Ann Thorac Surg 2012;93:1715-1717. doi:10.1016/j.athoracsur.2011.08.057
© 2012 The Society of Thoracic Surgeons
Case Reports
Intracoronary Fiducial Embolization After Percutaneous Placement for Stereotactic Radiosurgery
Emily A. Farkas, MDa,*,
David A. Stoeckel, MDb,
Anis S. Nassif, MDd,
Michael J. Lim, MDc,
Keith S. Naunheim, MDa
a Division of Cardiothoracic Surgery, Saint Louis University School of Medicine, St. Louis, Missouri
b Department of Internal Medicine, Division of Pulmonology, Saint Louis University School of Medicine, St. Louis, Missouri
c Division of Cardiology, Saint Louis University School of Medicine, St. Louis, Missouri
d Department of Radiology, Saint Louis University School of Medicine, St. Louis, Missouri
Accepted for publication August 24, 2011.
* Address correspondence to Dr Farkas, Division of Cardiothoracic Surgery, Saint Louis University, 3635 Vista Ave, 8th Fl, Des Loges Towers, St. Louis, Missouri 63110 (Email: efarkas{at}slu.edu).
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Abstract
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Although well established for the treatment of intracranial and prostatic pathology, stereotactic radiosurgery has only recently emerged as a modality for the treatment of malignant lung lesions. Utilization of radio-opaque markers, called fiducials, facilitate dose-intensive radiation focused on the tumor with sparing of surrounding normal tissue. There is a paucity of literature regarding complications that occur secondary to placement of these fiducials. The following report details a case in which intracoronary migration resulted in a hemodynamically significant acute coronary syndrome.
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Introduction
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In the last decade, stereotactic radiotherapy has expanded its application toward multiple tumors in a variety of locations and clinical scenarios. Radio-opaque markers called fiducials may be placed through any route currently used for biopsy or fine-needle aspiration, including the percutaneous, transrectal, transurethral, endoscopic, or bronchoscopic approaches with or without adjunctive electromagnetic navigation. Once embedded within or adjacent to the tumor, fiducials direct the precise delivery of a highly collimated beam of radiation in a single fraction, facilitating maximal tumor treatment with minimal exposure to contiguous structures. Migration and embolization of fiducials represent unique risks in stereotactic radiosurgery, introducing potential for suboptimal local oncologic impact and significant distant clinical sequelae.
A 73-year-old woman presented for cardiothoracic surgical consultation after identification of a new right upper lobe opacity on chest imaging. This was noted on surveillance chest radiographs obtained 3 years after a left upper lobectomy for stage IA squamous cell lung carcinoma. The patient was asymptomatic with a normal cardiopulmonary exam and no evidence of palpable adenopathy. Fusion computed tomographic (CT) and positron emission tomographic imaging demonstrated an isolated hypermetabolic lesion, and needle biopsy confirmed malignant cells with probable squamous differentiation. The tumor was regarded as a new primary neoplasm of the contralateral lung and the patient was presented to the multidisciplinary Thoracic Oncology Board.
Secondary to high-grade bilateral carotid artery stenoses and marginal pulmonary reserve, the patient declined open surgical therapy and elected to pursue treatment with stereotactic radiosurgery. Five gold 0.8-mm x 3.0-mm fiducials (MedTech, Ft. Myers, FL) were inserted percutaneously, adjacent to the right upper lobe mass, utilizing CT guidance and a 19-gauge 14.7-cm coaxial needle and biopsy core system. An immediate postprocedural scan demonstrated a small anterior pneumothorax but repeat chest film revealed no progression. It was noted, however, that 1 of the 5 fiducials had migrated to a location that appeared to be in the contralateral hemithorax, leaving just 4 fiducials remaining in the peritumoral area (Fig 1A). Further imaging would later identify the location of this fiducial as being within the trabeculae of the left ventricular free wall. In light of the stability of the pneumothorax, the absence of symptomatology, and normal hemodynamic indices, no intervention was suggested and the patient was discharged to home with plans for subsequent stereotactic radiosurgery.
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Fig 1. (A) Chest film after initial fiducial placement with 4 fiducials visualized. (B) Chest film after presentation to emergency room with only 3 fiducials visualized.
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Five days later the patient returned to the emergency room with the acute onset of chest pain. Plain films were significant for resolution of the pneumothorax as well as the interval disappearance of another previously placed fiducial in the right upper lobe mass (Fig 1B). An initial troponin of 0.08 ng/mL progressed to 19.0 ng/mL in the subsequent 24 hours, and inferior lead ST segment elevations were prominent on electrocardiographic assessment. Two-dimensional echocardiography revealed severe hypokinesis of the inferior septum, septal apex, and inferior wall.
