A multicentre, retrospective database analysis suggests improved open abdominal aortic aneurysm (AAA) outcomes when surgeon volume is greater than seven cases yearly and performed in hospitals with a 30-day mortality rate less than 5%.
“Open AAA repair has decreased in frequency owing to the increasing adoption of endovascular techniques, prompting concern that the decreased yearly clinical experience will affect operative results,” said senior author Adam Doyle (University of Rochester Medical Center, Rochester, USA).
The Society for Vascular Surgery (SVS) published updated practice guidelines in 2018 that recommended open AAA repair be limited to centres that meet a case volume threshold and outcome target. Specifically, open AAA repair should be conducted in centres that have a mortality rate of less than 5% and that perform at least 10 open repairs per year. Doyle said: “In the present study, we used a pragmatic approach to gauge the effect of the SVS guidelines by analysing two groups—one that met the recommendations versus one that did not. We then tried to determine if surgeon versus hospital volume was more important for good outcomes.”
As reported in the February 2022 edition of the Journal of Vascular Surgery, Doyle and colleagues utilised the Statewide Planning and Research Cooperative System (SPARCS) managed by the New York Department of Health to determine mortality and morbidity following open AAA repair between the two groups.
The study, which queried records from 2000–2014, involved 7,594 patients treated by 542 surgeons at 137 hospitals. The annual open AAA repair case volume averaged:
- 12.9 (median seven) for the hospitals, and
- Five (median three) for the surgeons
Overall, 4,000 cases were performed in centres meeting the SVS criteria versus 3,594 cases performed in centres that did not. Comparing outcomes between the groups, the researchers noted significant differences in:
Centres meeting criteria:
- One-year mortality 9.2%
- 30-day mortality 3.5%
Centres not meeting criteria:
- One-year mortality 13.6% (p<0.001)
- 30-day mortality 6.9% (p<0.001)
Of note, complication rates between the groups were similar except the rate of pulmonary complications, which was significantly lower in centres meeting the SVS criteria.
“In the present study, we attempted to bring previous theoretical volume-outcome work into the practical sphere by directly evaluating current guidelines,” said Doyle. “These data showed a positive correlation between the 2018 SVS AAA guidelines and outcomes for elective open AAA repair within the SPARCS dataset.
“Further, whether the surgeon volume or hospital volume better predicts outcomes has been disputed. Our analysis suggests the superior outcomes are achieved by surgeons who perform greater than seven open AAA cases yearly and by centres with an established open AAA 30-day mortality rate of less than 5%.”
Doyle suggested: “This supports centralising elective open AAA operations to higher-volume surgeons at high-quality centres. This may have educational value for trainees as high-volume surgeons tend to practice at teaching hospitals.”
Each year, nearly 200,000 people in the USA are diagnosed with an AAA, the authors note, adding that approximately 15,000 people die each year from a ruptured AAA.
This study supports the SVS guidelines for open AAA repair and provides guidance for patients who have the opportunity to choose where and by whom their aneurysm is to be fixed, JVS editors said.