Author + information
- Ma Dongxing1
Percutaneous left atrial appendage (LAA) occlusion devices have been developed to prevent the formation of thrombus in the LAA. Our objective was to evaluate the early effectiveness and safety of a left atrial appendage (LAA) occluder (LAMaxTM, KYD BioMedical, China) in canine model using trans-esophageal echocardiography (TEE) and angiography.
A total of 30 hybrid dogs (28.7±2.9 kg) were used. After fasting for 12 hours, the animals were first anesthetized with an intramuscular injection of xylazine hydrochloride (0.1mg/kg) and then fixed by four limbs in the supine position. More anesthesia were added if necessary. Endotracheal intubation was performed for mechanical ventilation. ECG monitoring was used during experiment. In order to choose a particular LAA occluder for implantation, the dogs were examined by TEE and angiography to determine the orifice diameter and depth of LAA, the number of LAA lobes, and LAA lobe classification. Percutaneous LAA occlusion involved a trans-septal approach and the deployment of a LAA occluder inside the LAA guided by TEE and angiography. After releasing the device from the delivery cable, the effectiveness of occlusion was evaluated by angiography and TEE.
Due to the difficulty of transseptal punture in the dextroverted hearts, four dogs were given up after failing several attempts of transseptal puncture. Twenty-six dogs were successfully implanted: 23 dogs with LAMaxTM devices, and 3 dogs with LAMaxTM plus devices. The success rate of instant occlusion was 100%. By using angiography and TEE, it was found that the LAAs in 25 dogs were completely occluded, 1 dog had a small amount of residual shunt, 2 dogs had small amounts of pericardial effusion, 1 dog had serious pericardial effusion, 3 dogs had an increase of mitral regurgitation because the occlusion disc of the device pushed the mitral valve, 1 dog had an impact on pulmonary venous flow, and the compression ratio of anchoring disc was 10% ∼ 50%. Among 26 dogs with implanted device, 23 dogs survived for more than one week after the implantation, while 3 dogs were sacrificed for confirmation within one day after the device implantation.
Our results demonstrate that the new domestic LAA occlude (LAMaxTM) is safe, and effective on instant occlusion of LAA. The combination of angiography and TEE plays an important role for the implantation of LAMaxTM devices. Further investigation is needed before clinical applications.