Cardiovascular malformations and complications in Turner syndrome.

BACKGROUND: Turner syndrome (gonadal dysgenesis with sex chromosome abnormalities) is recognized to be a disorder in which cardiovascular malformations are common. The prevalence and natural history of these findings, the risk for aortic dissection, and the occurrence of cardiovascular disease have all been the subject of debate, as have been the American Academy of Pediatrics recommendations for cardiac screening of patients with Turner syndrome.
OBJECTIVE: To evaluate a large population of patients both cross-sectionally and longitudinally to determine the prevalence of cardiovascular malformations, the risk for dissection of the aorta, to determine whether there are phenotype:karyotype correlations that can allow for specific recommendations, and to devise an appropriate screening protocol. DESIGN AND METHODS: Data have been collected for patients with Turner syndrome. These individuals have been seen in an ongoing clinic established for the study of the natural history of Turner syndrome. Data from physical examinations, evaluations by cardiologists, echocardiography results, medical and surgical complications, medical records, and causes of death were analyzed. A total of 244 of 462 individuals in this population with karyotype-proven Turner syndrome could be evaluated because echocardiograms had been obtained. In addition, the medical literature was reviewed for occurrences of aortic dissection in patients with Turner syndrome.
RESULTS: A total of 136 (56%) of 244 of these patients had cardiovascular abnormalities, 96 (71%) were structural, 40 (29%) were functional, including hypertension (HBP), mitral valve prolapse and conduction defects. Coarctation of the aorta and bicuspid aortic valve, alone or in combination, comprised >50% of the cardiac malformations. Bicuspid valve was often not detected by examination, but only by echocardiography. Aortic dissection occurred in three of the patients. In one, it was traumatic; in a second, it occurred at the site of coarctation repair. The third patient had long-standing HBP with malignant obesity. In the literature, there have been 42 case reports of aortic dissection in Turner syndrome. In all except 5, predisposing risk factors of coarctation, bicuspid aortic valve, and/or HBP were present. Of these 5, sufficient information regarding predisposing risk factors was provided for only 2. No phenotype:karyotype correlations could be drawn with any certainty.
CONCLUSIONS: When the diagnosis of Turner syndrome is made, a screening echocardiogram should be obtained. Referral to a cardiologist first may be appropriate, but physical examination does not substitute for visualization. Individuals with and without evidence of structural cardiac malformations should be monitored for HBP on a lifelong basis. In the absence of structural cardiac malformations or HBP, the risk for aortic dissection appears small, and repeated echocardiography or magnetic resonance imaging to follow aortic root diameters does not appear to be warranted based on data currently available. Protocols for following patients with structural malformations need to be individualized, and wholesale recommendations have little merit. A longitudinal study using magnetic resonance imaging or cardiac echocardiography to establish normal parameters for aortic root diameters and to follow aortic root changes is needed.