Propensity scored analysis of outcomes after ruptured abdominal aortic aneurysm

Abstract

Abstract Background This study examined the population outcome of ruptured abdominal aortic aneurysm (rAAA) in England, the role of endovascular repair (EVAR), and the relationship between outcome and hospital workload. Methods Data were retrieved from Hospital Episode Statistics between 1 April 2003 and 31 March 2008. Propensity scoring was used to compare the outcomes of stratified patients undergoing EVAR and open repair. The relationship between workload and outcome was determined. Results Some 3725 urgent and 4414 rAAA repairs were included. Mortality rates were 21·3 per cent for urgent repair and 46·3 per cent for rAAA repair. EVAR was employed for 16·3 and 7·6 per cent of urgent and rAAA repairs respectively. EVAR was associated with significantly reduced mortality for urgent repair (odds ratio (OR) 0·531, 95 per cent confidence interval 0·415 to 0·680; P < 0·001) and rAAA repair (OR 0·527, 0·416 to 0·668; P < 0·001). A propensity scored analysis confirmed the benefit of EVAR for rAAA repair (P < 0·001). Repair of rAAA at hospitals with a higher elective aneurysm workload was associated with lower mortality rates irrespective of the mode of treatment (P < 0·001). Higher-volume hospitals were more likely to operate on rAAA (P = 0·033). Conclusion EVAR offered a survival advantage over open repair for non-elective aneurysm procedures. Services for the treatment of rAAA should incorporate access to EVAR and would benefit from being based in units with a high elective caseload.