A patient with a prosthetic aortic valve develops fever and bacteraemia with Staphylococcus epidermidis within 60 days of surgery. Echocardiogram shows a perivalvular abscess. This is best classified as which form of infective endocarditis?
- A Early prosthetic valve endocarditis (PVE) — caused by perioperative contamination with coagulase-negative Staphylococci, characterised by perivalvular infection and high mortality ✓
- B Late PVE — presenting >12 months post-surgery with viridans streptococci from community-acquired bacteraemia
- C Native valve endocarditis from S. epidermidis skin translocation unrelated to surgery
- D Marantic (non-bacterial thrombotic) endocarditis complicated by secondary infection
Explanation
Prosthetic valve endocarditis (PVE) occurring within 60 days of implantation is classified as early PVE, caused by intraoperative or early postoperative contamination. Coagulase-negative Staphylococci (particularly S. epidermidis) are the predominant organisms, adhering to the sewing ring via biofilm formation. Early PVE typically involves the valve ring/sutures, causing perivalvular abscesses, dehiscence, and ring abscess — explaining the perivalvular location on echo. Mortality is high (30–50%) and surgical intervention is often required. Late PVE (>12 months) more closely resembles native valve endocarditis in organism spectrum (viridans Streptococci) and carries a better prognosis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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