Abdominal Aortic Aneurysm

Overview

An abdominal aortic aneurysm is an abnormal bulging and widening of the aorta within the abdominal cavity. The aorta is the body's largest artery, running from the heart through the chest and down into the abdomen, where it supplies blood to the lower body and legs. The normal diameter of the abdominal aorta is approximately 2 centimeters. When this diameter exceeds 3 centimeters, the condition is classified as an aneurysm; once it surpasses 5.5 centimeters, the risk of rupture increases substantially and surgical repair is generally recommended.

Abdominal aortic aneurysm is far more common than thoracic aortic aneurysm and accounts for the vast majority of all aortic aneurysm cases. It most often develops in the segment of the aorta below the renal arteries, which is why most cases are referred to as infrarenal abdominal aortic aneurysms.

The condition typically follows a silent course for many years, producing no symptoms. As a result, most aneurysms are discovered incidentally during imaging performed for another reason; an abdominal ultrasound, CT scan, or a physical examination in which a pulsating mass is felt in the abdomen. As the aneurysm enlarges, however, it may cause abdominal or back pain.

The most feared complication is sudden rupture of the aneurysm wall. Rupture causes massive internal hemorrhage and is almost uniformly fatal without immediate surgical intervention. Early detection and appropriate monitoring are therefore genuinely life-saving.

Symptoms

The great majority of abdominal aortic aneurysms produce no symptoms for a prolonged period. Symptoms typically emerge as the aneurysm grows larger.

Abdominal aortic aneurysm symptoms include the following:

• Abdominal pain. A dull, persistent, or intermittent ache around the navel or in the lower-to-middle abdomen may develop. The pain can sometimes radiate to the back or groin. Pain that begins mildly and gradually intensifies over time may indicate aneurysm growth.
• Back pain. A deep, constant ache in the lower back is common. This pain can be confused with kidney stones or musculoskeletal discomfort. As the aneurysm enlarges, it may press against the vertebral column, worsening the pain.
• Pulsating sensation in the abdomen. Some individuals notice a regular throbbing or pulsating feeling around the navel or in the center of the abdomen. This sensation is often more noticeable when lying flat on the back.
• Groin or leg pain. Blood clots that form inside the aneurysm sac can break off and travel to the leg arteries, causing sudden leg pain, numbness, pallor, or coldness.
• Abdominal pain after eating. When a large aneurysm compresses the arteries supplying the intestines, pain may develop after meals. Affected individuals may avoid eating, leading to unintentional weight loss.

The following symptoms may indicate rupture or contained leakage and require calling emergency services immediately:

• Sudden, extremely severe abdominal or back pain. Pain described as "tearing," "ripping," or unbearable in onset is the most critical warning sign.
• Low blood pressure and signs of shock. Sudden pallor, profuse sweating, a rapid and weak pulse, dizziness, and altered consciousness may signal internal hemorrhage and cardiovascular collapse.
• Abdominal rigidity and distension. Blood leaking into the abdominal cavity after rupture causes the abdomen to become tense and rigid.

When to See a Doctor

Because abdominal aortic aneurysm so often develops without symptoms, regular screening of individuals with known risk factors is critically important.

Schedule a medical evaluation if:

• You are over 65 and currently smoke or have a significant smoking history; a one-time screening ultrasound is recommended
• You have a family history of abdominal aortic aneurysm
• You have unexplained, persistent abdominal or back pain
• You have noticed a pulsating or throbbing sensation in your abdomen
• You experience sudden coldness, numbness, or color change in your legs
• You have a known aneurysm and notice any change in your symptoms

Call emergency services immediately if you experience:

• Sudden, severe abdominal or back pain
• Sudden dizziness, a drop in blood pressure, or fainting
• Abdominal pain accompanied by profuse sweating and pallor

Causes

Abdominal aortic aneurysm develops when processes that compromise the structural integrity of the aortic wall allow it to weaken and balloon outward. Multiple causes often act together.

Possible causes of abdominal aortic aneurysm include the following:

• Atherosclerosis. This is the most common underlying cause. Over many years, cholesterol-rich plaques accumulate within the aortic wall, eroding its structural strength and reducing its elasticity; creating conditions favorable for aneurysm formation. Because atherosclerosis is also the primary driver of heart attack and stroke, patients with abdominal aortic aneurysm frequently have coexisting cardiovascular disease.
• High blood pressure (hypertension). Chronically elevated blood pressure exerts sustained mechanical stress on the aortic wall, progressively weakening it and predisposing it to dilation.
• Genetic predisposition. There is a strong hereditary component to abdominal aortic aneurysm. Individuals with a first-degree relative (parent or sibling) affected by the condition face a significantly elevated risk. Certain genetic disorders that weaken connective tissue also predispose to aneurysm development.
• Aortitis (inflammation of the aorta). Rare inflammatory arterial diseases (including Takayasu arteritis and giant cell arteritis) can damage and weaken the aortic wall. Untreated infections such as syphilis may also trigger aortitis.
• Trauma. Significant blunt abdominal trauma can injure the aortic wall and, over time, predispose to aneurysm formation.
• Connective tissue disorders. Genetic conditions such as Marfan syndrome and Ehlers-Danlos syndrome cause intrinsic structural weakness of the aortic wall. In these conditions, aneurysms can develop at a younger age and may progress more rapidly.

