EVAR vs Open Repair for Abdominal Aortic Aneurysm: How the Decision Is Made

Once an abdominal aortic aneurysm (AAA) has reached the size, growth rate or symptoms at which repair is advised, there are two ways to repair it. Open repair replaces the weakened segment with a fabric graft through an abdominal incision. Endovascular aneurysm repair (EVAR) relines the aorta from the inside with a stent-graft delivered through the groin arteries. Both work. They differ in how hard the first weeks are, how durable the repair is, and how much follow-up they demand. This page sets out the evidence and the reasoning so that the conversation in clinic starts from an informed position.

Two ways to repair the same aneurysm

Open repair has been performed since the 1950s. It involves a general anaesthetic, a laparotomy or flank incision, clamping of the aorta and sewing in a graft. Recovery means several days in hospital, often including a period in intensive care, and some weeks before normal activity. Once healed, the repair is usually permanent and routine imaging follow-up is not normally required.

EVAR, introduced in the 1990s, places a stent-graft inside the aneurysm through small groin punctures or incisions, usually under regional or general anaesthetic. Most people go home within a day or two and are back to normal activity within one to two weeks. The aneurysm sac is left in place around the graft, which is why EVAR needs lifelong imaging surveillance: the graft can move, leak or lose its seal as the aorta changes shape over years.

Watch: EVAR: Repairing an Aortic Aneurysm from Within · Read: EVAR for aortic aneurysms in Singapore

What the trials actually showed

Four randomised trials compared EVAR with open repair in people fit enough for either operation. Their long-term results, rather than their headline early results, are what shape today's advice.

Pooled analysis of the trials shows the pattern clearly: EVAR saves lives in the first weeks and months, the two approaches are equivalent through the middle years, and in the later years the balance tips towards open repair in some datasets because of late failure of early-generation stent-grafts. Modern devices, better anatomical selection and disciplined surveillance are expected to narrow that late gap, but 15-year data on current devices do not yet exist.

Why NICE and the ESVS disagree

In 2020 the UK's National Institute for Health and Care Excellence (NICE NG156) took the long-term trial data at face value and recommended open repair for unruptured AAA in people fit for it, with EVAR reserved for those whose medical condition rules out open surgery. The European Society for Vascular Surgery, in its 2019 and 2024 guidelines, reached a different conclusion: either repair may be offered, with the choice individualised to anatomy, age, life expectancy, surgical risk and the patient's own preference. The ESVS leans towards EVAR in older or higher-risk patients and towards open repair in younger, fit patients with a long life expectancy, and it stresses that EVAR must be followed by lifelong surveillance to be safe.

The disagreement is not about the data; it is about how to weigh an early, certain benefit against a late, uncertain one, and how much confidence to place in newer devices. In practice most vascular surgeons in Singapore and internationally follow the European position: the right operation is the one that fits the individual.

Anatomy: who is suitable for EVAR

EVAR depends on the stent-graft sealing against healthy artery above and below the aneurysm. The CT angiogram is therefore the first decider. The features that matter are:

• The neck – the segment of normal aorta between the renal arteries and the aneurysm. A neck that is too short, too wide, sharply angled, cone-shaped or lined with thrombus or calcium makes a durable seal less likely. Short or absent necks may be treatable with fenestrated or branched stent-grafts, which is a different procedure with its own trade-offs.
• The iliac arteries – the delivery system has to pass through them, and the graft limbs have to seal in them. Narrow, tortuous or heavily calcified iliac arteries, or aneurysms that extend into them, complicate EVAR.
• The overall shape – a very tortuous aneurysm or one with a large thrombus load can affect both the delivery and the long-term stability of the graft.

Pushing a standard EVAR into anatomy outside the manufacturer's instructions for use is associated with more endoleaks and reinterventions. When the anatomy is marginal, the honest choice is often between a complex endovascular repair and open surgery rather than between standard EVAR and open surgery.

Fitness, age and life expectancy

Open repair is a bigger physiological insult: the aorta is clamped, there is more blood loss and the recovery is longer. People with significant heart, lung or kidney disease, previous abdominal surgery or frailty may not tolerate it, and for them EVAR's early safety advantage is decisive. Conversely, a fit person in their sixties with an expected life of twenty years or more will live long enough for EVAR's late disadvantages to matter and for the burden of annual surveillance to accumulate. A single, durable open repair can be the better investment for that person, provided their anatomy and fitness allow it.

Formal assessment usually includes cardiopulmonary exercise testing or an equivalent functional assessment, blood tests of kidney function, and a review by an anaesthetist. The aim is to estimate the risk of each operation for you specifically, not for an average patient.

Surveillance and reintervention

After EVAR, imaging follow-up is lifelong: typically a scan within the first month or two, then annually, with the method (duplex ultrasound, CT or both) chosen to balance accuracy against radiation and contrast exposure. Roughly one in five people will need a further procedure in the ten years after EVAR, most of them minor and endovascular, to deal with endoleaks, limb narrowing or graft migration. Missing surveillance is the single most important cause of late EVAR failure; our page on aortic stent surveillance and endoleaks explains what is checked and why, and what to do if you have lost touch with follow-up after a repair elsewhere.

After open repair, reintervention is uncommon. Late problems do occur – incisional hernias, and rarely aneurysms forming at the graft edges – so a scan every few years is reasonable, but the intensity of follow-up is much lower.

When the aneurysm is not straightforward

Aneurysms that involve the renal or visceral arteries, extend into the chest, or arise in people with a connective-tissue or heritable aortic condition sit outside the standard EVAR-versus-open question. Options there include fenestrated and branched EVAR, open thoracoabdominal repair and hybrid procedures, and the decision depends heavily on the experience of the team. These are the cases where a second opinion from a surgeon who offers both open and endovascular repair is most valuable, because the recommendation should not be limited by what one team happens to do.

Questions to ask your surgeon

• Is my anatomy within the instructions for use of the device you are proposing? If not, what are the alternatives?
• Do you perform both open and endovascular repair, and roughly how many of each a year?
• What is my estimated risk from each operation, and how was it assessed?
• If I have EVAR, what will surveillance involve, how often, and who is responsible for arranging it?
• What is the likelihood I will need a further procedure, and what would it typically be?
• If I am fit for both, which would you choose for yourself at my age, and why?

Getting a second opinion in Singapore

Sudden severe abdominal or back pain, collapse or a cold painful leg in someone with a known aneurysm needs emergency assessment: call 995 in Singapore.

Common questions about EVAR versus open repair

Is EVAR always the safer option?

It is safer in the first month. Over ten years and more, the trials found survival to be similar, and in one large trial EVAR did worse in the later years because of late sac ruptures. Safety therefore depends on the time horizon that matters for you.

Can I have EVAR and simply skip the follow-up scans?

No. Surveillance is part of the treatment. A stent-graft that is leaking or has moved can allow the aneurysm to grow and rupture without any symptoms, and the trials show that most of EVAR's late problems are detectable and treatable if looked for.

If open repair is more durable, why is EVAR done so often?

Because many people with aneurysms are older or have other illnesses that make open surgery risky, and because the recovery from EVAR is far easier. For them the early advantage outweighs the later uncertainty. The debate is really about fit, younger patients, for whom either operation is reasonable and the choice should be shared.

Does it matter whether my surgeon does both operations?

It helps. A surgeon who offers only one technique has an obvious reason to recommend it. A surgeon who does both can match the operation to your anatomy and fitness rather than the other way around.