ABSTRACT NUMBER: ESOC2026A19 RISK PROFILES FOR ENDOVASCULAR THROMBECTOMY: WHY SOME ACUTE ISCHEMIC STROKE PATIENTS HAVE STIFFER CLOTS

Abstract Background and aims Endovascular thrombectomy (EVT) fails to achieve first-pass recanalization in up to 40% of acute ischemic stroke (AIS) patients. Recent biomechanical data indicate that thrombus stiffness affects interactions between endovascular devices and clots; however, the factors driving this variability in thrombus mechanical properties are not known. We aimed to identify patient-specific determinants of thrombus stiffness in AIS. Methods In 73 patients with anterior circulation occlusions, thrombus stiffness was measured by unconfined compression testing in 346 sections (median per patient = 6.5, IQR: 4–11). Associations between clinical characteristics (age, sex, comorbidities, prior stroke, smoking, medication use) and thrombus median stiffness were assessed using multivariable linear regression. These factors were selected based on their potential influence on thrombus formation and composition in AIS, including effects on coagulation, platelet function, and vascular risk (e.g., hypertension, hypercholesterolemia, diabetes mellitus, atrial fibrillation, and smoking). Results We found that smoking (adjusted β=0.478, 95% CI 0.084–0.872, p=0.019, 3-fold) and hypercholesterolemia (adjusted β=0.354, 95% CI 0.001–0.708, p=0.049, 2.3-fold) were statistically significantly associated with higher thrombus stiffness, while hypertension showed a borderline association (adjusted β=0.323, p=0.056, 2.1-fold). No significant associations were observed for age, sex, atrial fibrillation, diabetes mellitus, prior ischemic stroke, or antiplatelet therapy after adjustment. Conclusions Smoking, hypercholesterolemia, and hypertension were independently related to stiffer thrombi in AIS, which may complicate EVT. Recognizing patients prone to forming particularly stiff thrombi could guide pre-procedural risk stratification and EVT strategy selection. Conflict of interest LB, BF, FG received funding from the European Union’s Horizon Europe research and innovation programme under the grant agreement No 101136438 (GEMINI). All authors: nothing to disclose.