The Effect Of False Lumen Visceral Branches On Early-term False Lumen Thrombosis And Its Hemodynamic Characters In Patients With Stanford B Aortic Dissection Treated With Tevar

Background : Thoracic aortic dissection is a highly fatal aortic disease,and Thoracic Endovascular Aortic Repair(TEVAR)has become the first choice for the complex Stanford type B aortic dissection(TBAD).Patients with complete thrombosis within the false lumen(FL)has a better prognosis after TEVAR,whereas patients with a patent false lumen or partial thrombosis had a higher risk of aortic dilatation and death.For the prognosis of dissection,changes of hemodynamics directly influence the process of dissection remodeling.Computational fluid dynamics(CFD)have been widely used in basic research related to cardiovascular system and attempted to be applied in clinical practice.Methods:A single-center retrospective cohort study was carried to analyze the effect of FL visceral branches on early-term FL thrombosis.Patients were divided into a true lumen(TL)branches’ group and a FL branches’ group.The relative risk(RR)of FL thrombosis was calculated.For the multifactorial analysis affecting FL thrombosis,odds ratios(ORs)were calculated by applying a one-way logistic regression model,and factors with p < 0.2 were included to construct the Least Absolute Shrinkage and Selection Operator(LASSO)-logistic regression model and generalized linear regression model.A rigid wall,three-element Windkessel model(3EWM)boundary condition was applied to simulate the blood flow in aortic dissection.A TL branches’ model and a FL branches’ model were created for CFD analysis.Results:The risk of incomplete thrombosis in the FL was increased 2.556-fold(RR 3.556,95% CI 1.835-6.890,P<0.001)by the FL visceral branches compared to the TL branches in early term.Other factors affecting early-term false lumen thrombosis included age(OR 0.936,P=0.014),dissection involving the plane of the common iliac artery bifurcation and beyond(OR 16.200,P=0.003),number of preoperative intimal tears(OR 5.368,P<0.001),number of postoperative intimal tears(OR 89.083,P<0.001),and number of FL branches(OR 7.239,P<0.001).A generalized linear model was constructed to show a statistically significant effect of dissection involving the common iliac artery bifurcation plane(B=0.1646,P<0.001)and the number of FL visceral branches(B=0.395,P<0.001)on the number of postoperative intimal tears.In the FL branches’ model,there were regions of lower Time-average Wall Shear Stress(TAWSS),higher Oscillatory Shear Index(OSI),and higher Relative Residence Time(RRT)in the proximal and the middle of the FL.In the regions where there were FL branches,the TAWSS was higher,the OSI and RRT were lower,which were not conducive to thrombosis.In the TL branches’ model,the proximal end of the false lumen remained a region of low TAWSS,high OSI,and high RRT.And the visceral branches’ region is lower TAWSS,higher OSI and higher RRT compared with the FL branches’ model,which were related with higher chances of thrombosis.Conclusion:After TEVAR of TBAD,the abdominal FL visceral branch acts as an outflow tract of FL,which is a major factor affecting early-term FL thrombosis.There is a correlation between this factor and the extent of dissection involvement and the number of postoperative intimal tears.The presence of a FL branches resulted in elevated FL TAWSS and reduced OSI and RRT between the proximal intimal tear and the FL brunches,which influenced early-term FL thrombosis.