Intraprocedural tail-first pulmonary artery migration of a leadless pacemaker: a protective sleeve–assisted helix-side retrieval strategy—a case report

Abstract

Background

Leadless pacemaker migration into the pulmonary artery is an exceptionally rare but potentially serious complication. Tail-first (proximal helix–oriented) migration poses additional risk, as traction on the exposed helix may cause vascular injury.

Case summary

A 72-year-old woman with bradycardic atrial fibrillation underwent implantation of an Aveir™ VR leadless pacemaker. Immediately after device release, fluoroscopy revealed a tail-down shift suggesting inadequate mechanical engagement, accompanied by frequent premature ventricular contractions and non-sustained ventricular tachycardia, prompting immediate retrieval. During the retrieval procedure, the device became completely dislodged and migrated into the left pulmonary artery with the helix oriented proximally.

In this orientation, standard docking button retrieval was not feasible. The Aveir™ retrieval catheter was advanced into the pulmonary artery, the helix was captured, and the device was enclosed within the protective sleeve before successful extraction.

The new device was subsequently re-implanted at a more apical septal site, and stable fixation was achieved.

Discussion

In previously reported cases of pulmonary artery migration of the Aveir™ pacemaker, retrieval was performed using non-dedicated flexible sheaths and snare catheters. In contrast, this case demonstrates that advancing the dedicated retrieval system to enclose the grasped helix enabled controlled retrieval while minimizing direct contact between the exposed helix and the pulmonary arterial wall. This case also highlights that satisfactory electrical parameters alone may not guarantee adequate mechanical fixation. Although this technique may represent a practical bailout strategy when engagement of the docking button is not feasible, further clinical experience is required to establish its safety and reproducibility.

Learning points.

• Tail-first pulmonary artery migration of an Aveir™ leadless pacemaker presents a unique retrieval challenge because the docking button is inaccessible.

• Protective sleeve–assisted retrieval enables safe removal by advancing the catheter into the pulmonary artery and enclosing the grasped helix before extraction.

Introduction

The Aveir™ leadless pacemaker system (Abbott, Abbott Park, Illinois, USA) is widely used for the treatment of symptomatic bradycardia. Although device dislodgement has been reported rarely,^1–7 migration into the pulmonary artery is an extremely rare complication.^1–3,5

Standard retrieval is performed using a dedicated retrieval catheter to grasp the docking button at the device tail. However, previously reported cases of pulmonary artery migration were managed using non-dedicated systems with deflectable sheaths and snare catheters. Such approaches may increase the risk of vascular injury due to traction on the exposed helix during retrieval.

We report a case of tail-first migration of an Aveir™ VR leadless pacemaker into the pulmonary artery, in which the docking button was inaccessible. Successful retrieval was achieved using a protective sleeve–assisted technique with helix enclosure.

Summary figure

Retrieval of an Aveir™ VR leadless pacemaker from the pulmonary artery using the dedicated retrieval system. Fluoroscopic sequence demonstrating the retrieval procedure. The device migrated into the pulmonary artery and was captured by the retrieval catheter under fluoroscopic guidance. The helix and device body were subsequently enclosed within the protective sleeve, enabling successful retrieval. A simple bench experiment demonstrated the relative flexibility of the protective sleeve compared with an ablation catheter under the experimental conditions. RAO, right anterior oblique; LAO, left anterior oblique; RVOT, right ventricular outflow tract.

