The Effects Of Hemodynamics On Aortic Elasticity And Left Ventricular Function In Bicuspid Aortic Valve Patients

Part I:The Effects of Hemodynamics on Aortic Elasticity in Bicuspid Aortic Valve PatientsPurposes: To investigate the effects of different severity degrees of aortic valve stenosis and regurgitation on the aortic elasticity in patients with BAV.Methods: A total of 145 patients diagnosed with isolate BAV and 30 cases of healthy volunteers with sex and age matched at the same period(control group)were selected from September 2018 to December 2020 in Union Hospital Wu Han.LVEF of all subjects included was >50%.According to 2017 AHA guidelines for classification aortic valve disease,BAV patients were divided into three groups: BAV with normally functioning(BAV-nf group),BAV with isolate aortic stenosis(BAV-AS group),BAV with isolate aortic regurgitation(BAV-AR group).Then,BAV-AS group and BAV-AR group were further graded into subgroups respectively: mild AS(AS1 group),moderate AS(AS2 group),severe AS(AS3 group);mild AR(AR1 group),moderate AR(AR2 group),severe AR(AR3 group).General clinical information was collected.Dynamically acquire two-dimensional ultrasound images of the aorta to evaluate the aortic valve function,aortic diameter,aorta elasticity.The aortic diameter and aortic elastic parameters of BAV-nf group and control group were compared,and then to explore the changes of aortic diameter and aortic elastic parameters with the increased severity of AS or AR.The influencing factors of aortic elasticity in patients with BAV were analyzed by univariate and multiple linear regression.Results:(1)Comparison of aortic diameter and aortic elastic parameters between control group and BAV-nf group: Compared with control group,the diameters of aortic anulus,SOV,STJ,AAo,PAo and PDAo were significantly larger in BAV-nf group(all P value<0.05).After adjustment for age,sex,BSA,SBP,DBP,the diameter of STJ,AAo and PAo of BAV-nf group was still larger than those of control group(all P value<0.05).Compared with control group,the strain and DIS of the ascending aorta were all decreased,and the SI was increased in BAV-nf group(all P value<0.05).There were still statistically significant differences between two groups of elastic parameters of the ascending aorta,even after adjustment for age,sex,BSA,SBP,DBP(all P value<0.05).With or without adjustment,there were no statistically significant differences between two groups in the elastic parameters of the sinus of the aorta(all P value>0.05).(2)Comparison of aortic diameter and aortic elastic parameters among BAV-nf group,AS1 group,AS2 group and AS3 group: After adjustment for age,sex,BSA,SBP,DBP,hypertension history and smoking,the diameter of AAo,PAo in AS1 group,AS2 group and AS3 group was still significantly larger than BAV-nf group(all P value<0.05),but there were no statistically significant differences among the three groups(all P value>0.05).With or without corrections,there was no statistically significant difference in other aortic diameter between the four groups(all P value<0.05).Compared with BAV-nf group,the strain of ascending aorta was decreased and SI was increased in AS1 group,AS2 group and AS3 group(all P value<0.05),and the pairwise comparison among the three groups all showed statistical difference(all P value<0.05).Compared with BAV-nf group,DIS of ascending aorta in AS1 group,AS2 group and AS3 group was significantly decreased(all P value<0.05),but there was no statistical difference among the three groups(all P value>0.05).Compared with the BAV-nf group,the strain and DIS of So V in AS2 and AS3 groups were decreased and SI was increased(all P value<0.05),while there was no statistical difference among the AS1,AS2 and AS3 groups(all P value>0.05).(3)Comparison of aortic diameter and aortic elastic parameters among BAV-nf group,AR1 group,AR2 group and AR3 group: Compared with BAV-nf group,the diameter of AA inAR2 and AR3 groups was increased(all P value<0.05)and the diameter of AA in AR3 group was larger than those of AR1 group,even after adjusting for age,sex,BSA,SBP,DBP,hypertension history and smoking(all P value<0.05).With or without corrections,there were no statistical differences in So V,STJ,AAo,PAo,PDAo among the four groups (all P value>0.05).With or without corrections,the SI of the So V was significantly increased in AR1,AR2 and AR3 groups than BAV-nf group(all P value<0.05),and the pairwise comparison among the three groups all showed statistical differences(all P value<0.05).Compared with BAV-nf group,the strain and DIS of So V in AR1,AR2 and AR3 groups were decreased(all P value<0.05),and the reduction was more obvious in AR3 group than those in AR1(all P value<0.05).(4)Univariate and multivariate linear regression analysis:In BAV-AS patients,the AVA/BSA was independently associated with the ascending aortic elasticity: strain(?=2.93,P<0.001),SI(?=-18.85,P<0.001),DIS(?=2.46,P<0.001).The Rvol was independently associated with the elasticity of So V: strain(?=-0.18,P<0.001),SI(?=0.36,P<0.001),DIS(?=-0.12,P<0.001).In BAV-AR patients,the Rvol was independently correlated with the elasticity of So V: strain(?=-0.04,P<0.001),SI(?=0.15,P<0.001),DIS(?=-0.03,P<0.001);and ascending aorta: strain(?=-0.04,P<0.001),SI(?=0.09,P<0.001),DIS(?