CTP-Derived Venous Outflow Profiles Correlate With Tissue-Level Collaterals Regardless of Arterial Collateral Status.

Background and purpose: Tissue-level collaterals (TLC), which quantify the state of arterial blood flow transiting through cerebral ischemic tissue, have been shown to be related to the clinical outcomes of acute ischemic stroke (AIS), regardless of the arterial collateral status on computed tomography angiography(CTA). Herein, we investigated whether venous outflow (VO) profiles on computed tomographic perfusion (CTP) were linked to TLC, regardless of the arterial collateral status.

Methods: Consecutive anterior circulation AIS patients with large vessel occlusion(LVO) undergoing thrombectomy in a retrospective cohort were evaluated between January 2021 and August 2023 at two comprehensive stroke centers. All patients underwent pretreatment noncontrast computed tomography (NCCT), computed tomography perfusion (CTP) and follow-up NCCT or head magnetic resonance imaging (MRI) within 72hours of endovascular treatment (EVT). The VO profile parameters were recorded based on time-density curve derived from the CTP, including the peak time of VO (PTV) and total VO time (TVT). As the quantitative index of TLC, hypoperfusion intensity ratio (HIR) ≦0.4 was considered favorable for TLC. The primary outcome was tissue-level collaterals (TLC), defined by the HIR. Logistic regression analysis was used to assess the association between VO characteristics and TLC, whereas receiver operating characteristic (ROC) analysis was used to evaluate the value of VO parameters in predicting favorable TLC.

Results: This study enrolled 221 eligible patients, among whom patients with favorable TLC were found to have a shorter PTV than patients with unfavorable TLC (12 seconds vs.16.5 seconds, P < 0.001) in univariable analysis. A shorter PTV was significantly associated with a favorable TLC (odds ratio [OR], 0.811; 95% confidence interval [CI], 0.709 to 0.927; P=0.002). Multivariable binary logistic stepwise regression analysis revealed that PTV was negatively correlated with TLC, regardless of the arterial collateral status was good (Good: OR,0.777;95%CI,0.660-0.914; P=0.002; Poor: OR,0.729; 95%CI, 0.569-0.932; P=0.012). ROC analysis revealed that the PTV threshold for predicting favorable TLC was ≤13s, with an area under the curve (AUC), sensitivity, and specificity of 0.754, 0.728, and 0.699, respectively. The comprehensive predictor combined with PTV had an optimal predictive ability for TLC with an AUC of 0.894 (sensitivity=0.839, specificity=0.864).

Conclusion: Cerebral VO profiles in patients with anterior circulation AIS with LVO were related to TLC regardless of arterial collateral status, while PTV≤13s was a good predictor of favorable TLC.