IJCA-17846; No of Pages 5 International Journal of Cardiology xxx (2014) xxx–xxx

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International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard

Left atrial appendage occlusion: Initial experience with the Amplatzer ™ Amulet™☆ Xavier Freixa a,b, Ali Abualsaud a, Jason Chan a, Mohamed Nosair a, Apostolos Tzikas a,c, Patrick Garceau a, Arsène Basmadjian a, Réda Ibrahim a,⁎ a b c

Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada Department of Cardiology, Thorax Unit, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain Interbalkan European Medical Center, Thessaloniki, Greece

a r t i c l e

i n f o

Article history: Received 13 August 2013 Received in revised form 28 January 2014 Accepted 22 March 2014 Available online xxxx Keywords: Left atrial appendage Stroke Amulet Amplatzer cardiac plug Atrial fibrillation

a b s t r a c t Background: The Amplatzer™ Amulet™ (Amulet) is the evolution of the Amplatzer™ Cardiac Plug, a dedicated device for percutaneous left atrial appendage (LAA) occlusion. The new device has been designed to facilitate the implantation process, improve the sealing performance and further reduce the risk of complications. The objective of the study was to describe the initial experience with the Amplatzer Amulet for percutaneous LAA occlusion. Methods: This was a prospective single-center study of patients undergoing percutaneous LAA occlusion. The indication for LAA closure was a formal contraindication for oral anticoagulation or previous history of stroke due to INR lability. All procedures were done under general anesthesia and transesophageal echocardiography (TEE) guidance. Transthoracic echocardiography was performed 24 h after the procedure in order to rule out procedural complications before discharge. Further follow-up was done with a clinical visit and TEE at 1–3 months. Results: Between July-2012 and June-2013, 25 patients with a mean CHA2DS2-VASC of 4.3 ± 1.7 underwent LAA occlusion with the Amplatzer Amulet. The device was successfully implanted in 24 patients (96%) without any procedural stroke, pericardial effusion or device embolization. None of the patients presented any clinical event at follow-up. Follow-up TEE showed complete LAA sealing in all patients with no residual leaks N 3 mm and no device embolization. One patient (4.1%) presented a device thrombosis at follow-up without clinical expression. Conclusion: In this initial series of patients, the Amulet showed a remarkable acute and short-term performance in terms of feasibility and safety as depicted by the high successful implantation rate and the low incidence of complications. © 2014 Elsevier Ireland Ltd. All rights reserved.

1. Introduction Despite the relatively recent introduction of the technique, percutaneous left atrial appendage (LAA) occlusion is growing rapidly in reference centers all over the world. In fact, percutaneous LAA occlusion is currently considered a valid alternative in patients with non-valvular atrial fibrillation (NVAF) and a formal contraindication for oral anticoagulation but it might also be considered in those at high-risk of bleeding or drug cessation (IIB indication) [1].

☆ Conflict of interests: Dr. Freixa, Tzikas and Ibrahim are consultants and proctors for St. Jude Medical. ⁎ Corresponding author at: Montreal Heart Institute, 5000, Belanger Street, Montreal, Quebec H1T 1C8, Canada. Tel.: +1 514 376 3330 #3800. E-mail address: [email protected] (R. Ibrahim).

The LAA is very heterogeneous in size and morphology [2]. One of the main challenges of the technique is related to the proper apposition of the device, which is not variable in shape, in a highly variable structure like the LAA [2]. The Amplatzer™ Cardiac Plug (ACP) (AGA-StJude, Minneapolis, MN, USA) and the Watchman™ (Atritech-Boston Scientific, Natick, MA, USA) are currently the most widely used devices for LAA occlusion. Although different in design, both devices have shown very promising data [3–6]. Despite the encouraging results, the need of device evolution is deemed necessary in order to facilitate the implantation process and reduce the occurrence of short and longterm complications. The Amplatzer™ Amulet™ (Amulet), an evolution of the ACP, keeps the main shape of the ACP consisting of a distal lobe and a proximal disc but features other novelties designed not only to ease the implantation process but also to minimize the risk of complications [7]. Our group implanted the first-in-man Amulet for LAA occlusion in July 2012 [7]. The present paper describes the first worldwide

http://dx.doi.org/10.1016/j.ijcard.2014.03.154 0167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved.

