Loeys-Dietz Aortic Threshold — EECC MCQ

Correct answer: E — Surgery is recommended at a lower threshold (≥42 mm, or ≥40 mm with risk factors) than Marfan syndrome, as Loeys-Dietz has a higher risk of dissection at smaller aortic diameters

Loeys-Dietz syndrome, particularly with TGFBR1/TGFBR2 mutations, is an aggressive heritable thoracic aortopathy: aortic dissection can occur at smaller diameters than in Marfan syndrome. Therefore the key exam principle is not to wait for the usual degenerative aneurysm threshold of 55 mm or the Marfan threshold of about 50 mm. Prophylactic open aortic root/ascending aortic intervention is considered at a lower threshold, classically around ≥42 mm, and around ≥40 mm when high-risk features are present. This patient has a TGFBR2-related Loeys-Dietz syndrome and an ascending aorta of 42 mm, so the correct answer is E. TEVAR is not the preferred approach for an ascending aortic/root aneurysm; management should be by specialist open aortic surgery in an experienced centre.

Reference: 2024 ESC Guidelines for the management of peripheral arterial and aortic diseases, European Heart Journal 2024;45:3538–3700. https://academic.oup.com/eurheartj/article/45/36/3538/7738955