Is the management of bioprosthetic (biological) valve endocarditis different from that of mechanical valve endocarditis?

Management of Bioprosthetic vs. Mechanical Valve Endocarditis

The core management principles for both bioprosthetic and mechanical valve endocarditis are fundamentally the same, with differences primarily in pathogenesis patterns and surgical considerations rather than in the overall treatment approach. 1

Pathophysiological Differences

• In early prosthetic valve endocarditis (PVE), infection typically involves the junction between the sewing ring and annulus, leading to perivalvular complications (abscesses, dehiscence, pseudo-aneurysms, fistulae) regardless of valve type 1
• In late bioprosthetic PVE, infection more commonly affects the valve leaflets, causing vegetations, cusp rupture and perforation - a pattern specific to bioprosthetic valves 1
• Mechanical valves have less biological tissue available for bacterial colonization, which may explain some differences in infection patterns 2

Diagnostic Considerations

• Diagnosis is challenging for both valve types, with echocardiography and blood cultures being less sensitive in PVE compared to native valve endocarditis 1
• Transesophageal echocardiography (TOE) is mandatory for suspected PVE but has lower diagnostic value than in native valve endocarditis 1
• Persistent fever should trigger suspicion of PVE in any prosthetic valve patient 1
• Identification of a new periprosthetic leak is a major diagnostic criterion, potentially requiring additional imaging modalities like CT or nuclear imaging 1

Medical Management

• Antibiotic therapy principles are identical for both valve types:
  • Antibiotics should be continued for 4-6 weeks, and for at least 2-3 weeks after normalization of body temperature 1
  • The microbiology differs between early PVE (≤1 year post-surgery) and late PVE (>1 year), with staphylococci and fungi more common in early PVE 1

Surgical Management Considerations

• Indications for surgery are the same for both valve types:

  • Failure of medical therapy to control infection (persistent fever, elevated inflammatory markers) 1
  • Hemodynamically significant prosthetic valve leak with ventricular dysfunction 1
  • Large vegetations, particularly with embolism 1
  • Development of intracardiac fistulae 1

• Surgical principles for both valve types include:

  • Complete removal of infected prosthesis 1
  • Extensive debridement of infected and non-viable tissue 1
  • Laboratory examination of debrided tissue 1
  • Use of autologous or heterologous pericardium for reconstruction when needed 1

Valve Selection for Replacement in PVE

• The European Society of Cardiology does not favor any specific valve substitute for PVE but recommends a tailored approach for each individual patient, as mechanical and biological prostheses have shown similar operative mortality. 1

• For extensive aortic root destruction:

  • Homografts or stentless xenografts may be preferred over standard prosthetic valves 1
  • The anterior mitral leaflet of aortic homografts can be used for outflow tract reconstruction 1

• For complex cases with locally uncontrolled infection:

  • Total excision of infected tissue followed by valve replacement and repair of associated defects is recommended 1
  • Foreign material should be minimized 1

Long-term Outcomes and Considerations

• Some research suggests mechanical valves may have lower recurrence rates of endocarditis compared to bioprosthetic valves 3, 2, 4
• A recent meta-analysis indicated bioprosthetic valves may be associated with higher risk of infective endocarditis compared to mechanical valves 5
• However, the ESC guidelines emphasize that when complete debridement of annular abscesses is achieved, mechanical prostheses and xenografts have shown similar results for persistent/recurrent infection and survival 1

Follow-up Recommendations

• Follow-up is identical for both valve types:
  • Regular clinical and echocardiographic follow-up during the first year after treatment completion 1
  • Blood samples (white cell count, CRP) and blood cultures at initial follow-up visit and when clinically indicated 1
  • Good oral health maintenance and preventive dentistry are mandatory 1
  • Patient education about signs and symptoms of recurrent infection 1

Caveat

• The choice between mechanical and bioprosthetic valves for replacement in PVE should consider patient-specific factors beyond the risk of recurrent endocarditis, including age, need for anticoagulation, and comorbidities 1