Please cite this article as: Freixa X, et al, Left atrial appendage occlusion: Initial experience with the Amplatzer™ Amulet™, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.03.154


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experience with the Amulet in a series of patients who underwent LAA occlusion. 2. Methods Between July 2012 and June 2013 all consecutive patients who underwent percutaneous LAA closure with the Amulet at the Montreal Heart Institute, University of Montreal, Montreal, Quebec, Canada were prospectively included in the study. All clinical, procedural, echocardiographic and outcome variables were prospectively collected. Patients were more than 18 years old, had AF (paroxysmal, persistent or permanent) with a high risk for stroke (CHADS2 score ≥ 2), and at least one contraindication for oral anticoagulation therapy. Exclusion criteria for LAA closure included: LAA thrombus, mobile aortic atheroma or symptomatic carotid artery disease. All patients provided written informed consent before the procedure. The Director of Professional Services at the Montreal Heart Institute approved the review of medical charts and documentation. This initiative was initiated by the investigators and was not financed by any company. In addition, the authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology. 2.1. The Amplatzer™ Amulet™ The Amulet, like the ACP, is a self-expanding device for LAA occlusion with a distal lobe and a proximal disc connected by an articulated waste. The distal lobe conforms to the inner LAA wall in a depth between 10 and 15 mm, the articulated waist allows a proper orientation of the device into the LAA, and the proximal disc seals the LAA ostium. The Amulet is also retrievable and repositionable and is implanted from the femoral vein (12–14 French delivery sheath size) using a transeptal approach. Despite the similarity in design compared to the ACP, the Amulet has several novelties: 1) device pre-loaded system, 2) increased number of stabilizing wires (6 to 10 pairs) on the lobe (Fig. 1), 3) inverted attaching end-screw on the disc to reduce the risk of device thrombosis (Fig. 2), 4) new delivery cable with an inner 0.014″ wire for tension release, 5) larger available sizes (31 mm and 34 mm), 6) longer lobe length (7.5 to 10 mm), 7) longer connecting waist (5.5 to 8 mm) and 8) larger disc diameters (lobe + 6 to 7 mm). A more comprehensive description of the Amulet dimensions and other novel features have been reported elsewhere [7].

disc and not the lobe as complete LAA sealing is the main goal of the device. Successful deployment was defined in case of final mild leak (one-third filling of the LAA behind the device), trace leak (barely detectable filling) or absent leak (no detectable filling) [8]. 2.3. In hospital and short-term follow-up A transthoracic echocardiography (TTE) and a chest X-ray were performed the day after the procedure to rule out the presence of pericardial effusion or device embolization before discharge. Patients were treated with dual anti-platelet therapy (aspirin 80 mg/day and clopidogrel 75 mg/day) for a minimum of three months followed by aspirin indefinitely. Clinical follow-up was performed by a programmed clinical visit (1 to 3 months after the index procedure) supplemented by medical-record review of any subsequent hospital admissions or additional visit. Patients underwent TEE prior to the clinical visit in order to assess the presence of device leaks and rule out complications such as pericardial effusion, device thrombosis or device embolization. 2.4. Statistical analysis The results are expressed as mean ± standard deviation (SD) for normally distributed data. Continuous variables that were not normally distributed are expressed as medians with interquartile ranges (IQR). Statistical analyses were done with the SPSS package v16.0 (Chicago, IL, USA).

3. Results During the study period, 25 patients underwent percutaneous LAA occlusion with the Amulet. Indications for the procedure were the inability to receive anticoagulation treatment in spite of a clear clinical indication in 22 patients (88%) and a prior history of cardioembolic events due to INR lability in 3 (12%). The main reason for contraindicating oral anticoagulation was gastrointestinal bleeding in 10 (45.5%), intracranial bleeding in 6 (27%), non-gastrointestinal bleeding in 5 (23%) and multiple falls in 1 (4.5%). Baseline characteristics of the study population are shown in Table 1.

