EVAR trial

Abdominal aortic aneurysm is a common condition that affects approximately 5% of men and 1% of women over 60 years of age. Abdominal aortic aneurysms are swellings that enlarge over time, and may cause death if they burst (rupture).

Endovascular (abdominal aortic) aneurysm repair (EVAR) involves the introduction of a stent graft into the area affected by the aneurysm. Once in place, blood flows through the stent and this removes the pressure from the area of the aorta affected by the aneurysm and hence reduces the risk of rupture. 

The procedure has been widely used in Australia since the early 1990s and is now considered the treatment of choice for AAA by many clinicians. Before its introduction, open repair was the only alternative surgical treatment for this condition and continues to be used by many surgeons in Australia. Generally, EVAR is safer than open repair in the short term, but may result in more complications over time.

Between 1998 and 2006, an Australian study (audit) of the procedure was undertaken through the research arm of the Royal Australasian College of Surgeons (ASERNIP-S ). The study looked at the mid to long-term outcomes for patients after the EVAR procedure and results were reported to the Australian Government. Based on the strength of evidence pertaining to the audit, in 2007 the Minister for Health and Ageing endorsed the recommendation that the procedure should receive public funding.

The results of the audit were also used to develop a model to predict whether some individuals are more likely to have a better outcome after the procedure, based on their pre-operative information. The model has been made widely available and has been scrutinised through the process of peer-review in the published literature.

The aim of this study is to assess how good the model is at predicting outcomes after EVAR for a new cohort of patients and to determine whether additional pre-operative information will help to make it more accurate.