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Endocarditis & Infections of the Heart

Endocarditis & Infections of the Heart. Nausheen Akhter, MD Core Curriculum March 4, 2008. Contents. Epidemiology and Microorganisms Pathophysiology Clinical Features Diagnosis and Treatment Prevention and Guidelines Other Infections: Bacterial Pericarditis, Infected Devices.

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Endocarditis & Infections of the Heart

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  1. Endocarditis & Infections of the Heart Nausheen Akhter, MD Core Curriculum March 4, 2008

  2. Contents • Epidemiology and Microorganisms • Pathophysiology • Clinical Features • Diagnosis and Treatment • Prevention and Guidelines • Other Infections: Bacterial Pericarditis, Infected Devices

  3. Infective Endocarditis (IE) • IE is an infection of the endothelial lining of the heart valves, mitral or tricuspid chorda tendinea, valve annulus, and aortic root. • Pre-existing heart disease is found in 2/3 of the cases of left-sided IE. • 1/3 patients have normal or clinically unrecognized valve disease. • 3.6 to 7.0 cases/100,000 patient-years

  4. Epidemiology Braunwald 8th Edition

  5. Epidemiology • Who is at high risk for developing endocarditis? People with prosthetic heart valves, previous incidents of endocarditis, complex congenital heart disease, IVDU, and surgically devised systemic pulmonary shunts. • What patients have a moderate risk for developing endocarditis? Acquired valvular dysfunction, HCOM, and uncorrected congenital defects. Zevitz, M. Pearls of Wisdom Board Review

  6. Epidemiology • Patient Populations • MVP (7-30% of NVE not related to IVDU or nosocomial infection) • Risk is mostly in pts with thickened valve leaflets (>5mm) and MR murmur. • MVP + murmur 52/100,000 vs. no murmur 4.6/100,000 person-yr • RHD • MV > AV • CHD (10-20% young adults, 9% older adults) • PDA, VSD, and biscupid aortic valve most common • HIV • Not significant risk for IE, unless IVDU Braunwald 8th Edition

  7. Epidemiology • Patient Populations • IVDU (2-5%/patient-year) • TV>MV>AV=multiple sites • TV IE is associated with pleuritic chest pain, SOB, cough, and hemoptysis. CXR may have septic pulmonary emboli. • IVDU is a risk factor for recurrent NVE • HIV, 27 to 73% of IVDU with IE, risk and mortality is inversely related to CD4 counts. Braunwald 8th Edition

  8. Epidemiology • Patient Populations • Prosthetic Valve Endocarditis (PVE) • 10 to 30% of all IE in developed countries • “Early” PVE, symptoms within 60 days, occurs at greater frequency than “late” • 0-12 months, PVE in mechanical > bioprosthetic • >12 months, PVE bioprosthetic > mechanical • By 5 years, PVE bioprosthetic = mechanical Braunwald 8th Edition

  9. Epidemiology • Patient Populations • Health care-associated • Nosocomial and community-acquired as a consequence of indwelling devices • HD is independently associated with S. aureus. • Catheter-associated S. aureus bacteremia is the predominant risk factor for IE in this group. • Treat as presumed IE, if persistent fever or bacteremia for 4 days after catheter removed. Braunwald 8th Edition

  10. Distribution of Types of IE • Isolated AV IE is observed in 55-60% of cases. • Isolated MV IE occurs in 25-30% of cases. • IE of both valves occurs in 15% of cases. • Prosthetic valve IE constitutes 10-25% of all cases of IE. • Prosthetic valve IE is more common with prosthetic AV, multiple valves, and after replacement of an infected native valve Roldan CA. The Ultimate Echo Guide

  11. Distribution of Types of IE • Right-sided IE constitutes 5-10% of all cases. • 80% TV is involved • Most commonly associated with IVDU • Also occurs in patients with right heart wires or catheters. • What is the incidence of culture-negative endocarditis? • 5-10% Roldan CA. The Ultimate Echo Guide

  12. Microorganisms NEJM 345 (18), 2001

  13. Microorganisms • What is the most common organism associated with endocarditis? • Streptococcus viridans • What organisms are most frequently implicated in endocarditis of IVDU? • Gram negative, fungal and S. Aureus • Fungi cause what percentage of PVE? • 15% • What is the most frequent organism reported with myocardial abscess? • S. Aureus Zevitz, M. Pearls of Wisdom Board Review

  14. Microorganisms • History of contact with mammals and/or birds may suggest infection by what organisms? • Coxiella burnetii (Q fever), Brucella species or Chlamydia psittaci • A nosocomial cluster of cases postoperatively may be caused by what organisms? • Legionella or Mycobacterium species • What organism, once accounted for 25% of cases, now only 1-2% of cases? • Neisseria gonorrhoeae Zevitz, M. Pearls of Wisdom Board Review

  15. Pathophysiology • It is hypothesized that platelet-fibrin deposition occurs spontaneously on abnormal valves and at sites of cardiac endothelium injury or inflammation and that these deposits are called nonbacterial thrombotic endocarditis (NBTE). • NBTE are the sites at which microorganisms adhere during bacteremia to initiate IE. • 2 mechanisms in the formation of NBTE: • Endothelial injury • Hypercoagulable state. • 3 hemodynamic circumstances that may initiating NBTE: • (1) a high-velocity jet striking endothelium; (2) flow from a high- to a low-pressure chamber; and (3) flow across a narrow orifice at high velocity. Braunwald 8th Edition

