Less than a quarter of aortic centres meet optimal open AAA repair volume threshold in new study

Salvatore Scali

In an assessment of open aortic surgery by the International Consortium of Vascular Registries (ICVR), 13–16 procedures per year predicted the most significant reduction in mortality after intact open abdominal aortic aneurysm (AAA) repair. However, researchers found that only 23% of centres across 11 countries met the ≥13 procedures per year volume threshold, with considerable variation between nations.

Writing in the European Journal of Vascular and Endovascular Surgery (EJVES), Salvatore Scali (University of Florida College of Medicine, Gainesville, USA) and colleagues note that the twofold purpose of their analysis was to identify an “optimal centre volume threshold” that is associated with the most significant mortality reduction after open AAA repair, and also determine how this reflects contemporary practice.

In their observational study, the investigators focused on open AAA repairs performed between the years 2010 and 2016 among 11 countries within the ICVR database—a total of 178,302 procedures. The primary endpoint of the study was postoperative in-hospital mortality.

Overall, the research team analysed 154,912 (86.9%) intact and 23,390 ruptured AAAs. Among all patients, a majority (63.1%; n=112,557) underwent endovascular aneurysm repair (EVAR), while the remaining 65,745 patients received open AAA repair, they state.

Scali et al report in EJVES that “a significant inverse relationship” between increasing centre volume and lower perioperative mortality after intact and ruptured open AAA was evident (p<0.001), but not with EVAR.

In addition, they highlighted that an annual centre volume between 13 and 16 procedures per year was associated with the most significant mortality reduction after intact open AAA repair (adjusted predicted mortality < 13 procedures per year, 4.6%; 95% confidence interval [CI], 4–5.2%] vs. > 13 procedures per year, 3.1%; 95%CI, 2.8–3.5%).

The researchers also found that the mean number of open AAA repairs per centre, for both intact and ruptured AAAs, decreased significantly (2010–2013 = 35.7 vs. 2014–2016 = 29.8; p<0.001). In fact, they report that only 23% of centres (n = 240 of 1,065) met the > 13 procedures per year volume threshold. Elaborating on this finding, they noted “significant variation” between nations—in Germany, for example, only 11% of centres met the threshold, while in Denmark, the figure was 100%.

Scali et al concluded that achieving the “optimal” threshold of ≥ 13 procedures per year requires “significant reorganisation of open AAA repair practice delivery in many countries, and would affect provision of non-elective aortic services”. They add: “Low volume centres continuing to offer open AAA repair should aim to achieve mortality results equivalent to the high-volume institution benchmarks, using validated data from quality registries to track outcomes.”

Commenting on this collaborative Vascunet/ICVR study involving data from vascular registries in Europe, the USA, and Australasia, Scali and Kevin Mani (Uppsala University, Uppsala, Sweden), co-chair of the ICVR collaboration and senior author, state: “This study underscores the changing landscape of aortic practice in many countries, and the reduced number of open aortic repairs that requires future adaptation of vascular services. It also shows the power of registry collaboration within the ICVR to allow for large scale, international studies of vascular practice, and identify areas for further improvement of care delivery.”


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