Ann Thorac Surg 1997;63:236-238
© 1997 The Society of Thoracic Surgeons
Case Report
Early Cardioverter Defibrillator Infection: Value of Indium-111 Leukocyte Imaging
Rafeeque A. Bhadelia, MD,
Elizabeth Oates, MD
Department of Radiology, New England Medical Center Hospitals and Tufts University School of Medicine, Boston, Massachusetts
Accepted for publication July 11, 1996.
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Abstract
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In the early postoperative period, it may be difficult to diagnose an infected implantable cardioverter-defibrillator system using anatomic imaging modalities such as computed tomography alone. We describe a case that illustrates the complementary physiologic role of indium-111-labeled leukocyte scintigraphy in identifying and defining the extent of early postoperative implantable cardioverter-defibrillator infection.
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Introduction
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An implantable cardioverter defibrillator (ICD) can effectively control life-threatening ventricular tachyarrythmias. Although unusual, infection is the most serious complication and may occur early (<2 months) or late (>2 months) after placement of the device [1–5]. Early postoperative ICD infection may be difficult to diagnose using conventional anatomic imaging modalities such as computed tomographic scan because of normal postoperative fluid collections and nonspecific inflammatory changes [4, 6]. We present a case that illustrates the complementary physiologic role of indium-111-labeled leukocyte scintigraphy in identifying and defining the extent of early postoperative ICD infection.
A 74-year-old woman underwent aortocoronary bypass grafting and ICD placement for coronary artery disease and myocardial infarction. The ICD system consisted of two patches and two rate-sensing electrodes wired to a pulse generator box in a left abdominal intrarectus muscle pouch (Fig 1
). One week after the operation, the patient had recurrent fever spikes and leukocytosis. Clinical examination results were negative. A contrast computed tomographic scan showed small fluid collections adjacent to the patches without significant enhancement; metal artifacts obscured soft-tissue details of the generator box site. Scintigraphy (Fig 2) showed intense localization of 111In-labeled leukocytes around the patches, electrodes, and generator box; activity tracked along the wires from the generator to the electrodes. A diagnosis of ICD system infection was made. At operation, copious purulent material surrounded the patches and generator. The entire device was explanted. Culture showed methicillin-resistant Staphylococcus aureus sensitive to vancomycin. The patient was treated with intravenous antibiotics and discharged to a rehabilitation center in stable condition 3 weeks later.
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Fig 1. . Composite image created from chest and abdominal radiographs shows implantable cardioverter-defibrillator patches (short, thick arrows), rate-sensing electrodes (long, thin arrow), connecting wires (open arrow), and pulse generator box (arrowhead).
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Fig 2. . Indium-111 leukocyte scintigraphy shows intense localization of labeled leukocytes around both defibrillator patches (short, thick arrows), rate-sensing electrodes (long, thin arrow), connecting wires (open arrow), and pulse generator box (arrowhead).
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Comment
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Implantable cardioverter-defibrillator infections usually begin at the generator pocket due to contamination from skin flora and spread along the wires to involve the other components [4]. During the perioperative period, hematogenous seeding from a distant infected site may also occur [4]. Although early postoperative ICD infection may be suspected, it is often difficult to implicate the device as the source of infection when localizing symptoms and signs are absent. Accurate diagnosis is imperative because unnecessary removal of an uninfected ICD may predispose the patient to life-threatening tachyarrythmias. Anatomic imaging modalities, such as computed tomographic scan and echocardiography, may demonstrate fluid collections [7]; computed tomography may show contrast enhancement around an abscess. These findings are nonspecific and may represent expected postoperative changes. Although aspiration of a postoperative fluid collection may yield a bacteriologic diagnosis, it may not be advisable because of risk of infecting a sterile collection [1].
Because few leukocytes migrate to sterile surgical sites [8], localization of radiolabeled leukocytes signals postoperative infection. As in this patient, 111In leukocyte scintigraphy is an ideal modality for the diagnosis of early ICD infections because of its high specificity and accuracy in evaluating postoperative cardiothoracic infections [6]. In contrast, gallium-67 citrate scans can be falsely positive in the immediate postoperative period due to inflammation at the surgical site. Gallium scintigraphy requires a longer period between injection and imaging (48 to 72 hours) as opposed to 111In leukocyte imaging (<24 hours), an important consideration in management of a patient with an infected ICD.
This case demonstrates the important role for 111In leukocyte scintigraphy in confirming and defining the extent of ICD infection to guide appropriate surgical management.
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Footnotes
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Address reprint requests to Dr Oates, Division of Nuclear Medicine, Department of Radiology, New England Medical Center 228, 750 Washington St, Boston, MA 02111.
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References
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- Kelly PA, Wallace S, Tucker B, et al. Postoperative infection with automatic implantable cardioverter defibrillator: clinical presentation and use of the gallium scan in diagnosis. PACE 1988;11:1220–5.
- Wunderly D, Maloney J, Edel T, McHenry M, McCarthy PM. Infections in implantable cardioverter defibrillator patients. PACE 1990;13:1360–4.
- Taylor RL, Cohen DJ, Widman LE, Chilton RJ, O'Rourke RA. Infection of an implantable cardioverter defibrillator: management without removal of the device in selected cases. PACE 1990;13:1352–5.
- Spratt KA, Blumberg EA, Wood CA, Kutalek SP, Reboli AC. Infections of implantable cardioverter defibrillators: approach to management. Clin Infect Dis 1993;17:679–85.[Medline]
- Gupta S, Prevel CD, Shaheen K, et al. Wound complications and treatment of the infected implantable cardioverter defibrillator generator. J Card Surg 1993;8:671–7.[Medline]
- Oates E, Payne DD. Postoperative cardiothoracic infection: diagnostic value of indium-111 white blood cell imaging. Ann Thorac Surg 1994;58:1442–6.[Abstract]
- Goodman LR, Almassi GH, Troup PJ, et al. Complications of automatic implantable cardioverter-defibrillators: radiographic, CT, and echocardiographic evaluation. Radiology 1989;170:447–52.[Abstract/Free Full Text]
- Abdel-Nabi H, Hinkle GH, Olsen JO. Nonvisualization of sterile surgical incisions with indium-111 labeled leukocytes. Clin Nucl Med 1985;10:618–21.[Medline]
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Abstract
Introduction
