Structural abnormalities in the non-dilated ascending aortic wall of bicuspid aortic valve patients

Background: A bicuspid aortic valve (BAV) is the most common congenital cardiac malformation. The development of the aortic valve is closely related to the development of the ascending aorta, associated with structural differences in the bicuspid aorta. Here we describe the non-dilated ascending aortic wall in bicuspid aortic valve patients. Methods: BAV (n=41) and tricuspid aortic valve (TAV) (n=18) non-dilated ascending aortic wall samples were studied. We investigated the following features of the aortic wall: vessel wall thickness, endothelial cell morphology, atherosclerosis, and elastic lamellae organization. Medial pathologic features encompassing elastic fiber thinning, fragmentation and degeneration, overall medial degeneration, mucoid extracellular matrix accumulation, and smooth muscle cell nuclei loss were studied. Furthermore, we included apoptosis, periaortic inflammation, and the level of expression of differentiated vascular smooth muscle cells. Results: The non-dilated BAV ascending aortic wall is characterized by a significantly thinner intimal layer, without features of atherosclerosis (P<.001). The medial layer is significantly thicker (P<.001) with more mucoid extracellular matrix accumulation (P<.001). All other medial pathologic features were more prominent in the TAV (P<.001). The media has significantly less differentiated vascular smooth muscle cells (P<.001) between the neatly regulated elastic lamellae which are thinner in the BAV as compared to the TAV (P<.0001). Conclusions: The BAV ascending aorta without dilatation is characterized by a differentiation defect of vascular smooth muscle cells in the media and a significantly thinner intimal layer without overt pathologic features

Histopathology of aortic complications in bicuspid aortic valve versus Marfan syndrome: relevance for therapy?

Patients with bicuspid aortic valve (BAV) and patients with Marfan syndrome (MFS) are more prone to develop aortic dilation and dissection compared to persons with a tricuspid aortic valve (TAV). To elucidate potential common and distinct pathways of clinical relevance, we compared the histopathological substrates of aortopathy. Ascending aortic wall biopsies were divided in five groups: BAV (n = 36) and TAV (n = 23) without and with dilation and non-dilated MFS (n = 8). General histologic features, apoptosis, the expr

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

Can transforming growth factor beta and downstream signalers distinguish bicuspid aortic valve patients susceptible for future aortic complications?

Patients with a bicuspid aortic valve have an extreme high risk to develop a thoracic aortic aneurysm and dissection (TAAD). TAADs form a leading cause of death worldwide, with the majority of deaths being preventable if individuals at risk are identified and properly managed. Risk stratification for TAADs in bicuspidy is so far solely based on the aortic diameter. Exclusive use of aortic wall dimension, as in the current guidelines, is however not sufficient in selecting patients vulnerable for future aortic wall complications. Moreover, there are no effective medical treatments for TAADs to retain progressive aortic dilatation and thus prevent or delay aortic complications. Only surgical replacement of the aorta increases life expectancy in patients with a risk for a TAAD. Therefore, the next major challenge in the management of TAADs is the development of a personalized patient-tailored risk stratification for early detection of patients with an increased risk for TAADs, who will benefit from surgical resection of the aorta. Several signaling pathways have been studied in recent times to develop a patient specific risk stratification model. In this paper we discuss TGF-β signaling and downstream signalers as potential markers for future aortic complications in bicuspid aortic valve patients

Can transforming growth factor beta and downstream signalers distinguish bicuspid aortic valve patients susceptible for future aortic complications?

Patients with a bicuspid aortic valve have an extreme high risk to develop a thoracic aortic aneurysm and dissection (TAAD). TAADs form a leading cause of death worldwide, with the majority of deaths being preventable if individuals at risk are identified and properly managed. Risk stratification for TAADs in bicuspidy is so far solely based on the aortic diameter. Exclusive use of aortic wall dimension, as in the current guidelines, is however not sufficient in selecting patients vulnerable for future aortic wall complications. Moreover, there are no effective medical treatments for TAADs to retain progressive aortic dilatation and thus prevent or delay aortic complications. Only surgical replacement of the aorta increases life expectancy in patients with a risk for a TAAD. Therefore, the next major challenge in the management of TAADs is the development of a personalized patient-tailored risk stratification for early detection of patients with an increased risk for TAADs, who will benefit from surgical resection of the aorta. Several signaling pathways have been studied in recent times to develop a patient specific risk stratification model. In this paper we discuss TGF-β signaling and downstream signalers as potential markers for future aortic complications in bicuspid aortic valve patients

Can general histopathology distinguish bicuspid aortopathy?

Cardiolog