Prosthetic Valve Endocarditis

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Prosthetic Valve Endocarditis

• Ri ???/VS???
• 2006/10/9

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Outline

• Epidemiology
• Category
• Microbiology
• Special Consideration in PVE
• Clinical Manifestation
• Diagnosis
• Management

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Endocarditis

• Native valve endocarditis
• Prosthetic valve endocarditis (PVE)

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Epidemiology

• Endocarditis in developed contries1.56.2
  cases/100,000 population-year
• Prosthetic valve endocarditis1.53 at 1 year
  after valve replacement36 at 5 years
• ?mechanical valves at higher risk for
  infection than are bioprostheses during the
  first three months after surgery, the rates of
  infection for the two valve types converge
  later and are similar at five years
• Harrisons Principles of Internal Medicine 16th
  p.732

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Prosthetic Valve Endocarditis

• lt 2 months
• Intraoperative contamination on the prosthesis
• Bacteremic postoperative complication?wound
  infection, IV catheter infection, UTI, pneumonia
• 212 months
• CoNS nosocomial, with a delayed onsetMRCoNS
  lt1year 85 vs. gt1 year 2
• gt 12 months
• Portals of entry and microbiology similar to NVE

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Microbiology
Eleftherios Mylonakis, Stephen B. Calderwood.
Infective Endocarditis in Adults. NEJM, Vol.
3451318-1330
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Special Consideration in PVE
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Important Factors

• Type of prosthesis
• Previous native valve endocarditis
• Male gender
• Long cardiopulmonary bypass time

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Pathogenesis

• Free of thrombotic material ?Do not allow
  adherence of microorganisms
• Sewing ring, adherent thrombi?biofilm

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Mechanical Prostheses

• Early PVE
• Rarely remains restricted to leaflets alone
• -Valve dehiscence-Myocardial abscess
  38-Paravalvular abscess 63
  Staphylococci need surgical treatment
• ?paravalvular leak fistula

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Bioprosthesis

• Less susceptible to early infection
• Often restricted to the leaflets?more likely to
  be curable by ABx treatment

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Diagnosis
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Clinical Manifestation
Adapted form Harrisons Principles in Internal
Medicine, 16th ed., p.733
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• A. Sphincterhemorrhage
• B. Conjunctival patechia
• C. Osler node
• D. Janeways lesion
• Early PVE often lake of peripheral vascular
  lesions

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Laboratory
Adapted form Harrisons Principles in Internal
Medicine, 16th ed., p.733
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Modified Duke Criteria
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Modified Duke CriteriaClinical Criteria
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Echocardiography

• TransThoracic Echocardiography(TTE)
• Conveniet, noninvasive
• Sen. 57 Spe.63 in PVE
• Intense reverberation ? limit its abilityPoor
  acoustic window
• TransEsophageal Echocardiography(TEE)
• More invasive
• Sen. 86 Spe. 88 in PVE
• Insufficient to assess the anterior aspect of an
  aortic prosthesis, esp. mitral prosthesis()

Comparison of transthoracic and transesophageal
echocardiography for detection of abnormalities
of prosthetic and bioprosthetic valves in the
mitral and aortic positions. Am. J. of Cardio.
Vol.71, Issue2, 15 January 1993, Pages 210-215
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Bacteremia w/o Echo Findings

• Leukocyte scans
• MRI

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PVE from Nosocomial Bacteremia
Ann Intern Med 1993119560 7.

• 6 University teaching hospitals in U.S.171 pts
  with PV, bacteremia() in hospitalization
• 74(43) PVE-56(33) at the time of bacteremia
  was discovered-18(11) a few days after
  bacteremia (mean45days)
• Of the 18 pts (new onset)-6 Staph. epidermidis
  4 Staph. Aureus-15 Mitral involved

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• 94-month period51 pts with prosthetic valve or
  mitral ring had Staphylococcus aureus
  bacteremia?32(63) had early IE, 19(37) had
  late IE (Early lt 1 yr s/p op Late gt1 yr s/p
  op)

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Culture-negative IE

• After antibiotics treatment
• Slow-growth CoNS, Fungus
• Unusual pathogens?Serologic Test

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Eleftherios Mylonakis, Stephen B. Calderwood.
Infective Endocarditis in Adults. NEJM, Vol.
3451318-1330
serology test suggested by NGC
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Management
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Surgical Intervention

• NGC Guideline
• Early PVE (less than 12 months after surgery)
• Late PVE complicated by 1. prosthesis
  dysfunction including significant
  perivalvular leaks or obstruction, 2. persistent
  positive blood cultures, 3. abscess formation,
  4. conduction abnormalities, 5. large
  vegetations, particularly by staphylococci

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Medical Treatment
Eleftherios Mylonakis, Stephen B. Calderwood.
Infective Endocarditis in Adults. NEJM, Vol.
3451318-1330
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Follow Up Blood Culture

• Repeated B/C daily until sterile,
• 4 to 6 weeks after therapy to document cure.
• Rechecked if recrudescent fever()
• Blood cultures become sterile
• viridans streptococci, HACEK, enterococci lt 2
  days
• S. aureus endocarditis, 3 to 5 days under
  b-lactum 7
  to 9 days with vancomycin

Adapted form Harrisons Principles in Internal
Medicine, 16th ed., p.734
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Follow Up Echo

• Vegetations become smaller with effective therapy
• 3 months after cure, half are unchanged and 25
  are slightly larger.

Adapted form Harrisons Principles in Internal
Medicine, 16th ed., p.734
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N.B. Staphylococcus aureus PVE

• Mortality rates for S. aureus prosthetic valve
  endocarditis Medical treatment? gt 70
  Surgical treatment? 25
• S. aureus PVE with intracardiac complications?
  surgical treatment ?mortality 20X
• Surgical treatment should be considered for
  patients with S. aureus native aortic or mitral
  valve infection who have TTE-demonstrable
  vegetations and remain septic during the initial
  week of therapy.

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Take Home Message

• Patients with prosthetic valve had bacteremia
  50 had PVE
• Early PVE Staphylococcus (S.a CoNS)Late PVE
  similar to native valve
• MRSA PVE ?need surgical intervention?Medication
  Vancomycin, Rifampin, GM

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• Thank You for
• Your Kind Participation