Turner syndrome (45,X and its variants with mosaicism, Xq isochromosome or ring X) carries an elevated risk of aortic dissection, a complication that can appear at surprisingly young ages. The problem, specialists acknowledge, is that there is still no reliable way to know which individual patient is in danger. Current guidelines, built on scarce evidence, recommend considering preventive surgery when the aortic diameter grows by more than 5 mm per year. A team from the John Radcliffe Hospital in Oxford and Imperial College London reviewed their own clinical series to test whether that measure — the speed of aortic growth — actually helps stratify risk.
The researchers retrospectively identified 151 adult women with Turner syndrome. Of these, 70 had more than one transthoracic echocardiogram performed after the age of 16, with a median interval between scans of 4.7 years. Two experts measured diameters at the sinuses of Valsalva and the ascending aorta. Mean growth was 0.13 mm per year at the sinuses of Valsalva and 0.23 mm per year at the ascending aorta, with considerable spread between patients, reflected in standard deviations of 0.59 and 0.82 mm respectively. In other words, most of the aortas studied barely changed, while a small number changed a great deal.
The most striking finding of the work is that classic risk factors for aortic dilatation and conditions associated with Turner syndrome were not related to that growth rate. Neither bicuspid aortic valve, nor coarctation, nor hypertension, nor karyotype predicted which aortas grew faster in this cohort. Four of the 151 women suffered an aortic dissection, at a mean age of 25 years. Two of them had previous serial echocardiograms: the first grew 0.67 mm per year at both levels; the second, 11 mm per year at the sinuses of Valsalva and 4 mm per year at the ascending aorta. Only one of the four survived, and she did so, the authors stress, because she was carrying a Turner syndrome cardiac alert card that told emergency staff about her risk.
Five women underwent preventive aortic replacement and one died postoperatively. The authors conclude that mean aortic growth in their Turner population was higher than in women without the syndrome and was not explained by known risk factors. They therefore propose that the growth rate itself, measured through serial studies and assessed by expert observers, be treated as a useful variable when deciding who needs closer surveillance. The study is retrospective and single-centre, and only half of the cohort had more than one image, so its findings need confirmation in larger series before recommendations change.
Source: Risk assessment for aortic dissection in Turner syndrome: The role of the aortic growth rate. Calanchini M, Bradley-Watson J, McMillan F, Myerson S, Fabbri A, Turner HE, Orchard E. Clinical Endocrinology 2024;100(3):269-276. DOI: 10.1111/cen.15017.
