Is the intimal thickness a key contributor to thoracic aortopathy?

Background: An aortic dissection is the most devastating complication of thoracic aortic disease. Several non- and syndromic conditions such as a bicuspid aortic valve (BAV) and Marfan syndrome (MFS) have a severely increased risk to develop a thoracic aortic aneurysm and dissection. To date, the medial layer has been extensively studied in search of the pathogenetic mechanisms leading to aortic complications. Objective: We aim to determine whether intimal layer pathology is characteristic in all thoracic aortopathy regardless of the underlying etiology. Method: A total of 176 aortic wall specimen were studied for the intimal layer architecture including the intimal thickness, endothelial cell morphology, and atherosclerosis. Specimens were derived from four patient groups: BAV (n = 70, age 57 ± 8.9 years), isolated tricuspid aortic valve (TAV) (n = 38, age 64.9 ± 11.0 years), MFS with a TAV (n = 8, age 34.2 ± 11.0 years), type A dissections with a TAV (n = 60, age 62.7 ± 10 years). Results: The intimal layer is significantly thinner in BAV, MFS, and type A aortic dissection as compared to the isolated TAV patients (p < 0.001). Intimal atherosclerosis was also significantly less present in the three groups as compared to the isolated TAV (p < 0.05). Discussion: A thin intimal layer is a common finding in the thoracic aortopathy patients. Studies aiming at preventing future aortic complications should focus on the intimal pathology as a common effector pathway in thoracic aortopathy.