discussion
To our knowledge,it has rarely been reported that a planted LAmbre device gets dislocated during the procedure of Left Atrial Appendage Occlusion before and the procure was meeting COST criteria.A LAmbre device (Lifetech Scientific Corp., Shenzhen, China)is one of the “anchor and seal”devices and it consists of an umbrella and a cover connected by a short central waist1.The distal umbrella comprises 8 claws with individual stabilizing hooks attaching to them to facilitate anchoring to LAA wall1.Once some of the hooks fail to anchor to the LAA wall steadily,the occluder may become mobilizable in horizontal direction while the tug test proves it is stable in the vertical direction.In this situation,the device could detach from the landing position once losing the traction from the delivery sheath and that may account for the present case.The size of the LAmbre device should be 4-6 mm larger than the measured LAA orifice, specifically based on the structure of the LAA and the compression degree of the implant. The choice of a 34-38mm LAmbre device was reasonable in this case but this patient’s LAA was in a chicken-wing shape and the landing disc was not deployed coaxially with the LAA.Both of the umbrella and the cover are circular, the eccentricity and irregularity of the LAA orifice have been verified implicated in residual leak2 and they may have potential influence on the stability of the device. To ensure the device solid,we should confirm the following points to make sure the occluder is in the optimal position before releasing it completely:the umbrella is rectangular or inverted trapezoid, the 8 mark points are located in the same horizontal plane with the center point,the upper edge is smooth and fixed, and the cover is in the shape of concave.
Watchman device differs from LAmbre in structure and it is a self-expanding nitinol framed structure with fixation barbs and a permeable polyester fabric to cover the orifice of the LAA3.Watchman device has limitations like limited recapture and repositioning capabilities3.Li et al4.reported a case of successful percutaneous retrieval of a detached watchman device by clipping device hub via a 12-F transseptal sheath after two failed attempts.One of the advantages of the LAmbre device is that it can be deliberately recaptured, completely retrieved and redeployed.Qiu et al .and Sanhoury et al.reported two cases of successful retrieval of LAmbre device with the devices respectively located in the aortic arch and the abdominal aorta.Both of their patients were asymptomatic during the procedure.Unfortunately,the the device was trapped in our patient’s mitral valve and caused hemodynamic changes rapidly.We immediately put the patient on life support and tried percutaneous recapture but that didn’t work .The device was subsequently removed by a cardiovascular surgery.As Wang et al.reported,the occluder can hardly be retrieved through a percutaneous sheath and usually lead to device-related injury when it is trapped in left ventricle(LV)5.As far as we know,a successful percutaneous recapture of a LAmbre device trapped in the mitral valve has never been reported till now.For the LAmbre device,when we rotate the sheath counterclockwise repeatedly,the unloading of the occluder may occur.To avoid this situation,we must keep an eye on the occluder and operate prudently especially when we rotate the sheath with the occluder in the state of half release. If the device unexpectedly falls in the LA or the aorta and the patient’s hemodynamic parameters are stable,we can still attempt to retrieve the device by using forceps or snares through a adjustable curved sheath.A catheter should be used to fix the implant via femoral access and then we need to advance a pigtail to the mitral valve orifice through the septum to prevent the occluder from falling into the LV further.During this procedure, ACT should be frequently tested to avoid thrombosis.If the device locates in the mitral valve or LV and causes hemodynamic changes,percutaneous retrieval can hardly work and a surgery should be performed as quickly as possible to retrieve the implant.
Kang-zheng YUAN and Jian WANG contributed equally to this work.