Analysis suggests reassessment of operative threshold for AAA repair during COVID-19

Brandon McGuinness

According to a recent analysis, the decision to delay operative repair of abdominal aortic aneurysm (AAA) should consider both patient age and local COVID-19 prevalence in addition to aneurysm size. Furthermore, endovascular aneurysm repair (EVAR) should be considered when possible due to a reduced risk of harm and lower resource utilisation.

Writing in the Journal of Vascular Surgery, Brandon McGuinness (McMaster University, Hamilton General Hospital, Hamilton, Canada) and colleagues note that the worldwide COVID-19 pandemic has forced healthcare systems to delay elective operations, including AAA repair, to conserve resources. The present study provides a structured analysis of the decision to delay AAA repair and quantify the potential for harm.

The investigators constructed a decision tree modelling immediate repair of AAA relative to initial non-operative (delayed repair) approach. They considered risk of COVID-19 contraction and mortality, aneurysm rupture, and operative mortality.

McGuinness and colleagues performed a deterministic sensitivity analysis for a range of patient ages (50 to >80), probability of COVID-19 infection (0.01–30%), aneurysm size (5.5–>7cm), and time horizons (3–9 months). They also conducted probabilistic sensitivity analyses (PSA) for three representative ages (60, 70, 80), and analyses for EVAR and open surgical repair.

McGuinness et al report that patients with aneurysms 7cm or greater demonstrated a higher probability of survival when treated with immediate EVAR or open surgical repair, compared to delayed repair, for patients under 80 years of age.

When considering EVAR for aneurysms 5.5–6.9cm, immediate repair had a higher probability of survival except in settings with high probability of COVID-19 infection (10–30%) and advanced age (70–85+ years). In addition, a non-operative strategy maximised the probability of survival as patient age or operative risk increased.

Probabilistic sensitivity analyses demonstrated that patients with large aneurysms (>7cm) faced a 5.4–7.7% absolute increase in the probability of mortality with a delay of repair of three months. The authors also note that young patients (60–70 years) with 6–6.9cm aneurysms demonstrated an elevated risk of mortality (1.5–1.9%) with a delay of more than three months. Those with 5–5.9cm aneurysms demonstrated an increased survival with immediate repair in young patients (60), however this was small in magnitude (0.2–0.8%).

Finally, they state that the potential for harm increased as length of surgical delay increased. For elderly patients requiring open surgical repair, in the content of endemic COVID-19, delay of repair improves probability of survival.

Speaking to Vascular News, McGuinness comments on the study findings: “It is important to focus on more than aneurysm size when deciding to delay operative repair of a AAA. Practitioners need to consider the risk their patient faces of perioperative mortality as well as COVID related mortality.”

He adds: “Patients with low operative risk stand to gain the greatest net benefit from operative repair. If they are young and at a low risk of COVID related mortality, they take on a greater risk with delay of surgery. This paper aims to contextualise these other considerations that should go into decision making along with aneurysm size.”

The authors do acknowledge, however, the “constantly evolving” nature of the COVID-19 pandemic and warn that the length of time these recommendations are applicable to practice is “hard to predict”.


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