Histologic differences between the ascending and descending aortas in young adults with fibrillin-1 mutations

This study aimed to review the clinical results of young adult patients with aortic disease associated with mutations in the fibrillin-1 gene (FBN1) and disclose the histologic differences between the ascending and descending aortas.

Between 2012 and 2015, 94 patients aged less than 50 years underwent surgery for thoracic aortic diseases. Forty-two patients (44.7%) had FBN-1 mutations. Of these, 40 patients (42.5%) with surgical specimens for histologic evaluation were included in the study. With the histologic results including the specimen sampled at their previous operations, cystic medial necrosis was classified into 3 grades according to the degree of the cystic area.

Thirty-nine patients (97.5%) had aortic root dilatation (Z ≥2), and 13 patients (32.5%) had ectopia lentis. Thirty-nine patients (97.5%) fulfilled the diagnostic criteria for Marfan syndrome. There were no in-hospital deaths. The majority (27/29: 93.1%) of the specimens of the ascending aorta revealed cystic medial necrosis pattern. With grade III being the most severe condition, these cases were classified into grade I (n = 2), grade II (n = 5), and grade III (n = 20). In contrast, only 6 specimens (6/17: 35.3%) of the descending aorta showed a cystic medial necrosis pattern that was classified into grade I (n = 2) and grade III (n = 4), (P < .00001).

Fewer specimens of the descending aorta revealed cystic medial necrosis compared with those of the ascending aorta. This difference might influence the characteristic aortic disease in Marfan syndrome associated with FBN-1 mutations.