Aortic Dissection in Turner Syndrome - Risk factors and Long-term Outcomes

Abstract

Background: Turner syndrome (TS) affects 1/2500 live born girls and is caused by a complete or partial loss of an X chromosome. It is characterized by short stature, ovarian dysfunction, congenital heart disease and an elevated risk of aortic dissection. The phenotype may vary but those with mosaicism are often less affected. Aim: The main aim of this thesis was to study aortic dissection in TS, including its incidence, risk factors, aortic growth, and mortality. Materials and methods: The studies included almost 500 women with TS who had been followed according to applicable guidelines with regular monitoring from 1995 to 2022 at various Turner centers at university hospitals in Sweden. The estimated incidence of aortic dissection was high, with 354/100,000 person years. Identified risk factors for aortic dissection included high blood pressure, bicuspid aortic valve and/or aortic coarctation, and dilatation of the ascending aorta. Previous growth hormone treatment, ongoing estrogen replacement therapy, or genotype were not associated with aortic dissection. An ascending aortic width above or equal to 3.3 cm increased the risk of aortic dissection in TS. However, all models failed to predict aortic dissection in a pregnant woman with a smaller aortic diameter. The growth rate of the ascending aorta was twice as high in TS as in the general female population. Mortality was three times higher in women with TS compared with matched controls, primarily due to cardiovascular diseases. Aortic dissection was the main cause of death in young women with TS. Conclusion: Aortic dissection was more prevalent in TS than in the general female population and shown to be the main cause of death in young TS women. Hypertension, dilated aorta, and congenital heart defects increased the risk of aortic dissection, while genetic, hormonal and, metabolic factors were not seen to be predictive at the 25 year follow-up in Sweden.