Recommendations
Key Recommendations
If the patient has a suspected ruptured or symptomatic AAA, get immediate help from a senior colleague to organise immediate imaging (with either bedside aortic ultrasound or contrast-enhanced computed tomography angiography [CTA]) and discuss with a regional vascular service.[42] Do not delay diagnosis and management of a ruptured AAA while waiting for the results of imaging.[69]
Suspect ruptured AAA in any patient presenting with new abdominal and/or back pain, cardiovascular collapse, or loss of consciousness, particularly if aged over 60 years.[3][42]
A patient with an unruptured AAA is usually asymptomatic. In the minority of patients who experience symptoms, abdominal, flank, or back pain are typical.[3] Unruptured AAA may be found incidentally on physical examination or imaging performed for other reasons such as screening.
Guidelines differ in their recommendations for diagnostic imaging for suspected ruptured or symptomatic AAA. In the UK, the National Institute for Health and Care Excellence (NICE) recommends bedside aortic ultrasound as first line.[42]
Palpate the abdomen to look for a pulsatile epigastric mass in any patient with suspected ruptured or intact AAA. However, be aware that abdominal palpation has a low sensitivity for detection of AAA. Detection rates are affected by aortic diameter, clinician experience, and body habitus of the patient.[3] The sensitivity of abdominal palpation for detecting AAA decreases in patients with an abdominal girth more than 100 cm.[70]
Aortic ultrasound is also used for surveillance of an asymptomatic AAA to guide decisions on surgical repair versus conservative management with surveillance.[3][42]
Smoking is the most important risk factor for development, expansion, and rupture of AAA.[3]
Suspect ruptured AAA in a patient with new abdominal and/or back pain, cardiovascular collapse, or loss of consciousness.[3][42] Index of suspicion should be particularly high if they are aged over 60, male, or have:[3][13][42][48][49][71][72][73][74]
An existing diagnosis of AAA
A current or previous history of smoking
A history of hypertension
A family history of AAA
Previous cardiac or renal transplant.
Practical tip
Symptoms of ruptured AAA may mimic those of renal colic, especially in older patients.[69]
Unruptured AAAs are usually asymptomatic.[3][4]
In the minority of patients who experience symptoms, abdominal, flank, or back pain are typical. Less commonly, they may experience pelvic, groin, or thigh pain.
Symptoms may also be related to complications, either by compression of nearby organs (duodenal obstruction, lower limb oedema, ureteral obstruction) or distal embolism.[3]
Ask about risk factors for AAA, which include:[1][3][13][14][22][42][54][57][60][61]
Smoking
Current or previous history of smoking is the strongest risk factor for AAA.[3] It increases a patient's risk of AAA development, expansion, and rupture.[3][13][22][23][43][72]
In men who have never smoked, the most important risk factors for AAA include older age and a first-degree relative with a AAA.[4]
Family history of AAA
Older age
Congenital/connective tissue disorders
Hypertension
Coronary, cerebrovascular, or peripheral arterial disease
COPD
Hyperlipidaemia.
More info: Risk factors
Risk factors that increase the risk of expansion of known AAA include smoking, previous cardiac or renal transplant, previous stroke, older age (>70 years), and severe cardiac disease.[3][73][74][75]
The prevalence of AAA is higher in men than in women, meaning that men account for around 4-5 times the overall total number of ruptured AAAs compared with women.[50][51] However, women have a higher rate of AAA rupture than men.[42]
Evidence suggests that diabetes protects against the growth and enlargement of AAA.[26][27][28] However, the protective mechanism is yet to be determined. Operative and long-term survival is lower among AAA repair patients with diabetes than those without, suggesting an increased cardiovascular burden.[26][29]
In addition, ask about a history of previous abdominal surgery or previous endovascular aortic aneurysm repair.
Signs of a ruptured AAA are usually dramatic and include pallor, haemodynamic collapse, and abdominal distension.[3][69]
Palpate the abdomen to look for a pulsatile epigastric abdominal mass and pain or tenderness in any patient with suspected ruptured or intact AAA.
