Bicuspid aortic valve: theoretical and clinical aspects of concomitant ascending aorta replacement

Abstract

Bicuspid aortic valve (BAV) is associated with annuloaortic ectasia, dissection and ascending aortic aneurysm. The high incidence of this congenital malformation and aortic disease suggests a close correlation between the two phenomena. Abnormalities in different phases of cell migration of the neural crest might be responsible for the occurrence of abnormalities in the aortic valve, media layer of the ascending aorta and vessels of the aortic arch. Previous studies have shown that patients with normal BAV or slight dysfunction may present with dilation of the aortic root. The hemodynamic changes caused by BAV without stenosis or insufficiency seem to be an insufficient explanation for these findings. Several mechanisms have been proposed to explain the molecular and hystological aspects of this disease. We found a reduced fibrillin-1 content in both ascending aorta and pulmonary trunk as a possible cause. Histologically, the ascending aorta can present cystic medial necrosis and elastic fragmentation, similar to Marfan's disease. Some authors concluded that many patients, mainly those with aortic regurgitation, should have the aortic valve and the ascending aorta replaced at the same procedure, even if a mild dilatation (45 mm) is present in patients with BAV if life expectancy is anticipated to be greater than 10 years to prevent further aneurysms or ruptures.