What is the risk period for prosthetic valve endocarditis after valve replacement, specifically the time frame during which the risk is highest?

From the Guidelines

The risk of prosthetic valve endocarditis is highest in the first 3-6 months after prosthetic valve implantation. This initial period represents the time of greatest vulnerability as the prosthetic material becomes incorporated into the surrounding tissue. During this time, the surgical wound is still healing, and the prosthetic valve material has not yet been fully endothelialized, leaving exposed surfaces that can serve as attachment sites for circulating bacteria. Blood-borne pathogens can more easily adhere to these non-endothelialized surfaces of the prosthetic valve, leading to infection.

Key Points to Consider

• The risk of prosthetic valve endocarditis remains relatively constant after the initial 3-6 months, but the first year is still a critical period for monitoring and prevention 1.
• Antibiotic prophylaxis is recommended for patients with prosthetic cardiac valves, including transcatheter-implanted prostheses and homografts, before dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa 1.
• Patients with prosthetic material used for cardiac valve repair, such as annuloplasty rings and chords, are also at risk of developing infective endocarditis, although the risk is lower than that of prosthetic valves 1.
• The 2017 AHA/ACC guidelines recommend prophylaxis against infective endocarditis for patients with prosthetic cardiac valves, including transcatheter-implanted prostheses and homografts, before dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa 1.

Prevention and Monitoring

• Patients with prosthetic valves should establish and maintain the best possible oral health to reduce potential sources of bacterial seeding 1.
• Regular professional dental care and the use of appropriate dental products, such as manual, powered, and ultrasonic toothbrushes; dental floss; and other plaque-removal devices, can help maintain optimal oral health 1.
• Careful monitoring during the first year post-valve replacement is essential to detect any signs of infective endocarditis early, as the risk of adverse outcomes is high in this population 1.

From the Research

Risk Period for Prosthetic Valve Endocarditis

The risk period for prosthetic valve endocarditis after valve replacement is a critical consideration for patient care and management. According to various studies, the risk of prosthetic valve endocarditis is highest during the early period after surgery.

Early Onset Prosthetic Valve Endocarditis

• Early onset prosthetic valve endocarditis is defined as endocarditis occurring within 12 months after valve replacement 2, 3.
• The incidence of early onset prosthetic valve endocarditis peaks at around 5 weeks and levels off to a stable rate by 12 months, with a cumulative risk of 3% at that time 4.
• Staphylococcal species, such as S. epidermis and S. aureus, are the dominant microbial causes of early prosthetic valve endocarditis 4.
• Risk factors for early onset prosthetic valve endocarditis include the use of multiple cryoprecipitate or plasma units during surgery, bloodstream infection, pneumonia, and the presence of a central line or dialysis catheter in the postoperative period 3.

Late Onset Prosthetic Valve Endocarditis

• Late onset prosthetic valve endocarditis is defined as endocarditis occurring more than 12 months after valve replacement 2.
• The clinical characteristics and outcomes of late onset prosthetic valve endocarditis differ from those of early onset prosthetic valve endocarditis, with a higher incidence of mitral valve involvement and Streptococcus spp. infections 2.
• The long-term mortality rate is higher for late onset prosthetic valve endocarditis, with a 10-year mortality rate of 85.1% compared to 40.3% for early onset prosthetic valve endocarditis 2.

Time Frame of Highest Risk

• The time frame during which the risk of prosthetic valve endocarditis is highest is within the first year after surgery, with the majority of cases occurring within the first 12 months 5, 2, 4.
• The risk of death, reinfection, and reoperation is significant within the first year after surgery for aortic prosthetic valve endocarditis, with a cumulative incidence of 19.0% at 30 days and 36.2% at 1 year 5.