Aortic Aneurysmal Disease Overview

Aortic Aneurysmal Disease

• Defined as aortic dilation with a diameter increase of at least 50% compared to unaffected individuals of the same age and sex.
• Medial degeneration and fragmentation of elastic fibers are the primary mechanisms behind thoracic aortic aneurysm (TAA) formation.

Genetic Conditions Associated with TAA

• Common conditions include Marfan syndrome (MFS), Loeys-Dietz syndrome (LDS), vascular Ehlers-Danlos syndrome, Turner syndrome, bicuspid aortic valve (BAV), and familial thoracic aortic aneurysm disease.
• These disorders can be single-gene or complex/polygenic.

Family History and Physical Examination

• A thorough family history may reveal TAA, BAV, or syndromic conditions.
• Physical examination identifies connective tissue dysplasia features, such as:
  • Skin: Striae, atrophic scars, translucent skin.
  • Musculoskeletal: Tall stature, long limbs, scoliosis, pectus deformities.
  • Cardiac: Signs of BAV and mitral valve disease, murmurs, and clicks.

Genetic Testing and Management Guidelines

• Genetic testing is essential for syndromic conditions (MFS, LDS) and recommended for patients under 60 with a positive family history.
• A medical genetics consultation aids in determining the benefit of aortopathy panel testing.

Degenerative Disease Insights

• The most common cause of TAA in older patients, predominantly affecting the descending thoracic aorta.
• Normal aortic expansion rate is approximately 0.9 mm in men and 0.7 mm in women each decade.
• Age, sex, and body size affect aortic dimensions, aiding in the interpretation of imaging results.

Aortitis Types

• Aortitis can be noninfectious (e.g., giant cell arteritis in those over 60) or infectious.
• Noninfectious types are more common and include giant cell arteritis, Takayasu arteritis, and several autoimmune diseases.
• Diagnosis combines clinical evaluations, imaging, and pathology.

Imaging Techniques

• Transthoracic echocardiography (TTE) inadequately visualizes distal aorta; transesophageal echocardiography (TEE) is better for diagnosing aortopathies.
• Computed tomography angiography (CTA) is the primary imaging modality but has limitations in detecting active inflammation and requires iodinated contrast.
• Magnetic resonance angiography (MRA) excels in anatomical assessment and detecting inflammatory changes.
• 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) helps identify metabolic activity associated with inflammation and monitors treatment response.

Follow-Up Recommendations

• Annual follow-up for degenerative aortic conditions between 35-45 mm; biannual for 45-55 mm.
• Abnormal findings necessitate imaging every 3-6 months; stable disease requires annual follow-ups.

Management of TAA

• Aggressive hypertension management is crucial.
• Beta-blockers are the first-line therapy, often followed by angiotensin II receptor blockers (ARBs).
• A meta-analysis shows beta-blockers and ARBs equally reduce aortic growth by approximately 50%.

Surgical Considerations

• Repair recommendations are similar for degenerative and inflammatory aortic diseases.
• Rapid expansion and dissection risks elevate in aortitis versus degenerative forms; clinical remission is advised before elective surgery.
• Avoidance of competitive sports and heavy lifting is recommended for patients with TAA.

Specific Patient Considerations

• Annual imaging during pregnancy for aortic dilation; beta-blockers are preferred during pregnancy, while ARBs are contraindicated.
• For BAV-related TAA, surgical intervention is recommended if the aortic dimension exceeds 55 mm.
• Lower thresholds for surgery apply to MFS (≥50 mm) and LDS (≥40-42 mm).

Repair Complexity

• Supracoronary tubular graft repairs are less complex when TAA is limited to above the sinotubular junction.
• Aortic arch involvement complicates repair; the classic elephant trunk procedure is one method, although newer safer techniques are now used to reduce mortality risks.