1. INFECTIVE ENDOCARDITIS
Manoj Kuduvalli

2. Definition
Bacterial or Fungal infection within the heart (although chlamydial and rickettsial infections are known) ; the role of viruses is unknown

3. ORIGINAL CLASSIFICATION (Prior to Antibiotic era)

4. Current Criteria for Classification
Underlying Anatomy:
› Native Valve Endocarditis
› Prosthetic Valve Endocarditis
Infecting Organism
› Serves as basis for therapy and prognosis

5. Native Valve Endocarditis Underlying Predisposing Conditions
›› % of non IV Drug abusers have a
predisposing condition
› Mitral Valve Prolapse %
› Rheumatic Heart Disease %
› Degenerative Aortic and %
Mitral valve disease
› Congenital Heart Disease %

6. Native Valve Endocarditis Microbiology
›› Streptococci %
Viridans Streptococci (50% of all Strep)
›› Staphylococci ~ 25%
Mostly Coagulase +ve Staph. Aureus
Staph. Epidermidis
›› Enterococci ~ 10%

7. Native Valve Endocarditis Microbiology
Viridans Streptococci
Infect primarily abnormal valves
Indolent clinical course
Highly sensitive to Penicillins
Staph. aureus
Infect normal and abnormal valves
Fulminant course with rapid destruction of valves and multiple metastatic abscesses
Mostly resistant to Penicillins and sensitive to penicillinase resistant ß-lactams
Common with soft tissue infections, and infected IV catheters

8. Native Valve Endocarditis Microbiology
Staph. Epidermidis
Indolent Course
Affects abnormal valves
Enterococci
Normally affects damaged valves
Recent history of genitourinary or gastrointestinal manipulation, disease or trauma
Usually sensitive to Penicllin+Gentamicin
Resistant strains prevalent

9. Prosthetic valve endocarditis
5 - 15% of all Infective Endocarditis
Overall incidence 1 - 4%
Risk of PVE peaks at 15 days postop. , then rapidly declines by 150 days

10. Prosthetic Valve Endocarditis Classification
Early ( < 60 days )
Reflects perioperative contamination
Incidence around 1%
Microbiology
Staph ( %)
Staph. Epiderm (~ 30%)
Staph. Aureus (~ 20%)
Gram -ve aerobes (~20%)
Fungi (~ 10%)
Strep and Entero (5-10%)
Late ( > 60 days)
After endothelialization
Incidence % / pt. year
Transient bacteraemia from dental, GI or GU
Microbiology
resembles native valve endocarditis

11. IE in IV Drug Abusers Right sided predilection Tricuspid Valve ~ 55%
Aortic Valve ~ 25%
Mitral Valve ~ 20%
Pulmonary Valve %
Mixed Rt. And Lt. Side 5 - 6%

12. IE in IV Drug Abusers Skin most predominant source of infection
Also contamination of drugs and paraphernalia
% of Rt. sided IE results in pneumonia and septic emboli
Microbiology
Staph aureus ~60%
Streptococci and Enterococci ~20%
Gram -ve bacilli ~10%
Fungi (Candida and Aspergillus ~5%

13. IE in adults with congenital heart disease
Common defects
VSD PDA
Bicuspid AV PS
Coarctation of Aorta
Occurs in defects with
--mild or no hemodynamic consequences
--high gradients
--high velocity jets impinging on endocardium

14. Microbiology very important since virulence of the infecting organism is a significant factor in determining the success rates of both medical and surgical treatment

15. Pathogenesis Requires interaction between › Host vascular endothelium
› Host haemostatic response
› Adventitiously circulating organisms

16. Pathogenesis of Vegetations

17. Hemodynamic factors predisposing to Infective Endocarditis
High velocity abnormal jet stream
Flow from high to low pressure chamber
Narrow orifice between two chambers creating pressure gradient

19. Pathology

20. Common sites of origin of extravalvular spread

21. Pathology Initially affects
Valve leaflets in native valve endocarditis
Can extend into annulus
Annulus in prosthetic valve endocarditis
Due to presence of sewing rim

