Deep venous outflow as a surrogate for collaterals in late-window patients with successful revascularization from the DEFUSE 3 cohort

Abstract

Background Deep venous outflow (VO) may be an important surrogate marker of collateral blood flow in acute ischemic stroke patients with a large vessel occlusion (AIS-LVO). Researchers have yet to determine the relationship between deep VO status in late-window patients and imaging measures of collaterals, which are key in preserving tissue. Materials and Methods We performed a multicenter retrospective cohort study on a subset of DEFUSE 3 patients recruited across 38 centers between May 2016 and May 2017 who underwent successful thrombectomy revascularization. Internal cerebral vein opacification was scored on a scale of 0–2. This metric was added to the cortical vein opacification score to derive the comprehensive VO (CVO) score from 0 to 8. Patients were stratified by favorable (ICV+) and unfavorable (ICV−) ICV scores, and similarly CVO+ and CVO−. Analyses comparing outcomes were primarily conducted by Mann–Whitney U and χ2 tests. Results Forty-five patients from DEFUSE 3 were scored and dichotomized into CVO+, CVO−, ICV+, and ICV− categories, with comparable demographics. Hypoperfusion intensity ratio, a marker of tissue level collaterals, was significantly worse in the ICV− and CVO− groups (p = 0.005). ICV− alone was also associated with a larger perfusion lesion (138 ml vs 87 ml; p = 0.023). No significant differences were noted in functional and safety outcomes. Conclusions Impaired deep venous drainage alone may be a marker of poor tissue level collaterals and a greater degree of affected tissue in AIS-LVO patients presenting in the late-window who subsequently undergo successful revascularization.