Reduced lung function in patients with abdominal aortic aneurysm is associated with activation of inflammation and hemostasis, not smoking or cardiovascular disease

Objective Abdominal aortic aneurysmsoften coexist with reduced lung function and chronic obstructive pulmonary disease (COPD). These conditions are each associated with cigarette smoking, cardiovascular disease, and evidence of increased inflammatory and hemostatic activity. The aim of this study was to determine if these factors accounted for the link between aneurysms and pulmonary disease. Methods The design was a case-control study comparing patients with an asymptomatic abdominal aortic aneurysmwith population-based controls without an aneurysm. Aneurysms were diagnosed by ultrasound scan, and pulmonary function was measured by respiratory questionnaire and spirometry. Activation of inflammation and hemostasis was measured by assay of plasma interleukin-6 (IL-6), fibrinogen, von Willebrand factor (vWF), tissue plasminogen activator (tPA) antigen, fibrin D-dimer, and plasmin antiplasmin complexes. Results Cases with an abdominal aortic aneurysm(n = 89) had more COPD and worse expiratory lung function as measured by forced expiratory volume in 1 second (FEV 1 ) and forced vital capacity (FVC) than controls (n = 98) (FEV 1 , 1.9 vs 2.2 L, P 1 /FVC, 0.67 vs 0.75, P P = .33). Cases also had higher levels of lifetime cigarette smoking (30 vs 24 pack-years, P P = .01), plasma fibrinogen (3.5 vs 3.1 g/L, P = .02), IL-6 (2.8 vs 1.8, pg/mL, P P = .01), and D-dimer(442 vs 93 ng/mL, P 1 fell from 2.3 (95% confidence interval [CI], 1.5 to 3.5) ( P P ≥ .05). Conclusion The association between reduced respiratory function and abdominal aortic aneurysmwas not accounted for by cigarette smoking or cardiovascular disease. We hypothesize that activation of inflammation and hemostasis in response to injury may be an important explanation of the association between aneurysm formation and reduced respiratory function. Further studies are required to test this hypothesis.