When is endocarditis prophylaxis indicated?

Endocarditis prophylaxis is indicated primarily for patients who have prosthetic heart valves. This is because individuals with prosthetic valves are at significantly increased risk of developing infective endocarditis upon exposure to bacteremia, such as may occur during invasive procedures. Prophylactic antibiotics help to prevent potential bacterial colonization of the prosthetic material, which can lead to serious complications.

In cases of unrepaired atrial septal defects, endocarditis prophylaxis is generally not recommended because the defects typically do not pose the same risk as prosthetic materials. Mitral valve prolapse without a murmur also does not require prophylaxis, as the risk of developing endocarditis in these patients is low. Similarly, while aortic stenosis can lead to increased risk of endocarditis, the standard guidelines typically focus on structural abnormalities and prosthetic devices, so prophylaxis is not routinely indicated for aortic stenosis alone. Therefore, the presence of a prosthetic valve remains the most established and clinically acknowledged indication for endocarditis prophylaxis.