Preoperative volume of mildly delayed time predicts 24-hour complete reperfusion after successful mechanical thrombectomy

BACKGROUND: Successful macrovascular recanalization after mechanical thrombectomy (MT) does not always ensure tissue-level microvascular reperfusion, highlighting the need for reliable preoperative imaging biomarkers to predict microvascular success. AIMS: To investigate whether the preoperative volume of mildly delay time (DT 2-4 s), as quantified by MIStar CT perfusion (CTP), can predict 24-hour complete reperfusion (CR) in patients achieving successful MT. METHODS: We retrospectively analyzed patients with acute anterior circulation large vessel occlusion treated between January 2015 and December 2022 who achieved successful recanalization (eTICI 2b-3). All participants received baseline and follow-up CTP at 24 h processed by MIStar. CR was defined as 100% reperfusion on follow-up imaging. The relationship between preoperative DT 2-4 s volume and CR was evaluated using multivariable logistic regression and Receiver Operating Characteristic (ROC) curve analysis. RESULTS: Sixty patients (mean age 65 years, 58.3% male) were included, with 36 (60%) achieving CR. Preoperative DT 2-4 s volume was significantly smaller in the CR group (64.8 ± 27.2 ml) compared to the incomplete group (113.5 ± 52.3 ml; p < 0.001). After adjusting for confounders, DT 2-4 s remained independently associated with CR (adjusted OR 0.94; 95% CI 0.9 to 0.98). ROC analysis yielded an AUC of 0.81. A threshold of DT 2-4 s < 95 ml predicted CR with a sensitivity of 0.84, a specificity of 0.81. CONCLUSION: Preoperative DT 2-4 s volume is a novel and sensitive biomarker for predicting 24-hour complete tissue-level reperfusion. It identifies patients at risk of microvascular failure despite successful large-vessel recanalization.