Case presentation

A 72-year-old woman with bradycardic atrial fibrillation was referred for leadless pacemaker implantation. Her medical history included mitral valve replacement with a 25 mm Epic bioprosthetic valve and tricuspid annuloplasty with a 28 mm Carpentier–Edwards annuloplasty ring. An Aveir™ VR leadless pacemaker was delivered through a 27 Fr introducer sheath via the right femoral vein and positioned at the mid-septal region of the right ventricle. Pre-mapping measurements showed a pacing threshold of 1.5 V at 0.4 ms, an R-wave amplitude of 15.0 mV, and an impedance of 450 Ω. The LP control knob on the delivery catheter was then rotated clockwise under fluoroscopic guidance until the radiopaque chevron marker reached the manufacturer-recommended 1.5-turn endpoint (Figure 1A and B). After screw-in, impedance increased to 560 Ω, a current of injury of ∼3–4 mV was observed, and electrical parameters remained satisfactory (R-wave sensing 5.5 mV and pacing threshold 1.5 V at 0.4 ms). After confirming fixation by the standard deflection test, the device was released (Figure 1C). Immediately after release, fluoroscopy showed a tail-down shift of the device (Figure 1D) accompanied by frequent premature ventricular contractions and non-sustained ventricular tachycardia, suggesting inadequate mechanical engagement. Because of the risk of further migration or ventricular arrhythmia, retrieval and re-implantation were planned.

Figure 1.

Fluoroscopic images during the procedure. (A and B) Baseline RV gram in the RAO and LAO projections. (C) Device position before the first release. (D) Tail-down shift observed after the initial release. (E) Tail-up position. (F) Complete dislodgement and migration into the pulmonary artery. (G) Advancement of the protective sleeve towards the RV outflow tract. (H) After the retrieval catheter was positioned adjacent to the migrated device, engagement of the helix with a tri-loop snare advanced beyond the protective sleeve tip. (I) Full enclosure of the device, including the helix, within the protective sleeve before retrieval. Abbreviations: RAO = right anterior oblique; LAO = left anterior oblique; RV = right ventricle.

An Aveir™ retrieval catheter was introduced through the femoral sheath, with the tip positioned just proximal to the tricuspid valve. As the catheter advanced into the right ventricle, the device tail was displaced towards the right ventricular outflow tract (RVOT). During the retrieval manoeuvre, the device abruptly migrated into the left pulmonary artery in a tail-first orientation (Figure 1E and F; Supplementary material online, Video S1). Because the docking button was inaccessible, we adopted a protective sleeve–assisted retrieval strategy to protect the exposed helix. With the protective sleeve leading and the retrieval catheter maintained in a retracted position, the system was advanced from the right ventricle through the RVOT into the pulmonary artery under fluoroscopic guidance while maintaining gentle tangential contact with the vessel wall (Figure 1G; Supplementary material online, Video S2).

After optimal positioning, the dedicated tri-loop snare was deployed, the helix was grasped, and the device was enclosed within the protective sleeve (Figure 1H and I). The device was then retrieved from the pulmonary artery.

Visual inspection of the retrieved device and catheter confirmed that the snare had grasped the helix proximal to its tip, with no deformation of the helix or adherent tissue observed. (Figure 2A and B).

Figure 2.

Images of the retrieved leadless pacemaker with the helix captured by the snare. (A) Photograph of the retrieved Aveir leadless pacemaker. The device is shown after removal, with the helix securely captured by the snare. (B) Close-up view of the helix, highlighting the engagement point of the snare. The retrieved device is shown with the helix securely engaged by the snare. Direct traction on the exposed helix without enclosure within the protective sleeve of the dedicated retrieval system may result in injury to the vessel wall. Enclosing the helix within the protective sleeve before retrieval may reduce direct contact between the exposed helix and the vessel wall.

The interval from pulmonary artery migration to retrieval was ∼10 min.

A new Aveir™ VR was subsequently implanted at a more apical septal site. Compared with the initial implantation, in which the device was positioned at a nearly horizontal angle, the second implantation was performed with the device oriented at ∼20° from horizontal on the right anterior oblique view and directed more towards the ventricular septum on the left anterior oblique view. The post-fixation pacing threshold was 1.5 V at 0.4 ms, the R-wave amplitude was 5.0 mV, and the impedance was 450 Ω. Unlike the initial implantation, no tail-down shift or ventricular ectopy was observed after release. Post-procedural transthoracic echocardiography demonstrated no pericardial effusion.

