Analysis reveals correlation between surgeon annual volume and mortality for the repair of abdominal aortic aneurysms

AAA repair

An AAA repair is typically performed on patients that have an enlarged aorta exceeding 5.5cm and there are two procedures available. One option is an open procedure, which involves a large incision made in the abdomen of a patient to insert a graft. The other is an endovascular (EVAR) procedure, which involves making a small incision in the groin through which instruments are inserted into the artery via a catheter and threaded up to the aneurysm. A stent and graft are then placed to support the aneurysm.

Analysis

Using Hospital Episode Statistics data, we analysed 11,745 elective open AAA repairs and 24,544 elective EVAR AAA repairs between April 2009 and March 2019. Surgeon annual volume included any repair of AAA performed by the surgeon within the year prior to the index procedure. The study adjusted for case-mix (age on admission, sex, index of multiple deprivation, and comorbidities that tested significant including congestive heart failure and renal disease) as well as provider annual volume and year of index operation.

Findings

For open repairs of AAA, surgeon annual volume was found to be a significant variable influencing mortality, with a strong negative exponential trend (Figure 2). It was not found to be statistically significant for mortality following EVAR procedures (Figure 4). Respectively, the crude rates of mortality were 3.62 per cent and 0.75 per cent as shown in Figures 1 and 3. The analysis suggests that an increase in the number of AAA repairs a surgeon performs in a year would marginally decrease the odds of mortality following open procedures.

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Figure 1 – Relationship between surgeon annual volume and the crude death rate for elective open repairs of AAA

Figure 2 – Relationship between surgeon annual volume and the adjusted probabilistic rate of death for elective open repairs of AAA

Figure 3 – Relationship between surgeon annual volume and the crude death rate for elective EVAR repairs of AAA

Figure 4 – Relationship between surgeon annual volume and the adjusted probabilistic rate of death for elective EVAR repairs of AAA