Experimental study of a new micro-invasive endovascular technique for treatment of megalosplenia and hypersplenism

Objective To investigate the imaging, pathological, hematocytic and immunological changes pre-and post swine splenic arterial embolization, using a coaxial microcatheter balloon occlusion technique through the trunk of the splenic artery to form the ″cast-like″ embolization of the splenic arterial branches; winth further evaluation of the potential utility and safety for management of megalosplenia-hypersplenism. Methods Swines in experimental group were treated with a coaxial microcatheter technique using a balloon catheter to occlude the trunk of the splenic artery with emulsion of N-butyl 2-cyanoacrylate and iodized oil to form the cast-like embolization. Swines in control group were treated with the routine method, using the PVA particles and gelfoams for the selective transcatheter embolization of the splenic artery. The imaging,pathologic, hematologic,and inmmunologic changes were observed for the two groups. Results (1) In the experiment group, CT plain scan showed size decrease of spleen after 30 minutes of balloon occlusion of the splenic artery(P 0.05) and conspicuous shrinkage after four weeks of cast-like embolization(P 0.05). (2)In the experiment group ,selective celiac arterial angiography performed at 1,4,8,12 weeks after the treatment showed that the tiny vascular recanalizations of the occluded splenic arteries was found after four weeks and complete occlusion of the splenic trunk without collateral branches in 3 animals. In the control, the splenic artery was visualized after 4 weeks without establishment of collateral branches. (3)Pathologic findings included: at the first week after the embolization, the splenic parenchyma presented with congestion and coagulation of the white pulp and red pulp. At the fourth week after the cast-like embolization, the embolic spleen appeared as yellow-brown with shrinkage without any remained normal structures. At the 8th and 12th weeks, atrophy of the embolic spleen occurred more obviously with diffuse fibrosis. In the control, the infarct and hemorrhagic necrosis of spleen were found more severe than those of the experimental animals at the first and fourth weeks after the embolization and simultaneously multi-focus infarct, granulation and loss of the normal structures in the parenchyma. Conclusions Transcatheter selective splenic arterial embolization with emulsion of N-butyl 2-cyanoacrylate and iodized oil, through a balloon catheter occluding the trunk of the splenic artery, is an effective new method for treatment of megalosplenia and hypersplenism and still more with less side effect together with prevention of recanalization and collateral circulation formation.