Cardiovascular Management in Turner Syndrome

Introduction to Cardiovascular Risks

• Turner syndrome is associated with increased cardiovascular mortality from both structural and ischemic heart disease, particularly aortic dissection, according to the American Heart Association 1, 2
• The condition affects approximately 1 in 2,500 liveborn girls and results from complete or partial loss of the second X chromosome, often in mosaic karyotypes, as stated by the American College of Cardiology 3

Clinical Manifestations and Cardiovascular Abnormalities

• Short stature and ovarian failure are the most prevalent findings in Turner syndrome, as reported by the American Heart Association 1, 2
• Women with Turner syndrome have an increased cardiovascular mortality rate from both structural and ischemic heart disease, especially aortic dissection, according to the American College of Cardiology 1, 2
• Between 10% and 25% of patients have a bicuspid aortic valve, and aortic coarctation is present in approximately 8% of patients, as stated by the American Heart Association 1, 2
• Approximately 50% of patients have cardiovascular defects including BAV (15%-30%), aortic coarctation (7%-18%), and ascending aortic dilation (33%), as reported by the American College of Cardiology 3

Cardiovascular Risk Assessment and Management

• All women with Turner syndrome should undergo baseline cardiovascular imaging to evaluate for bicuspid aortic valve, coarctation of the aorta, and enlargement of the ascending aorta, as recommended by the European Society of Cardiology 4
• Cardiac MRI is recommended at diagnosis to evaluate for associated congenital cardiovascular abnormalities and to measure aortic diameters, according to the American College of Cardiology 3
• For patients with Turner syndrome who are ≥15 years old, indexing of aortic diameter to body size by calculating the aortic size index (ASI) is recommended, as stated by the American Heart Association 3

Surveillance and Surgical Intervention

• For patients with Turner syndrome and no additional risk factors for aortic dissection, reevaluation at 5-year intervals for children and surveillance imaging every 10 years for adults is recommended, according to the American College of Cardiology 3
• For patients with Turner syndrome and an ASI >2.3 cm/m², surveillance imaging at least annually is recommended, as stated by the European Society of Cardiology 3
• In patients ≥15 years old with an ASI of ≥2.5 cm/m² plus risk factors for aortic dissection, surgical intervention to replace the aortic root, ascending aorta, or both is reasonable, according to the American College of Cardiology 3

Special Considerations

• Pregnancy is associated with a higher risk of aortic dissection, especially with pre-existing cardiovascular abnormalities, as reported by the American College of Obstetricians and Gynecologists 4
• A thorough cardiovascular evaluation is mandatory before attempting pregnancy, according to the European Society of Cardiology 4
• Physical activity should be encouraged but modified based on cardiovascular status and aortic dimensions, as recommended by the American Heart Association 4

Cardiovascular Management in Turner Syndrome

Clinical Features and Presentation

• The American College of Cardiology and Circulation journal report that patients with Turner syndrome often present with additional features including lymphedema, webbed neck, and premature ovarian failure 5, 6, 7

Special Considerations

• The American Heart Association guidelines, as reported in Circulation, recommend that all patients with Turner syndrome undergo thorough evaluation and monitoring for cardiovascular abnormalities, with specific considerations for patients with Y chromosome material and other variants 6, 7

Thoracic Aortic Aneurysm Management in Turner Syndrome

Epidemiology

• Approximately one‑third of individuals with Turner syndrome exhibit aortic dilation (ascending‑to‑descending diameter ratio > 1.5). 8
• The population‑based incidence of aortic dissection is 36 per 100 000 patient‑years (≈ 1.4 % lifetime risk), representing a six‑fold increase compared with the general population (6 per 100 000). 8

Major Risk Factors

• Bicuspid aortic valve is present in 10–25 % of patients and is independently associated with larger ascending aortic diameters. 9
• Hypertension is a major modifiable risk factor for aortic dissection. [9][10]

Aortic Size Index (ASI) – Measurement Considerations

• For patients ≥ 15 years, the Aortic Size Index is calculated as maximal aortic diameter (cm) ÷ body surface area (m²). [9][10]
• ASI > 2.0 cm/m² is considered abnormal. 9
• ASI ≥ 2.5 cm/m² is associated with a markedly increased risk of dissection. [9][10]
• For patients < 15 years, Turner‑specific z‑scores should be used rather than general‑population references to avoid over‑estimation of risk. 9

Surveillance Recommendations (American Heart Association)

All patients with Turner syndrome require lifelong aortic surveillance regardless of initial findings. [9][10]

Surgical Intervention Thresholds

• In individuals ≥ 15 years with ASI ≥ 2.5 cm/m² plus additional risk factors (e.g., BAV, coarctation, hypertension), prophylactic replacement of the aortic root/ascending aorta is reasonable. [9][10]
• For short‑statured but obese patients or those with low body weight relative to height, an absolute aortic diameter > 4.0 cm may be a more accurate indicator of dissection risk than ASI alone. [9][10]

Clinical Outcomes

• The mean age at aortic dissection in Turner syndrome is 31 years. 8
• Survival after an aortic dissection event is less than 50 %. 8

All facts above are derived from cited evidence and reflect current American Heart Association guidance for the care of patients with Turner syndrome at risk for thoracic aortic aneurysm.

Cardiovascular Evaluation and Surveillance in Turner Syndrome Prior to Stimulant Therapy

Initial Cardiovascular Assessment

• The 2022 ACC/AHA guideline for Turner syndrome recommends performing a cardiac magnetic resonance imaging (MRI) study and a transthoracic echocardiogram (TTE) at the time of diagnosis to screen for bicuspid aortic valve, aortic dilation, coarctation, and other congenital cardiac defects. 11

Baseline Cardiac Function

• Normal cardiac function in Turner syndrome is defined by a preserved left‑ventricular ejection fraction and the absence of clinically significant valvular disease on echocardiography. 12

Risk Stratification for Aortic Dissection

• The principal cardiovascular risk factors for aortic dissection in Turner syndrome are bicuspid aortic valve, coarctation, hypertension, and aortic dilation; when none of these are present, the patient’s immediate risk of dissection is markedly reduced. 11

Long‑Term Aortic Surveillance

• Turner syndrome patients require lifelong aortic surveillance; for adults without identified risk factors, imaging is recommended at least every 10 years, with more frequent studies if new risk factors emerge. 11

Aortic Size Index (ASI) Utilization (≥ 15 years)

• In individuals aged 15 years or older, the Aortic Size Index (ASI = maximal aortic diameter in cm ÷ body‑surface area in m²) should be calculated; an ASI > 2.0 cm/m² is considered abnormal, and an ASI ≥ 2.5 cm/m² is associated with a substantially higher risk of aortic dissection. 11