【Animal Modeling】-Animal study on two different types of left atrial appendage occluder

  Objective To evaluate the feasibility and safety of occlusion of the left atrial appendage in animals with two different left atrial appendage occluders, the single-disc cylindrical type and the double-disc split type.

  Methods 14 healthy experimental dogs were occluded by single-disc cylindrical or double-disc split LAA occluder through the femoral vein, and the effect of occlusion was evaluated by intraoperative left atrial angiography. Gross specimens were examined to analyze the cause of death. The surviving experimental dogs were sacrificed on the 45th day, 80th day, 110th day and 15th month after operation, respectively.

  Results The left atrial appendage was occluded in 6 experimental dogs with a single-disk cylindrical occluder. 5 experimental dogs died 30 minutes to 8 hours after the operation, and 1 experimental dog survived to 15 months and was sacrificed. Gross cardiac anatomy found 4 There were a lot of thrombus on the surface of the occluder in the experimental dogs, and about 1/5 of the surface of the occluder in the surviving experimental dog was not covered by new tissue; One experimental dog was completely occluded; the new tissue completely covered the surface of the occluder 110 days after operation, HE and immunofluorescence staining showed complete intima formation, and new blood vessels were visible.

  Conclusion The incidence of acute thrombosis and immediate death rate after implantation of the single-disc cylindrical occluder is high; the double-disc split type left atrial appendage occluder is used to close the left atrial appendage and has low complications after the left atrial appendage occlusion. The 4-mesh covering disc was completely endometrialized.