ORIGINAL INVESTIGATION

The Chicken‐Wing Morphology: An Anatomical Challenge for Left Atrial

Appendage Occlusion

XAVIER FREIXA, M.D.,1 APOSTOLOS TZIKAS, M.D., PH.D.,2 ARSÈNE BASMADJIAN, M.D.,3

PATRICK GARCEAU, M.D.,3 and RÉDA IBRAHIM, M.D.3

From the 1Department of Cardiology, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain; 2St. Luke’s Hospital,Thessaloniki, Greece; and 3Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada

Objectives: To describe the particular assessment and closure strategy that was followed in patients with left atrialappendages (LAA) with an early and severe bend.Background: The presence of a chicken‐wing morphology with an early and severe bend constitutes one of the mostdifficult anatomical settings for transcatheter LAA occlusion.Methods: Between November 2009 and December 2012, patients who presented chicken‐wing LAA with an early(<20mm from the ostium) and severe bend (<180°) were identified and included in the analysis. A particularimplanting strategy consisting of deploying the distal lobe of the device inside the chicken‐wing bend was used in allcases.Results: Among 42 patients who underwent LAA occlusion during the study period, 5 (12%) presented the pre‐specified anatomy. Following the mentioned implanting strategy, all patients underwent successful LAA occlusionusing the Amplatzer Cardiac Plug (n¼ 2) and the Amplatzer Amulet (n¼ 3). Successful occlusion was achieved inall patients. None of them presented any procedural complication. Follow‐up transesophageal echocardiography at3 months showed successful LAA sealing in all patients and no device embolization or thrombosis.Conclusions: According to our results, the pre‐specified closing implantation technique for chicken‐wing LAAs withan early and severe bend might be a valid strategy for this challenging anatomical setting. Further cases will benecessary to confirm the results. (J Interven Cardiol 2013;9999:1–6)

Introduction

Percutaneous left atrial appendage (LAA) occlusionis a complex interventional technique with a significantlearning curve.1 One of the main challenges of thetechnique is related to the heterogeneous anatomy of theLAA.2 The chicken‐wing morphology is a commonanatomy characterized by the presence of an obviousbend in the proximal or middle part of the dominantLAA lobe.2 Occasionally, the bend of the appendage isso severe that it creates a 180° curve. In general, thepresence of such a severe bend represents an importantchallenge for the successful deployment of a closure

device.We describe the assessment and closure strategythat were used in 5 patients with a chicken‐wingmorphology LAAwith an early and severe bend.

Methods

Patient Selection. Between November 2009 andDecember 2012, patients who presented a chicken‐wing LAAwith an early (<20mm from the ostium) andsevere bend (<180°) assessed by transesophagealechocardiography (TEE) were identified and includedin a retrospective analysis. The absence of a properlanding area due to the early bend of the lobe does notallow a conventional implanting strategy. Patients withsevere bends located>20mm from the ostiumwere notincluded since no contact between the device and thedistal bend was anticipated and no specific implanta-tion technique was therefore required. All patients

Conflict of interest: Dr. Ibrahim and Tzikas are consultants for St.Jude Medical.Address for reprints: Réda Ibrahim, Montreal Heart Institute, 5000,Belanger Street, Montreal, Quebec, Canada H1T 1C8. Fax: 514‐593‐2158; e‐mail: reda.ibrahim@icm-mhi.org

© 2013, Wiley Periodicals, Inc.DOI: 10.1111/joic.12055

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provided written informed consent before theprocedure.Imaging. The size and morphology of the LAA

was assessed by TEE approximately 1 week before theprocedure. As shown in Figure 1, higher degrees ofTEE angulation allowed visualization of the distallobe as depicted by “absence” followed by completevisualization of the distal lobe at 0° and 135°,respectively. Procedures were guided both by TEEand angiography. The angiographic default projectionfor most of the LAA occlusion procedures is RAO‐30°Cranial‐20°. However, in patients with a chicken‐wingLAA, a RAO‐30° Caudal‐20° projection was found tobe useful as it allowed better visualization of the distallobe (Fig. 2). LAA dimensions were measured at adepth of 10mm from the ostium in mid‐diastole withboth TEE and angiography. In addition, the distancebetween the ostium and the beginning of the lobe bendwas measured with the objective to anticipate whetherthe distal part of the device would open proximal orwithin the distal lobe. In general, we observed that adistance below 20mm would greatly increase the

likelihood for the device to deploy within the distallobe. For this purpose, a 135° projection on TEE wasused as it usually provided the shortest distancebetween the ostium and the beginning of bend (Fig. 1).Implanting Strategy. Procedures were performed

using the Amplatzer™ Cardiac Plug (ACP St‐JudeMedical, MN, USA) until June 2012 (n¼ 2) andthe second generation ACP (n¼ 3), also known as theAmplatzer™ Amulet, as of July 2012. Both devicesshare a similar main design consisting of a distal lobethat anchors inside the LAA and a proximal disc thatseals the ostium of the LAA. Procedures wereperformed under general anesthesia with TEE andangiographic guidance. After cannulation of the rightfemoral vein, a low and posterior transseptal puncturewas performed. Heparin was then given to keep ACTabove 250 seconds. Once selective angiograms wereperformed (Fig. 3—Step 1), TEE and angiographicmeasurements were used to choose the size of thedevice. Since one side of the device must “hang” insidethe distal bend of the LAA, a discretely largeroversizing strategy was used: 3–6mm in relation to

