Aortic dimensions in Turner syndrome.

Am J Med Genet A. 2015 Jun 27. doi: 10.1002/ajmg.a.37208. [Epub ahead of print].

Aortic dimensions in Turner syndrome.

Quezada E1Lapidus J2Shaughnessy R1Chen Z2Silberbach M1.

Comment: Patients with Turner syndrome are at risk for development of thoracic aortic aneurysm and have elevated lifetime risk for aortic dissection or rupture. Normative data from healthy populations have been used to establish thresholds for defining aortic dilation and qualifying its severity, often by indexing to body size parameters (e.g. body surface area). Because Turner syndrome usually presents with short stature, the typical thresholds are not applicable for these patients. This uncertainty leads to significant challenges for risk stratification and clinical decision making. Quezada and colleagues have addressed this significant knowledge gap by establishing standard echocardiographic measurements for aortic size based on a healthy cohort with Turner syndrome. In total, 481 patients of median age 25 (range 3 to 70) years were included. Most had XO karyotype, but as many as 40% reported a different type of X chromosome structural abnormality (e.g. translocation) or mosaicism. Patients with aortic valve stenosis or regurgitation, unoperated congenital heart disease, or history of aortic dissection or replacement, were excluded. However, patients with history of coarctation repair (12%) or hypertension (20%) were included. The aortic diameter was measured using 2D transthoracic echocardiography at 8 levels (aortic annulus to descending aorta). In multivariate linear regression models, bicuspid aortic valve (25% of cohort) was significantly associated with aortic diameter at the levels of annulus, root, sinotubular junction, and ascending aorta, and therefore excluded. Ultimately, the regression parameters (based on body surface area calculated with the Haycock formula) for each of the 8 aortic segments are defined in the manuscript. As recommended for routine clinical care of these patients, longitudinal follow up will help to define the long term risk of aortic dissection or rupture and enhance clinical interpretation of Z-score values.