Risk Factors

Several factors are associated with an increased likelihood of developing an abdominal aortic aneurysm:

• Smoking. This is the most important and only modifiable risk factor. Smokers face a 3–5 times higher risk of developing an abdominal aortic aneurysm compared to non-smokers. Tobacco smoke directly damages the aortic wall, accelerates atherosclerosis, and increases the rate of aneurysm growth. Risk rises with cumulative pack-years of smoking.
• Advanced age. Risk increases sharply after age 60. The condition is most prevalent in men over 65.
• Male sex. Men develop abdominal aortic aneurysms 4–6 times more frequently than women. However, women who do develop them are more prone to rupture at smaller diameters and tend to have worse surgical outcomes.
• Family history. A first-degree relative with an abdominal aortic aneurysm substantially elevates an individual's risk, making early screening especially important for these individuals.
• High blood pressure. Uncontrolled hypertension accelerates both aneurysm formation and growth.
• Atherosclerotic disease. Individuals with established coronary artery disease or peripheral artery disease have a higher prevalence of abdominal aortic aneurysm.
• High cholesterol. Elevated LDL cholesterol accelerates atherosclerosis, increasing aneurysm risk.

Diagnosis

Abdominal aortic aneurysm is diagnosed through imaging. Physical examination may reveal a pulsating abdominal mass, but this finding is unreliable for detecting smaller aneurysms or accurately measuring diameter. Imaging is always required for definitive diagnosis and size assessment.

Diagnostic methods include the following:

• Abdominal ultrasound. This is the preferred modality for screening and routine surveillance. It involves no radiation, is inexpensive, widely available, and reliably measures aortic diameter. One-time screening ultrasound is recommended for men aged 65–75 who have ever smoked. Image quality may be reduced in obese patients.
• CT angiography (CTA). This provides detailed three-dimensional images of the aneurysm, its size, shape, length, and relationship to adjacent vessels. It is the gold standard for surgical and endovascular treatment planning. Because it involves contrast material and radiation, it is reserved for diagnosis and pre-procedural planning rather than routine screening.
• MR angiography (MRA). This provides detailed aortic imaging without radiation. It is particularly useful for patients in whom CT contrast is contraindicated due to impaired kidney function. It is not preferred for emergency evaluations given its slower acquisition time.
• Physical examination. An experienced clinician may palpate a pulsating abdominal mass during examination; however, this method cannot reliably detect small aneurysms or measure their size. Imaging confirmation is always necessary.

Once diagnosed, the monitoring frequency and treatment plan are determined by aneurysm size. Small aneurysms (3.0–4.4 cm) typically warrant annual ultrasound; moderate aneurysms (4.5–5.4 cm) are monitored every six months.

Treatment

The goal of treatment is to prevent rupture. The approach is determined by aneurysm size, rate of growth, and the patient's overall health and surgical risk.

Treatment options include the following:

• Surveillance (watchful waiting). For small aneurysms (generally below 5.5 centimeters) the risk of elective surgery exceeds the risk of rupture, so regular imaging surveillance is preferred. Rigorous control of risk factors, particularly blood pressure and smoking, is essential during this period. Imaging is performed annually or every six months depending on size.
• Medical therapy. No medication shrinks an existing aneurysm, but certain drugs can slow its growth and reduce rupture risk. Beta-blockers and ACE inhibitors reduce pressure on the aortic wall. Statins slow the progression of atherosclerosis and may help stabilize the aneurysm wall.
• Endovascular aneurysm repair (EVAR). This is currently the most commonly performed repair technique. A catheter is introduced through a groin artery and a folded metal stent graft is deployed inside the aneurysm sac. The stent expands to support the aortic wall and reroute blood flow through the normal channel, relieving pressure on the aneurysm. Recovery is substantially faster than open surgery (typically one to three days in hospital) with reduced general anesthesia risk and lower complication rates. However, not all patients are anatomically suitable, and long-term re-intervention rates are slightly higher than with open surgery.
• Open surgical repair. This is the traditional approach. The abdomen is opened, the diseased aortic segment is removed, and a synthetic graft is sewn in its place. It is preferred when EVAR is anatomically unsuitable, in younger low-risk patients, and in emergency rupture cases. Recovery takes longer (several weeks) but long-term durability is excellent, and re-intervention rates are lower than with EVAR.
• Emergency surgery. Rupture or a symptomatic aneurysm (regardless of size) requires immediate surgical intervention. Both EVAR and open repair may be used depending on the patient's hemodynamic stability and the center's capabilities.
• Surgical thresholds. Repair is generally recommended when the aneurysm diameter exceeds 5.5 centimeters, when growth exceeds 0.5 centimeters per year, or when symptoms are present. In women, the threshold may be applied at 5.0–5.5 centimeters given their higher rupture risk at smaller sizes.

