Histological and genetic studies in patients with bicuspid aortic valve and ascending aorta complications

Aneurysm diameter and growing rate does not represent a definite parameter for operation in bicuspid aortic valve (BAV), ascending aortic aneurysm and normal root patients. Thus, we investigated histological and immunohistochemical aspects of different segments of ascending aorta (precisely, aortic root without dilatation, aneurysmatic tubular portion, dissected ascending aorta) and genetic features of patients with BAV and ascending aorta complication (aneurysm or dissection).

Aorta tissue samples of 24 BAV patients were examined. The patients comprised of 18 men and 6 women; the mean age was 54.2 ± 14.3 years. All patients underwent composite aortic root replacement (button Bentall operation). Multiple histological sections were prepared from each aortic specimen. The evaluated features included elastic fibre fragmentation, cystic medial change, smooth muscle cell necrosis, medial fibrosis, and the markers of medial apoptosis and the metalloproteinases. Furthermore, genetic risk factors were also investigated.

The same medial degenerative lesions in tissue samples of different aorta segments (precisely of aortic root without dilatation, and aneurysmatic ascending aorta portion) were observed. More significant associations between single nucleotide polymorphisms (-786T/C endothelial nitric oxide synthase enzyme, D/I angiotensin-converting enzyme, -1562C/T metalloproteinase-9 and -735C/T metalloproteinase-2) and aneurysm risk were detected in BAV patients than in controls.

Based on our histological and genetic data, we underline that a surgical approach in patients with BAV, ascending aortic aneurysm and normal root, should consider not only the diameter of the aneurysmatic aortic portion but also the histological features of the whole ascending aorta and the genetic risk profile.