Valve Phenotype and Risk Factors of Aortic Dilatation After Aortic Valve Replacement in Japanese Patients With Bicuspid Aortic Valve

Background: The aim of this study was to assess the risk factors for dilatation of the aorta over time in Japanese patients with bicuspid aortic valve (BAV) undergoing aortic valve replacement (AVR), focusing on the possible impact of valve fusion phenotype. Methods and Results: Of 167 BAV patients undergoing AVR (24% of overall AVR patients, n=702), 135 patients in whom surgical intervention for the aorta was not undertaken were focused on (74 had right-left fusion and 61 non-right-left fusion type). During a mean follow up of 5.2 years, aortic growth rate (mm/year) of the ascending aorta was similar between the valve phenotype. In multivariate logistic regression, the presence of aortic regurgitation > moderate was significantly associated with a rapid dilatation of the ascending aorta, defined as >0.7 mm/year (odds ratio 2.1, 95% confidence interval 1.2-3.7, P=0.03). Independent predictors of dilatation of the aorta up to more than 45 mm were: a diameter of the ascending aorta >40 mm at the time of surgery (odds ratio 3.7, 95% confidence interval 1.2-11.4, P=0.02) and length of follow up (odds ratio 1.3-increase per year, 95% confidence interval 1.0-1.5, P=0.04). Conclusions: The presence of aortic regurgitation and the ascending aorta of >40 mm at the time of surgery emerged as significant predictors of dilatation of the aorta after AVR but valve fusion phenotype was not.