Unusual presentation of cryolife O'Brien(R) stentless aortic valve bioprosthesis dysfunction mimicking infective endocarditis

OBJECTIVES: We previously reported a possible but unusual prosthetic-valve infective endocarditis (PV-IE) occurring on a Cryolife O'Brien Stentless Porcine Xenograft (CLOB) (anatomic damages suggestive of IE but negative inflammatory and microbiological markers). We reviewed all cases of aortic PV-IE admitted in our institution and compared the clinical presentation, bacteriological and echocardiographic features according to the type of prosthesis. METHODS: Sixty consecutive cases with possible or definite aortic PV-IE (23 CLOB, 26 mechanical valve and 11 stented bioprosthesis) were admitted between 2002 and 2008. RESULTS: Patients with CLOB had more prosthetic dehiscence (P = 0.006) and severe regurgitation (P = 0.01) than those with mechanical or stented prosthetic valves. In contrast, they had less fever (P = 0.003), lower C-reactive protein (CRP) levels (P = 0.02) and more frequently negative blood cultures (P = 0.08). Differences were due to seven patients who presented with no fever, low CRP, negative blood culture, negative valve culture and PCR when performed, despite echocardiographic features suggestive of IE (abscess or valve dehiscence). All were first operated on since 2004 when the manufacturing process changed and required a second surgery. The French Authority of Health was informed leading to the withdrawal of the CLOB from the market in 2010. CONCLUSIONS: One-third of patients with CLOB admitted for possible or definite PV-IE presented with anatomic damages suggestive of IE but with negative inflammatory and microbiological markers. The exact aetiology remains unclear, but the present data have led to the worldwide withdrawal of prosthesis in 2010. A close follow-up of patients implanted with CLOB should be advised, especially if it has been manufactured since 2004.