22. Pathology - Embolic Phenomena
Incidence
Clinically %
Pathologically %
More with large mobile vegetations
Fungi (Candida and Aspergillus)
Group B and G Streptococci
Staph aureus
Result in
Infarcts
Abscesses
Mycotic aneurysms

23. Pathology Immune Complex Associated
Glomerulonephritis
Arthritis
Osler’s nodes

24. Clinical Features Onset usually within 2 weeks of infection
› Indolent course
- Malaise
- Fatigue
- Night sweats
- Anorexia
- Weight loss
› Explosive course
- CCF
- S/o severe systemic sepsis

25. Clinical features › Fever - Usually < 39 °C, remittent › Murmurs
- May be absent in
- elderly
- severe debility
- CCF
- Already on antibiotics
› Murmurs
- Appearance of new murmur or true
change in existent murmur indicates
infection with virulent organism

26. Other Clinical Features
Splenomegaly ~ 30%
Petechiae %
Conjunctivae
Buccal mucosa
palate
skin in supraclavicular regions
Osler’s Nodes %
Splinter Haemorrhages %
Roth Spots ~ 5%
Musculoskeletal (arthritis)

27. Complications Congestive Cardiac Failure (Commonest complication)
Valve Destruction
Myocarditis
Coronary artery embolism and MI
Myocardial Abscesses
Neurological Manifestations (1/3 cases)
Major embolism to MCA territory ~25%
Mycotic Aneurysms %

28. Complications Metastatic infections Rt. Sided vegetations
Lung abscesses
Pyothorax / Pyopneumothorax
Lt. Sided vegetations
Pyogenic Meningitis
Splenic Abscesses
Pyelonephritis
Osteomyelitis
Renal impairment d/t Glomerulonephritis

29. Diagnosis Blood Cultures Other Laboratory Parameters
Positive in 95% cases
Other Laboratory Parameters
Anaemia
Leucocytosis (WCC may be normal in indolent infection)
Thrombocytopenia
 ESR (may be absent in CCF and renal failure)
Urine - Microscopic hematuria / proteinuria

30. Echocardiography
Can demonstrate lesion / vegetation in % of cases
Difficult in prosthetic valve endocarditis
TOE better than TTE
Can demonstrate
Morphology of valve
Annular abscesses
Hemodynamics of the valves
Serial observations can contribute to decision for surgery

31. Treatment
Medical
Surgical

32. Principles of Medical Management
Sterilization of Vegetations with antibiotics
- prolonged Slowly metabolising bacteria
due to high density, hence  sensitivity
- high dose
Bacteria deep inside
vegetations
-bactericidal

33. Principles of Medical Management
Acute onset, fulminant
-Within two to three hours of
clinical diagnosis.
-Take cultures, but do not wait
for results
Timing of Therapy
Subacute onset, or having
received recent antibiotic
-Within two to three days Can wait for culture reports

34. Principles of Medical Management
Isolation of organisms very important
Therapy before isolation of organism
Native valve endocarditis and in IV drug abusers
Directed against Staph aureus
Prosthetic valve endocarditis
Broad spectrum antibiotics directed against
Staph aureus
Staph epidermidis
Gram –ve bacilli

35. Indications for Surgery Left sided native valve endocarditis
Valvular disruption leading to severe insufficiency and CCF
Extravalvar extension
Embolization of vegetations
Failure of medical management
Positive blood culture and systemic signs of infection after “adequate” antibiotic therapy
Resistant organisms
such as MRSA, Fungi , Pseudomonas
Echo detected vegetation > 1 cm ??

36. Indications for Surgery Right sided native valve endocarditis
Indications differ because:
- Consequences of valve disruption and emboli are less
- Success with antibiotics seems to be better
--Failure of medical treatment
--CCF, with its complications Indications (elective)
--Recurrent pulmonary emboli
with complications
--Extravalvar spread (rare)

37. Indications for surgery Prosthetic valve endocarditis
Early infection almost always require surgery
Late infection
Antibiotic therapy succeeds more often with
Bioprosthesis compared to mechanical valves
CCF due to prosthesis dysfunction
Indications Multiple emboli
Persistent infection

