Risk factors for postoperative death following elective surgical repair of abdominal aortic aneurysm

Abstract

Abstract Background In regional and national studies death within 30 days of elective open surgical repair of an abdominal aortic aneurysm has been reported to be 7–8 per cent or even higher. Identification of preoperative factors associated with this mortality risk is important for informing surgical policy and may suggest suitable preoperative interventions. Methods During the course of the UK Small Aneurysm trial, 820 patients aged 60–80 years underwent elective open surgical repair of an abdominal aortic aneurysm. The relationship between 30-day mortality rate and 13 prespecified potential prognostic factors (including age, sex, aneurysm diameter, electrocardiographic evidence of myocardial ischaemia, lung function, creatinine level, hospital centre and tube or bifurcated graft) was studied. Results The postoperative mortality rate was 5·6 per cent overall (46 deaths in 820 patients). In univariate analyses postoperative mortality risk was associated significantly with higher serum creatinine (P = 0·002), poor lung function with low forced expiratory volume in 1 s (FEV1) (P = 0·003) and older age (P = 0·03). Evidence of the relationship between age and postoperative death was weaker (P = 0·08) after adjustment for creatinine and FEV1. The predicted postoperative mortality risk ranged from 2·7 per cent in younger patients with a low creatinine level and high FEV1 to 7·8 per cent in older patients with above average creatinine levels and below average FEV1. There was no evidence of between-hospital or between-surgeon variability in postoperative risk. Conclusion Poor preoperative lung and renal function were associated strongly with postoperative death. Age was less important once these two prognostic indicators were taken into account. The potential for preoperative improvement in lung and renal function to reduce the postoperative mortality rate should be addressed in future studies.