# Venous outflow time profiles: promising imaging biomarkers for futile recanalization in acute ischemic stroke due to large vessel occlusion

## TL;DR

This study shows that venous outflow time profiles from 4D-CTA scans can predict poor outcomes in stroke patients who undergo clot removal, even after successful treatment.

## Contribution

The study introduces venous outflow time profiles as novel imaging biomarkers for predicting futile recanalization in acute ischemic stroke patients.

## Key findings

- Prolonged ischemic-side venous outflow duration (rCVF31) is an independent predictor of futile recanalization.
- Older age and lower baseline ASPECTS scores are also significant predictors of poor outcomes.
- Venous outflow parameters can help stratify outcomes in stroke patients undergoing endovascular thrombectomy.

## Abstract

To investigate whether venous outflow (VO) profiles derived from four-dimensional computed tomographic angiography (4D-CTA) correlate with futile recanalization (FR).

This study consecutively enrolled acute ischemic stroke patients with large vessel occlusion (AIS-LVO) who underwent endovascular thrombectomy (EVT) and achieved successful recanalization (modified thrombolysis in cerebral infarction [mTICI] score of 2b–3). An unfavorable functional outcome was defined as a modified Rankin Scale (mRS) score of 3–6 at 90 days after EVT. VO profiles were assessed using 4D-CTA, including the cortical vein opacification score (COVES) and three cortical venous filling (CVF) time points per hemisphere: initial opacification (CVF1), optimal opacification (CVF2), and complete outflow (CVF3). Intervals between the time points CVF21 and CVF31 and bilateral CVF time differences (rCVFs) were calculated. A binary logistic regression analysis was performed to identify independent predictors of FR.

A total of 167 AIS-LVO patients were enrolled, with 84 patients in the favorable outcome group (FOG, mRS 0–2) and 83 patients in the futile recanalization group (FRG, mRS 3–6). Compared with patients in FOG, patients in FRG were older, had higher National Institutes of Health Stroke Scale (NIHSS) scores, a greater prevalence of atrial fibrillation, lower Alberta Stroke Program Early CT Score (ASPECTS), and prolonged rCVF3 and rCVF31 (all p and FDR-corrected p < 0.1). A multivariable analysis identified age (adjusted odds ratio [aOR] = 1.06, 95% CI = 1.03–1.10, p = 0.001), ASPECTS (aOR = 0.73, 95% = CI 0.59–0.89, p = 0.002), and rCVF31 (aOR = 1.26, 95% CI = 1.04–1.52, p = 0.016) as independent predictors of FR.

In addition to older age and lower baseline ASPECTS, prolonged ischemic-side venous duration (quantified by rCVF31) can independently predict FR. These findings suggest that VO parameters serve as novel imaging biomarkers for outcome stratification in AIS-LVO patients undergoing EVT.