The present patient had bradycardic atrial fibrillation requiring ventricular pacing and had previously undergone tricuspid annuloplasty. The 2021 ESC Guidelines discuss the use of leadless pacemakers in selected patients and considerations after tricuspid valve surgery. However, they do not specifically address retrieval of a dislodged leadless pacemaker.⁸ Surgical retrieval may need to be considered when the device has remained in the pulmonary artery for a prolonged period or has migrated into the distal pulmonary artery. In our case, because migration occurred intraprocedurally and the device remained in the proximal pulmonary artery, a percutaneous retrieval strategy was considered appropriate.

Among the previously reported cases, Amin et al. and Goto et al. reported tail-first pulmonary artery migration, and both cases were managed using non-dedicated systems with deflectable sheaths and snare catheters.^1–3,5

Non-dedicated approaches may be acceptable in tip-first dislodgement when docking button engagement is feasible. However, in tail-first configurations, traction on the exposed helix may increase the risk of vascular injury. In this setting, the protective sleeve may help prevent direct contact between the helix and the vessel wall during retrieval.

Although a guidewire-assisted approach may facilitate catheter delivery, we avoided this strategy because removal of the guidewire could cause deformation of the protective sleeve, potentially hindering advancement of the retrieval catheter.

A simple bench experiment compared the flexibility of the protective sleeve with a commonly used ablation catheter (ThermoCool SmartTouch SF, Biosense Webster). (see Supplementary material online, Video S3). The ablation catheter bent at ∼100 g under vertical force, whereas the protective sleeve required ∼270 g, indicating greater resistance to deformation. Under oblique force, both devices bent at ∼10–30 g. These findings should be interpreted cautiously because they may not fully reflect in vivo conditions. Nevertheless, the protective sleeve should be advanced tangentially rather than orthogonally against the vessel wall.

The precise mechanism underlying the initial instability remains uncertain. However, the implantation angle, inadequate septal fixation with insufficient helix penetration, and altered right ventricular geometry related to prior tricuspid annuloplasty may have contributed. Despite satisfactory electrical parameters before release, mechanical fixation proved inadequate, suggesting that the decision to release the device should not rely solely on electrical parameters.

In contrast, stable fixation was achieved at a more apical septal site with more direct septal orientation.

The immediate tail-down shift after device release may represent an early fluoroscopic warning sign of inadequate mechanical fixation, warranting careful reassessment before further device migration occurs.

Although the exact mechanism of migration remains uncertain, the device may have remained attached only by the tip of the helix. A change in device orientation during the retrieval attempt may then have resulted in complete disengagement.

Previous cardiac surgery may have reduced the risk of procedure-related pericardial effusion. Therefore, the safety of this approach in patients without previous cardiac surgery remains uncertain. Further clinical experience is needed to confirm its reproducibility.

Conclusion

Tail-first pulmonary artery migration of an Aveir™ VR leadless pacemaker requires careful procedural planning because standard docking button retrieval is not feasible. In this case, a protective sleeve–assisted helix-side retrieval technique provided a feasible bailout option.

Lead author biography

Ryobun Yasuoka, MD, PhD, is a cardiologist in the Division of Cardiology at Kindai University Hospital, Osaka, Japan. His clinical and research interests focus on cardiac electrophysiology, including device therapy, catheter ablation, and arrhythmia management. His recent work includes the analysis of implantable cardioverter-defibrillator therapies and functional data analysis of cardiovascular imaging. He is actively involved in clinical research aimed at improving procedural safety and optimizing treatment strategies for patients with arrhythmias.

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports online.

Author contributions

Ryobun Yasuoka (Conceptualization, Data curation, Investigation, Writing—original draft, Writing—review & editing [lead]), Motohide Tanaka (Conceptualization, Data curation, Investigation [equal], Writing—original draft [supporting]), Takashi Noda (Writing—original draft, Writing—review & editing [supporting]), Gaku Nakazawa (Project administration, Supervision [supporting]), and Takashi Kurita (Methodology, Supervision, Writing—review & editing [supporting])

Consent: The authors confirm that written informed consent for publication of this case report, including the accompanying images, was obtained from the patient in line with the COPE guidelines.

Funding

None.

Data availability

Data are available from the corresponding author upon reasonable request.