Successful Surgical Extraction of an Embolized Iliac Vein Stent from the Right Heart: A Case Report

Introduction

Stenting of the iliac vein remains one of the therapeutic options for the treatment of symptomatic venous outflow obstruction. Embolization of peripheral venous stents due to improper technique is a feared complication, with an estimated incidence of 1% to 3% [1,2]. These migrated stents can move unimpeded to the right heart causing catastrophic outcomes. Additionally, the migrated stents can damage the structures en route. Here we describe an interesting case of an embolized iliac vein stent in the right heart that was successfully extracted by surgical approach.

Case Report

A 52-year-old woman with a past medical history of hyper-tension, diabetes mellitus type 2, and iliac vein stent placement for May-Thurner syndrome presented to her primary care physician in March of 2023 for evaluation of shortness of breath, chest pain, and dizziness, which had been occurring for 2 days. Her vital signs were temperature of 36.7°C, heart rate of 85 beats/min, blood pressure of 95/66 mmHg, respiratory rate of 16 breaths/min, and oxygen saturation of 96% on room air. Physical examination revealed no cardiopulmonary abnormalities. She was admitted to the hospital for further evaluation. A chest X-ray showed a large stent in the cardiac silhouette. A transthoracic echocardiogram revealed an echo-dense structure across the tricuspid valve extending from the right atrium into the right ventricle.

Further review revealed that a Zilver Vena stent, sized 16×60 mm, was initially placed in the left iliac vein in July 2022 to treat May-Thurner syndrome. She reported that symptoms of leg swelling improved after the procedure. She did not have any symptoms until she presented acutely for the symptoms described above. After a multidisciplinary discussion, an endovascular retrieval by a vascular surgeon was attempted on March 23, 2023. After obtaining access to the left femoral vein, an Ev3 25-mm single lobe snare was used to attempt retrieval. However, this was unsuccessful, as it could not capture the stent. Therefore, a trilobe snare was then used, which was able to engage the stent; however, retrieval attempts only led to elongation of the stent, as the proximal portion was clinging onto the tricuspid valve. Further attempts led to a fracture of the distal one-third of the stent that was retrieved. A cardiothoracic surgeon was then consulted, and the decision was made to attempt to remove the stent via a median sternotomy. Preoperative cardiac catheterization showed only minimal coronary artery disease. The patient was then taken to the operating room. After induction with general anesthesia, a transesophageal echocardiogram probe was inserted, and a median sternotomy was performed. The surgeon noted at least moderate tricuspid regurgitation. The patient went into atrial fibrillation with rapid ventricular response, for which a direct cardioversion with internal paddles was performed using 10 J, with conversion to sinus rhythm. A cardiopulmonary bypass was initiated after cannulating the superior vena cava, inferior vena cava, and distal ascending aorta. The right atrium was then opened obliquely with a 6.35-cm incision. The stent was visualized projecting across the tricuspid valve and appeared to be endothelialized, since it had been 8 months from the time of implantation. The stent was seen across the tricuspid valve, chordae, papillary muscle, and right ventricle free wall. The stent was cut out and removed, and the tricuspid valve was left intact (Figures 1–4). No other foreign bodies were noted in the right heart. The left atrial appendage was then occluded with a 35-mm Atriclip. The sternum was then closed using Valkyrie sternal plates. A mediastinal tube was left in place after the procedure. A postoperative transesophageal echocardiogram showed only mild tricuspid regurgitation. The postoperative course was uncomplicated, and the patient was eventually discharged home.

Discussion

Obstruction of the left external iliac vein due to external compression by the right iliac artery is referred to as May-Thurner syndrome [3]. Interventional therapy utilizing endovascular stenting has been proven to be effective [4]. Recent advancements in revascularization using endovenous stenting have transformed the approach to treating chronic venous blockage, particularly in the femoral iliocaval system. Although this treatment method has been deemed safe and effective, it is not without potential complications, such as stent thrombosis, venous perforation, and stent migration, as documented in various cases [5–8]. The migration of a venous stent into the cardiopulmonary system poses a severe danger, as it can lead to pulmonary infarction, tricuspid regurgitation, and potential right-sided heart failure. Fortunately, this complication is uncommon, occurring in only 1% to 3% of cases [9].

Stents in the iliocaval segment were shown to have the highest incidence of stent migration [9]. Stent migration typically happens due to improper placement caused by inaccurate measurements of the stent or vessel circumference, inadequate alignment of the stent, or selecting a lesion without a significant degree of obstruction [10]. Furthermore, prior studies have reported that migration was more likely to occur with smaller diameter (≤14 mm) and shorter length (≤60 mm) stents [9]. Two methods have been documented for retrieving migrated stents: endovascular retrieval and surgical retrieval. Recent studies indicate that the endovascular approach demonstrates significant superiority, boasting a success rate of 90%, when compared with the surgical technique [9]. Nevertheless, in instances in which the stent has migrated beyond the tricuspid valve or pulmonary vasculature, the surgical approach can be a feasible option, especially when the endovascular approach fails. As stenting of the venous system is on the rise, it remains prudent for professional medical societies to formulate appropriate guidelines to improve procedural outcomes. It is also important for the operator to prevent complications by appropriate sizing of the stent by using intravascular ultrasound and avoiding stents with diameters ≤14 mm and lengths ≤60 mm.

Conclusions

Two methods have been documented for retrieving migrated stents: endovascular retrieval and surgical retrieval. The endovascular approach is the preferred initial option for the extraction of embolized iliac vein stents into the heart. However, in 10% of the cases when such an approach fails, the surgical approach remains a feasible option.