In Vivo Experimental Study Of The Arterial Distribution And Level Of Occlusion Of Different Embolic Particles

There are two parts in our study.Part 1.The feasibility study of the arterial distribution and level of occlusion of microspheres in the live rat modelObject:To investigate the feasibility of using a microscope to study the arterial distribution and level of vessel occlusion of microspheres in live rats.Materials and methods:The separation and catheterization of mesenteric artery were performed under the microscope.The time of separation and catheterization was recorded.The movement and distribution of 80μm microspheres were observed by microscope while injecting the suspension.The proximal and distal vascular diameters were measured.Results:Technical success was achieved in all 10 Wistar rats.The mean time of separation and catheterization was 16.92±2.68min and 15.96±3.75min,respectively.The mean number of catheterizaion was 3.40±0.97.172 microspheres were located in intestine zone,only 12 were observed in mesentery zone.116 microspheres were observed in the furcation.The distal and proximal vascular diameter was 51.62±10.70μm and66.97±12.88μm,respectively.The real vascular diameter was 59.29±11.79μm.Conclusion:This method of using microscope to study the arterial distribution and level of vessel occlusion in live rats is feasible.It can be used to study the arterial distribution of clinical embolic agents in both normal vessels and tumor vessels.Part 2.The difference of arterial distribution and level of occlusion between different embolic particles in the live rabbit model:an experimental studyObject:To study the difference of arterial distribution and level of occlusion between embosphere microspheres and PVA particles in the live rabbit model.Materials and Methods:16 rabbits were randomly devided into 4 groups,namely group A(560-710μm PVA particles),group B(150-350μm PVA particles),group C(500-700μm Embosphere microsphere),group D(100-300μm Embosphere microsphere),4 in each group.The differences of stopping position,distribution area and level of vessel occlusion were compared between particles with different size but same shaped and particles with different shape but similar size.Results:For the same shape groups,large-size particles occluded significantly larger vessels than small-size particles(group A>group B,group C>group D,both P<0.001);the proporation of large-size particles in bifurcation was not significantly higher than that of small-size particles(group A>group B,X~2=1.408,P=0.235;group C>gourp D,X~2=0.963,P=0.327).For the similar-size groups,PVA particles occlued significantly larger vessels than Embosphere while the particle size was similar(group A>group C,group B>group D,both P<0.001);the proporation of Embosphere in bifurcation was significantly higher than that of PVA particles(group A<group C,X~2=4.325,P<0.038;group B<group D,X~2=6.68,P<0.01).The large-size particles(group A and group C)were found only in arteries in mesentery.The small-size particles(group B and group D)mainly blocked arteries in intestinal wall,and there was no significant difference between group B and group D(X~2=0.183,P=0.669).Conclusion:Embosphere microspheres can occlude the vessels in smaller diameter compared with reference PVA particles when their sizes are similar.The stopping position of embolic particles in the artery is mainly related to the shape of particles.The size of embolic particles is the key factor to determine the distribution area of the particles.