Complications

The most serious complications of abdominal aortic aneurysm are the following:

• Rupture. Sudden tearing of the aneurysm wall causes massive hemorrhage into the abdominal cavity. The mortality rate is extremely high; even among patients who reach the hospital, more than half may not survive. Rupture risk rises sharply with aneurysm diameter: the annual rupture risk for aneurysms below 5 cm is less than 1 percent, while aneurysms above 7 cm carry a risk exceeding 20 percent per year.
• Thromboembolic events. Blood clots that form inside the aneurysm sac can break off and block the arteries supplying the legs, causing acute limb ischemia; a sudden emergency characterized by leg pain, pallor, coldness, and absent pulses. Smaller emboli can lodge in digital arteries, leading to toe gangrene.
• Compression of adjacent structures. An enlarging aneurysm can press against the ureters (causing urinary obstruction), the intestines, or the spine, leading to pain, hydronephrosis, or chronic bowel problems.
• Aortoenteric fistula. In rare cases (typically in patients who have previously undergone graft repair) an abnormal connection forms between the aorta and the intestine, causing life-threatening gastrointestinal hemorrhage.
• Surgical complications. Repair carries the risk of kidney failure, heart attack, stroke, bowel ischemia, sexual dysfunction, and infection. These risks are considerably higher in emergency rupture surgery than in elective repair.

Living with an Abdominal Aortic Aneurysm

Receiving a diagnosis of abdominal aortic aneurysm can be anxiety-provoking. However, because most aneurysms grow slowly, the great majority of patients who are appropriately monitored and who commit to the necessary lifestyle changes can live well and avoid serious complications.

Stop Smoking

Quitting smoking is the single most impactful action you can take to slow aneurysm growth. It is never too late; studies consistently show that the rate of aneurysm expansion decreases significantly after cessation. Take full advantage of the support available to you: nicotine replacement therapy, prescription medications, and behavioral counseling programs are all effective tools.

Control Your Blood Pressure

Take your prescribed blood pressure medications consistently and aim for the target values recommended by your doctor (typically below 130/80 mmHg). Monitor your blood pressure at home regularly and keep a record to share at appointments. Restrict daily sodium intake to no more than 5 grams. Stress management also contributes to blood pressure control.

Physical Activity

Moderate-intensity aerobic exercise (brisk walking, swimming, cycling) supports cardiovascular health and is generally appropriate for most patients with a monitored aneurysm. However, heavy lifting, straining, and high-intensity activities can cause sudden spikes in aortic pressure and must not be undertaken without explicit guidance from your physician. Always ask specifically which activities are safe for your situation.

Diet and Nutrition

Follow a heart-healthy dietary pattern that limits saturated fat, trans fat, and sodium. A Mediterranean-style diet (emphasizing vegetables, fruits, whole grains, fish, and olive oil) helps slow atherosclerosis progression. Maintain healthy cholesterol and blood sugar levels, and aim to stay within a healthy weight range.

Regular Imaging Surveillance

Never miss a scheduled follow-up imaging appointment; changes in aneurysm size can only be tracked through consistent monitoring. Have ultrasound or CT angiography performed at the intervals your doctor recommends. If growth is detected, your treatment plan will be reviewed promptly.

Recognize Emergency Warning Signs

You and your household should know the warning signs of rupture: sudden, severe abdominal or back pain, sudden pallor, profuse sweating, and loss of consciousness. In any of these situations, call emergency services immediately; every minute matters. Know in advance which hospital to go to and which physician to contact in an emergency.

Preparing for Your Appointment

Coming prepared to your appointment helps your medical team evaluate your condition efficiently and plan the most appropriate course of care.

What you can do:

• Bring any previous imaging studies (ultrasound, CT, MRI) and their reports
• Note when symptoms such as abdominal or back pain began and how they have evolved
• List all current medications, vitamins, and supplements
• Be prepared to describe your smoking history in detail (years smoked, daily quantity)
• Report any family history of aortic aneurysm or sudden cardiovascular death
• Record your recent blood pressure readings and bring them to the appointment
• Write down your questions in advance

Questions you may wish to ask your doctor:

• How large is the aneurysm, and how quickly is it growing?
• Is surgery needed now, or is surveillance appropriate?
• How often do I need imaging follow-up?
• Which activities should I avoid?
• If surgery is needed, would open repair or an endovascular approach be used?
• Should my family members be screened?
• Will quitting smoking slow the aneurysm's growth?
• What should I do in an emergency, and which hospital should I go to?

Questions your doctor may ask:

• Do you have abdominal or back pain? If so, how long have you had it?
• Have you noticed a pulsating sensation in your abdomen?
• Do you smoke or have you smoked? For how many years?
• Is your blood pressure regularly monitored? What are your typical readings?
• Is there a family history of aortic aneurysm or sudden vascular events?
• Have you been diagnosed with heart disease or peripheral artery disease?
• Do you experience pain, numbness, or coldness in your legs?