Prophylaxis against infective endocarditis: summary of NICE guidance

The National Institute of Clinical Evidence (NICE) in the UK has recently published guidelines on the use of antibiotic prophylaxis for the prevention of infective endocarditis (IE) in patients predisposed to the condition because of structural heart disease(1). The guidelines no longer recommend their use during dental and other invasive procedures of the respiratory tract, genitourinary and upper and lower gastrointestinal tract, a significant change from current practice. The guidelines apply to all high risk patients, even those with prosthetic valve replacements, congenital heart disease and previously treated IE. In particular the guidelines point out the lack of high quality evidence linking such procedures to IE and their prevention by antibiotics. Other recently published guidelines, for example by the American Heart Association(2), have also highlighted the absence of an adequate evidence base but have stopped short of recommending such a change to current practice. This undoubtedly raises questions and anxiety amongst patients used to taking antibiotic prophylaxis and those involved in the treatment of IE.

The report highlights reactions to antibiotics (including anaphylaxis) as an argument against their use on a population scale. However the Cardiologist in outpatients’ clinic is able to ask the individual patient about previous antibiotic use and reactions, making the argument less relevant in practice.

Unlike most areas where NICE issues guidance, there are no randomised control trials on antibiotic prophylaxis for IE and those studies that exist are small, observational and case-controlled. Although there is inconclusive evidence in favour of antibiotic prophylaxis in this area, the statistical power of such studies is poor and false negative results are a possibility. One could view the change in guidelines as an excellent opportunity to see if the incidence of IE does indeed change with their introduction. However, IE is not a notifiable disease in the UK and we are unaware of any current system in place that could accurately detect a rise in incidence on a national level corrected to the use of antibiotic prophylaxis in individual cases.

IE is a serious, life threatening condition often requiring many weeks of intravenous antibiotics, the possibility of open-heart surgery and prolonged inpatient stays with an overall mortality rate estimated at around 20%(1). Regardless of opinion on the sparse and inconclusive evidence for, as well as against the use of antibiotic prophylaxis, we would call for a system that can robustly assess the outcome of such a substantial change in practice to be in place alongside their implementation given the potential for lives to be lost.

Dr Neil Herring
Clinical Lecturer in Cardiovascular Medicine, Oxford University Specialist Registrar in Cardiology, Northampton General Hospital

Dr David C. Sprigings
Consultant Cardiologist, Northampton General Hospital

Conflicts of interest: none declared

References:

1. http://www.nice.org.uk/guidance/index.jsp?action=byID&o=11938

2. Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL, Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns JC, Ferrieri P, Gardner T, Goff D, Durack DT. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2007, 116(15):1736-54.

Competing interests: None declared