The classic triad of a pulsatile abdominal mass with hypotension and abdominal and/or back pain is present in about 50% of patients with a ruptured AAA.[3]
However, be aware that abdominal palpation has a low sensitivity for detection of AAA. Detection rates are affected by aortic diameter, clinician experience, and body habitus of the patient.[3] The sensitivity of abdominal palpation for detecting AAA decreases in patients with an abdominal girth more than 100 cm.[70]
Include in your examination an assessment for peripheral artery aneurysm (femoral and popliteal).[76]
Consider infectious AAA if a patient has a fever.
Typically there is also a history of arterial trauma, intravenous drug misuse, local or concurrent infection, bacterial endocarditis, or impaired immunity.
Aortic ultrasound
If the patient has a suspected ruptured or symptomatic AAA, get immediate help from a senior colleague to organise immediate imaging (with either bedside aortic ultrasound or contrast-enhanced computed tomography angiography [CTA]).[3][42] Do not delay diagnosis and management of a ruptured AAA while waiting for the results of imaging.[69]
Guidelines differ in their recommendations for diagnostic imaging for suspected ruptured or symptomatic AAA. In the UK, the National Institute for Health and Care Excellence (NICE) recommends bedside aortic ultrasound as first line.[42] Contrast-enhanced CTA is recommended as first-line imaging, over bedside aortic ultrasound, by some guidelines.[3][42][69]
Discuss the patient with a regional vascular service if:[42][69]
AAA is confirmed on bedside aortic ultrasound
OR
Bedside aortic ultrasound is not immediately available or is non-diagnostic but AAA is still suspected.
Bedside ultrasound can confirm the presence and size of an AAA, but cannot definitively rule out a ruptured AAA.[69]
A normal-sized aorta viewed on ultrasound in the presence of severe hypotension does not exclude the diagnosis of ruptured AAA or other abdominal pelvic aneurysm.[69] Consider contrast-enhanced CTA for these patients. See Computed tomography angiography (CTA) below.
However, ultrasound confirmation of AAA in a patient with symptoms or signs of rupture supports the diagnosis of a ruptured AAA.[69]
Aortic ultrasound is also used for:
Surveillance of asymptomatic AAA to guide treatment decisions with either surgical repair or conservative management[3][42]
Follow-up after surgery with endovascular aneurysm repair (EVAR) (using colour duplex ultrasound).[42]
Computed tomography angiography (CTA)
Once the diagnosis of AAA is made, contrast-enhanced CTA is used to assess the extent and anatomy of disease and to assist with operative planning (open or endovascular).[3][42][77]
Contrast-enhanced CTA is the recommended definitive imaging modality for AAA rupture, and is also recommended as first-line imaging, over bedside aortic ultrasound, by some guidelines.[3][42][69] Do not delay diagnosis and management of a ruptured AAA while waiting for the results of imaging.[69]
CTA should be performed in a haemodynamically stable patient, and preferably after transfer to a regional vascular centre if the clinical diagnosis of ruptured AAA is clear without CTA.[3][42][69]
It should also be considered for definitive diagnosis of ruptured AAA if a normal-sized aorta is viewed on ultrasound in the presence of severe hypotension.[69] In this scenario, ultrasound does not exclude the diagnosis of ruptured AAA or other abdominal pelvic aneurysm.[69]
CTA is also important for follow-up after surgical repair with EVAR.[3][42]
Positron emission tomography-computed tomography (PET-CT)
Used for the diagnosis and follow-up of aortic pathologies associated with inflammatory aneurysm, aortic infection (including mycotic AAAs), infected prostheses, and stent grafts.[3][78]
Laboratory tests
If a patient has a suspected ruptured or symptomatic AAA, send blood samples for cross match and a clotting screen.
Full blood count may show anaemia if there is haemorrhage due to ruptured AAA. Leukocytosis and a relative anaemia with positive blood cultures are indicative of infectious AAA.[12]
Elevated erythrocyte sedimentation rate and C-reactive protein support a diagnosis of possible inflammatory AAA.[3][7]
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