Abdominal aortic aneurysm

Disease Description (Causes and Symptoms)

• Definition summary: An abdominal aortic aneurysm (AAA) is a condition in which the wall of the aorta located in the abdomen abnormally expands, increasing in diameter. It is usually fusiform but may also be saccular.
• Main causes/risk factors: Aging, atherosclerosis, smoking (increased risk), hypertension, family history (increased risk when a first-degree relative is affected), genetic factors, trauma, and, rarely, infection (such as syphilis).
• Key pathophysiology: Damage to the elastin and collagen structures of the aortic wall, along with inflammation, weakens the wall. According to the law of Laplace, the stress placed on the wall increases as the diameter increases, raising the risk of further expansion and rupture.
• Clinical symptoms: Usually asymptomatic (often discovered incidentally in asymptomatic individuals). When symptoms occur, they may include abdominal fullness, a sensation of pulsation in the abdomen, dull or localized abdominal or back pain, and occasionally pulsatile pain. If rupture occurs, it can progress to acute severe abdominal pain, back or side pain, and shock (hypotension and decreased consciousness), constituting a medical emergency that can be fatal.

Treatment Methods

• Nonsurgical management (observation and risk-factor modification)
  • Small, asymptomatic AAAs are monitored for changes in size through regular imaging follow-up (ultrasound or CT).
  • Lifestyle management: Immediate smoking cessation, blood pressure control (antihypertensive medication), lipid management (statins), and management of diabetes and other cardiovascular risk factors.
  • Medication does not reduce the size of the aneurysm itself, but is recommended to prevent cardiovascular events (myocardial infarction and stroke) (e.g., statins and, when necessary, antiplatelet agents).
• Surgical treatment (repair)
  • Indications: In general, when symptoms are present (such as abdominal pain), when the maximum diameter of the abdominal aorta reaches the surgical threshold (usually 5.5 cm or more in men), or when there is rapid annual growth (e.g., >1 cm/year). (A lower threshold may be applied in women in some cases — consult the attending physician.)
  • Traditional open repair: The damaged aorta is removed and a prosthetic vascular graft is anastomosed. Long-term outcomes are good.
  • Endovascular Aneurysm Repair (EVAR): A minimally invasive procedure in which a stent graft is inserted through the femoral artery to redirect blood flow. It has the advantage of reducing early operative mortality in older patients or those at high risk for open surgery. However, long-term follow-up (e.g., monitoring for endoleaks) is required.
  • Emergency treatment for ruptured AAA: The mortality rate is extremely high (approximately 80–90% in cases of rupture). Emergency surgery (open repair or EVAR when feasible) is required. Although approaches to preoperative fluid replacement are controversial, a strategy of traditionally avoiding excessive fluid administration and maintaining an appropriate perfusion pressure (e.g., targeting a systolic blood pressure of 90–100 mmHg) is commonly used (this varies according to hospital guidelines and the patient's condition).
• Complication management and follow-up
  • After EVAR: Monitoring is necessary for endoleaks, stent migration or occlusion, infection, and other complications.
  • After open surgery: Monitor for bleeding, infection, organ ischemia (intestinal or renal), and spinal cord ischemia (rare), among other complications.

Summary of Precautions

• Uncontrolled excessive fluid administration and early elevation of blood pressure can worsen bleeding; in emergency situations, follow the instructions of a specialist.
• Smoking cessation and management of cardiovascular risk factors are important for slowing disease progression and reducing systemic complications.
• Whether surgery is needed and when it should be performed are determined by considering the size, symptoms, and the patient's overall condition, so the matter should be discussed thoroughly with the attending medical team.

Outpatient Visit Checklist (Items to Bring and Points to Confirm)

• Documents/items to bring
  • A list of currently taken medications (including prescriptions and supplements), with the time of administration and dosage indicated
  • Previous test results (ultrasound or CT images or radiology reports) — if possible, the original images (CD/DVD/USB) or report documents
  • Records of previous surgeries and major illnesses (such as heart disease, lung disease, and kidney disease)
  • Allergy information (especially contrast-agent and medication allergies)
  • Smoking history, alcohol-use history, and family history (especially a family history of AAA)
• Symptom-related preparation
  • The timing, pattern, and severity of recent pain (pain diary), and records of whether shortness of breath or fainting occurred
  • Weight changes and blood pressure records (if possible)
• Medication-related
  • If taking anticoagulants (such as warfarin or DOACs), check in advance whether they should be discontinued (in consultation with a doctor).

Examples of General Questions to Ask the Doctor

• Does the size of this aneurysm meet the criteria for surgery? (Or how often are follow-up tests needed?)
• What is my individual risk level for surgery (open repair vs. EVAR), considering my age and heart, lung, and kidney conditions?
• If we observe it without surgery, how high is the risk of rupture, and what lifestyle precautions should I take as a result?
• How do my current medications (especially anticoagulants) affect surgery? Should they be discontinued?
• What is the expected recovery period after surgery, and when can I expect to return to daily activities?

Examples of Disease-Specific Questions

• What is the aortic diameter measured on my imaging (ultrasound/CT), and how does this measurement compare with the surgical threshold (e.g., 5.5 cm)?
• Is my anatomy (such as the condition of the aortic branches and iliac arteries) suitable for EVAR, and what is the expected risk of complications (e.g., endoleak) if EVAR is performed?

(Note: The information above is general medical information. Decisions regarding an individual's diagnosis and treatment should be made in consultation with the attending medical team.)