Markers of inflammation in men with small abdominal aortic aneurysm.

Background: Markers of inflammation and fibrin turnover are elevated in individuals with a large (>55 mm) abdominal aortic aneurysm (AAA). Fibrin degradation generates D-dimer, known to possess multiple proinflammatory effects, and levels are elevated during early AAA development. This study characterized the plasma inflammatory response during early AAA pathogenesis to determine the effect of D-dimer levels.

Methods: The study compared 75 men with a small AAA (range, 30-54 mm) with 90 age-, sex-, and race-matched controls. Plasma interleukin-6 (IL-6), complement C3, high-sensitivity C-reactive protein (hsCRP), fibrinogen, and D-dimer levels were measured.

Results: Mean levels of fibrinogen (2.92 vs 2.59 g/L; P = .003), hsCRP (2.07 vs 1.29 ng/mL; P = .005), and D-dimer (346.7 vs 120.2 ng/mL; P < .001) were higher in men with a small AAA. These markers correlated with maximum aortic diameter determined by ultrasound imaging. On multivariate analysis, D-dimer levels were elevated in AAA individuals independent of smoking, cardiovascular disease (CVD), atherosclerotic risk factors, and inflammatory parameters. Fibrinogen and hsCRP levels remained elevated after adjustment for these covariates but lost significance when D-dimer was added to the model.

Conclusion: C-reactive protein and D-dimer levels are elevated during early AAA development. D-dimer levels are most tightly associated with AAA status, however, and may mediate the observed elevation in acute-phase reactants.