Infective Endocarditis Prophylaxis'' Where are we now

1
Infective Endocarditis Prophylaxis.. Where are
we now?

• Dr. Claire Healy

31st March 2009
2
Infective endocarditis

• Infection of endocardium
• acute
• subacute
• chronic
• Annual incidence 1.7 6.2 per 100,000 cases

3

• Occurs on
• Defective valves
• Prosthetic valves
• Congenital heart defects e.g.
• Ventricular septal defect
• Patent ductus arteriosus
• Normal valves
• 40 with IE have
• Normal heart
• Undiagnosed defect

4
Turbulent blood flow traumatises endothelium
Nonbacterial thrombotic endocarditis
Bacteraemia
Further deposition of fibrin and platelets
Underwood 2004
5
Causative organisms

• Streptococcus Viridans (50)
• e.g. S. mutans, S. sanguis
• Enterococcus faecalis
• Staphylococcus aureus
• More uncommonly other bacteria, fungi

6
Pathology

• Vegetations along valve edges
• mass of fibrin, platelets and infectious
  organisms
• MV gt AV gt TV

7
Clinical Features

• Malaise, fever, night sweats, weight loss,
  anaemia
• Valve destruction ? heart failure
• ? new/changing
  murmurs
• Embolic events ? abscesses in brain, liver
• Immune complex deposition ? vasculitis
• 
  ? arthralgia
• 
  ? glomerulonephritis
  

8
Investigations

• Normochromic normocytic anaemia
• ? WCC white cell count
• ? ESR erythrocyte sedimentation rate
• Blood cultures repeated samples
• Echocardiography

9
Mortality

• Fatal if untreated
• 6 sensitive streptococci
• 30 Staph. aureus

10
Management

• IV antibiotics 2/52
• (benzylpenicillin and gentamicin before results)
• Oral antibiotics 2-4/52

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Dental treatment and infective endocarditis

• Is there a link?

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MAYBE.

• Viridans group part of normal oral flora
• Antibiotic prophylaxis prevents viridans group
  experimental endocarditis in animals
• In some cases temporal relationship between IE
  development and dental treatment.

13
BUT..

• Activities of daily living, e.g. eating,
  toothbrushing, flossing, produce bacteraemia
• Magnitude of bacteraemia after dental procedures,
  toothbrushing etc. less than that necessary to
  produce IE in experimental animals
• Contradictory studies on effect of antibiotic
  prophylaxis on level of bacteraemia after dental
  procedures

14
Bacteraemia

• How often they occur?
• Magnitude?
• Duration?

15
Frequency of bacteraemia
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Magnitude of bacteraemia
17
Duration

• Most positive blood cultures were within 10 mins
  after extraction
• Only a small no. of positive blood cultures
  between 30-60 mins

18
Cumulative risk

• Cumulative exposure of 5370 minutes of
  bacteraemia over 1 month in dentate patients from
  chewing food, toothbrushing, flossing
• 6-30 minutes with single extraction
• Gunteroth 1984 Am J Cardiol 54797-801

19

• Toothbrushing twice daily for 1 year has a 154
  000 greater risk of producing bacteraemia than a
  single extraction
• Roberts GJ 1999 Pediatr Cardiol 20317-325
• Dentists are innocent!

20
Role of oral hygiene

• Available evidence supports importance of good OH
  in preventing IE
• Patients with poor OH have similar levels of
  bacteraemia before extraction as after extraction

21
Dental procedures

• Old guidelines cover bleeding-prone procedures
• No data to support visible bleeding during dental
  treatment as a predictor of bacteraemia
• No evidence base to decide what procedures might
  require prophylaxis

22
Effect of antibiotics on bacteraemia

• Controversial
• Recent studies suggest amoxycillin may reduce
  frequency and duration of bacteraemia but does
  not eliminate it
• No evidence that any reduction reduces risk of IE

23
Effect of chlorhexidine on bacteraemia

• Most of evidence suggests no clear benefit

24
Clinical studies

• 1. 2 year case control study
• The Netherlands
• Compared IE cases with controls with matched
  cardiac defect
• Both groups had similar dental treatments in
  preceding 180 days
• 5/25 cases who developed IE within 30 days of
  dental treatment did so despite adequate
  prophylaxis
• Van der Meer 1992 Lancet

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• 2. Multicentre case-control study
• - US study
• - Controls without IE were more likely to have
  undergone dental procedure than cases of IE
• Strom 1998 Ann Intern Med

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Temporal association between IE and dental
procedure

• Many reviews and case reports included cases with
  dental treatment up to 6 months prior to IE
• Time frame between bacteraemia and IE estimated
  at
• 78 within 7 days
• 85 within 14 days

27
Previous prophylaxis regimes

• Expert consensus opinion
• Poor evidence base!

28
Problem

• No Randomised Placebo-Controlled Double- Blind
  Trial
• Ethical considerations
• Large numbers required 6000 patients

29
Concerns with antibiotic use

• Hypersensitivity reactions
• Anaphylactic deaths gt IE deaths?
• Fatal anaphylactic reactions in 15-25/106 who
  receive dose of penicillin
• Of those with prior penicillin use, 1/3 previous
  allergy, 2/3 no previous allergy
• AHA not aware of any case of fatal anaphylaxis in
  previous 50 years

30
Concerns with antibiotic use

• Resistance
• Widespread use promotes emergence of resistant
  viridans group strep and enterococci
• Results in decreased efficacy of treatments for
  IE
• Cost

31

• PROPHYLAXIS??
• IF AND WHEN

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Prophylaxis when?

