---
title: Abdominal aortic aneurysm
description: What an abdominal aortic aneurysm is, why it develops, how it is found, which approaches to monitoring and treatment clinical guidelines describe and when to call an ambulance.
type: disease
aliases:
  - AAA
  - infrarenal aortic aneurysm
  - aneurysm of the abdominal aorta
sources:
  - tier: guideline
    org: esc
    title: 2024 ESC Guidelines for the management of peripheral arterial and aortic diseases
    year: 2024
    doi: 10.1093/eurheartj/ehae179
    url: https://doi.org/10.1093/eurheartj/ehae179
  - tier: guideline
    org: minzdrav-rf
    title: Аневризмы брюшной аорты
    year: 2025
    url: https://cr.minzdrav.gov.ru/view-cr/53_2
  - tier: guideline
    org: nice
    title: 'Abdominal aortic aneurysm: diagnosis and management (NG156)'
    year: 2020
    url: https://www.nice.org.uk/guidance/ng156
  - tier: guideline
    org: aha-acc
    title: '2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines'
    year: 2022
    doi: 10.1161/CIR.0000000000001106
    url: https://doi.org/10.1161/CIR.0000000000001106
  - tier: reference
    org: msd-manuals
    title: Abdominal Aortic Aneurysms (AAA) (MSD Manual Professional Version)
    year: 2024
    url: https://www.msdmanuals.com/professional/cardiovascular-disorders/diseases-of-the-aorta-and-its-branches/abdominal-aortic-aneurysms-aaa
sources_checked: 2026-10-12
review: null
---

An abdominal aortic aneurysm (AAA) is an abnormal widening of the abdominal part of the aorta. Under the definition given in the Russian Ministry of Health guideline, it is an increase in the aortic diameter to more than twice normal, or a local bulge of the wall; under another definition, an aneurysm is an aortic diameter of 3 cm or more (the MSD Manual uses the same cut-off).<Cite n={[2, 5]} /> The American ACC/AHA guideline gives an ultrasound criterion of a diameter greater than 3.0 cm.<Cite n={4} /> Most aneurysms cause no symptoms, but an aneurysm can rupture, and rupture is life-threatening.<Cite n={[2, 5]} /> Another dangerous disease of the aorta, [aortic dissection](../aortic-dissection/), is covered in a separate article.

<Diagram name="abdominal-aortic-aneurysm">
  <p slot="normal">
    Normally the abdominal aorta below the renal arteries is on average 18–22 mm in
    diameter.<Cite n={2} />
  </p>
  <p slot="disease">
    Most aneurysms begin below the renal arteries.<Cite n={[2, 5]} /> Usually the aorta widens
    all the way round (a fusiform aneurysm), and its inside is often lined with a layer of blood
    clot (mural thrombus).<Cite n={[4, 5]} /> An aneurysm is usually defined as a diameter of 3 cm
    or more.<Cite n={[2, 5]} />
  </p>
</Diagram>

## Why it happens

<Patient>

In an aneurysm the middle layer of the aortic wall weakens and breaks down, and the aorta widens.<Cite n={[2, 4]} /> Aneurysms and atherosclerosis share risk factors, and aneurysms are often linked with atherosclerosis.<Cite n={[4, 5]} />

The main risk factor is smoking.<Cite n={[2, 4, 5]} /> The risk is also higher in older people, in men and in people whose relatives have had an abdominal aortic aneurysm.<Cite n={[2, 4]} /> Atherosclerosis and high blood pressure also raise the risk.<Cite n={2} /> Most people affected are over 60; below the age of 60 this kind of aneurysm is very rare.<Cite n={2} /> Men are affected several times more often than women.<Cite n={[2, 5]} />

An aneurysm usually grows slowly, and smoking makes it grow faster.<Cite n={[2, 4, 5]} /> The main danger is rupture: the larger the aneurysm, the higher the risk, while for small aneurysms it is very low.<Cite n={[3, 5]} />

</Patient>

<Student>

In 89–96% of cases an AAA is infrarenal, and in 28% it coexists with an iliac artery aneurysm.<Cite n={2} /> AAA shares risk factors with atherosclerosis but is histopathologically distinct: it is characterised by medial degeneration.<Cite n={[2, 4]} />

At least 10–25% of patients with AAA have a family member with the same condition (ACC/AHA).<Cite n={4} /> According to the Russian Ministry of Health guideline, AAA is 4–8 times less common in women than in men; according to MSD, 3 times.<Cite n={[2, 5]} /> In patients younger than 60, the Russian Ministry of Health guideline recommends looking for genetic disorders and connective tissue disease; MSD lists Marfan, Ehlers–Danlos and Loeys–Dietz syndromes among inherited causes.<Cite n={[2, 5]} />

According to the Russian Ministry of Health guideline, an AAA grows on average by 2.2 mm per year, faster at larger diameters (from 1.3 mm/year at 3.0 cm to 3.6 mm/year at 5.0 cm); smoking adds 0.35 mm/year.<Cite n={2} />

