Experimental Study Of A New Endovascular Technique For Treatment Of Megalosplenia And Hypersplenism

Obejective: To investigate the imaging,pathological,hematocytic, and immunological changes pre- and post swine splenic arterial embolization, using a coaxial microcatheter technique under a balloon catheter occluded the trunck of the splenic artery. To evaluate the potential utility of the new method for management of megalosplenia-hypersplenism.Methods: Seven swines were divided into the experiment and control group.Two swines as the control were treated with the routine method, using the PVA particle and gelfoams for the transcatheter embolization of the splenic artery. Five swines as the experimental group were treated with a new method, using a coaxial microcatheter technique under a balloon catheter occluded the trunck of the splenic artery. An emulsion of N-butyl 2-cyanoacrylate and iodized oil was used for the selective embolization of the splenic artery in the experiment group. The general reaction of the animals, the imaging,pathological, hematological,and immunological changes were observed.Statistics. Measurement data were espressed as means±SD and analyzed by t Test with a STATA7.0 software.Results: (1)In the experiment group ,the first pig showed the symptoms ofvomiting, anorexia and fantod, but these symptoms disappeared in the folbwing day. The third one showed the same symptomsa as the first one but more severely, and died of necrotizing pancreatitis confirmed by pathology in the second dayafter the procedure. The other three appeared normal in the general condition after the treatment. In the control,two swines showed anorexia ,fantod , weak breath for 2 days after the procedure.(2)In the experiment group, selective splenic arterial angiography showed that the contrast medium was slowed dowm in the splenic artery obviously and stagnated in the spleen, and CT plain scan showed decreased in the size of the spleen after 30 minutes under the balloon occlusion of the splenic artery(35~38°/o, p<0.05). (3)In the experiment group selective celiac arterial angiography performed at 1,4,8,12 weeks after the treatment showed that the tiny vascular recanalization of the occluded splenic artery was found in 1 animal, completed occlusion of the splenic trunck without collateral branch was found in 3 animals. In the control,the splenic artery was visualized after 4 weeks without collateral branches established. (4)Pathological findings included:a) Changes of the splenic arteries. In the experiment group, an acute inflammatory reaction was seen in the splenic arteries at the first week after the treatment. The reaction manifested that the endothelial cells were disappeared, and intima and tunica media were destroyed. The extima of the splenic arteries was intact. At the fourth week after the embolization, granulation was seen in the splenic artery lumen, with foreign-body giant cell reaction and newly capillary, in addition to the white thrombus and the embolic glue. At the 8th and 12th week after the embolization, the granulation in the splenic artery lumen was substituted by fibrosis, and calcific tissue was seen in the vascular wall.b) Changes of the spleen in the experiment animals. At the first week after the embolization, the capsule of the spleen became thicker. The splenic parenchyma presented with congestion and destruction of the white pulp and red pulp. The splenic sinusoid and trabeculae disappeared. At the fourth week after the embolization, the embolic spleen appeared yellow-brown and shrunk. Light microscopic examination showed that the white pulp and red pulp of the spleen shrunk without the normal structures. At the e1 and 12 week, atrophyof the embolic spleen was seen obviously without the normal structures, and the granulation was substituted by the fibrosis and calcific tissue.c) In the control,the infarct and the hemorrhagic necrosis of the spleen was seen more severe than that of the experiment animal at the first week after the embolization. At the fourth week after the embolization, the parenchyma of embolic spleen appeared multi-focus infarct, granulation, and loss of the the normal structures.d) In the both control and the experiment animals, no necrosis or ischemic of the stomach, the gallbladder and the liver occurred. The coagulation necrosis of pancreatic gland cell was seen in one pig.(5) Hemotologic changes:a) In the experiment group,the white blood cell (WBC) and neutrophilic granulocyte increased at the first and third day after the embolization. In the control, WBC and neutrophilic granulocyte increased.b) Biochemistry changes. There were no significant differences on the blood biochemical tests in the living pigs before and after the embolization,at the first,third ,fifth day and the last day(P>0.05).c) Immunologic changes. There were no significant differences on the immunological test (IgG> IgM> IgA)in the living pigs pre and post the embolization (P>0.05).Conclusions:a) Transcatheter selective splenic arterial embolization using an emulsion of N-butyl 2-cyanoacrylate and iodized oil, under a balloon catheter occluded the trunck of the splenic artery, is an effective new method for treatment of megalosplenia and hypersplenism.b) In comparison with the conventional transcatheter splenic arterial embolization technique, the new method had a less reaction after the embolization.c) Using the new method, recanalization and establishment of collateral branchescould be prevented after embolization of the spleen.