What is the cardiovascular risk in individuals with Turner syndrome?

Cardiovascular Risk in Turner Syndrome

Patients with Turner syndrome have a significantly increased risk of aortic dissection and cardiovascular mortality due to structural heart defects, hypertension, and aortic complications that require lifelong surveillance and management. 1

Cardiovascular Abnormalities and Prevalence

Turner syndrome affects approximately 1 in 2,500 females and is associated with significant cardiovascular risks:

• Structural cardiac defects (present in ~50% of patients) 1:

  • Bicuspid aortic valve (15-30%)
  • Aortic coarctation (7-18%)
  • Ascending aortic dilation (33%)

• Aortic dissection risk:

  • Incidence of 36:100,000 Turner syndrome years (1.4% lifetime risk) vs. 6:100,000 in general population 1, 2
  • Average age of dissection: 31 years, with less than half of patients surviving the event 1
  • Distribution: 85% in ascending aorta (Type A) and 15% in descending aorta (Type B) 1, 2

• Hypertension:

  • Affects up to 50% of patients, often developing at an early age 3, 4
  • Major modifiable risk factor for cardiovascular complications

• Other cardiovascular risks:

  • Increased risk of ischemic heart disease 5
  • Increased stroke risk 5
  • Metabolic syndrome components (dyslipidemia, glucose intolerance) 6

Risk Assessment and Monitoring

Initial Evaluation

• TTE and cardiac MRI at diagnosis to evaluate for:
  • Bicuspid aortic valve
  • Aortic root and ascending aortic dilation
  • Aortic coarctation
  • Other congenital heart defects 1

Aortic Risk Assessment

• For patients ≥15 years old:
  • Calculate Aortic Size Index (ASI) = aortic diameter (cm) ÷ BSA (m²) 1
  • ASI >2.0 cm/m² is abnormal
  • ASI ≥2.5 cm/m² indicates significantly increased risk of aortic dissection 1
• For children <15 years old:
  • Use Turner syndrome-specific z-score to assess aortic dilation 1

Surveillance Recommendations

• Without risk factors for aortic dissection:

  • Children: Every 5 years
  • Adults: Every 10 years
  • Before planned pregnancy 1

• With risk factors (BAV, coarctation, hypertension, aortic dilation):

  • ASI ≤2.3 cm/m²: Every 2-3 years
  • ASI >2.3 cm/m²: At least annually
  • Frequency should be adjusted based on aortic diameter, growth rate, hypertension severity, and valve function 1

Surgical Intervention Criteria

• ASI ≥2.5 cm/m² plus risk factors (BAV, coarctation, hypertension):

  • Surgical intervention to replace aortic root/ascending aorta is reasonable 1

• Without risk factors but ASI ≥2.5 cm/m²:

  • Surgical intervention may be considered 1

• Absolute aortic diameter >4.0 cm in short-statured but obese patients:

  • May be more accurate than ASI for determining dissection risk 1

Management Recommendations

• Blood pressure control:

  • Aggressive management of hypertension is essential 2, 3
  • Beta-blockers may reduce the rate of aortic dilatation 2

• Pregnancy considerations:

  • High-risk period for aortic complications
  • Requires pre-pregnancy cardiovascular assessment and close monitoring 1, 2

• Emergency management:

  • Sudden, severe abdominal or chest pain should prompt immediate evaluation for aortic dissection 2
  • Strict blood pressure control and surgical consultation if dissection suspected

Common Pitfalls and Caveats

1. Underestimating risk due to small stature: Absolute aortic diameters alone may underestimate dissection risk; always use indexed measurements (ASI) 1

2. Inadequate imaging: Echocardiography may not visualize the entire aorta; cardiac MRI is preferred for comprehensive assessment 7

3. Overlooking non-aortic cardiovascular risks: Focus on aortic disease shouldn't overshadow management of other cardiovascular risk factors like hypertension, dyslipidemia, and glucose intolerance 6

4. Missing associated anomalies: Partial anomalous pulmonary venous return (15.7%) and elongation of transverse aortic arch (31.4%) are also common and may contribute to cardiovascular risk 7

5. Inadequate transition of care: Lifelong surveillance is necessary but often lost in transition from pediatric to adult care 1, 5