Aortic Distensibility and Dimensions and the Effects of Growth Hormone Treatment in the Turner Syndrome

Abstract

In Turner's syndrome (TS), an increased risk for cardiovascular malformations exists, including aortic dilation of unknown cause. Abnormal biophysical wall properties may play an important role. Magnetic resonance imaging has been successfully used to assess aortic size and wall distensibility. The aim of this study was to assess aortic biophysical properties and dimensions in TS. Thirty-eight former participants of a growth hormone (GH) dose-response study in TS (mean age 12 +/- 2 years, mean body surface area 1.7 +/- 0.2 m2) and 27 controls (mean age 21 +/- 2 years, mean body surface area 1.8 +/- 0.1 m2) were enrolled. Previously, patients had been assigned to 1 of 3 groups treated with different GH dosages: group A (0.045 mg/kg/day), group B (0.067 mg/kg/day), and group C (0.09 mg/kg/day). All underwent magnetic resonance imaging > or =6 months after GH discontinuation to determine aortic dimensions and distensibility at 4 predefined levels: (1) the ascending aorta, (2) the descending aorta, (3) the level of the diaphragm, and (4) the abdominal aorta. Patients had larger aortic diameters at all but level 4 and tended to have reduced distensibility at level 3. Distensibility in group A was significantly less compared with that in group C at level 4. Compared with controls, patients in group A had larger aortic diameters at all but level 4 and reduced distensibility at level 4. The results for patients in groups B and C were not different from those for controls. In conclusion, patients with TS formerly treated with GH have dilated aortas and signs of impaired wall distensibility. The severity of abnormalities seems related to the GH dose, with a beneficial effect of a larger GH dose on the abnormalities.