• A number of revised guidelines have recently been
  produced
• BSAC (2006)
• AHA (2007)
• NICE (2008)
• Australian (2008)

33
What are guidelines?

• Clinical guidelines are recommendations on the
  appropriate treatment and care of people with
  specific diseases and conditions.
• They are based on best available evidence

34

• Stassen L, Rahman N, Rogers S, Ryan D, Healy C,
  Flint S. Infective endocarditis prophylaxis and
  the current AHA, BSAC, NICE and Australian
  guidelines.
• Journal of the Irish Dental Association 2008
  54264-270

35
NICE

• National Institute for Clinical Excellence
  independent UK organisation that assesses
  clinical and cost-effectiveness evidence and
  produces guidelines on healthcare issues
• 2008 guidelines
• No prophylaxis indicated

36
AHA

• Prophylaxis for those with worst outcome if
  develop IE
• e.g. prosthetic valve viridans strep endocarditis
  mortality 20
• native valve viridans strep endocarditis
  mortality 5

37
WHO?

• Prosthetic heart valve
• Previous infective endocarditis
• Cardiac transplant recipients who develop cardiac
  valvulopathy
• Certain congenital heart disease

38
WHO?

• Certain congenital heart disease
• Unrepaired cyanotic CHD (includes palliative
  shunts and conduits)
• Completely repaired congenital heart defect with
  prosthetic material or device within 1st 6 months
  of procedure
• Repaired CHD with residual defect at /adjacent to
  site of a prosthetic patch / device

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WHEN?

• All dental procedures that involve manipulation
  of gingival tissue or the periapical region of
  teeth or perforation of the oral mucosa,
• e.g.
• Extraction
• Periodontal probing, scaling, root planing and
  surgery
• Biopsy
• Suture removal
• Subgingival restorations
• Orthodontic band placement

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WHEN NOT?

• LA through non-infected tissues
• Dental radiographs
• Placement of removable appliances
• Placement of orthodontic brackets
• Shedding of primary teeth
• Trauma to lips/oral mucosa

41
WHAT?

• BSAC guidelines
• One hour pre-op (gt10 years)
• Amoxycillin 3g po
• If penicillin allergic, clindamycin 600mg po
• Allergic to penicillin and unable to swallow
  capsules, azithromycin 500mg po
• Alternatively intravenous options
• Pre-operative chlorhexidine (0.2) mouthrinse

42
Prophylaxis

• Appropriate prophylaxis for appropriate
  treatments
• Check for drug allergy
• Check for antibiotic treatment in last 4 weeks
  no antibiotic prescribed more than twice in 1
  month
• 0.2 chlorhexidine MW 5 mins before procedure
• If patient is on Warfarin, antibiotics may
  interfere with INR

43
Amoxycillin

• Drug of 1st choice
• Well absorbed from GIT
• High serum concentrations
• Few side-effects
• BUT increasing resistance to penicillin
• in viridans streptococci

44
Treatment planning

• When prophylaxis required maximise treatment
  carried out long treatment sessions

45
Treatment plan

• Non-allergic
• Week 1 amoxycillin
• Week 3 clindamycin
• Week 5 amoxycillin
• Week 7 clindamycin

46
Treatment plan

• Allergic to penicillin
• Week 1 clindamycin
• Week 3 clindamycin
• Wait 4 weeks
• Week 7 clindamycin

47
Prevention

• ..an underemphasis on maintenance of good oral
  hygiene and access to routine dental care, which
  are likely more important in reducing the
  lifetime risk of IE than the administration of
  antibiotic prophylaxis for a dental
  procedure AHA 2007
• oral hygiene
• diet advice
• fluoride

48
Benefits of new guidelines

• Simplified and greater clarity than old
  guidelines
• Fewer patients require antibiotic prophylaxis
• Will stimulate prospective studies on assocation
  between IE and dental treatment and allow
  development of further evidence-based guidelines
• Reduce litigation

49

• Studies necessary to establish effect of new
  guidelines on incidence of IE
• IE uncommon, so may be years before effect seen

50
Irish Situation

• No chief dental officer
• OLCHC AHA
• DDSH in process of adopting AHA/BSAC guidelines
• CDSH initially NICE, have now changed to AHA/BSAC

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Irish attitudes to guidelines

• NICE guideline on antibiotic prophylaxis against
  infective endocarditis attitudes to the
  guideline and implications for dental practice in
  Ireland
• Ní Riordáin and McCreary BDJ (2009) 206E11
• Postal survey of dentists, cardiologists and
  patients who have previously required prophylaxis.

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Dentists (290/500 responders)

• Current guidelines followed
• 78 used BSAC
• 17 used AHA
• 1 used NICE
• Intention to implement NICE
• Immediate implementation 17
• Required clearance from cardiologist/GMP 59
• Required guidance from official body 19

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Cardiologists (20/54 responders)

• 70 followed AHA5 followed NICE
• 75 happy for GDP to implement change without
  consultation

54
Dental patients (34/50 responders)

• 2/3 concerned re NICE guidelines
• Only 9 happy for GDP to implement them
• 79 required verbal/written confirmation from
  cardiologist

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In conclusion

• Considerable changes have occurred in prophylaxis
  guidelines
• Resistance to change expected
• Changes will facilitate development of new
  evidence based guidelines