Relation between hospital volume and outcome of elective surgery for abdominal aortic aneurysm: a systematic review

OBJECTIVES: Our aim was to analyse the relation between hospital volume and peri-operative mortality in abdominal aortic aneurysm surgery. DESIGN: Systematic review. METHOD: The Medline, Embase and Cochrane databases were searched to identify all population based studies reporting on the volume outcome relationship published between 1966 and 2006. Two independent observers performed methodological quality assessment and data extraction. Outcome was 30-day or in-hospital mortality in relation to hospital volume. RESULTS: Twenty-four articles were included. Overall peri-operative mortality ranged from 2.3 to 9.9%. The cut-off values for a high- or low-volume hospital appeared to range from 8 to 50 operations annually. The peri-operative mortality in low volume hospitals (LVH) ranged from 3.0 to 13.8% (median 6.2%) and from 1.8 to 7.4% in high volume hospitals (HVH) (median 4.3%). In 14 studies a significantly lower mortality was found in HVH as opposed to LVH; in 10 articles no such difference between HVH and LVH could be proved. CONCLUSION: We found some evidence for a relation between the volume of AAA surgery and peri-operative mortality. There seems to be a nonsignificant trend in favour of high volume hospitals. However we could not derive an unequivocal volume threshold for safely performing AAA surgery