2.2. Device implantation The procedure was performed under general anesthesia with simultaneous fluoroscopic and TEE guidance (iE33 ultrasound system and X7-2t matrix array transducer, Philips Healthcare, Andover, MA, USA). The same operator performed all procedures. The size of the device was selected based on angiographic and TEE measurements. Several contrast injections of 8 to 10 ml in the RAO 30° Cranial 20° with a 5 French marked Pigtail (Merit Medical, UT, USA) were used for the angiographic assessment. For TEE, the LAA was assessed in the mid-esophageal and high-esophageal views from 0° to 180°. The largest, smallest, and the mean LAA diameter in a depth between 10 and 15 mm from the ostium measured in mid diastole on either angiography or TEE were used to choose the size of the device. The degree of device over-sizing was based on the anatomy of the LAA and the experience of the operator but was typically 2 to 6 mm larger than the average LAA diameter and usually no less than the largest LAA diameter. In fact, the device selection criteria was similar to the one used with the ACP. The degree of sealing was assessed behind the disc of the device by contrast injection through the delivery system after implantation. We chose to evaluate the leak behind the

3.1. Procedural information The Amulet was successfully implanted in 24 patients (96%). In one patient, the smallest device (16 mm) was attempted but not implanted as the LAA was bi-lobar and presented a small and short (b10 mm) landing area. Echocardiographic and procedural data are shown in Table 2. The selection of the Amulet size was based on imaging (angiography and TEE). Overall, the device was oversized by 1.1 ± 1.9 mm and 2.2 ± 2.1 mm in relation to the largest angiographic and TEE diameter, respectively. A higher degree of oversizing was observed compared to the mean angiographic (2.3 ± 2.0 mm) and TEE diameters (3.6 ± 2.0 mm). Three patients presented very large LAAs with a landing diameter N31 mm

Fig. 1. Comparison between the ACP and the Amulet highlighting the difference in the number of stabilizing wires. Note: The Amulet (right panel) contains a higher number of stabilizing wires (white arrows) compared to the ACP (left panel).

Please cite this article as: Freixa X, et al, Left atrial appendage occlusion: Initial experience with the Amplatzer™ Amulet™, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.03.154

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Fig. 2. Comparison between the ACP and the Amulet highlighting the inversion of the disc end-screw. Note: Lateral (A) and oblique (C) view of the ACP showing the protruding end-screw of the disc. Lateral (B) and oblique (D) view of the Amulet highlighting the inverted end-screw of the disc.

that were successfully sealed with a 34 mm device. In addition, four patients presented a very challenging anatomy with a chicken-wing LAA characterized by an early (b 20 mm from the ostium) and severe bend (~180°) that was occluded by implanting the lobe of the device inside the wing of the appendage (sandwich technique). There was no intra-procedural device embolization, stroke or pericardial effusion. One patient (4%) presented a transient ST elevation (1 min) during the procedure without further consequence. Transthoracic echocardiography 24 h post-procedure also ruled out the presence of pericardial effusion or device embolization. The mean hospital stay after the procedure was 1.08 ± 0.27 days.

Table 1 Baseline characteristics. n = 25 Age (years) Male gender n (%) Hypertension n (%) Diabetes mellitus n (%) Prior stroke n (%) Chronic atrial fibrillation n (%) Left ventricle ejection fraction b50% n (%) Baseline creatinine (mmol/L) CHA2DS2-VASC score HASBLED

74.7 ± 7.7 16 (64) 22 (88) 11 (44) 8 (32) 16 (64) 4 [16] 115.3 ± 39.0 4.1 ± 1.7 4.6 ± 1.1

3.2. Clinical and echocardiographic follow-up Clinical follow-up at 2–3 months was available in 21 patients (87.5%). None of them presented any stroke, peripheral embolism, bleeding episode or hospital readmission.