NICE stresses that AAAs are more likely to rupture in women than in men; in the UKSAT study cited by ACC/AHA, the mean maximum diameter at rupture was 5.0 cm in women and 6.0 cm in men.<Cite n={[3, 4]} />

</Student>

## Symptoms

<Patient>

Most often an aneurysm causes no symptoms at all. People do not know they have one until it is found during tests, for example on an ultrasound or CT scan done for another reason.<Cite n={[2, 5]} />

Symptoms usually appear when the aneurysm is large: constant or recurring pain or discomfort in the abdomen, a feeling of pulsation in the abdomen, or feeling full after eating only a little.<Cite n={2} /> Pain in the abdomen, back or side caused by the aneurysm is a warning sign: it can mean the aneurysm is about to rupture.<Cite n={[2, 4]} />

Rupture usually causes pain in the abdomen or back and a sharp fall in blood pressure, and the person may lose consciousness.<Cite n={[3, 5]} />

</Patient>

<Student>

AAA is usually asymptomatic; most aneurysms are found incidentally on physical examination or on ultrasound, CT or MRI done for other reasons.<Cite n={[2, 5]} /> ACC/AHA considers pain in the back, abdomen or flank attributable to the AAA, sometimes radiating to the groin, a high-risk symptom of impending rupture.<Cite n={4} />

AAA rupture is acute bleeding beyond the true aortic wall, with blood collecting in the retroperitoneal and/or intraperitoneal space.<Cite n={2} /> The classic triad (hypotension, abdominal and/or back pain, and a pulsatile abdominal mass) is present in about 50% of patients with rupture; the most common misdiagnoses are renal colic and myocardial infarction.<Cite n={2} /> NICE advises thinking about ruptured AAA in people with new abdominal and/or back pain, cardiovascular collapse or loss of consciousness, especially with a known AAA, age over 60, smoking and hypertension.<Cite n={3} />

Mortality from ruptured AAA is estimated at 80–90%, with most patients never reaching hospital (ACC/AHA); without treatment it approaches 100% (MSD).<Cite n={[4, 5]} />

</Student>

## How it is diagnosed

<Patient>

A doctor can sometimes feel a pulsating mass in the abdomen, but feeling the abdomen is not a reliable way to find an aneurysm, especially in people with a large waist.<Cite n={2} /> The main test is an ultrasound scan of the abdominal aorta: it is quick, involves no radiation and almost always finds an aneurysm.<Cite n={[2, 4]} />

If surgery is planned, a CT angiogram (a CT scan with contrast dye) is done. It helps choose the treatment and plan the operation, but involves radiation and an iodine-based contrast agent.<Cite n={[2, 3, 4]} /> If an aneurysm is found, the whole aorta is checked.<Cite n={1} />

Because an aneurysm usually causes no symptoms, some people without complaints are advised to have a preventive ultrasound scan (screening). The Russian Ministry of Health guideline recommends it for men aged 65 and over who have ever smoked, and for men and women aged 65 and over whose parent, brother, sister or child has an abdominal aortic aneurysm.<Cite n={2} /> If you have been found to have an aneurysm, tell your close relatives: they may need to be checked too.<Cite n={3} />

</Patient>

<Student>

The Russian Ministry of Health guideline recommends abdominal ultrasound and duplex ultrasound of the aorta as the first step for everyone with suspected AAA.<Cite n={2} /> The sensitivity of ultrasound for detecting an aneurysm approaches 100%.<Cite n={4} /> The sensitivity of abdominal palpation is below 50%, and lower still with a waist circumference over 100 cm.<Cite n={2} />

CT angiography is used to assess the extent of disease, choose the treatment method and plan surgery; before elective repair NICE recommends thin-slice contrast-enhanced arterial-phase CT angiography.<Cite n={[2, 3, 4]} /> When an aortic aneurysm is found at any location, ESC recommends assessing the entire aorta at baseline and during follow-up.<Cite n={1} />

The sources describe screening differently. Russian Ministry of Health guideline: ultrasound screening for men aged ≥65 who have ever smoked, and for men and women aged ≥65 who are first-degree relatives of patients with AAA; screening of men over 65 should be considered.<Cite n={2} /> ESC: men aged ≥65 with a history of smoking (I A) and first-degree relatives of patients with AAA from age 50, unless the aneurysm has a clearly identified acquired cause (I C).<Cite n={1} /> ACC/AHA additionally considers screening reasonable in women aged ≥65 who have ever smoked (2a).<Cite n={4} />

</Student>

## How it is treated

<Patient>

A small aneurysm is usually not operated on but monitored: ultrasound scans are done regularly, and more often the larger the aneurysm.<Cite n={[1, 2, 4]} /> While an aneurysm is small, the risks of surgery outweigh its benefit.<Cite n={3} />

The most important thing you can do yourself is to stop smoking: this slows the growth of the aneurysm and lowers the risk of rupture.<Cite n={2} /> High blood pressure needs treatment.<Cite n={[3, 5]} /> An aneurysm often signals that other blood vessels are diseased too, including those of the heart, so preventing heart and blood vessel disease matters.<Cite n={[1, 2, 3]} /> There is no medicine yet that can stop an aneurysm growing. But guidelines advise cholesterol-lowering medicines (statins): they protect the heart and blood vessels and, according to studies, may slow the growth of the aneurysm.<Cite n={[1, 2]} /> Which medicines are needed is for the doctor to decide.

