Abstract 304: Association Between Plaque Morphology and Time Interval After the Neurologic Index Event in Patients With Symptomatic Carotid Stenosis

Abstract

Objectives: Instable plaques are more common in patients with symptomatic carotid stenosis compared to asymptomatic patients. Clinically symptomatic patients are at high risk for a recurrent stroke in the first days after a neurologic index event. Histopathologic plaque stabilisation or remodelling mechanisms of symptomatic plaques are unclear. Therefore, our study aimed to find changes of plaque morphology in dependence of time interval between neurologic index event and plaque removal. Methods: Plaques of patients that were removed from surgically treated patients with symptomatic carotid stenosis between 2004 and 2016 were included. Histological analyses of those carotid plaques were performed to assess the type of plaque (American Heart Association classification), the stability of plaque (thickness of the fibrous cap </>200μm), the extent of calcification, inflammation, neovascularization and the deposition of collagen and elastin. Statistical analysis was applied in form of an ordinal regression analysis, adjusted for common risk factors of atherosclerosis. Results: Out of 348 included plaques, the patients’ median age was 71 (Q1-Q3, 65 - 77) years and 69% were male. Median time interval between index event and plaque removal was 10 days (Q1-Q3, 4-28 days). Most common index event was a transient ischemic attack with 37% (128 of 348), followed by stroke in 28% (97 of 348), amaurosis fugax in 22% (76 of 348) and instable symptoms (crescendo transient ischemic attack, stroke in evolution) in 12% (43 of 348), respectively. The ordinal regression analysis revealed, that the time interval as continuous independent variable had no significant influence on plaque type, plaque stability, extent of calcification, inflammation or neovascularization and the deposition of collagen and elastin. Conclusions: The examined plaque morphology features of patients with symptomatic carotid stenosis showed no differences in relation to the time interval between neurologic index event and plaque removal. To find potential symptomatic plaque remodelling mechanisms, currently ongoing molecular and histomorphological analysis aim at identifying novel markers of apoptosis and cell fate-driven mechanisms in fibrous cap-enriched vascular smooth cells.