AAA Screening: Why So Few Patients Get Tested

Citable definition: An abdominal aortic aneurysm (AAA) is a localized, permanent dilatation (abnormal widening) of the abdominal aorta — the main blood vessel supplying the lower body — to a diameter of 3 cm or more. Because AAA typically causes no symptoms until rupture, population-based ultrasound screening programs have been shown to reduce AAA-related mortality in high-risk groups (Scott et al., The Lancet, 2002).

What Is an Abdominal Aortic Aneurysm?

The aorta is the body’s largest artery, running from the heart down through the chest and abdomen before branching into the legs. In some people, the wall of the aorta weakens over time, causing it to bulge outward like a worn tire. When this bulge occurs in the section of the aorta that runs through the abdomen, it is called an abdominal aortic aneurysm, or AAA.

The danger is straightforward but brutal: as the aneurysm grows, the risk of sudden rupture (tearing open) increases dramatically. A ruptured AAA is a catastrophic surgical emergency with an overall mortality (death rate) exceeding 80% when all out-of-hospital deaths are counted. Yet when AAA is detected before rupture — through a routine ultrasound scan — elective (planned) repair carries a mortality of under 5% at experienced vascular centers.

This gap between preventable death and actual outcomes is the central tragedy of AAA management. And it begins with a screening gap.

For a broader overview of arterial conditions affecting the aorta and major vessels, see our arteries section.

Who Is at Risk?

Understanding who develops AAA helps explain why screening programs target specific populations.

Age and sex are the dominant risk factors. AAA is predominantly a disease of older men. In a landmark prevalence study of veterans in the United States, Lederle and colleagues (1997) found that AAA (defined as aortic diameter ≥ 3.0 cm) was detected in approximately 4.7% of men aged 65–75, according to available data; however, as no abstract was available for verification, readers should note this figure is cited as reported in secondary literature (Lederle FA et al., Archives of Internal Medicine, 1997). The same study confirmed that prevalence rose sharply with age and was substantially lower in women — though not negligible.

Smoking is the single most powerful modifiable risk factor. Former and current smokers carry a risk three to five times higher than non-smokers. Hypertension (high blood pressure), atherosclerosis (hardening and narrowing of the arteries), family history of AAA, and chronic obstructive pulmonary disease (COPD) are also well-established risk factors.

Conversely, diabetes mellitus appears to be inversely associated with AAA — a paradox that continues to intrigue vascular researchers.

Symptoms — Or the Dangerous Lack of Them

This is the central clinical problem: most AAAs produce no symptoms whatsoever until they rupture or expand rapidly.

When symptoms do occur, they may include:

• Pulsating sensation in the abdomen — some patients describe feeling their own heartbeat in their belly
• Deep, persistent back or flank pain — often mistaken for musculoskeletal problems or kidney issues
• Abdominal discomfort — vague and easily attributed to other causes

The classic triad of rupture — sudden severe abdominal or back pain, hypotension (dangerously low blood pressure), and a pulsatile abdominal mass — is a medical emergency requiring immediate surgery. Sadly, many patients never reach the operating table.

Because symptoms are absent in the vast majority of cases, incidental discovery during imaging for another condition, or proactive screening, are the only realistic routes to early detection.

Diagnosis — What to Expect

Ultrasound: The Gold Standard for Screening

Abdominal ultrasound is the recommended first-line screening tool. It is:

• Non-invasive (no needles, no radiation)
• Highly accurate — sensitivity (ability to correctly identify AAA) approaches 95–100% in experienced hands, according to available data
• Inexpensive relative to the cost of emergency surgery
• Quick — typically completed in under 15 minutes

A systematic review prepared for the US Preventive Services Task Force (USPSTF) confirmed that ultrasound screening is effective for detecting AAA in high-risk populations, as reported in secondary literature (Fleming C et al., Annals of Internal Medicine, 2005).

CT Angiography

If an aneurysm is detected on ultrasound, a CT angiogram (a detailed X-ray scan using contrast dye to visualize blood vessels) is typically ordered before any intervention. This provides precise measurements of aneurysm size, shape, and relationship to surrounding vessels — essential information for surgical planning.

Surveillance Intervals

Not every AAA requires immediate surgery. Small aneurysms are monitored with regular ultrasound:

Thresholds are approximate and should be discussed with your vascular specialist. Based on ESVS 2019 and NICE guidelines.

Treatment — From Watchful Waiting to Surgery

Conservative Management (Small AAAs)

For small aneurysms under the repair threshold, management focuses on slowing growth and reducing cardiovascular risk:

• Smoking cessation — the single most impactful intervention
• Blood pressure control — ACE inhibitors or ARBs are commonly used
• Statin therapy — to manage atherosclerosis and cardiovascular risk
• Regular surveillance ultrasound as per the schedule above

Surgical Repair (Large or Symptomatic AAAs)

Two main approaches exist:

1. Open Surgical Repair (OSR) The traditional approach, involving a large abdominal incision to replace the aneurysmal segment with a synthetic graft. Highly durable but carries greater short-term surgical risk, particularly in older or frail patients.

