INTRODUCTION: Acute coronary syndrome due to coronary artery aneurysm is well known. The coronary artery aneurysm is usually due to atherosclerotic disease, but may be caused by either dissection or recent intervention or vasculitis. We describe a case of acute coronary syndrome caused by coronary artery mycotic aneurysm caused by methicillin resistant Staphylococcus aureus (MRSA).
CASE PRESENTATION: A 61 year old man was admitted with angina, fever, chills and rigors, and poor appetite. He was status post coronary artery bypass graft (CABG in 1985) and status post 14 coronary artery stents with the most recent two stents placed 8 months ago. He also had diabetes and end-stage kidney disease requiring hemodialysis. Ten days prior to admission he was hospitalized at another facility for MRSA bacteremia that persisted despite adequate intravenous antimicrobial therapy. During that prior hospitalization, he reported pus drained from his fistula. He became febrile shortly after admission. His admitting physical examination only revealed a non-functional AV fistula in the left arm. The laboratory work showed positive cardiac enzymes, however, the EKG was negative for ischemia (Non-ST Elevation Myocardial Infarction- NSTEMI). Because the blood cultures yielded MRSA, the NSTEMI was managed medically. The AV fistula was removed and yielded MRSA, but the bacteremia persisted. Trans-esophageal echocardiogram was negative for vegetation. The patient was injected with 1 mCi of In-111 labeled autologous leukocytes intravenously. Whole body scan and spot images of the chest were taken at 24 hours. These images revealed increased uptake in the anterior mediastinum. SPECT images of chest were also taken for better localization and possible correlation with recommended CT. A CT scan of chest was obtained which revealed several findings corresponding to location of abnormality on the WBC scan. There was a 3.9 × 2.8 cm area of increased density with two fluid collections measuring 2.3 × 1.6 cm and 3.7 × 3.7 cm (Image 1). The enhancing nodule appears to communicate through a thin channel with a dilated vessel seen anterior to the aorta just superior to and possibly communicating with the right ventricle. Multiple bypass clips were seen in the area of these fluid collections. Cardiac catheterization revealed aneurysms of the left main, left circumflex, saphenous vein graft (SVG) to diagonal and right coronary artery (RCA) (Image 2). It appeared that the aneurysm had ruptured with fistulous communication from SVG to RCA to possibly the left atrium and ventricle. A diagnosis of mycotic aneurysm of the coronaries was made; the patient refused surgery.
DISCUSSIONS: This is the first case report describing the diagnosis of Coronary Mycotic Aneurysm with aid of WBC scan, complemented with CAT scan of the chest and cardiac catheterization. Previously, the mycotic aneurysm has only been described either on autopsy or pathology after the resection of the mycotic aneurysm. Mycotic aneurysm is a rare entity associated with a high mortality and morbidity. Risk factors include recent invasive procedure, or seeding of coronary stents or endocarditis. Early identification of mycotic aneurysm is associated with better prognosis.
CONCLUSION: A high index of suspicion is required for diagnosing mycotic aneurysm in the patients with history of CABG or percutaneous coronary intervention, who present with acute coronary syndrome and persistent bacteremia with no identifiable source of infection.
DISCLOSURE: Nadish Garg, No Financial Disclosure Information; No Product/Research Disclosure Information