Hemodynamic Effects Of Fetal-type Posterior Communicating Artery On Posterior Communicating Artery Aneurysms

Background and Objective:Fetal type posterior communicating artery(FTP)is an anatomical variation.Some studies reported that posterior communicating artery aneurysm(PCoAA)combined with FTP is prone to rupture.However,the differences between hemodynamic factors in PCoAAs with FTP and in PCoAAs without FTP and whether these differences are related to the PCoAA rupture have been rarely discussed.The purpose of this study was to investigate the hemodynamic differences between PCoAAs with or without FTP and the correlation between FTP and PCoAA rupture.Methods:210 PCoAAs were retrospectively collected from the prospective database of the first affiliated hospital of Nanchang university between January 2015 to June 2017.They were subdivided according to with or without FTP,ruptured or unruptured aneurysm,and the stenosis of proximal parent artery.Patient-specific models based on their three-dimensional digital subtraction angiography images were constructed and analyzed by a computational fluid dynamic method.hemodynamic parameters of the aneurysms were calculated and included the TAWSS(time-averaged wall shear stress)?WSSmin(minimum wall shear stress)?WSSmax(maximum wall shear stress)?WSSnorm(normalized wall shear stress)?OSI(oscillatory shear index)?Vmin(minimum velocity)?Vmax(maximum velocity)?Pmax(maximum pressure)?RRT(relative residence time)?EL(energy loss)?LSA(low wall shear stress area)All variables were analyzed by Mann–Whitney U TEST.Results:The hemodynamics of the ruptured PCoAA group(n = 141)was significantly different from the unruptured PCoAA group(n = 69).There was a higher oscillatory shear index(P = 0.019)and a larger low wall shear stress area(P = 0.056)in ruptured PCoAA group than in unruptured PCoAA group..There was a significant difference in hemodynamics between FTP-PCoAA group(n = 77)and the FTP-PCoAA group(n= 133),with lower pressure in the FTP-PCoAA group(P = 0.005).Compared with thenormal,mild and severe proximal stenosis of the parent artery,the medium presents there was a high hemodynamic state in mild proximal stenosis group,such as high wall shear stress(WSSmin,P = 0.050;WSSmax,P = 0.035;TAWSS,P=0.035),faster flow rate(Vmax,P = 0.037;Vmin,P = 0.043),shorter relative residence time(P =0.035).The FTP-PCoAA group had higher energy loss than the nonFTP-PCoAA group(p=0.049)in the normal parent artery.There was no significant relation between FTP and PCoAA rupture.Conclusion:There are hemodynamic differences between the posterior communicating artery aneurysm with and t without the embryonic posterior communicating artery.However,there was no significant relation between the two groups.