Left atrial appendage occlusion devices: one size doesn't fit all? The turning point of a custom-made device

Abstract

Left atrial appendage occlusion (LAAO) has as a comparable efficacy and safety profile compared with oral anticoagulation therapy in patients with atrial fibrillation. The procedural success rate is high, but some challenging anatomies may preclude optimal closure with standard devices. Our patient underwent a first LAAO attempt with Amplatzer Amulet 34 mm (St. Jude Medical, Saint Paul, MN, USA) and Watchman FLX 35 mm (Boston Scientific, Marlborough, MA, USA), but device anchoring was not feasible or sub-optimal due to the oversized LAA. The procedure was postponed in order to perform a cardiac computed tomography angiography and a custom-made LAmbre Closure System 42/52 mm (Lifetech Scientific, Shenzhen, China), specifically fitted with patient's LAA anatomy, was successfully implanted. The procedure was straightforward, and the device perfectly adapted to our patient's anatomy, with no residual leak.

Learning objective

Left atrial appendage presents several morphologies and procedural success rate of left atrial appendage occlusion is high, but challenging anatomies may preclude optimal closure with standard devices. Our case emphasizes the importance of pre-procedural planning and the safety and feasibility of custom-made devices, overcoming procedural failure of a previous attempt with standard devices.

Introduction

Atrial fibrillation (AF) represents the most common cardiac arrhythmia worldwide and entails an increased mortality and morbidity, mainly due to a 5-fold increase in the risk of stroke events [1]. Several studies in patients with non-valvular AF suggest that the great majority of thrombi develop within the left atrial appendage (LAA) [2]. Left atrial appendage occlusion (LAAO) has emerged as a feasible alternative to oral anticoagulation (OAC) for stroke prevention in selected patients with non-valvular AF [3]. The procedural success rate is high in most interventions, but some particular morphologies may preclude optimal closure with standard devices. We present a case of LAAO performed with a custom-made device, overcoming procedural failure obtained with standard devices due to the large dimensions of the LAA.

Case report

A 79-year-old man suffered from hypertension, stage 3 chronic kidney disease, permanent AF on OAC therapy, and severe mitral regurgitation due to anterior mitral leaflet prolapse. His past medical history reported a microcytic anemia due to iron deficiency, requiring blood transfusions. He was diagnosed with angiodysplasia of the colon resulting in several severe bleeding episodes, with the need for invasive treatments and blood transfusions. Considering the patient's high bleeding risk (HAS-BLED score of 3) and high cardioembolic risk (CHADSVASC score of 4), it was decided to discontinue OAC therapy and to discuss within the heart team another therapeutic approach. It was decided that he should undergo combined intervention of mitral transcatheter edge-to-edge repair (M-TEER) and LAAO. The pre-procedural transesophageal echocardiogram (TEE) confirmed the extensive prolapse of the anterior mitral leaflet, resulting in severe eccentric regurgitation directed towards the lateral wall of the left atrium. The left atrium was dilated (left atrial volume index 70 ml/m), and the LAA was large and polylobate. He underwent a combined procedure of M-TEER and LAAO, under general anesthesia, with TEE guidance. After the implantation of a first MitraClip G4 XTW (Abbott, Abbott Park, IL, USA) between A2-P2 and subsequent implantation of an additional MitraClip G4 XT laterally to the first, with good result on the mitral regurgitation, we performed an echocardiographic study of the LAA, confirming a landing zone diameter of 38 mm (Fig. 1A-C). According to this, we attempted to implant the largest available devices, as an Amplatzer Amulet 34 mm (St. Jude Medical, Saint Paul, MN, USA) (Fig. 2A,B) and a Watchman FLX 35 mm (Boston Scientific, Marlborough, MA, USA), without success, since device anchoring was sub-optimal with large residual peri device leak, due to the oversized LAA (Fig. 2C). Therefore, the procedure was postponed in order to perform a cardiac computed tomography (CT) angiography, which was initially not conducted due to the patient's chronic renal failure (Fig. 3A,B). A few months later, a custom-made LAmbre Closure System (Lifetech Scientific, Shenzhen, China) 42/52 mm (lobe/disc), specifically designed according to a 3D reconstruction of cardiac CT and according to the patient's LAA anatomy was successfully implanted (Fig. 3C,D). Intraprocedural TEE confirmed the appropriate position of the device and the absence of peri-device leaks (Fig. 3E). The patient was discharged two days after the procedure, on dual antiplatelet therapy (aspirin and clopidogrel) for 3 months. No adverse events occurred at follow-up and the 3-month TEE confirmed the optimal result (Fig. 3F).

