Epidemiology and Outcomes of Abdominal Aortic Aneurysms in New Zealand: A 15-Year Experience at a Regional Hospital

Abstract

Abdominal aortic aneurysms (AAA) account for approximately 400 deaths per year in New Zealand (NZ). Waikato Hospital caters to a diverse population comprising a high proportion of the indigenous Māori ethnic group considered to be at higher risk of mortality and morbidity. Despite these population factors, there is no screening program for AAA. The aim of this study was to further define the epidemiology and outcomes of AAA repairs in NZ to investigate the utility of implementing a population-specific screening program. A retrospective study of all AAA repairs at Waikato Hospital between July 1996 and November 2010 was performed comparing long-term outcomes between Europeans and Māori considering acuity of presentation, age, gender, and type of repair. Perioperative and overall mortality data were obtained to generate Kaplan-Meier survival curves. 1,036 AAA repairs were performed. Māori presented younger (69.1 vs. 74.5, P<0.001), had lower male predominance (1.6:1 vs. 3.5:1, P<0.001), less elective repairs (44% vs. 67%, P<0.001), and more ruptured AAA (RAAA) (40% vs. 21%, P<0.001) despite the overall incidence of RAAA decreasing from 26% to 7.8% (P=0.01). Māori had a lower postoperative 10-year survival compared to Europeans (17.4% vs. 36.5%, P<0.001). There was an initial survival benefit for endoluminal over open repair but this converged at 4.9 years post repair. This study highlights the epidemiological trends and survival outcomes of AAA management in Māori and Europeans over 15years. It provides further evidence supporting the consideration of a population-specific screening program in future.