Table 2 Echocardiographic and procedural characteristics. n = 24 LAA largest angiographic diameters (mm) LAA largest TEE diameters (mm) LAA mean angiographic diameters (mm) LAA mean TEE diameters (mm) Device oversizing (compared to the largest diameter) – Angiography and device (mm) – TEE and device (mm) Device oversizing (compared to the mean diameter) – Angiography and device (mm) – TEE and device (mm) Amulet dimensions: n (%) – 20 – 22 – 25 – 28 – 34 Fluoroscopy time (min) Combined procedures: – Atrial septal defect closure n (%)

23.3 22.3 21.9 20.4

± ± ± ±

3.8 4.7 3.7 4.5

1.1 ± 1.9 2.2 ± 2.2 2.3 ± 2.0 3.6 ± 2.0 4 (16.6%) 8 (33.3%) 7 (29.2%) 2 (8.3%) 3 (12.5%) 19.8 ± 8.7 3 (12.5%)

Please cite this article as: Freixa X, et al, Left atrial appendage occlusion: Initial experience with the Amplatzer™ Amulet™, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.03.154


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Follow-up TEE was also available in 21 patients (87.5%). The mean time duration between the procedure and the control TEE was 1.46 months (IQR 1.2–2.3 months). All patients presented effective LAA sealing as none of them showed any residual leak N3 mm by TEE. Transesophageal echocardiography did not reveal any case of pericardial effusion or device embolization. One patient presented device thrombosis two months after the procedure. By mistake, the patient did not receive clopidogrel from the pharmacy during the first week after the procedure. Noteworthy, the same patient had a larger thrombus over an atrial septal defect (ASD) occluder that was implanted on the same day of his LAA occlusion. A chronic thrombocytopenia with a platelet count between 50,000 and 100,000 × 109/L was the only hematologic condition that was found. Since then, the thrombus has been treated with dalteparin for 7 months with progressive regression. The patient is still taking dalteparin and no clinical events were associated with the thrombosis of the device. 4. Discussion This initial clinical experience with the Amplatzer™ Amulet™ has shown a remarkable feasibility and safety of the device for percutaneous LAA occlusion. In our series, the Amulet showed a high successful implantation rate (96%). Although this was only an initial experience with the device, the procedural success was similar to previous registries with the ACP [4,6, 9–11] and Watchman [3,5] despite the presence of very challenging anatomies with three large LAAs (12.5%) and four complex chickenwing LAAs (16.7%). In fact, the presence of N 30 mm LAA is a contraindication for the ACP and Watchman but not for the Amulet as two larger sizes are available (31 and 34 mm) [12]. Another challenging situation is the presence of a complex chicken-wing with an early and severe bend. In the absence of a clear landing area, the lobe of the device must “sit” inside the wing of the LAA. In this setting and given the increased number of stabilizing wires, the longer waist length and the larger disc of the device, we felt that the Amulet provided more implantation forgiveness compared to the ACP and Watchman [13]. The device could not be implanted in only one patient (4%) with a small LAA and a short landing zone. No other percutaneous LAA occlusion systems were attempted as the LAA was considered too small and short. In this sense, it is important to point out that the length of the lobe is 1 mm (for 16 to 22 mm devices) to 3.5 mm (for 25 to 34 mm devices) longer than the first generation device (ACP) and therefore it needs a slightly larger volume and longer landing zone (10 to 15 mm). This feature should always be considered when measuring the LAA but is especially relevant in patients with short and tapered appendages. In contrast with previous registries, no procedural complications were observed and none of the patients had pericardial effusion or device embolization. Although certain registries with the ACP have also shown a very low complication rate [14] and the experience of our group with LAA occlusion might also explain this finding, the novel features of the device were felt to play a relevant role in reducing the occurrence of complications. The preloaded package speeded-up the preparation process and may have reduced the risk of air introduction into the delivery system. In addition, the increased number of stabilizing wires, the longer waist and the larger disc provided more stability and forgiveness to the system, reducing the manipulation inside the LAA and therefore the potential risk of pericardial effusion. Although the novel inner 0.014″ cable was used in all cases, it was found helpful in only 2 (8.3%) in which the delivery catheter was not coaxial to the axis of the LAA. In those cases, some changes in the position of the device, particularly of the disc near the left upper pulmonary vein ridge, were observed after releasing the tension from the delivery cable. Although our group did not experience any complication related with the novel delivery system, the inner 0.014″ wire has been a matter of controversy for some operators as it was found to add complexity to the device preparation, increase the risk of unintentional unscrew and

