Interleukin-6 release after carotid artery stenting and periprocedural new ischemic lesions

Carotid artery stenting (CAS) is currently a standard procedure to treat severe carotid artery stenosis. This procedure causes mechanical plaque rupture, potentially releasing soluble factors into the circulating blood. The purpose of this study is to clarify whether inflammation factors are released from an atherosclerotic plaque after CAS and whether local release of inflammation factors is associated with periprocedural new ischemic lesions. The study consisted of 35 patients with 40 severely stenotic carotid arteries who underwent CAS. Blood samples were obtained from the aorta before the procedure and from the carotid plaque site just after the procedure. Blood levels of interleukin-6 (IL-6), interleukin-18, matrix metalloproteinase (MMP)-2, and tissue inhibitor of MMP-1 were determined. Diffusion-weighted magnetic resonance imaging was performed before and after the procedure. Among inflammatory markers, IL-6 levels markedly increased at the plaque site in comparison to those at the aorta (P<0.001). The IL-6 levels in the local samples were significantly higher in symptomatic lesions than those in asymptomatic lesions. More importantly, higher local IL-6 levels were associated with the appearance of new ischemic lesions (P=0.003). The association remained significant (P=0.030) after controlling for potential risk factors for CAS. Association of local IL-6 levels and periprocedural new ischemic lesions suggests that massive release from the plaque and entry into the cerebral circulation of IL-6 might be one of important factors on periprocedural complications related to CAS.