Abdominal aortic aneurysm surgery

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Vishnu Vardhan Serla M.B.B.S. [3] Ramyar Ghandriz MD[4] Hibatullah Abdul Aleem, M.B.B.S[5]

Overview

Indications for operative repair of an abdominal aortic aneurysm include the presence of symptoms such as back pain or abdominal pain, the presence of a rupture or contained rupture, an abdominal aortic aneurysm diameter greater than 5.5 cm in males or greater than 5.0cm in females, a rate of expansion of greater than 0.5 cm in 6 months or 1 cm in one year, saccular morphology and an inflammatory or infectious aetiology. Open surgical repair is preferred in young patients, lower-risk patients with a life expectancy >10 years, in patients with unfavorable EVAR anatomy, in those unable to comply with lifelong surveillance, and in selected complex aneurysms when fenestrated/branched endovascular options are not available. An endovascular repair (EVAR) is preferred in older patients referred initial treatment modality for most anatomically suitable patients due to lower perioperative mortality, shorter length of stay, and faster recovery, but mandates lifelong surveillance for endoleak and sac behavior. Risk factors for postoperative morbidity and mortality include extensive atheromatous disease, mural calcification, thrombosis, juxtarenal extension of the aneurysm and the presence of inflammatory changes.

Indications

• Symptoms attributable to the aneurysm
• Rupture/contained rupture
• Distal emboli
• Saccular Morphology
• Pain or bowel obstruction
• AAA diameter: ≥5.5 cm in men and ≥5.0 cm in women
• AAA expansion: > 0.5 cm in 6 months or > 1.0 cm in 1 year
• Inflammatory or infectious etiology

Surgery

The treatment options for asymptomatic AAA are immediate repair, surveillance with a view to eventual repair, and a conservative approach. Appropriate patient selection and estimation of the risk of rupture is important, as once rupture occurs, emergency surgery is indicated and mortality from exsanguination is high. There are currently two modes of repair available for an AAA: open aneurysm repair (OR), and endovascular aneurysm repair (EVAR).

Conservative Treatment

• Smoking cessation
• Blood pressure control
• Indicated when repair carries a high risk of mortality and is unlikely to improve life expectancy.

Surveillance

• Surveillance is indicated when the risk of repair exceeds the risk of rupture.
• Although some controversies exist around the world, most vascular surgeons would not consider repair until the aneurysm reached a diameter of 5cm.
• The threshold for repair varies slightly from individual to individual, depending on the balance of risks and benefits when considering repair versus ongoing surveillance.
• The size of an individual's native aorta may influence this, along with the presence of comorbidities that increase operative risk or decrease life expectancy.
• For patients below repair threshold, surveillance ultrasound is recommended every 3 years for AAA 3.0–3.9 cm, annually for 4.0–4.9 cm (or 4.0–4.4 cm in women), and every 6 months for ≥5.0 cm in men or ≥4.5 cm in women.

Open Repair

An open repair is indicated in the following scenarios:

• Young patients as an elective procedure
• Expanding aneurysms
• Symptomatic aneurysms
• Ruptured aneurysms

Advantages:

• superior long-term durability
• lower rates of reintervention
• lower rates of post-repair rupture

Disadvantages:

• higher 30-day mortality
• longer hospital and ICU stay
• long-term risk of laparotomy-related complications (incisional hernia, bowel obstruction).

Endovascular Repair (EVAR)

Endovascular aneurysm repair (EVAR) is now the most commonly performed modality for elective infrarenal AAA in anatomically eligible patients, accounting for more than 75% of intact repairs in contemporary US registry data.

An endovascular repair (EVAR) is indicated in:

• Older patients
• High risk patients or those unfit for open repair

Abdominal aortic endoprosthesis, CT scan, original aneurysm marked in blue

Copyleft image obtained courtesy of http://en.wikipedia.org/wiki/File:Endovasc.jpg; Dr Haudebourg.

Advantages

Advantages of an endovascular repair over an open repair include the following:

• Lower mortality compared to open repair
• Reduced length of stay including a reduced time in the intensive care unit
• Earlier return to normal activity

Disadvantages

Disadvantages of an endovascular repair compared to an open repair include the following:

• Endovascular repair requires more frequent ongoing surveillance and a higher chance of requiring an additional procedure.

Fenestrated and Branched Endovascular Repair

• Approximately 15% of AAAs are juxtarenal (proximal neck <10 mm), pararenal, or suprarenal and are not manageable to standard infrarenal EVAR.
• Historically these required open repair with suprarenal clamping.
• fenestrated EVAR (FEVAR) and branched EVAR (BEVAR) now provide endovascular options that preserve perfusion of the renal and visceral arteries through fenestrations or branched limbs.

Complications

The most common complications related to repair of abdominal aortic aneurysm are related to cardiovascular and pulmonary status. Smokers, patients with co-existent chronic obstructive pulmonary disease and coronary artery disease are more at risk of developing complications such as:

• Myocardial ischemia
• Arrhythmias
• Pneumonia
• Atelectasis

Other complications include:

• Incomplete seal at proximal or distal stent attachment
• Leaking into the sac from branch vessels
• Failure of anastomosis between stent components
• Leakage through graft material
• Graft infection
• Acute renal failure
• Distal embolization
• Wound infection
• Colonic ischemia
• False aneurysm formation
• Aorto-duodenal fistula
• Peri-operative bleeding
• Perianeurysmal aortitis

Post-EVAR Surveillance Protocol

Lifelong imaging surveillance is required after EVAR. A risk-stratified protocol (per ESVS 2024) is recommended:

• Baseline CTA at 30 days to assess seal and detect early endoleak.
• Low-risk patients (adequate seal, no endoleak, stable sac): duplex ultrasound annually, with CTA only for new findings.
• High-risk / EVAR-failure patients (type I or III endoleak, <10 mm proximal seal, sac growth): CTA every 6 months and consideration of reintervention.
• Sac dynamics (shrinkage, stability, or growth) are the most important surveillance metric and should guide reintervention decisions.
• Adherence to surveillance declines over time; structured recall systems improve detection of late endoleak and reduce late mortality.

