Post-Sternotomy Hemorrhage due to Left Internal Thoracic Artery Pseudoaneurysm
Satoshi Yamashiro, MD,
Yukio Kuniyoshi, MD,
Katsuya Arakaki, MD,
Hitoshi Inafuku, MD,
Yuji Morishima, MD,
Yuya Kise, MD
Thoracic and Cardiovascular Surgery Division Department of Bioregulatory Medicine, University of the Ryukyus Okinawa, Japan
Satoshi Yamashiro, MD, Tel: +81 98 895 1168, Fax: +81 98 895 1422, Email: y3104{at}med.u-ryukyu.ac.jp, Thoracic and Cardiovascular Surgery Division, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
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ABSTRACT
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We describe a case of pseudoaneurysm of the internal thoracic artery, which was probably caused by infection. Four weeks after aortic valve replacement and coronary artery bypass surgery, an 84-year-old woman suddenly developed painful sternal instability and hypotension, with active hemorrhage from a left parasternal swelling. Selective arteriography revealed a pseudoaneurysm of the left internal thoracic artery. It was surgically excised, and the patient recovered uneventfully.
Key Words: Aneurysm • False • Mammary Arteries • Surgical Wound Infection • Sternum
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INTRODUCTION
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Pseudoaneurysms of the internal thoracic artery (ITA) are rare and have been described in the context of chest trauma, central venous catheterization, chest wall infection, and sternotomy.1–7 We describe a case of pseudoaneurysm of the left ITA, which seemed to be caused by infection, with destabilization and dehiscence of the sternum after aortic valve replacement and coronary artery bypass surgery.
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CASE REPORT
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An 84-year-old woman underwent successful elective aortic valve replacement and coronary artery bypass grafting with saphenous vein grafts to the left anterior descending, circumflex and right coronary artery. Twenty days later, painful sternal instability developed with localized redness of the median wound, pus discharge, and systemic low-grade fever. Laboratory investigations revealed a hemoglobin level of 11.3 g·dL–1, white blood cell count 6.8 x 103/µL, platelets 18.3 x 103/µL, and C-reactive protein 9.25 mg·dL–1. Sternal fracture and dehiscence due to infection were diagnosed. The pain disappeared after antibiotic treatment. Five days later, the patient became hypotensive with active hemorrhage from the left parasternal wound. Hemostasis was achieved by packing the chest wound with gauze. Computed tomography of the chest showed a pseudoaneurysm formation (Figure 1
). Selective arteriography revealed that the pseudoaneurysm was fed by a branch of the left ITA (Figure 2). Emergency surgery was performed through the previous median sternotomy. The bleeding was controlled with proximal and distal suture ligation of the left ITA. The pseudoaneurysm was isolated and resected without massive bleeding. The sternum and wound were debrided, and the wound was tightly closed. Cultures of pus revealed Staphylococcus epidermidis 1 week later. The patient recovered uneventfully.
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Figure 1. Computed tomography of the chest showing pseudoaneurysm formation (arrow). The position of the left internal thoracic artery (dotted line) is normal.
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Figure 2. Selective arteriography of the left internal thoracic artery: (A) Anteroposterior view, (B) Lateral view, (C) Extended view showing pseudoaneurysm (arrow) fed by a branch of the left internal thoracic artery (dotted line).
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DISCUSSION
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The ITA is an unusual site of aneurysm formation because it is unusually resistant to typical (nontraumatic) arterial pathologies; ITA pseudoaneurysm formation after median sternotomy is extremely rare.1 This complication can arise directly from trauma to the ITA caused by the sternal suture or from local infection.1–7 Although it may present as an asymptomatic anterior mediastinal mass, ITA aneurysm is frequently symptomatic with an increasing chest mass that occasionally causes dyspnea due to hemothorax.1,3–7 The ITA damage in our patient remained undetected as a contained pseudoaneurysm until it ruptured. We planned to use saphenous vein grafts for coronary revascularization because of the age of the patient; therefore, we did not harvest and mobilize the ITA at the initial operation. We did not recognize ITA injury during the initial surgery, and we suspect that it might have developed due to infection, rather than ITA injury by sternal wires or bone fracture fragments at the time of sternal dehiscence and subsequent closure. Enhanced computed tomography 2 weeks after the initial operation did not reveal aneurysmal dilation of the ITA, despite sternal dehiscence.
Median sternotomy is a safe and reliable approach that provides good access and usually secure closure. However, instability with occasional dehiscence can cause serious complications, particularly in the elderly in whom sternal dehiscence may arise due to osteoporosis.4 Moreover, sternal instability might accelerate local inflammation. Postoperative wound healing in our patient was uneventful until sternal dehiscence and instability occurred. Sanfelippo and colleagues7 reported severe complications in 7.3% (18/245) of patients undergoing sternotomy, presenting as sternal and mediastinal infection or sternal dehiscence. Sanchez and colleagues8 described a mycotic ITA pseudoaneurysm secondary to invasive aspergillosis in the chest wall of a patient with chronic granulomatous disease. The close proximity of the ITA to the chest wound caused the pseudoaneurysm in our patient, and the further traumatic insult of sternal instability might have contributed to its growth.
Although such pseudoaneurysms are usually treated by surgery, direct injection with thrombin and percutaneous investigations might avoid the need for repeat sternotomy.1–7 Surgery remains controversial when a pseudoaneurysm is caused by infection. According to the standard treatment regimen for an infectious aneurysm, we completely resected the aneurysmal wall, debrided surrounding infectious tissue, and tightly closed the sternum. Although distinctly rare, ITA pseudoaneurysm might contribute to life-threatening hemorrhage. Our experience with this patient highlights the importance of being aware that a bleeding pseudoaneurysm of the ITA might be an unusual cause of hemorrhage following sternotomy.
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REFERENCES
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- Sanchez FW, Freeland PN, Bailey GT, Vujic I. Embolotherapy of a mycotic pseudoaneurysm of the internal mammary artery in chronic granulomatous disease. Cardiovasc Intervent Radiol 1985;8:43–5.[Medline]
Asian Cardiovasc Thorac Ann 2009;
17:519-521
© 2009 by SAGE Publications
DOI: 10.1177/0218492309348633
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