Pulmonary infarction due to vascular stent migration.

Abstract: The case of a patient who developed pulmonary infarction after a vascular stent migrated to her pulmonary artery is presented. Stent migration is a known complication of vascular stents. The incidence is reported to be as low as 3%. Cases have been reported of successful retrieval of the stents. There are also reports of the stents being left in place without attempts to retrieve them, due to lack of symptoms. In this case, we opted to monitor the patient, despite the presence of pulmonary infarction. She appears to be tolerating the stent without any further complications.

Key Words: pulmonary infarction, vascular stents, complications

Case Report

54-year-old woman with end stage renal disease on chronic hemodialysis presented with pleuritic chest pain. The pain started suddenly four weeks before presentation. The patient had been working in the garden and assumed it to be a muscle spasm. She denied hemoptysis, cough, fever or chills. Physical examination was significant only for a right lung base pleural rub. Chest x-ray showed an intravascular stent in the right lower lobe pulmonary artery. Computed tomography showed an infarcted lateral segment of the right lower lobe and reactive pleural effusion. Another cut of the same computed tomography (Fig.) showed the migrated stent in the lower lobe pulmonary artery. The intravascular stent migrated from a peripheral hemodialysis shunt. The patient was treated symptomatically for her pleurisy and monitored for signs of pneumonia. Her symptoms improved without need for antibiotics or lung resection. Follow-up chest x-ray four months later showed the stent in the same position with some improvement of the distal lung infiltrates.

Discussion

Recent advances in minimally invasive techniques have expanded the use of various vascular stents. With this we anticipate that we will see more cases of stent migration. A 2001 report estimated the rate of stent migration to be around 3%. (1) Most cases of venous stent migration report stents in the right atrium or pulmonary artery. Most reports to date have emphasized techniques for removal, either surgically or retrieval via catheterization. (2-6) Successful removal of migrated stents is usually done not too long after the placement. Other cases reported leaving the stents in place due to lack of symptoms or the poor overall prognosis of the patient. (1,7) The only follow-up information on these two cases included one patient who died as a result of their underlying disease. No information was available in the other asymptomatic patient.

In our patient, we did not have information on the timing of the stent migration in relation to initial placement. We opted to monitor the patient since it had been at least 4 weeks since the appearance of pulmonary infarction symptoms. During this time, the stent had a chance to grow into the vascular endothelium, thus making retrieval more complicated and dangerous. In the event that the patient deteriorated and progressed to develop an infected lung segment, the plan was to remove the lobe with the stent surgically. Fortunately, the patient did not require this. To our knowledge, this is the only case reported in the literature of a patient with a pulmonary infarct related to a migrated stent who did well on follow-up without having the stent removed. This case demonstrates that observation for migrated vascular stents is a viable alternative and may not subject the patient to the increased risk of further procedures.

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References

1. Marcy P, Magne N, Bruneton JN. Strecker stent migration to the pulmonary artery: long-term result of a "wait-and-see attitude". Eur Radiol 2001;11:767-770.

2. Feldman T. Retrieval techniques for dislodged stents. Catheter and Cardiovasc Intervent 1999;47:325-326.

3. Walles T, Klima U, Lichtenberg A, et al. Minimally invasive removal of a dislocated stent from the right atrium after previous CABG. Ann Thorac Surg 2001;72:1382-1384.

4. Ashar RM, Huettl EA, Halligan R. Percutaneous retrieval of a Wallstent from the pulmonary artery following stent migration from the iliac vein. J Interv Cardiol 2002;15:101-106.

5. Saeed M, Knowles HJ Brems JJ, et al. Percutaneous retrieval of a large Palmaz stent from the pulmonary artery. J Vasc Interv Radiol 1993;4:811-814.

6. Srinathan S, McCafferty I, Wilson I. Radiological management of superior vena caval stent migration and infection. Cardiovasc and Intervent Radiol 2005;28:127-130.

7. Fernandez-Juarez G, Letosa RM, Mirete JO. Pulmonary migration of a vascular stent. Nephrol Dial Transplant 1999;14:250-251.

Patterning your life around other's opinions is nothing more than
slavery.
--Lawana Blackwell

Alexander Sy, MD, FCCP, FACP, FASM 

From the Department of Internal Medicine, University of South Carolina School of Medicine, Two Medical Park, Suite 502, Columbia, SC.

Reprint requests to Alexander Sy, MD, FCCP, FACP, FASM, Assistant Professor, Department of Internal Medicine, University of South Carolina School of Medicine, Two Medical Park, Suite 502, Columbia, SC 29203. Email: [e-mail]

Accepted April 12, 2006.

RELATED ARTICLE: Key Points

* Recent advances in minimally invasive techniques have expanded the use of various vascular stents, which we anticipate will lead to more cases of stent migration.

* This case demonstrates that observation for migrated vascular stents is a viable alternative and may not subject the patient to an increased risk of further procedures.