2. Endovascular Aneurysm Repair (EVAR) A minimally invasive technique where a stent-graft (a fabric tube supported by a metal scaffold) is delivered through small groin incisions via catheters (thin tubes) to line the aneurysm from within. EVAR offers faster recovery and lower short-term mortality, but requires long-term surveillance for complications such as endoleak (blood continuing to flow into the aneurysm sac).

Figures are approximate. Outcomes vary by center and patient profile. Always consult a vascular specialist.

For more on vascular treatment options, visit our treatments section.

The Screening Gap: Why So Few Patients Are Tested

Here is where the evidence becomes both compelling and frustrating.

The Multicentre Aneurysm Screening Study (MASS) — one of the most important randomized controlled trials in vascular medicine — followed 67,800 men aged 65–74 in the United Kingdom. Men invited for ultrasound screening had a 42% reduction in AAA-related mortality at four years compared to those not invited, as reported in secondary literature. The number needed to screen to prevent one AAA death was reported as 476 at four years, falling further with longer follow-up (Scott RAP et al., The Lancet, 2002).

This is powerful evidence. So why do screening rates remain low across Europe and North America?

1. Awareness Is Critically Low

Unlike breast cancer or colorectal cancer screening, AAA screening has never achieved mainstream public awareness. Many eligible men have simply never heard of it — and neither have their general practitioners in some settings.

2. Programs Are Narrow by Design

Current guidelines — including those from the ESVS (European Society for Vascular Surgery) and the USPSTF (US Preventive Services Task Force) — focus primarily on men aged 65–75 who have ever smoked. While this targets the highest-risk group, it is worth noting that the USPSTF 2019 update also recommends considering one-time screening for men aged 65–75 who have never smoked if they have other risk factors. Beyond these core recommendations, current guidelines still exclude:

• Women with significant risk factors
• Younger patients with connective tissue disorders

3. Opportunistic Screening Is Missed

Many patients undergo abdominal imaging (CT scans, ultrasounds) for entirely unrelated reasons — gallstones, kidney stones, back pain — without the aorta being systematically measured. Standardizing aortic measurement during any abdominal imaging would cost nothing extra and could save lives.

4. Healthcare System Fragmentation

In countries without a national AAA screening program, the responsibility falls to individual GPs (general practitioners) to refer eligible patients — a system that is inherently inconsistent. The UK’s NHS AAA Screening Programme, which invites all men at age 65, is considered a model program, yet even there, uptake is not universal.

5. Stigma and Avoidance

Some patients — particularly older men — avoid medical appointments out of fear of what they might find. Vascular specialists consistently note that the reassurance of a normal scan is itself a valuable health outcome.

Prevention — What You Can Do Today

While you cannot change your age, sex, or genetics, several evidence-based steps can meaningfully reduce your AAA risk:

1. Stop smoking — or never start. This is non-negotiable.
2. Control your blood pressure — aim for < 130/80 mmHg with your doctor’s guidance.
3. Manage cholesterol — through diet, exercise, and medication if prescribed.
4. Stay physically active — regular moderate exercise supports vascular health.
5. Know your family history — if a first-degree relative had an aortic aneurysm, tell your doctor.
6. Attend routine health checks — these are opportunities to discuss screening eligibility.

For practical, evidence-based prevention strategies, explore our prevention section.

When to See a Doctor — Clear Criteria

Seek emergency care immediately if you experience:

• Sudden, severe abdominal, back, or flank pain
• Feeling faint or collapsing alongside abdominal pain
• A pulsating mass in your abdomen

Make an appointment with your physician or vascular specialist if:

• You are a man aged 65 or over who has ever smoked and have never been screened for AAA
• You have a first-degree relative (parent or sibling) who had an aortic aneurysm
• You are a woman over 65 with a history of smoking or cardiovascular disease and wish to discuss your individual risk
• You have been told you have a “borderline” aortic measurement and are unsure of next steps

Do not wait for symptoms. With AAA, by the time you feel something, the window for safe intervention may already be closing.

Also available in French on petitveinard.fr

Sources

1. Scott RAP et al. “The Multicentre Aneurysm Screening Study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial.” The Lancet. 2002;360(9345):1531–1539. PMID: 12443577

2. Lederle FA, Johnson GR, Wilson SE et al. “Prevalence and associations of abdominal aortic aneurysm detected through screening.” Archives of Internal Medicine. 1997;157(13):1425–1431. PMID: 9224218

3. Fleming C, Whitlock EP, Beil TL et al. “Screening for abdominal aortic aneurysm: a best-evidence systematic review for the US Preventive Services Task Force.” Annals of Internal Medicine. 2005;142(3):203–211. PMID: 15684209

4. ESVS Clinical Practice Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms. European Journal of Vascular and Endovascular Surgery. 2019. DOI: 10.1016/j.ejvs.2018.09.020

5. US Preventive Services Task Force. Abdominal Aortic Aneurysm Screening Recommendation Statement. 2019. USPSTF

Medical Disclaimer: This article is produced by the Petit Veinard Editorial Board for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. The information presented reflects published scientific evidence and clinical guidelines at the time of writing but may not apply to your individual health situation. Always consult a qualified physician or vascular specialist before making any decisions about screening, diagnosis, or treatment. In case of sudden severe abdominal or back pain, call emergency services immediately.