ESCMID 2024: Dental Procedures and Antibiotic Prevention of Infective Endocarditis: What's New?

The session delves into recent advancements in dental procedures and antibiotic prevention of infective endocarditis (IE), addressing three key aspects: current evidence, new developments and future learnings. Current evidence suggests that antibiotic prophylaxis (AP) effectively prevents IE based on animal experiments and clinical trials showing reduced bacteremia post-dental procedures. However, it's unclear if this reduction in bacteremia correlates directly with preventing endocarditis, as no randomized trials have confirmed antibiotic efficacy in preventing IE. Human observational studies have challenged the efficacy of AP, suggesting that daily activities like tooth brushing also contribute to bacteremia risk. Additionally, antibiotic overuse leads to resistance concerns. Despite this, recent database analyses support the effectiveness of AP for IE. Expert guidelines recommend AP for IE, but implementation varies. In some countries where clinical efficacy in humans hasn't been demonstrated, prophylaxis rates are lower. Prophylaxis has historically targeted oral streptococci despite S. aureus becoming a prevalent IE pathogen.

Two major new information sections highlight that despite guideline changes, the impact on the incidence of IE remains uncertain. A systematic review of 16 qualitative studies found no significant increase in the crude incidence rate of IE after guideline introduction, except in one Dutch study, which was criticized for methodological flaws. There has been a notable change in the microbiological profile of IE, with fewer oral cavity organisms and a higher rate of staphylococci. However, restricting AP to high-risk patients has not increased streptococcal IE incidence in North American populations. Another large-scale observational analysis, including a case-crossover and cohort study, revealed a higher rate of dental procedures preceding IE onset, especially tooth extraction and oral surgery. This increase was observed only in high-risk patients, and AP was associated with a significant reduction in IE incidence following invasive dental procedures. Overall, there was a 50% reduction in endocarditis risk with AP and up to a 90% reduction for dental extraction and oral surgery in high-risk patients. These findings support guidelines recommending AP for high-risk individuals undergoing invasive dental procedures but show no efficacy in patients with moderate or low risk of IE. A recent systematic review and meta-analysis examined the impact of AP on the incidence of IE following invasive dental procedures (IDP). Analyzing data from 30 studies across 8 countries with over 1 million IE cases, the study found that AP significantly reduced the risk of IE, particularly among high-risk individuals. While five sub-studies supported the protective role of AP, three did not. However, meta-analysis revealed that high-risk individuals who received AP before IDP were 60% less likely to develop IE compared to those who did not receive AP. This finding influenced the European Society of Cardiology (ESC) task force in updating guidelines for endocarditis management.

The updated guidelines on AP for IE now include expanded definitions of individuals at high risk, with a class one recommendation for prophylaxis. New additions to the at-risk list include patients with ventricular assist devices. Recommendations also concede individuals at intermediate risk, suggesting that prophylaxis might be considered on a case-by-case basis. Specific patient groups warranting consideration include those with rheumatic heart disease, non-rheumatic degenerative valve disease, congenital valve abnormalities (e.g., bicuspid aortic valve), CIEDs, and hypertrophic cardiomyopathy. Additionally, there are updated class one recommendations for AP during oro-dental procedures for patients with cardiovascular disease at increased risk of IE, building upon existing 2015 guidelines. The newer recommendations for AP in certain cardiovascular procedures advise antibiotic use for patients with ventricular assist devices and those undergoing transcatheter mitral and tricuspid valve repair. It also suggests considering antibiotics for heart transplant recipients. However, it clarifies that AP is not recommended for patients at low risk of IE, though the definition of "low risk" isn't explicitly stated. It aligns with the AHA Guidelines, indicating that this approach applies to patients neither at high nor intermediate risk for IE.

The session also discussed the risk factors and considerations for dental procedures such as extractions, oral surgeries, and those involving manipulation of the gingival or periapical areas of the teeth. The guidelines highlight that while there is no significant change in risk for dental procedures, the panel identified certain non-dental procedures that might warrant AP. The guidelines state no clear evidence linking bacteremia from non-dental procedures to subsequent IE. However, observational studies have shown that some invasive non-dental medical procedures are associated with an increased risk of IE. Therefore, the task force suggests considering AP for high-risk patients undergoing these non-dental procedures, excluding those at intermediate risk. 

Two studies examined the association between invasive procedures (IP) and IE. The Swedish study analyzed over 7,000 IE cases from 1998 to 2011, identifying several outpatient and inpatient procedures linked to increased IE risk, such as bone marrow puncture and blood transfusion. However, methodological issues were noted, including potential biases and insufficient verification of IE diagnoses. Another UK study examined over 14,000 IE hospital admissions from 2010 to 2016, revealing associations between IE and procedures like bone marrow biopsy and blood transfusion. While this study had positive methodological aspects, such as thorough record analysis, it had limitations, such as excluding procedures during IE admissions and uncertainty regarding the validity of associations found. Further investigation is warranted before definitive conclusions can be drawn.

A 2019 study highlights the potential pitfalls of relying solely on clinical coding data to estimate disease incidence trends, particularly in endocarditis cases. The study in the UK revealed that using raw admission data led to a twofold overestimation of endocarditis incidence. It emphasizes the need to validate diagnostic codes and meticulous data curation to minimize errors in health record studies. In France, experts from the French Society for Infectious Diseases, including the endocarditis study group, opted against endorsing AP for non-dental procedures as per ESC guidelines. Instead, updated guidelines recommend specific antibiotic regimens for high-risk dental procedures. Notably, the 2021 AHA and 2023 ESC guidelines exclude clindamycin due to serious infection risks, introducing newer alternatives like cephalexin, azithromycin, and clarithromycin. The revised list of recommended antibiotics emphasizes simplicity and safety, with amoxicillin for non-allergic patients and azithromycin for allergic patients.

Based on sufficient evidence, the session highlights recommended AP for high-risk endocarditis patients before and after invasive dental procedures. However, it advises against prophylaxis for intermediate or low-risk patients. Additionally, there's insufficient evidence to support AP for high-risk endocarditis patients undergoing non-dental procedures, contrary to ESC guidelines. The recommended regimen for prophylaxis is straightforward: orally administer two grams of amoxicillin within an hour before invasive dental procedures in non-allergic adult patients.

European Society of Clinical Microbiology and Infectious Diseases (ESCMID) 2024, 27th April–30th April 2024, Barcelona, Spain