Prevention of infective endocarditis

Which of the following patient groups is NOT thought to be at increased risk of

infective endocarditis and therefore does NOT require prophylaxis against infective

endocarditis when undergoing an interventional procedure?

a) Moderate mitral regurgitation

b) A patient with a history of previous endocarditis but a structurally normal heart

c) Isolated atrial septal defect

d) Hypertrophic cardiomyopathy

e) Pulmonary stenosis

Answer: c

Explanation:

Infective endocarditis (IE) is a rare condition with significant morbidity and mortality.

Until relatively recently, in an attempt to prevent this disease, at-risk patients were

given antibiotic prophylaxis before dental and certain non-dental interventional procedures.

This status quo was challenged for a number of reasons including the lack of

efficacy of antibiotic prophylaxis regimes, the lack of association between episodes of

IE and prior interventional procedures, and the prevalence of bacteraemias arising from

everyday activities such as brushing teeth. As a result, in 2008 the National Institute for

Health and Clinical Excellence (NICE) produced new guidelines on the prevention of

IE. 

These guidelines identified patients at risk of IE. This included those with valve

replacement, acquired valvular heart disease with stenosis or regurgitation, structural

congenital heart disease (including surgically corrected or palliated structural conditions

but excluding isolated atrial septal defects, fully repaired ventricular septal

defects, fully repaired patent ductus arteriosus and closure devices that are considered to

have epithelialised), hypertrophic cardiomyopathy or a previous episode of IE. The

guidelines also stated that prophylaxis against IE should not, routinely, be offered to

people undergoing dental procedures and those undergoing non-dental procedures

at the following sites: upper and lower gastrointestinal (GI) tract, genitourinary (GU)

tract (including childbirth) and the upper and lower respiratory tract unless they fall

into the ‘at-risk’ group for IE. The antibiotic given to an ‘at-risk’ patient receiving

antimicrobial therapy because they are undergoing a GI or GU procedure at a site

where there is suspected infection should be broad enough to include those organisms

known to cause IE.

Reference

NICE Clinical Guideline 64. Prophylaxis against infective endocarditis: antimicrobial

prophylaxis against infective endocarditis in adults and children undergoing interventional

procedures. London: NICE, 2008. Online at www.nice.org.uk/nicemedia/pdf/

CG64NICEguidance.pdf (Accessed 30 October 2009)