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

OBJECTIVES: Aneurysm diameter and growing rate does not represent a sure parameter for operation in patients with bicuspid aortic valve, ascending aortic aneurysm and normal root. 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 bicuspid aortic valve and ascending aorta complication (aneurysm or dissection). METHODS: Aorta tissue samples of 24 bicuspid aortic valve patients were examined. The patients were 18 men and 6 women, the average 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 fragmentation of elastic fibers, 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. RESULTS: Same medial degenerative lesions in tissue samples of different aorta segments (precisely of aortic root without dilatation, and aneurysmatic ascending aorta portion) were observed. Significant associationsbetween 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 bicuspid aortic valve patients than controls. CONCLUSIONS: Based on our histological and genetic data, we underline that surgical approach in patients with bicuspid aortic valve, 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.