Multisite Vancomycin Intermediate-Sensitive Staphylococcus Aureus Infective Endocarditis With Giant Vegetations on Implantable Cardioverter-Defibrillator Lead
A 50-year-old woman was admitted to the hospital with shortness of breath, fever to 102.8°F, and leukocytosis. She had a history of nonischemic cardiomyopathy with ejection fraction of 25% to 35% and prior ventricular fibrillation arrest for which she had received a single-chamber implantable cardioverter-defibrillator about 18 months previously. She also had a history of end-stage renal disease requiring hemodialysis, diabetes mellitus, and hypertension. Over the preceding 5 months, she had experienced recurrent S. aureus dialysis catheter infections with bacteremia, for which she had received intravenous antibiotic therapy, including vancomycin.
On admission to the hospital, ECG showed sinus tachycardia at 108 bpm, left atrial abnormality, and left ventricular hypertrophy with secondary repolarization abnormality (Figure 1). The initial blood cultures grew out methicillin-resistant S. aureus, and she was placed on an intravenous antibiotic regimen of daptomycin and gentamycin. Despite treatment, she continued to have persistently positive blood cultures, fevers, and leukocytosis.
Transesophageal echocardiography was performed to evaluate for evidence of endocarditis. Multiple large vegetations coated the defibrillator lead from the right atrium to the right ventricle (Online-only Data Supplement Movies I and II), with a giant vegetation at the level of the tricuspid valve measuring approximately 2.6×1.8 cm (online-only Data Supplement Movie III). Smaller vegetations involved the native mitral valve, with a coating of bacterial growth seen over the leaflets and annulus, invading the tissue. There appeared to be a heterogeneous mix of older calcified vegetation and newer superimposed layers of bacterial growth (online-only Data Supplement Movies IV and V). Moderate mitral regurgitation with 2 regurgitant jets, one through each leaflet, was seen (online-only Data Supplement Movie VI). The aortic valve also appeared to have a vegetation (online-only Data Supplement Movie VII).
The diagnosis of multisite infective endocarditis, with primary involvement of the defibrillator lead, was made. The patient underwent emergent percutaneous lead extraction without complications. Cultures of the defibrillator lead vegetation grew out vancomycin intermediate-sensitive S. aureus. Afterward, she received a prolonged intravenous antibiotic course of linezolid, daptomycin, and gentamycin. She remained afebrile, and surveillance blood cultures were negative. However, follow-up transesophageal echocardiography showed persistent valve vegetations, and involvement of the mitral-aortic intervalvular fibrosa could not be ruled out. Cardiovascular surgery was consulted and recommended operative treatment, but the patient refused. A new defibrillator was deferred because of the risk of reinfection and could not have been accomplished via a transvenous approach because of a complete occlusion of the right innominate vein. After a prolonged hospital course, the patient died from a ventricular fibrillation arrest.
This case was unusual because of the presence of concomitant left- and right-sided endocarditis affecting multiple valves and an endovascular lead. Also unusual were the size of the vegetations observed and the virulence and resistance of the microorganism involved. It is likely that the route of initial S. aureus infection was via a hemodialysis catheter in the venous circulation, leading to the development of right-sided endocarditis, followed by subsequent hematogenous spread to the left-sided valves. Repeated courses of antibiotics probably led to the high-grade resistance of the S. aureus microorganism, a sobering illustration of a problem that the medical community faces.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/cgi/content/full/119/19/2643/DC1.