Figure 1. Complete TEE sequence of imaging of a chicken‐wing LAA showing an apparent conventional morphology with a clear landingarea (10mm depth) at 0° and 60° views (panels A and B). Further TEE views at 120° (panel C) and 135° (panel D) revealing the presenceof a previously “hidden” early and severe bend without a clear landing area with a distance of 14mm (white arrow) from the ostium to thebending point.

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the largest angiographic or TEE measurement. ATorqVue 45°–45° delivery sheath (AGA‐St‐Jude) wasthen placed into the LAA. Using the RAO‐30° Caudal‐20° projection, a long pigtail was advanced through thedelivery sheath and placed into the distal tip of theLAA. Subsequently, the delivery sheath was advancedand rotated toward the opening of the distal lobe usingthe pigtail as a guidewire (Fig. 3—Step 2). The pigtailwas preferred over a conventional guidewire as it wasconsidered a less aggressive maneuver with a lower risk

of perforation. In addition, the TorqVue 45°–45°delivery sheath was chosen as it provided betterrotation than the single 45° sheath. At this level, thedistal lobe of the device was partially deployed and acontrast injection was performed to confirm adequatepositioning (Fig. 3—Step 3). The distal lobe of thedevice was then fully deployed to keep one side withinthe distal bend of the LAA and the other side against thecontralateral wall (Fig. 3—Step 4). Once the distal lobewas adequately expanded, a firm backwards tension

Figure 2. RAO30° Cranial 20° angiographic projection not revealing the distal bend of the chicken‐wing LAA (panel A) andRAO30°Caudal 20°showing the true morphology of the LAA with the presence of an acute distal bend (panel B).

Figure 3. Implanting strategy sequence. Step 1 (panel A): initial angiographic injection at RAO30° Caudal 20°with amarker pigtail; Step 2 (panelB): advancement and rotation of the delivery sheath into the distal bend using a long pigtail as a guidewire; Step 3 (panel C): partial opening of thedevice (“ball opening”) and contrast injection to confirm adequate positioning at the beginning of the distal bend; Step 4 (panel D): completeopening of the distal device lobe inside the bend (black arrow) on one side and toward the contralateral wall on the other (white arrow); Step 5 (panelE): complete deployment of the device after applying a firm backwards tension to open the proximal disc and cover the ostium of the LAA (blackarrows); Step 6 (panel F): final RAO 30° cranial 20° projection to assess the final positioning of the device.

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was applied to open the proximal disc of the device andfully cover the LAA ostium (Fig. 3—Step 5). Finally, aRAO‐30° Cranial‐20° projection was performed toassess and assure optimal positioning of the disc atthe ostium level (Fig. 3—Step 6). Successful ACPimplantation was assessed by contrast injectionthrough the delivery system placed in front of thedevice after implantation and defined as less than one‐third LAA filling.3 TEE imaging was also used toconfirm optimal device positioning and lack ofcomplication. In general, 0°–90° views showed agood and flat apposition of the device whereas 120°–130° views tended to show the rotated position of thedistal device lobe within the LAA bend (Fig. 4).

Results

Among 42 patients who underwent LAA occlusionduring the study period, 5 (12%) presented the pre‐specified anatomy. Baseline and procedural character-istics are shown in Table 1. Successful implantationwas achieved in all patients. None of the patientspresented any intraprocedural air/device embolization,stroke or cardiac tamponade. Transthoracic echocardi-ography 24 hours postprocedure ruled out the presenceof pericardial effusion or device embolization. Allpatients were treated with dual antiplatelet therapy for3 months and then single therapy indefinitely. Follow‐up TEE was performed 3 months after the index

Figure 4. TEE assessment post LAA occlusion. Dual‐plane TEE views of the same patient showing the apparent flat and symmetric shape of thedevice post‐deployment at 0° (panel A) and the asymmetric shape with one side of the lobe sitting inside the chicken‐wing (white arrow).

Table 1. Basal and Procedural Characteristics

Patient 1 Patient 2 Patient 3 Patient 4 Patient 5

Age 70 81 79 72 76Gender Female Female Male Male MaleCHADS2 2 4 5 5 4CHADS2VA2SC 4 6 6 6 5Indication for LAA closure Intracranial

bleedingINR

labilityHemorraghic

strokeRetroperitoneal

bleedingIntracranialbleeding

LVEF (%) 60 45 50 45 60Largest LAA size� by angiography (mm) 23.6 19.7 19 16.5 31Largest LAA size� by TEE (mm) 26.5 19 16 17 31Type of device Amplatzer™

Cardiac PlugAmplatzer™Cardiac Plug

Amplatzer™Amulet

Amplatzer™Amulet

Amplatzer™Amulet

Device size (mm) 30 24 22 22 34

LVEF, left ventricular ejection fraction; LAA, left atrial appendage; CHADS2, C (cardiac heart failure)�H (hypertension)�A (age> 75)�D(diabetes)�S2 (stroke); CHA2DS2VASc, C (cardiac heart failure)�H (hypertension)�A2 (age� 75)�D (diabetes)�S2 (stroke)�V (vasculardisease), A (age 65–74), S (female sex).�Largest LAA diameter in a depth of 10mm from the ostium.

