[Animal modeling] - Animal experimental study on two different types of left atrial appendage occluders

  Objective To evaluate the feasibility and safety of left atrial appendage (LAA) closure with single disc cylindrical occluder and double disc split occluder.

  Methods The left atrial appendage (LAA) of 14 healthy dogs was occluded via femoral vein with single disk cylindrical or double disk split LAA occluder; The experimental dogs who died unexpectedly were immediately examined for gross specimens to analyze the cause of death. The surviving experimental dogs were killed on the 45th, 80th, 110th and 15th days after operation respectively. The surface tissues of the occluder were stained with HE and evaluated for endothelialization by DAPI and CD31 immunofluorescence.

  Results Left atrial appendage was occluded by single disk cylindrical occluder in 6 dogs. Five dogs died 30 min to 8 h after operation, and one dog survived to 15 months and was killed; The gross cardiac anatomy showed that there were a lot of thrombus on the surface of the occluder in 4 experimental dogs, and about 1/5 of the occluder surface in 1 experimental dog survived without new tissue coverage; The left atrial appendage (LAA) was occluded in 8 dogs with dual disc occluder, and 7 dogs were completely occluded; At 110 days after operation, new tissue completely covered the surface of the occluder, HE and immunofluorescence staining showed complete intima formation, and new blood vessels were seen.

  Conclusion The incidence of acute thrombosis and immediate death rate are high after single disk cylindrical occluder is implanted into left atrial appendage; The dual disc split left careful ear occluder is used to occlude the complications related to the left atrial appendage (LAA) device. The 4-eye covered disc is completely intimal after LAA occlusion.