Correlation of Infarct Volume, Collateral Status, and Reperfusion with Clinical Outcome Following Mechanical Thrombectomy in Acute Ischemic Stroke.

backgroundMechanical thrombectomy (MT) has widened eligibility beyond rigid time windows, yet outcomes still vary after angiographic success. Imaging-based core size, collateral status, and reperfusion quality may refine prognosis, while haemorrhagic complications can negate gains.

objectiveTo evaluate whether infarct core volume, collateral grade, and angiographic reperfusion independently associate with 90-day outcome after MT, to quantify the impact of symptomatic intracranial haemorrhage (sICH), and to identify an anterior-circulation core-volume threshold predictive of poor prognosis.

methodsSingle-centre, prospective cohort of adults with acute ischemic stroke (AIS) undergoing MT within 24 h (n = 41). Baseline core volume was measured on diffusion-weighted magnetic resonance imaging (MRI) (diffusion weighted image, DWI) using the ABC/2 method. Baseline core volume on DWI (ABC/2), entered per 10 mL, collateral grade (American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) for anterior; Basilar Artery on Computed Tomography Angiography (BATMAN) score ≥7 = good for posterior), and reperfusion modified Thrombolysis in Cerebral Infarction (mTICI) were evaluated. sICH was defined per European Cooperative Acute Stroke Study (ECASS) III. Reperfusion was scored by mTICI. Functional outcome at 90 days was dichotomised as good (modified Rankin Scale (mRS) ≤ 2 versus poor (mRS ≥ 3). Multivariable logistic regression tested independent associations. Receiver operating characteristic (ROC) analysis assessed the discriminatory performance of a pragmatic anterior-circulation core threshold.

resultsBaseline DWI core volume, higher mTICI grade, and sICH were independent predictors of 90-day outcome; collateral scores and time metrics were not retained after adjustment. A ~50 mL anterior-circulation core threshold demonstrated high discrimination for poor prognosis (area under the curve (AUC) = 0.91). sICH occurred in 34.1% (14/41) and strongly tracked with poor functional recovery. Reperfusion quality remained positively associated with independence at 90 days despite adjustment for core and sICH.

conclusionsOutcome after MT is chiefly determined by tissue burden at baseline, completeness of reperfusion, and avoidance of sICH. A ~50 mL DWI core threshold is a practical risk flag for counselling and audit, but should not be an absolute barrier to treatment. Given the small, single-centre sample and an unusually high sICH rate, these findings are exploratory and have limited generalisability; external validation in larger, harmonised cohorts is required.