sICAM-1 concentrations are associated with inflammation in contralateral carotid plaque in patients with ischemic stroke.

Background: Atherosclerotic plaques in the internal carotid artery are responsible for more than 15% of ischemic strokes. Carotid ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) detects plaque inflammation. Plasma ICAM-1 and LRP1 concentrations have been associated with inflammation in ipsilateral carotid plaque. The aim of the present study was to test the association between the soluble (s) form of these biomarkers and contralateral carotid plaques.

Methods: Prospective study conducted in 53 patients with a recent ischemic stroke and at least one atherosclerotic plaque in both carotid arteries. All of the patients underwent an early carotid ¹⁸F-FDG PET, and a blood sample was obtained at 7±1 days. Several plasma inflammatory markers were evaluated by Multiplex and sLRP1 levels were measured by commercial ELISA. Bivariate and multivariable linear regression was used to assess the association between inflammatory markers and the clinical variables, including contralateral maximum standardized uptake value (SUVmax) and mean SUVmax (mean of contralateral and ipsilateral SUVmax) of ¹⁸F-FDG uptake. Hazard ratio (HR) was estimated with Cox models adjusted for potential confounding factors to evaluate recurrence.

Results: Multivariable linear regression analysis showed an independent association between sICAM-1 and sVCAM-1 and mean SUVmax (CI=-0.064-0.325, p=0.004; CI=0.079-0.554, p=0.010). In addition, in bivariate regression analysis, sICAM-1 was associated with contralateral SUVmax (CI=0.049-0.382, p=0.012). Cox regression showed that mean SUVmax was associated with stroke recurrence (HR=5.604, p=0.044).

Conclusions: sICAM-1 was independently associated with mean carotid plaque inflammation and with inflammation in contralateral plaque. sICAM-1 could be an indicator of plaque inflammation even in asymptomatic plaques.