RELATIONSHIP BETWEEN ABDOMINAL AORTIC-ANEURYSM WALL COMPLIANCE AND CLINICAL OUTCOME - A PRELIMINARY-ANALYSIS

Background: Aortic compliance, as measured by the pressure-strain elas tic modulus (Ep) and stiffness (B), may allow a more precise estimate of abdominal aortic aneurysm rupture risk than size alone. Aim: To det ermine the relationships between AAA compliance, size, growth, and cli nical outcome. Methods: One-hundred and twelve patients with initially non-operated AAA (86 men, 26 women, mean age 73 years), recruited fro m five centres, underwent baseline compliance measurements and were th en followed for a median of 7 (range 2-18) months; 85 patients underwe nt repeated measurements (median 3, range 2-5) 3-6-monthly over a medi an of 12 (range 3-18 months). Results: Seven patients have ruptured an d 16 have undergone repair of non ruptured AAA. AAA that ruptured had significantly lower Ep and B (more compliant). In AAA that ruptured or required repair there was an inverse relationship between diameter an d Ep and B. In those undergoing repeated measurements AAA expansion wa s only associated with a significant increase in Ep and B in non-opera ted patients. Conclusions: Baseline AAA compliance was significantly r elated to rupture and the future requirement for operative repair. Fai lure of compliance to increase with size may be a marker for rapid gro wth, developmental symptoms and rupture.