Favorable Venous Outflow Linked to Reperfusion Success After Thrombectomy

Illustration of a blocked artery.
Study researchers assessed whether favorable venous outflow profiles were associated with successful reperfusion following thrombectomy in patients with AIS-LVO.

A favorable venous outflow (VO), determined by the cortical vein opacification score (COVES), is associated with reperfusion success and good functional outcomes in patients who undergo endovascular thrombectomy for acute ischemic stroke due to large vessel occlusion (AIS-LVO), according to study findings published in Neurology.

This retrospective study included 565 consecutive patients with AIS-LVO who were treated by endovascular thrombectomy at 2 comprehensive stroke centers in Germany and the United States. Study investigators used baseline CTA to evaluate collateral status (Tan scale) and VO with the COVES. They defined a favorable VR by a COVES between 3 and 6, and an unfavorable one by a COVES between 0 and 2.

The primary study outcome was excellent reperfusion status (defined by the modified Thrombolysis on Cerebral Infarction 2c/3), while the secondary outcome was good functional outcomes 90 days post-treatment.

Patients with favorable VO (VO+) were significantly younger (median, 72 years vs 76.5 years, respectively; P <.001), more likely to have received intravenous tPA (70% vs 40.9%, respectively; P <.001), and had less severe symptoms at presentation (P <.001) compared with patients with unfavorable VO.

Excellent vessel reperfusion during thrombectomy was associated with favorable VO in a multivariable logistic regression analysis (odds ratio [OR], 2.10; 95% CI, 1.39-3.16; P <.001).

A secondary outcome multivariable binary logistic regression analysis found independent associations between favorable clinical outcomes and both favorable VO+ profiles (OR, 8.9; 95% CI, 5.3-14.9; P <.001) and excellent post-thrombectomy vessel reperfusion status (OR, 2.7; 95% CI, 1.7-4.4; P <.001).

Limitations of this study included its retrospective design as well as the inclusion of only patients from 2 comprehensive stroke centers, which may limit the generalizability of the findings.

The study investigators concluded that the assessment of the venous microvascular system, among other alternative blood flow pathways, could “be an additional useful vascular biomarker associated with endovascular treatment success and good functional outcomes” in patients with AIS-LVO.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Faizy TD, Kabiri R, Christensen S, et al. Association of venous outflow profiles and successful vessel reperfusion after thrombectomy. Published online May 5, 2021. Neurology. doi:10.1212/WNL.0000000000012106