The effect of aortic morphology on peri-operative mortality of ruptured abdominal aortic aneurysm.

Aims To investigate whether aneurysmshape and extent, which indicate whether a patient with ruptured abdominal aortic aneurysm (rAAA) is eligible for endovascular repair (EVAR), influence the outcome of both EVAR and open surgical repair. Methods and results The influence of sixmorphological parameters (maximumaortic diameter, aneurysm neck diameter, length and conicality, proximal neckangle, and maximum common iliac diameter)on mortality and reinterventions within 30days was investigated in rAAA patients randomized before morphological assessment in the Immediate Management of the Patient with Rupture: Open Versus Endovascular strategies (IMPROVE) trial. Patients with a proven diagnosis of rAAA,who underwent repair and had their admission computerized tomography scan submitted to the core laboratory, were included. Among 458 patients (364men,mean age 76 years),who had either EVAR(n = 177) or open repair (n = 281) started, there were 155 deaths and 88 re-interventions within 30 days of randomization analysed according to a pre-specified plan. The mean maximumaortic diameter was 8.6 cm. There were no substantial correlations between the six morphological variables. Aneurysm neck length was shorter in those undergoing open repair (vs. EVAR). Aneurysm neck length (mean 23.3, SD 16.1 mm) was inversely associated with mortality for open repair and overall: adjusted OR 0.72 (95% CI 0.57, 0.92) for each 16 mm (SD) increase in length. There were no convincing associations of morphological parameters with reinterventions. Conclusion Short aneurysm necks adversely influence mortality afteropen repair of rAAA and preclude conventional EVAR. This may help explain why observational studies, but not randomized trials, have shown an early survival benefit for EVAR. [ABSTRACT FROM AUTHOR]