reduce the recapturing strength. For those reasons, the delivery system of the Amulet device is being redesigned in order to achieve a better balance between accuracy, simplicity, safety and strength. In this sense, the ACP delivery system might be a good alternative as it has shown a relevant performance over the last years. One of the most important findings of our study was the absence of relevant residual leaks (N3 mm) at TEE follow-up. The absence of residual leaks with the Amulet might be a result of a better sizing process with the increased experience of the team but also of a better device performance due to the improved anchoring, the larger dimensions of the lobe and the improved capacity to fully cover the LAA ostium with the larger disc [15]. The degree of device oversizing is a pivotal factor for the procedural success. Following the manufacturer recommendations, the degree of oversizing with the Amulet should range between 3 and 6 mm in relation to the angiographic or TEE diameters at the landing zone. In our series we use the mean angiographic and TEE diameter as the main parameter to guide the selection of the device. Since the LAA is oval in 80% of patients [16], the largest LAA diameter was felt to be misleading in certain occasions as it may result in excessive oversizing and thus apposition difficulties in elliptical appendages with large differences between the long and the short-axis diameters. In contrast, the mean diameter was found to be a more useful parameter for balancing the differences between axis. In addition, for more circular appendages, the mean diameters were also useful as the small differences between the short and long-axis resulted in very similar values between the mean and the largest diameter. The ideal imaging modality for patient screening and procedural guiding remains to be identified. Although 2D-TEE has demonstrated good results, other imaging techniques namely 3D-TEE [17] or multi-slice computed tomography (MSCT) might provide better spatial resolution and subsequently better device selection. The short-term follow-up revealed no clinical events or readmissions in any patient. The incidence of stroke with the ACP ranged between 0 and 1.6% per year depending on the series [4,6,9–11]. Control TEE showed no device embolization and only one case of device thrombosis. Interestingly, this patient presented a concomitant thrombus in the LAA and ASD devices that were implanted on the same day. Of note, the risk of device thrombosis was increased since the patient did not receive dual antiplatelet therapy after the procedure. In any case, the Amulet has been designed to prevent the occurrence of device thrombosis by inverting the attaching end-screw (Fig. 2). The incidence of device thrombosis with the ACP varied from 0 to 14% [4,6,9–11]. Importantly, most of the ACP thrombosis occurred at the level of the attaching end-screw pin as this was a prominent structure with a late endothelialization [11]. For this reason, the recessed pin of the Amulet is expected to reduce the incidence of device thrombosis by creating a flat surface that might promote a more rapid endothelialization.

5. Limitations The results of the present study must be interpreted with caution, as this was a single center and operator observational study with a relatively small number of patients, incomplete TEE follow-up and no comparison with other available devices. The aim of the present paper was to describe our initial experience with the Amulet as well as to provide data that operators might find useful when using this device. In conclusion, the present study describes our initial experience with the new Amplatzer™ Amulet™ device for LAA occlusion. Clinical results demonstrated feasibility with a high rate of procedural success and a low incidence of complications. Further data with a larger number of patients and longer follow-up will be necessary to confirm these results, evaluate the occurrence of device thrombosis and compare the closure performance with other available devices.

Please cite this article as: Freixa X, et al, Left atrial appendage occlusion: Initial experience with the Amplatzer™ Amulet™, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.03.154

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Please cite this article as: Freixa X, et al, Left atrial appendage occlusion: Initial experience with the Amplatzer™ Amulet™, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.03.154

Left atrial appendage occlusion: initial experience with the Amplatzer™ Amulet™.

The Amplatzer™ Amulet™ (Amulet) is the evolution of the Amplatzer™ Cardiac Plug, a dedicated device for percutaneous left atrial appendage (LAA) occlu...
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