NICE states that the following cardiac conditions put patients at higher risk of IE:

• Previous IE
• Valve replacement 
• Acquired valvular stenosis / regurgitation 
• Hypertrophic cardiomyopathy
• Congenital structural heart diseaseESC defines structural heart disease as an abnormality in the heart structure - valve / wall / chamber / great vessel. Note that coronary artery disease itself does not fall under the category of structural heart disease. Common congenital structural heart diseases: ⦁ ASD ⦁ VSD ⦁ Tetralogy of Fallot ⦁ Bicuspid aortic valve

Selected points from NICE, ESC, AHA guidelines to prevent IE:

• Maintain good oral hygiene
• Avoid non-essential invasive procedures (e.g. skin piercing, tattooing)
• Avoid IVDUIntravenous drug use
• Patient education

Antibiotic prophylaxis is NOT recommended routinely.

NICE specifically states that in the following scenarios, routine antibiotic prophylaxis against IE is not recommended:

• Dental procedures
  • Chlorhexidine mouthwash shouldn’t be offered as prophylaxis for dental procedures
• Non-dental procedures at the following sites:
  • Upper and lower GI tract
  • Upper and lower respiratory tract (including ENT procedures and bronchoscopy)
  • Genitourinary tract (including urological, O&G procedures, childbirth)

NICE acknowledges that the evidence reviews for this guideline covered only procedures at the sites listed in this recommendation. Procedures at other sites are outside the scope of the guideline.

NICE recommends that if a person is at risk of IE and is receiving antimicrobial therapy due to a GIGastrointestinal /GU procedure for suspected infection → give antibiotics that cover IE organisms. 

BNF recommends antibiotic therapy depending on native or prosthetic valve IE:

• Native valve
  • 1^st line: amoxicillin / ampicillin +/- gentamicin
  • Penicillin allergic / MRSA suspected / severe sepsis: vancomycin + gentamicin
  •  Severe sepsis with RF for gram -ve infection: vancomycin + meropenem
• Prosthetic valve
  • 1^st line: vancomycin + rifampicin + gentamicin (low-dose)

Duration of antibiotic therapy: generally 4-6 weeks
 

Organism	1st line antibiotic	MRSA / penicillin allergic
Staphylococci	Native valve → flucloxacillin	Native valve → vancomycin + rifampicin
	Prosthetic valve → flucloxacillin + rifampicin + gentamicin	Prosthetic valve → vancomycin + rifampicin + gentamicin
Streptococci	Benzypenicillin	Vancomycin / teicoplanin + gentamicin
Enterococci	Amoxicillin / ampicillin + gentamicin / benzylpenicillin	Vancomycin / teicoplanin + gentamicin
HACEK microorganisms Gram -ve organisms that are typically oropharyngeal commensals ⦁ Haemophilus species ⦁ Aggregatibacter actinomycetemcomitans ⦁ Cardiobacterium hominis ⦁ Eikenella corrodens ⦁ Kingella kingae	Amoxicillin / ampicillin + gentamicin	Ceftriaxone / cefotaxime + gentamicin