If the aneurysm is large, growing fast or causing pain, surgery is discussed.<Cite n={[1, 2, 4]} /> In open surgery, the diseased section of the aorta is replaced with a graft through a cut in the abdomen.<Cite n={[2, 5]} /> In endovascular repair, a stent graft is passed through small cuts in the groin into the aneurysm, where it shuts the aneurysm off from the bloodstream.<Cite n={[2, 5]} /> Endovascular repair is easier to recover from, but afterwards regular check-ups are needed to notice in time if the graft moves or leaks.<Cite n={[2, 5]} /> The method is chosen taking into account the anatomy of the aneurysm, age, health and life expectancy; the doctor makes the decision together with the patient.<Cite n={[1, 2, 4]} />

A ruptured aneurysm needs emergency surgery.<Cite n={5} /> Even after surgery, according to the Russian Ministry of Health guideline, about one patient in three does not survive.<Cite n={2} />

</Patient>

<Student>

Ultrasound surveillance intervals differ. Russian Ministry of Health guideline: every 3 years for a diameter of 3–3.9 cm, yearly for 4.0–4.9 cm, every 3–6 months for ≥5.0 cm.<Cite n={2} /> ACC/AHA also recommends ultrasound every 3 years for 3.0–3.9 cm, and ESC says it should be considered (IIa B); both move women to more frequent surveillance at a smaller diameter than men.<Cite n={[1, 4]} />

ESC recommends that general cardiovascular prevention (IIa C) and statins to reduce AAA growth and rupture (IIa B) should be considered.<Cite n={1} /> The Russian Ministry of Health guideline also recommends statins for patients with AAA regardless of aneurysm diameter, to slow growth and reduce rupture (ESVS/ESC IIa B); according to the Russian Ministry of Health guideline, no other drug class has been shown to slow growth.<Cite n={2} />

The threshold for elective repair depends on the source. ESC: ≥55 mm in men and ≥50 mm in women (I A).<Cite n={1} /> ACC/AHA: ≥5.5 cm in men and ≥5.0 cm in women.<Cite n={4} /> NICE: an asymptomatic AAA of 5.5 cm or larger (inner-to-inner diameter on ultrasound).<Cite n={3} /> Russian Ministry of Health guideline: in men at 5–5.5 cm, in women with acceptable surgical risk at ≥4.5–5.0 cm.<Cite n={2} /> Repair is also considered for rapid growth: ESC at growth of ≥5 mm in 6 months or ≥10 mm per year (IIb C); the Russian Ministry of Health guideline recommends urgent referral to a vascular surgeon at growth of ≥1 cm/year.<Cite n={[1, 2]} /> For a symptomatic AAA, ACC/AHA recommends repair and the Russian Ministry of Health guideline emergency referral to a surgeon.<Cite n={[2, 4]} /> In clinical trials, early repair of AAAs of 4.0–5.4 cm did not improve survival; with a life expectancy of less than 2 years, ESC does not recommend elective repair (III B).<Cite n={[1, 4]} />

The sources phrase the choice of method differently. With suitable anatomy and a life expectancy of more than 2 years, ESC says EVAR should be considered as the preferred therapy, based on shared decision-making (IIa B).<Cite n={1} /> The Russian Ministry of Health guideline recommends endovascular repair for most older patients with suitable anatomy, and open repair for most patients with a long life expectancy.<Cite n={2} /> NICE offers open surgical repair unless it is contraindicated.<Cite n={3} /> After EVAR, ESC and ACC/AHA recommend first follow-up imaging at 1 month and regular surveillance after that.<Cite n={[1, 4]} />

For ruptured AAA with suitable anatomy, ESC, ACC/AHA and the Russian Ministry of Health guideline recommend endovascular rather than open repair.<Cite n={[1, 2, 4]} />

</Student>

## When to call an ambulance

A ruptured aneurysm needs emergency medical care.<Cite n={2} /> Call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK) for sudden, severe pain in the abdomen or back, and for loss of consciousness or fainting.<Cite n={[2, 3]} /> If you know you have an aneurysm, be sure to tell the medical team.<Cite n={2} /> A rupture can be mistaken for renal colic or a heart attack, so do not wait to see whether the pain goes away.<Cite n={2} /> New pain in the abdomen, back or side in someone with a known aneurysm also needs urgent help: it may mean the aneurysm is about to rupture.<Cite n={[2, 4]} /> As with any heart condition, call an ambulance for fainting, chest pain or severe shortness of breath: this is the site's general safety rule, repeated at the bottom of every page.

<Quiz />