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procedure showing successful LAA sealing in allpatients and no device embolization or thrombosis.

Discussion

The shape of the LAA is highly variable. Thechicken‐wing anatomy is defined as an obvious bend inthe proximal or middle part of the dominant lobe. In aprevious study, it was found in the majority of thepatients (48%) with drug‐refractory atrial fibrillationreferred for catheter ablation.2 However, most of thetime, the bend is not severe (<90°) and is located more

distally. The variable morphology of the LAA mayimpede the optimal deployment and apposition ofocclusion devices in unfavorable anatomies. In ourgroup, the main exclusion criteria for percutaneousLAA occlusion are the presence of small and shortLAAs without landing area for the lobe of the device.According to our experience, other LAAmorphologiesare technically challenging but still feasible. Thechicken‐wing morphology with an early and severe(<180°) bend is one of the most difficult ones. In ourseries, this morphology was present in 12% but it didnot withhold the intervention in any case. With thepresented strategy and in the absence of a clear landing

Figure 5. Comparison between the ACP (left) and the Amplatzer Amulet (right) highlighting the greater diameter of the Amulet distal lobe (upperand lower panels) and waist (lower panel) and the increased number of stabilizing wires (upper panel).

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area, the lobe of the device was deployed more distally,a maneuver that it is typically easier with the secondgeneration of Cardiac Plug (Amplatzer Amulet) giventhe increased distance between the lobe and disc andthe higher stability due to the increased number ofstabilizing wires (Fig. 5).The degree of oversizing is usually one of the most

challenging decisions when implanting an LAAocclusion device. In our series, the implants were upto 6mm larger than the largest LAA measurementsbased on the manufacturer’s recommendations: over-sizing of 3–6mm for the Amplatzer Amulet and2–4mm for the ACP. However, since one side of thedevice must “hang” inside the distal bend of the LAA,the recommended oversizing of the Amulet (3–6mm)was felt to be more adequate for this specific anatomy.Moreover, despite the fact that one side of the lobe wasnot apposed on the wall of the appendage, we did notexperience any device embolization suggesting that itwas securely placed behind the bend of the appendage.Other technical points were the importance of having alow and posterior transeptal puncture that allowed amore coaxial access to the LAA and therefore an easiermanipulation of the delivery sheath. With this regard,the TEE bicaval view (superiority–inferiority) and theshort axis view of the aorta (anteriority–posteriority)were useful projections to cross through the low andposterior third of the septum. In fact and despite therepeated manipulation of the delivery sheath and theslightly higher degree of device oversizing, nopericardial effusions were documented. Anotherimportant point was the usefulness of the caudalview in angiography and the 120°–135° views in TEEfor the proper assessment of the distal bend. Inparticular, the 135° TEE view showed if the theoreticallanding area of the device was adequate as it providedthe shortest distance between the ostium and the

beginning of the bend. Other TEE views (0°–90°) andthe angiographic projections were found to bemisleading in assessing the adequacy of the landingarea (Fig. 1). Additional imaging modalities, namelymulti‐slice computed tomography, 3D TEE or 3Dangiography, should also be considered in challengingor unclear LAA anatomies. Although the limitednumber of patients is the main limitation of the study,considering the low prevalence of this particularanatomy and the high rate of procedural failure, theauthors believe that the present report is still relevant asit might help operators to guide the assessing andimplanting strategy in this challenging setting.

Conclusion

The present article describes the implantationtechnique that was followed for closing the LAA of5 patients with a challenging anatomy characterized bythe presence of an extreme chicken‐wing LAAwith anearly and severe bend.

References

1. Viles‐Gonzalez JF, Kar S, Douglas P, et al. The clinical impact ofincomplete left atrial appendage closure with the WatchmanDevice in patients with atrial fibrillation: A PROTECT AF(Percutaneous Closure of the Left Atrial Appendage versusWarfarin Therapy for Prevention of Stroke in Patients with AtrialFibrillation) substudy. J Am Coll Cardiol 2012;59:923–929.

2. Di Biase L, Santangeli P, Anselmino M, et al. Does the left atrialappendagemorphology correlate with the risk of stroke in patientswith atrial fibrillation? Results from amulticenter study. J AmCollCardiol 2012;60:531–538.

3. Ostermayer SH, Reisman M, Kramer PH, et al. Percutaneous leftatrial appendage transcatheter occlusion (PLAATO system) toprevent stroke in high‐risk patients with non‐rheumatic atrialfibrillation: Results from the international multi‐center feasibilitytrials. J Am Coll Cardiol 2005;46:9–14.

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