What is the reduction in rupture risk with Endovascular Aneurysm Repair (EVAR) in infra-renal Abdominal Aortic Aneurysm (AAA) patients?

From the Guidelines

EVAR significantly reduces rupture risk in patients with infrarenal Abdominal Aortic Aneurysms (AAAs), but the actual reduction rate is not explicitly stated in the provided evidence as a direct comparison to no intervention. However, according to the most recent and highest quality study provided 1, EVAR has a higher risk of aneurysm-related death, secondary intervention, aneurysm rupture, and death attributable to rupture compared to open repair after 8 years. The study found that the risk of aneurysm rupture is higher in EVAR patients with an odds ratio of 5 (95% CI, 1.1–23.3) compared to open repair. This suggests that while EVAR provides immediate benefits, its long-term outcomes may not be as favorable as open repair in terms of rupture risk.

Key considerations for EVAR include:

• Patient-specific anatomical characteristics of the aorta, such as neck diameter, length, and angulation, and iliac seal diameter, length, and vessel access, which must be considered in endovascular repair 1.
• The importance of adhering to the manufacturer's instructions for use to minimize the risk of graft migration, endoleaks, late rupture, and deaths 1.
• The need for lifelong surveillance with imaging to monitor for potential complications such as endoleaks, graft migration, or continued aneurysm growth 1.

In terms of the reduction in rupture risk, while the exact percentage is not provided in the evidence, it is clear that EVAR does reduce the risk of rupture, but the long-term benefits may be offset by the increased risk of aneurysm-related complications compared to open repair. Therefore, the decision to use EVAR should be made on a case-by-case basis, taking into account the individual patient's anatomy, comorbidities, and ability to comply with follow-up imaging requirements. The most important factor is to prioritize the patient's morbidity, mortality, and quality of life when making treatment decisions.

From the Research

Reduction in Rupture Risk with EVAR

• The reduction in rupture risk with Endovascular Aneurysm Repair (EVAR) in infra-renal Abdominal Aortic Aneurysm (AAA) patients is a significant consideration in treatment options.
• Studies have shown that EVAR can reduce the risk of rupture in infra-renal AAA patients, with one study indicating that the 30-day mortality rate for EVAR patients was 17% compared to 32% for conventionally treated patients 2.
• Another study found that EVAR is associated with lower incidence of post-operative acute renal failure, with an odds ratio for mortality after open repair of 1.94 compared to EVAR 3.
• A study comparing EVAR and open surgical repair for ruptured infra-renal abdominal aortic aneurysm found that EVAR was associated with lower 30-day mortality and better 5-year survival rates 4.

Comparative Outcomes

• A comparative study of infrarenal EVAR for penetrating aortic ulcer and abdominal aortic aneurysm found that technical success, 30-day morbidity, reintervention, complications, and mortality were comparable between the two groups 5.
• The study also found that late freedom from reintervention and survival were comparable between the two groups, suggesting that EVAR is a viable treatment option for infrarenal penetrating aortic ulcers.

Predicting Ultimate Failure

• A study analyzing the causes and timing of AAA rupture after EVAR found that most ruptures occurred within 2-3 years after EVAR, and that focus on surveillance during this period may reduce the AAA rupture rate 6.
• The study also found that structural graft failure was described in 96 patients, and a fatal course in 119 patients, highlighting the need for better stent-graft durability and longevity to reduce the AAA rupture risk after EVAR.

Long-term Survival

• A study found that EVAR reduces the 30-day mortality and improves long-term survival up to 5 years for patients with ruptured abdominal aortic aneurysms, with a cumulative 5-year survival rate of 37% for EVAR patients compared to 26% for open surgical repair patients 4.
• However, the study also found that almost one fourth of EVAR patients required secondary interventions, highlighting the need for close follow-up of all EVAR survivors.