Infective Endocarditis in Bicuspid Aortic Valve or Mitral Valve Prolapse Patients

Study Questions:

What are the clinical and microbiological features of infective endocarditis (IE) among patients with bicuspid aortic valve (BAV) or mitral valve prolapse (MVP), and how do they compare with those of IE among patients with and without a guideline indication for IE antibiotic prophylaxis?


This analysis involved 3,208 consecutive patients with IE prospectively included in the GAMES (Grupo de Apoyo al Manejo de la Endocarditis infecciosa en España) registry at 31 Spanish hospitals. Patients were classified as high-risk IE with IE antibiotic prophylaxis (IEAP) indication (high-risk group; n = 1,226), low- and moderate-risk IE without IEAP indication (low/moderate-risk group; n = 1,839), and IE with BAV (n = 54) or MVP (n = 89).


BAV and MVP patients had a higher incidence of viridans group streptococci IE than did the high-risk and low/moderate-risk group patients (35.2% and 39.3% vs. 12.1% and 15.0%, respectively; all p < 0.01). A similar pattern was seen for IE from suspected odontologic origin (14.8% and 18.0% vs. 5.8% and 6.0%; all p < 0.01). BAV and MVP patients had more intracardiac complications than did patients in the low/moderate-risk group (50% and 47.2% vs. 30.6%, both p < 0.01), and had similar rates of cardiac complications to high-risk group patients.


Compared to other patients with IE, IE among patients with BAV and MVP more often was associated with viridans group streptococci and IE from suspected odontologic origin, and complications were similar to those among high-risk IE patients. The authors concluded that these findings suggest that BAV and MVP should be classified as high-risk IE conditions, and the use of IE antibiotic prophylaxis should be reconsidered.


Current guidelines recommend the use of antibiotic prophylaxis to reduce the risk of IE only among patients thought to be at especially high risk of adverse outcomes associated with IE, and notably do not include patients with known BAV or MVP. However, debate regarding the guideline recommendations continues. Supporting a more restrictive use of IE prophylaxis are data suggesting that, even if overall rates of IE are increasing, culprit microorganisms often are Staphylococcal species that would not be affected by typical antibiotic prophylaxis regimens. However, data from this large multicenter registry suggest that, among patients with known native heart valve diseases of BAV or MVP, viridans group streptococci (which would be affected by antibiotic prophylaxis) play an important role. Further, this study offers data suggesting that patients with BAV or MVP are at high risk of adverse clinical outcomes. In the absence of prospective randomized data, there remains a rationale to discuss antibiotic prophylaxis for IE risk reduction with patients with significant native heart valve disease, including BAV or MVP.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Cardiac Surgery and VHD, Interventions and Structural Heart Disease

Keywords: Antibiotic Prophylaxis, Cardiac Surgical Procedures, Endocarditis, Endocarditis, Bacterial, Heart Valve Diseases, Mitral Valve Prolapse, Risk Reduction Behavior, Staphylococcus, Viridans Streptococci

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