Venous return index after mechanical thrombectomy predicts parenchymal hemorrhage and poor outcomes.

Background and purpose: The significance of early venous filling on digital subtraction angiography (DSA) after mechanical thrombectomy (MT) is unclear. This study introduces the Venous Return Index (VRI) to explore the relationship between VRI in different intracranial veins and outcomes after MT in acute anterior circulation large vessel occlusion (AC-LVO) stroke.

Methods: A retrospective analysis of AC-LVO stroke patients who underwent successful MT (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b) within 24 hours from April 2014 to March 2023 was conducted. VRI, defined as the relative appearance time of the target vein on DSA, was analyzed for 8 intracranial veins (vein of Trolard, superficial middle cerebral vein, sphenoparietal sinus, vein of Labbé, thalamostriate vein, internal cerebral vein, vein of Galen, and basal vein). The definition of parenchymal hemorrhage (PH) follows the ECASS (European Cooperative Acute Stroke Study) standard. An unfavorable outcome is defined as a 90-day modified Rankin Scale (mRS) score of 4-6. The study assessed the relationship between VRI and 24-hour PH as well as 90-day mRS.

Results: A total of 432 patients were included, with 22.5% experiencing PH and 42.4% having poor outcomes (mRS 4-6). The thalamostriate, internal cerebral, and great cerebral veins were independently associated with 24-hour PH and 90-day poor outcomes. The Alberta stroke program early CT score - blood Glucose -Thrombectomy attempts - Venous index (AGTV) scale, incorporating VRI from these veins, was developed to predict PH risk, with an area under the curve (AUC) of 0.887. The PH risk was 50.5% for AGTV ≥6 and 14.1% for AGTV <6.

Conclusions: VRI in the thalamostriate, internal cerebral, and Galen veins was independently associated with 24-hour PH and 90-day poor outcomes. The AGTV scale effectively predicts PH risk after MT.