  16. Pathophysiology • Bacteremia converts NBTE to IE. • Bacteremia rates are highest for trauma of the oral mucosa (especially gingiva), than GU, and GI tract. Braunwald 8th Edition

  17. Braunwald 8th Edition

  18. Clinical Features • Destructive effects of intracardiac infection • Embolization of septic fragments of vegetations to distant sites causing infarction/infection • Hematogenous seeding of remote sites • An antibody response with subsequent tissue injury caused by deposition of preformed immune complexes or antibody-complement interaction with antigens deposited in tissues. Braunwald 8th Edition

  19. Braunwald 8th Edition

  20. Braunwald 8th Edition

  21. Clinical Features • What signs and symptoms are associated with a myocardial abscess? • Low-grade fevers, chills, leukocytosis, conduction system abnormalities, nonspecific ECG changes and sign/sx of acute MI • Osler’s nodes are usually nodular and painful. • True • What other conditions are associated with Osler’s nodes? • NBTE, gonococcal infection and hemolytic anemia Zevitz, M. Pearls of Wisdom Board Review

  22. Diagnosis: Duke’s Criteria AHA/ACC Valve Guidelines 2006

  23. Diagnosis • TTE sensitivity • Vegetation <5mm 25% • Between 6-10mm 70% • TEE sensitivity 90-100% • Prosthetic endocarditis • TEE >> TTE Evangelista Heart 90: 614-617 (2004)

  24. Diagnosis • Class I Indications for Echocardiography in IE of Native and Prosthetic Valves: • Detection and characterization of valvular lesions, hemodynamic severity, and ventricular compensation • Detection of vegetations and characterization of lesions in patients with CHD • Detection of abscess, perforation or fistulas • Reevaluation studies in patients with complex endocarditis • In patients with highly suspected culture-negative IE • Evaluation of bacteremia without a known source in a patient with a prosthetic valve. Roldan CA. The Ultimate Echo Guide

  25. Diagnosis • Positive Echo findings: • Presence of vegetations defined as mobile echodense masses implanted in a valve or mural endocardium in the trajectory of the regurgitant jet or implanted in prosthetic material with no alternative anatomical explanation • Presence of abscess defined as definite region of reduced echo density, or echolucent cavities within annulus or adjacent myocardial structures • New dehiscence of valvular prosthesis Roldan CA. The Ultimate Echo Guide

  26. Braunwald 8th Edition

  27. BMJ Vol. 333, Aug. 2006 Evangelista Heart 90: 614-617 (2004)

  28. Detection of Complications • Valve perforation • Valvular, annular, or aortic root, or myocardial abscess • Valve psuedoaneurysm • Fistulas • Ring dehiscence • Valvular regurgitation

  29. PVE commonly extends beyond the valve ring into the annulus which can cause dehiscence, paravalvular regurgitation and conduction disturbances. Braunwald 8th Edition

  30. BMJ Vol. 333, Aug. 2006 Evangelista Heart 90: 614-617 (2004)

  31. BMJ Vol. 333, Aug. 2006

  32. Subaortic Complications of AV Endocarditis • “TEE Recognition of Subaortic Complicatons in AV endocarditis” • Karalis DG, et al. (Circulation 1992; 86: 353 – 362). • May 1988 – August 1991, 55 consecutive patients • 44% (N = 24) had subaortic complications. • Secondary involvement of the mitral-aortic intervalvular fibrosa (MAIVF) and the anterior mitral leaflet (AML) • Direct extension of infection and/or less commonly the infected AI jet striking the subaortic structures • Abscess, aneurysm, perforation

  33. Subaortic Complications of AV Endocarditis

  34. Subaortic Complications of AV Endocarditis

  35. Subaortic Complications of AV Endocarditis

  36. Subaortic Complications of AV Endocarditis

  37. Subaortic Complications of AV Endocarditis

  38. Subaortic Complications of AV Endocarditis • Secondary infections of the subaortic structures may be more common than appreciated. • The MAIVF and AML should be investigated in all patients with AV endocarditis. • Thickening of the posterior aortic root or AML with an eccentric MR color jet should alert to possible subaortic complications.

  39. Differential Diagnosis of IE • Valve excrescences • Ruptured chordae tendinea • Torn bioprosthetic leaflet • Libman-Sacks endocarditis • Rheumatic valvulitis • NBTE • Papillary fibroelastoma

  40. Libman-Sacks Endocarditis Rheumatic Valvulitis Google Images

  41. Papillary Fibroelastoma Ruptured chordae tendinea Google Images

  42. Medical Therapy NEJM 345 (18), 2001

  43. Indications for Valve Surgery • Endocarditis-related valvular heart failure (mortality 56 – 86%) • Moderate to severe CHF (NYHA III or IV) • No control of infection, difficult-to-treat microbes • Embolic risk (vegetation length > 15mm strong predictor of new EE and mortality) • Neurologic complications • Perivalvular infection/abscess • Valvular obstruction • Unstable prosthesis • Prosthetic infective endocarditis (esp. S. Aureus) • Fungal infective endocarditis

  44. Circulation 2005; 112: 69-75

  45. JACC 2001; 37: 1069

  46. Prevention/Guidelines Wilson, et al. Circulation. 2007; 115

  47. Rationale • IE prophylaxis regimen has been evolving for the past 50 years. • Basis for recommendations and quality of evidence limited to expert opinion, small trails [Class IIb, LOE C] • Several assumptions have led to development of abx prophylaxis in humans, and these assumptions have been recently questioned Wilson, et al. Circulation. 2007; 115

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