Expansion of Small-diameter Abdominal Aortic Aneurysms is Not Reflected by the Release of Inflammatory Mediators IL-6, MMP-9 and CRP in Plasma

ObjectivesThe aim of this study was to evaluate a possible correlation between plasma levels of interleukin-6 (IL-6), metalloproteinase-9 (MMP-9) and C-reactive protein (CRP) and the expansion of small abdominal aortic aneurysms (AAAs).DesignPatients were selected from a prospective randomised clinical trial and categorised in two groups, in which one group received active treatment (azithromycin) and the other received placebo. No statistical difference in the expansion rate of AAAs between the groups was found and the two groups were considered as one cohort in the present study.Material and methodsIn this study, 213 patients with AAAs between 35 and 49 mm were followed-up with ultrasound examination every 6th month. Blood samples were taken on two occasions (6 months apart). IL-6 and MMP-9 were analysed on one occasion using Quantikine® analysing kits (R&D Systems, Inc., USA). CRP was analysed using sensitive-CRP method.ResultsLevels of IL-6, MMP-9 and CRP did not correlate with AAA expansion. Neither was there any correlation between statin medication and changes in MMP-9 levels over the 6-month period. Patients on statins had a lower expansion rate than those not taking statins: 0.16 versus 0.25 cm per year.ConclusionNo correlation was found between levels of circulating IL-6, MMP-9, CRP and the expansion of small-diameter AAAs, indicating no clinical use of these markers in AAA surveillance.