Abstract WP237: Uric Acid Expressed Within Carotid Atherosclerotic Plaque And Serum Uric Acid Are Associated With Cerebrovascular Events

Introduction: Uric acid (UA) level within carotid plaque specimens and its association with cerebrovascular events has not been detected or quantified. Systemically, serum uric acid (SUA) is a marker of inflammation and risk factor for atherosclerosis. However, its association with carotid plaque instability and subsequent cerebrovascular events remains unclear. Hypothesis: We hypothesized that UA may play a role in carotid artery atherosclerosis and stroke pathogenesis. In patients undergoing carotid endarterectomy (CEA), we aimed to determine whether UA is present differentially in carotid plaques of symptomatic versus asymptomatic patients and whether SUA is associated with cerebrovascular symptoms before surgery and major adverse cardiovascular events (MACE) in the follow-up to CEA. Methods: We prospectively collected 32 carotid plaques during CEA. We qualitatively assessed the presence of UA by using Gomori methenamine silver (GMS) staining and immunohistochemistry with anti-UA antibodies. We extracted and measured the quantity of UA in carotid plaques by using an enzymatic colorimetric assay. A retrospective analysis of a clinical database of 534 consecutive patients who underwent CEA was performed. We defined as symptomatic those patients with history of stroke, TIA and amaurosis fugax. Results: UA positive staining was detected in higher number of carotid plaques from symptomatic compared to asymptomatic patients on both staining, GMS [20 (86.9%) vs 2 (22.2%); p=0.001] and immunohistochemistry anti-UA [16 (69.5%) vs 1 (11.1%); p=0.004]. Moreover, we found a significantly higher concentration of UA in carotid plaque from symptomatic compared to asymptomatic patients [25.1 (9.5) μg/g vs 17.9 (3.8) μg/g; p=0.021]. SUA level in patients prior to CEA was significantly higher in the symptomatic compared to the asymptomatic group [6.0 (4.8-7.1) mg/dL vs 5.2 (4.4-6.3) mg/dL; p<0.001] and it was significantly higher in patients who developed MACE after CEA versus those that did not [6.0 (4.8-7.1) mg/dL vs 5.4 (4.5-6.6) mg/dL; p=0.021]. Conclusions: UA may provide a mechanistic explanation as systemic biomarker and potential tissue contributor for carotid plaque instability and subsequent cerebrovascular and cardiovascular symptoms.