Large Mycotic Pseudoaneurysm of the Left Circumflex Treated with Antibiotics and Covered Stent

From the ^*Department of Medicine, Lehigh Valley Hospital, Allentown, Pennsylvania, and ^§Heart Care Group, Lehigh Valley Hospital, Allentown, Pennsylvania. The authors report no conflicts of interest regarding the content herein. Manuscript submitted August 28, 2008, provisional acceptance given November 3, 2008, manuscript accepted November 11, 2008. Address for correspondence: Nasir Sharieff, MD, MRCP, Resident, Department of Medicine, Lehigh Valley Hospital, 1240 S. Cedar Crest Blvd., Allentown, PA 18103. E-mail: nasirshariff@gmail.com

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ABSTRACT: Coronary artery mycotic aneurysms are rare complications of infective endocarditis. They are usually managed surgically with excision of the aneurysm. This surgical procedure has high morbidity and mortality. We report a case of a giant mycotic coronary aneurysm following infective endocarditis which was treated with intravenous antibiotics and covered stent. This case highlights a new treatment modality in critically ill patients.

J INVASIVE CARDIOL 2009;21:E37–E38

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Case Report. A 72-year-old male with a previous history of diabetes mellitus and end-stage renal disease on hemodialysis was admitted to the hospital with methicillin-sensitive Staphylococcal bacteremia. He was noted to have native aortic valve endocarditis with vegetations on the noncoronary and right coronary cusp. He was treated with cefazolin according to the sensitivity pattern. During his stay in the hospital, he had persistent fatigue and a noted elevated troponin of 3.8 ng/ml. Since he had a previous history of coronary artery disease with percutaneous coronary intervention to his left circumflex artery (LCX) (transluminal coronary rotational atherectomy with balloon dilatation 12 years previously) and coronary artery bypass surgery with transmyocardial revascularization (2 years previously), he was taken for coronary angiography. The angiographic study showed patent left internal mammary artery and saphenous vein bypass grafts. A large 3 cm x 3 cm size mycotic pseudoaneurysm arising from the proximal LCX was identified (Figures 1 and 2). Considering the patient’s hemodynamic condition and the risks of surgery, we decided to place a covered stent. A 4 x 26 mm PTFE-covered Jostent graft (Abbott Vascular, Abbott Park, Illinois) was placed in the LCX with complete resolution of the aneurysm (Figure 3). A repeat angiogram performed one week later showed no further filling of the aneurysm. At 6-month follow up, the patient had experienced no complications. Discussion. Coronary aneurysms have an incidence of 0.3–4.9% among patients undergoing coronary angiography.¹ The causes of coronary artery aneurysm include atherosclerosis, vasculitis, infections, angioplasty and congenital malformations.² A mycotic aneurysm is a localized, irreversible dilatation of an artery due to destruction of the vessel wall by infection. These aneurysms occur in the cerebral or systemic circulation of patients with endocarditis, usually at points of vessel bifurcation.³ When mycotic aneurysms develop as a complication of bacterial endocarditis, tiny septic emboli occlude the vasa vasorum or entire arterial lumen, which damages or destroys the muscular layer of the vessel. Subsequent intraarterial pressure causes dilatation and aneurysm formation. In the literature, the mortality rate associated with surgical treatment of mycotic aneurysms of the aorta is 36%.⁴ Similar high mortality rates for treatment of coronary mycotic aneurysms could be expected. Since 1970, there have been 33 case reports of coronary arterial mycotic aneurysms. The major artery involved is the left anterior descending in 11 patients, and the right coronary artery in 11 patients. In 7 patients, the primary artery involved was not known and 1 patient each had involvement of the left main and first diagonal arteries. Left circumflex arterial mycotic aneurysms were described in 2 patients. The age of the patients varied from 18 to 71 years. Seventeen patients were surgically treated. In 11 patients, the management was not described and in 4 patients, the condition was diagnosed post partum. Though there are case reports of mycotic aneurysms of the aortic arch⁵ and external iliac artery⁶ managed with antibiotics and covered stents, this management option has not be described in patients with mycotic aneurysms involving the coronary arteries. PTFE-covered stents have been shown to be effective devices for percutaneous management of atherosclerosis-related coronary aneurysms,¹ but there is nothing in the literature regarding their use to treat mycotic aneurysms. Since our patient was critically ill and the risk of surgery was very high, we opted to place a rcovered stent. The procedure was uncomplicated and the patient has been under follow up for the past 6 months. It needs to be acknowledged that unlike other foreign body implants, infections secondary to coronary stent placement are a rare but very serious complication.⁷ This complication rate would be higher for mycotic aneurysms treated with covered stents. We believe that the use of covered stents and antibiotics is an effective treatment for selected patients with mycotic pseudoaneurysms and does not warrant routine follow-up angiography. Follow up should be guided by the clinical condition of the patient and noninvasive imaging means such as a computed tomographic scan of the chest, followed by angiography if warranted. Conclusion. In light of our experience and after reviewing the literature, the use of covered stents with intravenous antibiotic therapy for coronary arterial mycotic aneurysms is an attractive alternative to open surgery. Further experience is needed to establish this form of treatment, especially for high-risk patients.

References

1. Briguori C, Sarais C, Siveieri G. Polytetrafluoroethylen-covered stent and coronary artery aneurysms. Catheter Cardiovasc Interv 2002;55:326–330. 2. Nichols L, Lagana S, Parwani A. Coronary artery aneurysm: A review and hypothesis regarding etiology. Arch Pathol Lab Med 2008;132:823–828. 3. Brown SL, Busuttil RW, Baker JD, et al. Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms. J Vasc Surg 1984;1:541–547. 4. Koeppel TA, Gahlen J, Diehl S, et al. Mycotic aneurysm of the abdominal aorta with retroperitoneal abscess: Successful endovascular repair. J Vasc Surg 2004;40:164–166. 5. Alpagut U, Ugurlucan M, Kafali E, et al. Endoluminal stenting of mycotic saccular aneurysm at the aortic arch. Tex Heart Inst J 2006;33:371–375. 6. Clarke MG, Thomas HG, Chester JF. MRSA-infected external iliac artery pseudoaneurysm treated with endovascular stenting. Cardiovasc Intervent Radiol 2005;28:364–366. 7. Kaufmann BA, Kaiser C, Pfisterer ME, Bonetti PO. Coronary stent infection: A rare but severe complication of percutaneous coronary intervention. Swiss Med Wkly 2005;135:483–487.