Rapid progression of Staphylococcus lugdunensis mechanical prosthetic valve endocarditis

Abstract

Summary A 66-year-old woman with a remote history of mitral valve replacement (mechanical bileaflet valve) due to rheumatic heart disease presented with symptoms consistent with infectious endocarditis. Subsequent blood cultures grew Staphylococcus lugdunensis. A transesophageal echocardiogram demonstrated large vegetations on the atrial aspect of the mitral valve, with a Doppler derived mean pressure gradient of 13 mmHg (Fig. 1 and Video 1). Appropriate i.v. antibiotics were initiated and a surgical consultation was obtained. A second transesophageal echocardiogram was performed 6 days later after she developed acute respiratory failure secondary to pulmonary edema, requiring mechanical ventilation (Video 2). This examination revealed a significant increase in size of the mitral vegetations, with the largest measuring 2.2 cm in maximum dimension, with new complete obstruction of one mechanical leaflet, and with dense spontaneous echo contrast secondary to prosthetic mitral valve obstruction. She subsequently underwent urgent open heart surgery and redo mitral valve replacement with a bioprosthetic valve. Valve obstruction due to large vegetations occurs rarely with infectious endocarditis and is more common with prosthetic (in comparison with native) valves (1, 2, 3). Serial transesophageal echocardiography imaging was helpful in diagnosing this life-threatening complication. Figure 1 (A) Initial transesophageal echocardiogram reveals a large vegetation on the atrial aspect of the mechanical mitral valve (arrow). (B) Repeat transesophageal echocardiogram 6 days later demonstrates a significant increase in size of the vegetation with valve obstruction (arrow). Note spontaneous echo contrast in the left atrium due to hemostasis. (C) Photograph of the explanted valve with vegetation surrounding the atrial aspect of the annular ring. (D) Photograph of the large vegetation seen in B on the atrial aspect of the mechanical valve. Video 1 Initial transesophageal echocardiogram reveals a large vegetation on the atrial aspect of the mechanical mitral valve. Download Video 1 via http://dx.doi.org/10.1530/ERP-15-0017-v1. Download Video 1 Video 2 Repeat transesophageal echocardiogram 6 days later demonstrates a significant increase in size of the vegetation with valve obstruction. Note spontaneous echo contrast in the left atrium due to hemostasis. Download Video 2 via http://dx.doi.org/10.1530/ERP-15-0017-v2. Download Video 2