Study On Risk Factors And Elasticity Of Ascending Aorta Dilation In Patients With Bicuspid Aortic Valve

Objective The study sought to analyze the risk factors of ascending aortic dilatation in patients with bicuspid aortic valve and explore the clinical value of evaluate ascending aortic elasticity by two-dimensional speckle tracking Imaging.Methods We studied 59 BAV patients categorized into two group according to ascending aortic dimension(non-dilated<45mm and dilated≥45mm).Investigated the risk factors of ascending aortic dilatation in BAV patients by analyzing the clinical features,standard echocardiography,ascending aortic elasticity evaluation indexes(aortic strain;stiffness index,SI;aortic distensibility,DIS)and two-dimensional speckle tracking imaging data(2D-STI).Compared the 2D-STI with the evaluation index of ascending aorta elasticity and explored the clinical value of 2D-STI in the evaluation of ascending aortic elasticity.The data of one week after BAV patients undergoing aortic valve replacement surgery were collected,and the self-comparison was performed before and after surgery to explore the changes of ascending aorta elasticity.Results(1)In univariate analysis,there were significant differences between the dilated and non-dilated group in age,left ventricular end-diastolic diameter,left ventricular end-systolic diameter,and aortic valve stenosis(P<0.05).In multivariate analysis,it was found that age,aortic valve stenosis and aortic valve regurgitation could be used as independent risk factors for BAV patients with ascending aortic dilation.ROC curve analysis showed that 45 years old,mild aortic valve stenosis and moderate aortic valve regurgitation were the best diagnostic thresholds,and their sensitivity and specificity were 100%,45.24%;88.24%,50.00%;41.18%,83.33%.(2)Compared with the non-dilated group,the dilated group had an increased SI and decreased DIS(P<0.05),while there was no significant difference in aortic strain between two groups.Both the maximum systolic area(As)and the minimum diastolic area(Ad)in the dilated group were significantly larger than non-dilated group(P<0.001),and were significantly positively correlated to systolic ascending aortic diameter(Ao S)and diastolic ascending aortic diameter(Ao D)(r = 0.749,P <0.001;r = 0.758,P<0.001).The fractional area change(FAC)was not significantly different between two groups(P> 0.05),but was positively related to the aortic strain(r = 0.493,P<0.001).The anterior radial velocity of the ascending aorta in the dilated group was lower than the non-dilated group(P<0.05),while the global circumferential strain,radial displacement,circumferential strain and circumferential strain rate of each segment in the two groups were not significantly different(P>0.05).(3)Comparison of ascending aortic elasticity evaluation indicators:the ROC curve was used to compare the predictive value of aortic strain,SI,DIS and anterior radial velocity on ascending aortic dilatation.The evaluation indicators were compared in pairs,and no significant difference was found among these four evaluation indicators(P> 0.05)which areas under the curve(AUC)were 0.658,0.691,0.679 and0.657.(4)Comparison of one week after aortic valve replacement with pre-operation:aortic strain,DIS,radial velocity and radial displacement of each segment were lower than before,and the SI was higher(P<0.01);The circumferential strain of the global and several segmental were also lower than before(P<0.05),while the Ao S,Ao D and circumferential strain rate of each segment were no significant difference(P> 0.05).Conclusions(1)Age,aortic valve stenosis and aortic valve regurgitation could be used as the independent risk factors for BAV patients with ascending aortic dilation.(2)BAV patients with age>45 years old,combined with mild or more aortic valve stenosis and /or moderate or more aortic valve regurgitation were at greater risk of ascending aortic dilation.(3)Aortic valve anatomy and jet angle were not the independent influencing factors for BAV patients with ascending aortic dilation.(4)Two-dimensional speckle tracking Imaging could be used as a new method for ascending aortic elasticity evaluation.(5)One week after aortic valve replacement in BAV patients,the elasticity of the ascending aorta was lower than pre-operation.