Elevated tissue plasminogen activator in patients with screening-detected abdominal aortic aneurysm

Objective: A population-based case-control study with historical and current data was conducted in a population with a high prevalence of disease to explore the hypothesis that the fibrinolytic system may be involved in the early pathogenesis of abdominal aortic aneurysm (AAA). Methods. Forty-two patients found to have AAA at: population-based screening were compared with 100 controls matched for age and sex. Mass concentration of tissue plasminogen activator (tPA mass) and tissue plasminogen activator/plasminogen activator inhibitor-I complex (tPA,/PAI-I complex mass) were analyzed in blood samples obtained at the screening (current), and in blood samples obtained from a study conducted 12 years previously on the same population (historical). Results. Current tPA mass levels were significantly higher in AAA patients compared with controls (13.6 vs 11.4 mu g/L, P =.016). A similar trend was observed in historical tPA mass levels (9.8 vs 8.2 mu g/L, P =.062). Current and historical mass concentrations of tPA/PAI complex in AAA patients were similar to those in controls. Current tPA mass levels retained the associations with AAA in a logistic regression model after adjustment for history of atherosclerosis (odds ratio [OR], 1.1 per mu g/L, P =.039) and current smoking (OR 1.1 per mu g/L, P =.039). When family history of AAA was added in a logistic regression model, the OR. for current tPA mass was 1.1 per mu g/L (P =.056) and 1.1 per mu g/L (P =.070) when treated hypertension was added. Conclusion: The finding of elevated tPA mass, in contrast to tPA/PAI-I complex, in plasma among patients with screening-detected AAA supports the hypothesis that the fibrinolytic system may be important in the early pathogenesis of AAA.