Haemostatic factors, atherosclerosis and risk of abdominal aortic aneurysm

Abdominal aortic aneurysms have traditionally been thought to be a consequence of severe atherosclerosis of the arterial wall. To date, the role of haemostatic factors in aneurysmal disease has not been extensively researched. The aim of this study was to see if such factors were independently related to the occurrence of aortic aneurysm. Furthermore, were the associations maintained after taking into account the presence of underlying atherosclerotic disease! Using data from the Edinburgh Artery Study, a nested case-control design was used involving 40 cases of aortic aneurysm, each being matched to five controls by sex and within a 5-year age band. After adjustment for age and sex, both fibrinogen (P less than or equal to 0.01) and fibrin D-dimer (P less than or equal to 0.001) were each associated with a significant increased risk of aneurysm. Further adjustment for packyears, history of cardiovascular disease and the ankle brachial pressure index resulted in odds ratios of 1.51 (95% CI 1.05 to 2.16, P less than or equal to 0.05) for fibrinogen and 3.75 (95% CI 1.80 to 7.82, P less than or equal to 0.001) for fibrin D-dimer. These associations probably arise as a consequence of fibrin deposition and turnover within the aneurysmal sac, although further prospective studies are needed before thrombotic factors can be used in the identification of a group who are at high risk of developing an abdominal aortic aneurysm.