Trituration Of The Non-adhesive Liquid CoHEMA Embolic Mixture

Objective To triturate a new type of non-adhesive embolic mixture and study the technical feasibility and embolic effect of using it to embolic rete mirabile(RMB)of domestic pigs.Materials and Methods1.Laboratory StudyThe mixture of HEMA and ethanol was heated to 50～60℃.After reaction,the compound was pured and mixed proportionally with pure water and absolute alcohol, which CoHEMA was obtained.The simulated convery-experiment and embolization-experiment were carried out in vitro.2.Animal ExperimentSix healthy domestic pigs were used in this study.The animals were 3 to 4 months old,weighed 25 to 30 kg,and were no matter male or female.Each pig was premedicated with intramuscular 1mg atropine and general anesthesia was maintained with ketamine and midazolam by intravenous administration during the procedure.A 5F vascular sheath was placed into the right common femoral artery.A 5F guiding catheter was used to select the common carotid artery,through which microcatheter was placed coaxially for superselective catheterization of the ascending pharyhgeal artery.The tip of the microcatheter was placed distal to the pharyngeal branch of ascending pharyngeal artery and selective angiography was performed.The national CoHEMA embolic mixture was aspirated into a 1-cc syringe and injected through the microcatheter.In order to prevent the mixture precipitation in the microcatheter,the mocrocatheter was flushed with 16%alcohol before injection of embolic mixture. Follow-up angiography was performed for observation of revascularization.The animals were killed and the RMB and the brain were taken out immediately for histological examination and the alterations of RMB and surrounding tissue were observed.According to the time interval of follow-up the animals were divided into three groups:acute term(immediately after embolization,1 week after embolization), subacute term(4 weeks after embolization)and chronic term(8 weeks,12 weeks,24 weeks after embolization),acute term included two animals,subacute term included one animal,chronic term included three animals.Results1.Laboratory StudyThe simulated convery test in vitro demonstrated that iohexol is suitable for contrast because it did not influent precipitation and embolization of the copolymer and the simulated embolic test in vitro could successfully embolize the AVM models and there was no copolymer adhered to the microcatheter lumen,which showed its nice biocompatibility with all categories of microcatheter.2.Animal ExperimentWe successfully embolized 6 RMB of 6 domestic pigs.After embolisms all the animals survived without the abnormal states of sence and movement.The effects of embolisms were satisfied.We draw the microcatheter easily.All the ascending pharyngeal artery or RMB of embolisms were not seen.The no embolisms of the ascending pharyngeal artery or RMB were seen by ramus anastomoticus(RA)and arteria anastomotica(AA)from internal maxillary arteries and RA or AA were larger than before in 3 pigs.In macroscopy all the brains were normal.The embolic mixture were seen in RMB,which diffused homogeneously from the caudal to the rostral.The RMB of embolisms were harder than the contrary sides and easily dissected.Histologic observation:Almost no inflammatory reaction was found inside the vessels and surrounding tissues.There was no vessel wall damage and morphological change in histopathology during acute term,subacute term and chronic term.Conclusion1.The national CoHEMA is non-adhensive and easy to be injected through delivery micro catheter.2.The best injection velocity of mixture is 0.083ml per min.3.The national CoHEMA is easy to control with low viscosity,better biocompatibility.4.The national CoHEMA is suitable dissolved in 16%alcohol.5.It is an ideal embolic mixture with embolic instability to be tested in clinic.