=-0.03,P<0.001)respectively.Conclusion: BAV patients with normally valve functioning have aortic dilatation and ascending aortic elastic injury.In BAV-AS patients,the ascending aorta and the aortic arch dilated,and the elasticity of the ascending aorta gradually decreased with the increase of the severity of stenosis.There is no significant dilation of the aortic aorta in BAV-AR patients,while the injury of aortic elasticity is obvious.The hemodynamic burden associated with aortic valve dysfunction is an important risk factor in aortic elasticity impairment in BAV patients.AVA/BSA is independently associated with aortic elastic injury in the ascending aorta in BAV-AS patients.Rvol is independently associated with the aortic elastic injury in BAV-AR patients.In addition,age,SBP,DBP,hypertension history and smoking are also associated with the injury of aortic elasticity.Therefore,cardiovascular risk factors of patients with BAV should be monitored more comprehensively in clinical diagnosis and treatment.Part II:The Effects of Hemodynamics on Left Ventricular Function in Bicuspid Aortic Valve PatientsPurposes: To investigate the effects of different severity degrees of aortic valve stenosis and regurgitation on the left ventricular function in patients with BAV.Methods: A total of 157 patients diagnosed with isolate BAV and healthy 30 cases of volunteers(control group)with sex and age matched at the same period were selected from September 2018 to December 2020 in Union Hospital Wu Han.LVEF of all subjects included was >50%.The grouping method is the same as in Part I.The general information of the subjects was collected and two-dimensional ultrasound images were collected dynamically for the measurement of the conventional data of the left ventricle.The left ventricle volume and global myocardial functions of all subjects were analyzed by 3D-STE.Left ventricular function was compared between BAV-nf group and control group,then to explore changes in global multidirectional strain in BAV patients with the increased severity of AS and AR.The influencing factors of left ventricular myocardial function in BAV patients were analyzed by univariate and multivariate linear regression.Results:(1)Comparison of left ventricular function between control group and BAV-nf group: Compared with control group,GLS(absolute value)and GRS were significantly decreased in the BAV-nf group(all P value<0.05),even after adjustment for age,sex,heart rate,BSA,SBP and DBP(all P value<0.05).With or without adjustment,GCS,LVEF,twist and torsion showed no statistically significant difference between two groups(all P value>0.05).Compared with control group,the E/A ratio and E value in BAV-nf group were significantly decreased(all P value<0.05).(2)Comparison of left ventricular function in BAV-nf,AS1,AS2,and AS3 group: With each categorical increase in aortic stenosis severity from normally functioning to severe aortic stenosis,there was an associated progressive decreased of GLS(absolute value),and GRS(all P value<0.05).There was no significant difference in GCS between normally functioning and mild stenosis,but GCS(absolute value)progressively decreased from moderate AS(all P value<0.05).Before adjustment,there were no statistical differences in twist and torsion among four groups(all P value>0.05).However,twist and torsion in AS3 group were significantly higher than those in other three groups after adjustment for age,sex,heart rate,BSA,SBP,DBP,hypertension history and smoking(all P value<0.05).The average e' value of AS2 and AS3 group was significantly higher than those in BAV-nf and AS1 group(all P value<0.05).The E/ e' ratio in AS3 group was significantly higher than those in other groups,and the differences were statistically significant(all P value<0.05).(3)Comparison of left ventricular function in BAV-nf,AR1,AR2,and AR3 group: With each categorical increase in aortic regurgitation severity from normally functioning to severe aortic stenosis,there was an associated progressive decreased of GLS(absolute value),GCS(absolute value)and GRS(all P value<0.05).With or without adjustment,there was no statistically significant difference in twist and torsion between the four groups(all P value>0.05).There were no statistical differences in E,A,E/A ratio,e' and E/e' among the four groups(all P value<0.05).(4)Univariate and multivariate linear regression analysis: In BAV-AS patients,the AVA/BSA was an independent determinant of GLS(?=-6.11,P<0.001),GCS(?=-9.33,P<0.001)and GRS(?=14.41,P<0.001).In BAV-AR patients,the Rvol was an independent determinant of GLS(?=0.09,P<0.001),GCS(?=0.13,P<0.001)and GRS(?=-0.17,P<0.001).Conclusion: BAV patients with normally valve functioning have left ventricular longitudinal and radial myocardial strain injury.With each categorical increase in aortic stenosis severity from normally functioning to severe aortic stenosis,there was an associated progressive decreased of the left ventricular longitudinal and radial myocardial strain,and the circumferential myocardial strain progressively decreased from moderate AS.However,with each categorical increase in aortic regurgitation severity from normally functioning to severe aortic regurgitation,there was an associated progressive decreased of the left ventricular longitudinal,radial myocardial strain and circumferential myocardial strain.The myocardial dysfunction of BAV patients might start in the subendocardium and then progressed to transmural dysfunction with increasing AS and AR severity.Left ventricular myocardial strain injury in BAV patients is associated with hemodynamic burden related to valve dysfunction.AVA/BSA is independently associated with multidirectional myocardial injury in BAV-AS patients.Rvol is independently associated with multidirectional myocardial injury in BAV-AR patients.