ABSTRACT
Objective To evaluate the feasibility and safety of a delivery pathway for the performance of percutaneous left atrial appendage (LAA) occlusion in experimental canine models. Methods Transseptal puncture was performed via femoral vein approach under fluoroscopic and angiographic guidance in 12 experimental dogs. A pigtail catheter was advanced into the left atrium (LA), which was followed by LA angiography. The diameters of the neck of LAA were measured on LAA angiogram obtained in appropriate projection. After the delivery sheath was advanced along the wire into LA, a pigtail catheter was inserted into the ostium of the LAA and the sheath was then advanced over the pigtail into the LAA. LAA angiography was then performed through the delivery sheath to confirm the position of the delivery sheath. One hour after the procedure both electrocardiography (ECG) and transthoracic echocardiography (TTE) were carried out in five dogs to check the results, immediately after which the five dogs were sacrificed to macroscopically observe the damages of the puncture site of inter-atrial septum as well as inside the LA and LAA. One hour and 2 weeks after the procedure TTE was conducted in the remaining 7 dogs and these dogs were followed up for one month. Results One dog died of pericardial tamponade during the operation. In 8 dogs the LAA was clearly displayed in the projection position of right anterior oblique (RAO) 30°/cranial (CRA) 20°,while in 3 dogs the LAA was well visualized in the projection position of RAO 30° , and in one dog in the projection position of RAO 30°/caudal (CAU) 20°. The diameter of LAA neck was (13.6 ± 5.2) mm. The delivery sheath was safely advanced into the LAA along the pigtail catheter in all dogs, and no air embolism, thrombus or pericardial tamponade occurred. Hematoma at puncture point of groin occurred in 2 dogs, which was absorbed through pressure dressing. Macroscopic examination of the heart performed immediately after the operation showed that no bloody pericardial effusion was found, and mild hematoma at posterior wall of LA was seen in one dog and mild damage of the upper-margin intima of LAA was noted in 2 dogs. The mean fluoroscopy time was (10.1 ± 2.5) minutes and the mean operation time was (58 ± 12) minutes. TEE showed no pericardial effusion 2 weeks after the procedure. During the follow-up period of one month no sudden death, stroke or infection occurred. Conclusion This method of placing the delivery sheath into the LAA is clinically safe and effective, and it can reliably establish a pathway to advance the LAA occluder into LAA.