A left heart catheterization demonstrated elevated left ventricular filling pressures and no angiographic evidence of disease in the left coronary circuit. The right coronary artery was a dominant vessel that was also angiographically free of disease, but was noted to have an obstruction in the posterior descending branch resulting in TIMI (thrombolysis in myocardial infarction) grade I flow defined as faint antegrade coronary perfusion to the distal vessel (Fig 2). Inflation of a 2.0-mm x 9.0-mm balloon to 4 atmospheres engaged the fiducial and dislodged it to a more proximal location, but retrieval was not possible. Follow-up angiography revealed improved TIMI grade II partial perfusion of the distal coronary artery and no evidence of perforation or dissection.
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Fig 2. The left heart catheterization with fiducial noted in posterior descending artery branch of the right coronary artery.
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The remainder of the patient's hospitalization was uneventful and she was discharged to home on post-event day 3 on aspirin and clopidogrel. Interval 64-slice electrocardiographic-gated CT angiography confirmed the locations of the 2 migrated marker beads in the posterior descending artery and the left ventricular lateral wall endocardium. Ejection fraction was calculated at 0.40.
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Comment
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Complications of percutaneous and transbronchial fiducial placement parallel those of CT-guided and bronchoscopic biopsy procedures, respectively. The rate of pneumothorax experienced during marker placement has been reported from 13% to 33% [1, 2]. Small series have described hemoptysis and postprocedural hemorrhage in up to 19%, as well as isolated cases of pulmonary edema, exacerbation of chronic obstructive pulmonary disease, and bronchospasm requiring intubation [1–4]. Interestingly, it has been reported that up to 26% of previously placed fiducials could not be found on imaging at the planning phase [3]. To our knowledge, no clinically significant migration has been documented in the literature, although one case of embolization through the pulmonary artery after deployment in a subcarinal tumor is described without clinical consequence [4]. Additionally, a recent report describes treatment of a liver lesion with fiducial embolization through the hepatic vein to the junction of the inferior vena cava and right atrium, requiring interventional catheter-based snare retrieval [5].
In our patient, because echocardiography suggested no evidence of a patent foramen ovale, it must be assumed that embolization was through a pulmonary venous tributary into the left-sided heart chambers. In cardiac surgical procedures, air embolization most commonly occurs through the right coronary ostia because of its anterior-superior location in the aortic root, and presumably this represents the pathway traveled by the 1-mm foreign body propelled by the bloodstream through the left ventricular outflow tract.
Within the last year, gold and platinum coils designed and intended for endovascular deployment through microcatheters have instead been delivered percutaneously in an attempt to find a more stable fiducial marker [6]. Limited retrospective evaluations of the coiled configurations suggest that migration may be decreased because of grooves on the surface as opposed to the currently utilized smooth cylindrical gold seed fiducials [7]. Although higher retention of coiled fiducials may permit implantation of fewer markers in the future, patients and clinicians should recognize that the potential for embolization into pulmonary and systemic circulations represents a novel source of morbidity from stereotactic radiotherapy as an alternative to open surgery.
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References
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- Whyte R, Crownover R, Murphy MJ, et al. Stereotactic radiosurgery for lung tumors: preliminary report of a phase I trial Ann Thorac Surg 2003;75:1097-1101.[Abstract/Free Full Text]
- Yousefi S, Collins BT, Reichner CA, et al. Complications of thoracic computed tomography-guided fiducial placement for the purpose of stereotactic body radiation therapy Clin Lung Cancer 2007;8:252-256.[Medline]
- Anantham D, Feller-Kopman D, Shanmugham LN, et al. Electromagnetic navigation bronchoscopy-guided fiducial placement for robotic stereotactic radiosurgery of lung tumors Chest 2007;132:930-935.[Medline]
- Reichner CA, Collins BT, Gagnon GJ, Malik S, Jamis-Dow C, Anderson ED. The placement of gold fiducials for Cyberknife stereotactic radiosurgery using a modified transbronchial needle aspiration technique Journal of Bronchology 2005;12:193-195.
- Hennessey H, Valenti D, Cabrera T, Panet-Raymond V, Roberge D. Cardiac embolization of an implanted fiducial marker for hepatic stereotactic body radiotherapy: a case report J Med Case Rep 2009;3:140.
- Mallarajapatna GJ, Susheela SP, Kallur KG, et al. Technical note: Image-guided internal fiducial placement for stereotactic radiosurgery (Cyberknife) Indian J Radiol Imaging 2011;21:3-5.[Medline]
- Hong JC, Yu Y, Rao AK, et al. High retention and safety of percutaneously implanted endovascular embolization coils as fiducial markers for image-guided stereotactic ablative radiotherapy of pulmonary tumors Int J Radiation Oncology Biol Phys 2010;81:85-90.[Medline]
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Abstract
Introduction