Fig. 1.

Periprocedural TEE images: TEE image at 130° (A), 45° (B), and 112° (C) showing a landing zone diameter of 38 mm (dotted yellow line) and a depth > 12 mm (dotted orange line); TEE guided transeptal puncture (D) with correct landing in the LAA (E), also assessed by the real-time X-ray and echo imaging fusion by EchoNavigator (F) (Philips).

LAA, left atrial appendage; TEE, transesophageal echocardiography.

Fig. 2.

Failure of attempt to implant a Boston Watchmann Flex 35 mm device due to 8 mm leak demonstrated both by angiography (A – orange arrow) and intraprocedural TEE (B – white arrow) and an Abbott Amulet 34 mm with unfeasible device anchoring due to the oversized LAA (C).

LAA, left atrial appendage; TEE, transesophageal echocardiography.

Fig. 3.

CCTA of patient's LAA: Ostium maximum diameter: 39 mm (A - green line), landing zone diameter: 37 mm (A - orange line), CCTA confirmed the absence of a thrombus in the LAA; measurements of the LAA at the level of the ostium, with diameters measuring 48 mm × 39 mm (B); Details of custom-made LAmbre™ device, specifically fitted with patient's LAA anatomy (C), final angiographic result after LAmbre device implantation showing appropriate position of the device and the absence of peri-device leaks (D); TEE at 3-month follow-up confirming correct device positioning and absence of peridevice leak and device-related thrombosis.

CCTA, cardiac computed tomography angiography; LAA, left atrial appendage; TEE, transesophageal echocardiography.

Discussion

LAAO has a net clinical benefit that is competitive with OAC therapy, proving useful in terms of stroke prevention in many patients especially those with an augmented risk of bleeding. Although the implant success rate is becoming increasingly higher and complication events have decreased in recent years, there are challenging scenarios where novel devices could facilitate the procedure and potentially improve the clinical outcomes [4]. Indeed, the LAA is a fragile structure composed of a variable number of pectinate muscle and multiple lobes, resulting in different morphologies. In addition, the orifice of the LAA is typically oval while standard LAAO devices are usually round, leading to potential residual leaks. The LAmbre device is “an umbrella in the left atrial appendage”, consisting of a fully recapturable and repositionable LAA occluder, constructed from nitinol mesh and polyester membranes. A recent review demonstrated an excellent implantation success rate and promising follow-up clinical data, also in challenging LAA anatomies [5] [6]. The primary advantage of LAmbre is its composition: reduced risk of LAA perforation is largely attributed to the unique umbrella shape of its anchors and the complementary hooks. The remarkable adaptability of the device is primarily due to the various combinations of cover and umbrella sizes available, making it suitable for nearly all LAA anatomies, with orifice diameters >12 mm. The flexible waist serves as a compliant junction between the two components, allowing them to adjust autonomously to the underlying anatomy, even in challenging anatomy, such as multilobed or giant LAA. Our patient's LAA anatomy was challenging, due to its large dimensions, and two standard devices failed in an appendage closure attempt. Another key point we must emphasize is the importance of pre-procedural planning. A notable limitation of the first procedure was that it was not performed using a dedicated CT scan due to the patient's renal failure. Additionally, the pre-procedural TEE did not adequately focus on LAA imaging.

Another comment about the first procedure regards the trans-septal puncture (TSP): it is well known that TSP required for TEER is in a different position than that required for LAAO. In this case, we managed to obtain a TSP that was keen for both procedures as demonstrated in Fig. 1. The site of entrance is posterior and not too high, and in fact the main axis of the landing zone was easily aligned with both the device sheaths. A custom-made LAmbre device, patient-tailored based on cardiac CT angiography reconstruction, overcame the issue and perfectly adapted to the giant anatomy and successfully excluded LAA. Previously, double-device LAAO using a combination of two standard devices (‘kissing-Watchman’ technology) have been reported to close large LAA, but it results in a challenging and complex procedure [7,8]. In the literature there are few data about successful giant LAA occlusion using a single LAmbre closure system [9,10] demonstrating the technical easiness and procedural feasibility. According to our experience, the procedure was straightforward, and the device perfectly adapted to our patient's anatomy, with no residual leak, confirmed also at 3-month follow-up.

Consent statement

Written informed consent was obtained from the patient.

Declaration of competing interest

The authors have no conflict of interest to declare.