3 type group(53.8%vs 37.9%,P=0.048),which was not a predictor of CED image typing after controlling for confounding variables.The HT group had a higher proportion of containing Class Ⅰ HS(namely Class Ⅰ HS and Class Ⅰ+Ⅱ HS)than the No-HT group(58.5%vs 34.6%,P=0.004),with an area under the ROC curve(AUC)of 0.619 for predicting HT,a sensitivity of 58.5%,and a specificity of 65.4%.No significant correlation was observed between ASL HS,MBE,and NWU(P>0.05).(2)The DTI-ALPS index had an excellent inter-observer agreement(Intraclass correlation coefficient=0.904,95%CI 0.680-0.975,P<0.001).The ipsilateral infarct DTI-ALPS index was lower in the CED 2-3 type group(1.242±0.088 vs 1.421 ± 0.129,P=0.012),which had an AUC of 0.892 for predicting CED 2-3 type,with an optimal cut-off value of 1.289,a sensitivity of 80.0%,and a specificity of 84.6%.The DTIALPS index showed a trend of decreasing and then increasing over time,dropping to a minimum around 72 h.There was a negative linear correlation between the DTIALPS index and NWU at 72 h(r=-0.728,P=0.017).There was no significant correlation between the DTI-ALPS index,MBE,and HT(P>0.05).(3)Very low frequency(594.4(288.8-1011.2)vs 594.4(288.8-1011.2),P=0.046)and low frequency(167.2(53.2-253.0)vs 267.9(133.5-534.3),P=0.047)were significantly lower in the MBE group,but they were not predictors of MBE after controlling for confounding variables.No significant correlation was found between HRV,CED image typing,HT,and NWU(P>0.05).Conclusion(1)ASL Class Ⅰ HS within the lesion region can predict HT,whereas Class Ⅱ HS around the lesion region is associated with milder cerebral edema.(2)The lower DTI-ALPS index is relevant to a higher CED image typing and more NWU,indicating that heavier impaired GS is associated with more severe cerebral edema.(3)Reduced HRV correlates with MBE,which appears to be associated with decreased vagal activity.