What conditions predispose to aortic dissection?

Conditions That Predispose to Aortic Dissection

Hypertension is the most common risk factor for aortic dissection, followed by genetic connective tissue disorders such as Marfan syndrome, Loeys-Dietz syndrome, and vascular Ehlers-Danlos syndrome. 1 These conditions significantly increase the risk of aortic wall weakening and subsequent dissection.

Genetic and Congenital Conditions

• Marfan Syndrome: Characterized by fibrillin-1 gene mutations affecting connective tissue. About 50% of aortic dissection patients under 40 years have Marfan syndrome 1

• Loeys-Dietz Syndrome: Features include characteristic facial features, bifid uvula/cleft palate, arterial tortuosity, and mutations in TGF-β receptors (TGFBR1 and TGFBR2). Patients may develop dissection at smaller aortic diameters than in Marfan syndrome 1

• Vascular Ehlers-Danlos Syndrome: Characterized by thin skin and increased risk of arterial rupture 1

• Turner Syndrome: Associated with aortic coarctation and dissection risk 1

• Bicuspid Aortic Valve: Strong risk factor for ascending thoracic aortic aneurysms and subsequent dissection 1

• Familial Thoracic Aortic Aneurysm and Dissection Syndrome (FTAAD): Autosomal dominant condition with 13-19% of non-syndromic thoracic aortic aneurysm patients having first-degree relatives with thoracic aortic aneurysms or dissection 1

Inflammatory Conditions

• Takayasu Arteritis: Inflammatory vasculitis affecting the aorta 1

• Giant Cell Arteritis: Can cause aortic inflammation and weakening 1

• Behçet Arteritis: Associated with aortic inflammation and potential dissection 1

Other Medical Conditions and Factors

• Advanced Age: Most common in those 65-75 years old 2

• Male Gender: Higher prevalence in men 3

• Pre-existing Aortic Aneurysm: The larger the dilatation, the greater the risk of dissection 1

• Prior Cardiac Surgery: Particularly aortic valve replacement or prior prophylactic aortic surgery 4

• Pregnancy: Especially in third trimester, with hormonal changes leading to histological changes in the aorta 1

• Cocaine or Stimulant Use: Causes acute hypertension and aortic stress 1

• Trauma: Deceleration or torsional injury (e.g., motor vehicle crash, fall) 1

• Polycystic Kidney Disease: Associated with vascular abnormalities 1

• Chronic Corticosteroid or Immunosuppression Use: Can weaken aortic wall integrity 1

• Infections: Those involving the aortic wall from bacteremia or adjacent infection 1

Risk Assessment and Monitoring

For patients with known risk factors, especially genetic syndromes:

1. Regular Imaging Surveillance:

   • Echocardiograms at least every 6 months if aortic root exceeds 4.5 cm in adults
   • More frequent imaging if rate of aortic growth exceeds 0.5 cm/year 1
   • Imaging of the entire aorta every 2-3 years 1

2. Preventive Measures:

   • Beta-blockers for aortic root dilation 1
   • Angiotensin II receptor blockers may be protective in preventing type B aortic dissections in Marfan syndrome 4
   • Blood pressure control targeting <135/80 mmHg 5

3. Surgical Intervention Thresholds:

   • Consider prophylactic surgery when aortic diameter approaches 5 cm in those with mutations known to predispose to earlier dissection
   • For bicuspid aortic valve, consider surgery at 5.0 cm
   • For others, consider at 5.0-5.5 cm 1
   • For Loeys-Dietz syndrome, earlier intervention is indicated due to dissection risk at smaller diameters 1

Special Considerations

• Pregnancy: Women with aortic disease should receive counseling before conception about dissection risk. The risk is highest in the last trimester (50%) or early postpartum period (33%) 1

• Extreme Exertion: Activities involving Valsalva maneuver (e.g., weightlifting) can trigger dissection in predisposed individuals 1

• Family Screening: Three-generation family history should be obtained for patients with thoracic aortic disease, with genetic counseling and testing recommended for those with risk factors for heritable disease 5

Early recognition of these predisposing conditions and appropriate monitoring can significantly reduce morbidity and mortality from aortic dissection.