Pre-Operative Assessment

• The ADAM trial suggested that the "biological age," as reflected by the condition of the vital organs such as the lungs, kidneys, and heart, was more important than the chronological age as a determinant of operative outcome.
• Patients with poor renal and pulmonary function have worse operative outcomes:

  • Chronic obstructive pulmonary disease
  • Elevated creatinine concentrations
  • Electrocardiographic evidence of ischemia

• Aortic factors implicated in postoperative morbidity and mortality include:

  • Extensive atheromatous disease
  • Mural calcification
  • Thrombosis
  • Juxtarenal extension of aneurysm
  • Inflammatory aortic aneurysms
  • The increased risk resulted from:

    • Longer suprarenal clamping time
    • Need for complex dissection
    • Increased hemodynamic stresses

Management of Patients With Peripheral Artery Disease

Management Overview

• 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease

Class I

1. Repair is recommended in men with AAA diameter ≥5.5 cm. (Level of Evidence: B)

2. Repair is recommended in women with AAA diameter ≥5.0 cm. (Level of Evidence: B)

3. Repair is recommended in patients with symptoms attributable to the aneurysm, regardless of diameter. (Level of Evidence: B)

• 2011 and 2005 ACCF/AHA Guidelines for the Management of Patients With Peripheral Artery Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic)

Class I

1. Open or endovascular repair of infrarenal AAAs and/or common iliac aneurysms is indicated in patients who are good surgical candidates. (Level of Evidence: A)

2. Periodic long-term surveillance imaging should be performed to monitor for endoleak, confirm graft position, document shrinkage or stability of the excluded aneurysm sac, and determine the need for further intervention in patients who have undergone endovascular repair of infrarenal aortic and/or iliac aneurysms. (Level of Evidence: A)

Class IIa

1. Open aneurysm repair is reasonable to perform in patients who are good surgical candidates but who cannot comply with the periodic long-term surveillance required after endovascular repair. (Level of Evidence:C)

Class IIb

1. Endovascular repair of infrarenal aortic aneurysms in patients who are at high surgical or anesthetic risk as determined by the presence of coexisting severe cardiac, pulmonary, and/or renal disease is of uncertain effectiveness. (Level of Evidence:B)

Multidisciplinary Care and Shared Decision-Making

Class I

1. Patients with extensive asymptomatic aortic disease, multiple comorbidities, or those requiring complex open or endovascular aortic repair should be referred to a high-volume centre with an experienced multidisciplinary aortic team. (Level of Evidence: B)

2. Shared decision-making is recommended in determining thresholds for intervention, deciding on the type of surgical repair, choosing between open surgical and endovascular approaches, and in medical management and surveillance decisions. (Level of Evidence: C)

3. Patients with acute aortic disease who require urgent repair should have their treatment plan developed by a multidisciplinary team with expertise in the management of aortic disease. (Level of Evidence: B)

Visceral Artery Aneurysms

Class I

1. Open repair or catheter-based intervention is indicated for visceral aneurysms measuring 2.0 cm in diameter or larger in women of childbearing age who are not pregnant and in patients of either gender undergoing liver transplantation. (Level of Evidence: B)

Class IIa

1. Open repair or catheter-based intervention is probably indicated for visceral aneurysms 2.0 cm in diameter or larger in women beyond childbearing age and in men. (Level of Evidence: B)

Symptomatic Aortic or Iliac Aneurysms

Class I

1. In patients with the clinical triad of abdominal and/or back pain, a pulsatile abdominal mass, and hypotension, immediate surgical evaluation is indicated. (Level of Evidence: B)

2. In patients with symptomatic aortic aneurysms, repair is indicated regardless of diameter. (Level of Evidence: C)

Aortic Aneurysm Rupture

Class I

1. Patients with infrarenal or juxtarenal AAAs measuring 5.5 cm or larger should undergo repair to eliminate the risk of rupture. (Level of Evidence: B)

2. Patients with infrarenal or juxtarenal AAAs measuring 4.0 to 5.4 cm in diameter should be monitored by ultrasound or computed tomographic scans every 6 to 12 months to detect expansion. (Level of Evidence: A)

Class IIa

1. Repair can be beneficial in patients with infrarenal or juxtarenal AAAs 5.0 to 5.4 cm in diameter. (Level of Evidence: B)

2. Repair is probably indicated in patients with suprarenal or type IV thoracoabdominal aortic aneurysms larger than 5.5 to 6.0 cm. (Level of Evidence: B)

3. In patients with AAAs smaller than 4.0 cm in diameter, monitoring by ultrasound examination every 2 to 3 years is reasonable. (Level of Evidence: B)

Class III (No Benefit)
1. Intervention is not recommended for asymptomatic infrarenal or juxtarenal AAAs if they measure less than 5.0 cm in diameter in men or less than 4.5 cm in diameter in women. (Level of Evidence: A)