Clinical Implications of Stroke Progressor Phenotypes defined based on ASPECTS decay and perfusion estimated infarct growth rate: insights from a large national thrombectomy registry

Introduction: Infarct growth rate (IGR) is highly heterogeneous among ischemic stroke patients, reflecting a spectrum of progressor phenotypes with clinical implications. We aim to compare different imaging approaches to investigate stroke progressors phenotypes and their clinical implications in patients undergoing thrombectomy. Methods: Data are from the prospective Italian Registry of Endovascular Treatment in Acute Stroke (IRETAS). Patients with M1/M2 occlusion and known symptom onset were included. Progressor phenotypes were defined using (1) NCCT-based definitions (ASPECTS points decay per hour < 0.25 pts/h=slow progressor, 0.25–0.50 pts/h=intermediate, and > 0.50 pts/h=fast); and (2) CTP-based definitions (CTP-estimated core divided by time of onset < 5 mL/h=slow progressors, 5–10mL/h=intermediate, and > 10 mL/h=fast). The primary outcome was 90-day good functional outcome (modified Rankin Scale [mRS] = 0–2). Associations were assessed with logistic regression analyses adjusted for age, sex, NIHSS, TICI score, thrombolysis, and imaging-to-recanalization time. Results: Of 26799 patients screened, 8322 (31.1%) were included (NCCT group: 8076; CTP group: 897 patients). NCCT-based progressor phenotype was associated with lower odds of good outcome (aOR 0.82 [95%CI = 0.72–0.92] per each progressor phenotype increase). ASPECTS decay per hour was associated with lower odds of good outcome (acOR 0.94 [95%CI = 0.89–0.99]). No significant association was observed for either CTP-based progressor phenotype or CTP-based IGR (mL/h). Similar findings were observed for secondary outcomes. Conclusions: In this large, real-world cohort of stroke patients, NCCT-based IGR was associated with functional outcomes, whereas CTP-based IGR was not. This highlights the need to refine and identify more accurate markers of infarct growth within perfusion imaging.