What are the guidelines for diagnosing and managing Abdominal Aortic Aneurysm (AAA)?

From the Guidelines

Abdominal aortic aneurysms (AAAs) should be diagnosed and managed based on size, growth rate, and patient-specific risk factors, with a focus on preventing rupture and minimizing morbidity and mortality. For diagnosis, one-time screening with ultrasound is recommended for men aged 65-75 who have ever smoked and selectively for men aged 65-75 who have never smoked or women with risk factors 1. Once detected, small AAAs (<5.0 cm in men, <4.5 cm in women) should be monitored with regular ultrasound surveillance—every 2-3 years for aneurysms 3.0-3.9 cm and annually for those 4.0-4.9 cm 1.

Key Considerations

• Surgical repair is generally indicated when the AAA reaches 5.5 cm in men or 5.0 cm in women, grows more than 0.5 cm in 6 months, or becomes symptomatic 1.
• Two surgical approaches are available: open surgical repair and endovascular aneurysm repair (EVAR), with the choice depending on patient anatomy, surgical risk, and life expectancy 1.
• Medical management includes smoking cessation, blood pressure control (target <140/90 mmHg) using ACE inhibitors or ARBs, statin therapy regardless of cholesterol levels, and antiplatelet therapy with aspirin 75-325 mg daily 1.
• Beta-blockers may be considered for patients with hypertension, and patients should also be counseled to avoid heavy lifting (>50 pounds) and activities that cause Valsalva maneuvers 1.

Surveillance and Monitoring

• The intervals between US surveillance examinations depend on aneurysm size, with more frequent monitoring for larger aneurysms 1.
• Imaging surveillance provides two primary purposes: to identify interval growth beyond the threshold for elective repair and to monitor the growth trajectory and identify a potentially increasing rate of growth 1.

Recent Guidelines

• The most recent guidelines from 2023 recommend one-time screening for AAA by ultrasonography in men age 65 to 75 years who have ever smoked, with a focus on preventing rupture and minimizing morbidity and mortality 1.

From the Research

Diagnosis of Abdominal Aortic Aneurysm (AAA)

• AAA is an abnormal ballooning of the major abdominal artery, which can be asymptomatic or present as an emergency requiring surgery 2.
• Clinical risk factors for the development of an aneurysm include tobacco use, hypertension, a family history of AAA, and male sex 3.
• Ultrasound is the preferred method of screening and is cost-effective in high-risk patients 3.
• Diagnosis can also be made through physical examination, palpation, auscultation, and imaging, which are readily available in a chiropractic office 4.

Management of AAA

• Repair is indicated when the aneurysm becomes greater than 5.5 cm in diameter or grows more than 0.6 to 0.8 cm per year 3.
• Asymptomatic patients with an AAA should be medically optimized before repair, including institution of beta blockade 3.
• Symptomatic aneurysms require urgent surgical attention, and rupture of an AAA is a surgical emergency requiring immediate repair 3.
• Surgical intervention is generally considered appropriate in AAAs > 5 cm in diameter, and all patients recovered after surgical repair of the aneurysm 4.
• Medical management of AAA is also important to limit the expansion of small AAAs and reduce the high incidence of other cardiovascular events in these patients 5.

Treatment Options

• Open surgical repair and endovascular approach are two treatment options for AAA, but two large randomized controlled trials did not find any improvement in mortality rate or morbidity with the endovascular approach compared to conventional open surgical repair 3.
• Pharmacological therapy, such as macrolides, tetracyclines, statins, angiotensin converting enzyme inhibitors, and anti-platelet drugs, may be used to limit AAA expansion, but there is no reliable pharmacological agent available to limit AAA expansion 6.
• Current randomised controlled trials are examining the efficacy of exercise, doxycycline, and angiotensin converting enzyme inhibition in limiting AAA progression 5.