The following are key points to remember from an American Heart Association (AHA) Science Advisory on nondental invasive procedures and risk of infective endocarditis (IE):

1. There are no published prospective, randomized clinical trials that have either established an association between invasive dental or nondental invasive procedures (NDIP) and the risk of subsequent IE, or defined the safety and efficacy of antibiotic prophylaxis in the prevention of IE following an invasive procedure.
2. In the past, the AHA/American College of Cardiology (ACC), European Society of Cardiology (ESC), and British Society for Antimicrobial Therapy guidelines recommended the use of antibiotic prophylaxis among patients at increased risk of IE before both dental procedures and NDIPs. However, a major shift in recommendations began with the 2007 AHA/ACC guidance, the 2009 ESC guidance, and the United Kingdom 2008 National Institute for Health Care Excellence (NICE) guidance; with limited or no recommendations for the use of antibiotic prophylaxis before NDIPs.
3. Two relatively recently published nationwide case-crossover studies respectively from Sweden and England found an association between several NDIPs and the risk of IE among high-risk patients.
   • The study by Janszky, et al., (J Am Coll Cardiol 2018;71:2744-52) found that an invasive procedure was more likely in the 7,013 patients with IE during the case period (12 weeks) before developing IE than in the control period (1 year before). Increased risk was associated with therapeutic procedures involving the skin, various operations, and blood transfusions; and diagnostic procedures including bone marrow puncture, coronary angiography, and some endoscopies including bronchoscopy. Risk differences were greatest in patients at high risk of IE.
   • The study by Thornhill, et al., (Heart 2022;109:223-31) similarly found that the incidence of an invasive procedure was significantly higher in the case period (3 months) preceding IE compared to the control period (the preceding 12 months). NDIPs associated with increased risk included cardiac implantable electronic device (CIED) procedures, upper and lower gastrointestinal endoscopy, bone marrow biopsy, blood transfusion, and bronchoscopy. Again, risks were much greater among patients at high risk of IE.
4. The use of a case-crossover design in these two studies enhanced the control of potential confounders and comorbidities, the use of nationwide cohorts eliminated concerns about adequate sample size, and mandatory registration of admissions and invasive procedures prevented self-selection and recall biases. These two studies therefore stand in contrast to six previously published studies (one cohort, five case-control) that also addressed the potential risk of IE after NDIPs but with more methodological limitations.
5. The authors of this AHA Science Advisory propose that there is sufficient evidence associating certain NDIPs with the subsequent occurrence of IE, particularly among patients at high risk, to warrant re-evaluation of advice regarding IE prevention in NDIPs.
6. The authors note that implications in clinical practice might be:
   • Education of clinicians performing NDIPs of the potential risks among patients with a high risk of IE, with possible goals of increased attention to sterility and infection prevention, and possible augmented or supplemental methods to prevent surgical site infection among patients in whom antibiotics already are routinely prescribed.
   • Education of primary and secondary care physicians regarding the possibility of IE among patients at high risk who undergo a NDIP with the goal of enhancing the early diagnosis and treatment of IE.

Clinical Topics: Valvular Heart Disease

Keywords: Antibiotic Prophylaxis, Endocarditis, Bacterial, Heart Valve Diseases

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