Raised plasma fibrinogen concentration in patients with abdominal aortic aneurysm.

A feature associated with abdominal aortic aneurysms (AAA) is the presence of intraluminal thrombi (ILT). Elevated plasma fibrinogen concentrations predict a greater risk of thrombosis. Therefore, the authors assessed the relationship between fibrinogen levels, AAA size, and ILT. An age- and sex-matched case-control study was conducted. Demographic data and plasma samples were obtained from 110 patients with AAA and 110 controls. All subjects had an abdominal ultrasound scan to determine the size of the aneurysm and the percentage of the ILT occupying the lumen. Plasma fibrinogen concentrations were measured by the Clauss method. Fibrinogen concentrations were significantly higher in patients with AAA than in controls (median: 2.89 vs 2.53 g/L; p<0.01). Patients with AAA who were current smokers had a larger median AAA size (4.50 vs 4.30 cm; p<0.04) and greater percentage of the ILT (40% vs 30%) than those who did not smoke. Fibrinogen was positively correlated with AAA size (r =0.323; p<0.01) and the percentage of ILT occupying the lumen (r =0.358; p<0.05). Fibrinogen levels were higher in the AAA group. The authors also demonstrated positive correlations between the AAA size, ILT, and fibrinogen concentration. Smoking was associated with larger aneurysms and ILT. Fibrinogen may be a useful marker to monitor the progression of AAA.