Prosthetic Valve Endocarditis

1. Prosthetic Valve Endocarditis Ri 張凱迪/VS柯文哲 2006/10/9

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

3. Endocarditis • Native valve endocarditis • Prosthetic valve endocarditis (PVE)

4. Epidemiology • Endocarditis in developed contries:1.5~6.2 cases/100,000 population-year • Prosthetic valve endocarditis1.5~3% at 1 year after valve replacement3~6% 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 ~Harrison’s Principles of Internal Medicine 16th p.732

5. Prosthetic Valve Endocarditis • < 2 months • Intraoperative contamination on the prosthesis • Bacteremic postoperative complicationwound infection, IV catheter infection, UTI, pneumonia • 2~12 months • CoNS: nosocomial, with a delayed onsetMRCoNS: <1year: 85% vs. >1 year: 2% • > 12 months • Portals of entry and microbiology: similar to NVE

6. Microbiology Eleftherios Mylonakis, Stephen B. Calderwood.: Infective Endocarditis in Adults. NEJM, Vol. 345:1318-1330

7. Special Consideration in PVE

8. Important Factors • Type of prosthesis • Previous native valve endocarditis • Male gender • Long cardiopulmonary bypass time

9. Pathogenesis • Free of thrombotic material Do not allow adherence of microorganisms • Sewing ring, adherent thrombibiofilm

10. 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

11. Bioprosthesis • Less susceptible to early infection • Often restricted to the leafletsmore likely to be curable by ABx treatment

12. Diagnosis

13. Clinical Manifestation Adapted form Harrison’s Principles in Internal Medicine, 16th ed., p.733

14. A. Sphincterhemorrhage B. Conjunctival patechia C. Osler node D. Janeway’s lesion *Early PVE: often lake of peripheral vascular lesions

15. Laboratory Adapted form Harrison’s Principles in Internal Medicine, 16th ed., p.733

16. Modified Duke Criteria

17. Modified Duke CriteriaClinical Criteria

18. 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

19. Bacteremia w/o Echo Findings • Leukocyte scans • MRI

20. PVE from Nosocomial Bacteremia Ann Intern Med 1993;119:560 –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 fewdays after bacteremia (mean:45days) • Of the 18 pts (new onset)-6: Staph. epidermidis; 4: Staph. Aureus-15: Mitral involved

21. 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: < 1 yr s/p op; Late: >1 yr s/p op)

22. Culture-negative IE • After antibiotics treatment • Slow-growth: CoNS, Fungus • Unusual pathogensSerologic Test

23. Eleftherios Mylonakis, Stephen B. Calderwood.: Infective Endocarditis in Adults. NEJM, Vol. 345:1318-1330 serology test suggested by NGC

24. Management

25. 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

26. Medical Treatment Eleftherios Mylonakis, Stephen B. Calderwood.: Infective Endocarditis in Adults. NEJM, Vol. 345:1318-1330

27. 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 : < 2 days • S. aureus endocarditis, 3 to 5 days under b-lactum 7 to 9 days with vancomycin Adapted form Harrison’s Principles in Internal Medicine, 16th ed., p.734

28. Follow Up : Echo • Vegetations become smaller with effective therapy • 3 months after cure, half are unchanged and 25% are slightly larger. Adapted form Harrison’s Principles in Internal Medicine, 16th ed., p.734

29. N.B. Staphylococcus aureus PVE • Mortality rates for S. aureus prosthetic valve endocarditis Medical treatment > 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.

30. 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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