38. Indications for Surgery Special situations
AIDS
Not usually indicated since life expectancy due to AIDS very poor
HIV +ve patient without AIDS
IV Drug Abusers
No change in indications since enough number survive > 10 years

39. As soon as there is a major indication
When to operate ?
As soon as there is a major indication
Valid reasons for delay
Acute CNS injury
--Hemorrhagic infarct (Wait for days to allow healing)
--Coma (very poor prognosis )
Renal failure due to Glom’nephritis
Follow through the acute phase
(Prerenal failure -- early operation)

40. Principles of operation
Repair or Replacement ?
(More important with mitral valves)
Repair contemplated only if:
--Infection well controlled
--Repair structurally feasible after involved tissue excised

41. Principles of operation
Early operation once indicated
Preop. knowledge of morphology of valve
Good exposure (may be difficult in mitrals)
Excision and debridement of all infected or involved tissue even if extensive reconstruction or permanent pacing required

42. Principles of operation
Look for extravalvar extension
If present, evacuate abscess cavity and repair with biological material such as autologous or bovine pericardium
Suture valve onto clean and relatively strong tissue
Temporary pacing leads

43. Which Prosthesis? Stented Bioprosthesis Mechanical
Stentless Bioprosthesis
Homograft

44. Important factor is location of infection
Choice of prosthesis
Important factor is location of infection
-- Infection of cusps only:
Choice does not matter, since all infected tissue is usually excised
-- Perivalvar extension:
No choice between mechanical and stented bioprosthesis (both with cloth sewing rims)
Homograft, maybe stentless bioprosthesis have lesser incidence of infection

45. Choice of prosthesis Mechanical v/s Bioprosthetic
No difference in linearized rates for recurrent or residual infection (~1-2% per patient year)
No difference in operative mortality and complication free survival
Infected bioprosthesis more easily sterilized (since infection initially involves leaflets)
However, infection in bioprosthesis may hasten SVD due to damage to leaflets

46. Choice of prosthesis Homograft v/s others
Hazard function for recurrent endocarditis has only low constant phase and has no high early hazard phase like other prosthesis
Homograft best choice if valved conduit is required for root replacement ( > 50% annular dehiscence or aortoventricular discontinuity)

47. Postoperative Antibiotics
To continue for 6 weeks if
› Operated for --Acute fulminant infection
--Failure of medical therapy
--Resistant organisms
› Excised valve yields positive cultures
› Periannular involvement
› Valve culture –ve, but organisms seen on
histology
› Positive blood cultures 3 – 4 days postop.

48. Results of Treatment Native valve endocarditis Medical Management
Mortality 10 – 60 %
Risk Factors
Virulent organisms s/a MRSA, G-ve bacilli, fungi
CCF
Persistence of systemic sepsis
Major septic embolus
Extravalvar extension
Acute renal failure

49. Results of Treatment Native valve endocarditis Surgical Management
Hospital Mortality 5 – 20%
Risk factors
Virulent organisms
Perivalvar extension
Intractable CCF
Renal and multiorgan failure

50. Results of Treatment Native valve endocarditis Surgical Management
Recurrent Endocarditis ~ 2%
Most occurs within 2 months post op.
Same organism
No fresh source of infection
Perivalvar leaks 3-7%

51. Results of Treatment Prosthetic valve endocarditis Medical Management
Mortality ~ 70%
Risk factors
Valve incompetence or perivalvar leak
Early postoperative onset
Virulent organism

52. Results of Treatment Prosthetic valve endocarditis Surgical Management
Hospital Mortality 0 –22%
Risk factors
Early postoperative infection
Virulent organism
Perivalvar extension
Delay in operation

53. Results of Treatment Prosthetic valve endocarditis Surgical Management
Long term results differ from valve replacement for NVE or other lesions
Have comparatively unfavourable rates of late death, recurrence of infection and reoperation

54. Antibiotic Prophylaxis
Protocol usually followed recommended by Dajani et al in JAMA 1990
Recommended in following conditions
Prosthetic valves
Previous history of infective endocarditis (even without underlying heart disease)
Most congenital heart diseases
Rheumatic or other acquired valve disease
IHSS
MVP with MR

55. Thank you!