Elective open abdominal aortic aneurysm repair: a seven-year experience

INTRODUCTION: The seven-year experience of elective abdominal aortic aneurysm (AAA) repair of a vascular surgical unit in a teaching hospital was reviewed to determine the factors associated with in-hospital mortality. METHODS: All patients who underwent elective open repair of an AAA between July 1, 1991, and June 30, 1998, were identified using International Classification of Diseases Ninth Revision (ICD-9) codes. Twenty-four variables were selected for investigation by reviewing the published literature and by discussion with local vascular surgeons. Data were obtained by retrospective medical record review. Variables were first analysed by univariate analysis, and those with a p-value up to 0.25 were included in multivariate analysis. RESULTS: Of the 219 patients reviewed, 8 (3.7%, 95% confidence interval, 1.6%, 7.1%) died during the admission. The mean age of patients was 69.9 years, and 81% of them were male. Univariate analysis found that female sex, renal artery involvement in the aneurysm, and aortic cross-clamp duration of 90 min or greater were significantly associated with mortality. Multivariate analysis found that female sex, use of a bifurcated graft, and performance of an additional procedure at the time of operation were the only variables independently associated with mortality. DISCUSSION: Use of a bifurcated graft was a significant prognostic variable on logistic regression analysis confirming that the technical difficulty of the operation and the morphology of the aneurysm are important factors in determining mortality. Why women may be at higher risk for death is unclear. This study also highlights that caution is required when interpreting raw audit data.