Infective endocarditis risk increased after many types of medical procedures

The findings could warrant reconsideration of prophylactic antibiotics for some patients, according to the study authors, who also called for assessment of the costs and benefits of elective procedures for patients at high risk of endocarditis.

A new study found evidence of an association between several medical procedures and the development of infective endocarditis.

The study included all adult patients treated for endocarditis at hospitals in Sweden between Jan. 1, 1998, and Dec. 31, 2011, for a total of 7,013 cases of infective endocarditis. Using a case-crossover design, the authors compared invasive medical procedures in the 12 weeks before patients developed endocarditis with a corresponding 12-week period in the same patients exactly one year earlier. Results were published by the Journal of the American College of Cardiology on June 11.

A significantly increased risk for infective endocarditis was found after certain cardiovascular procedures (particularly coronary artery bypass grafting), procedures involving the skin and management of wounds, transfusion, dialysis, bone marrow puncture, and some endoscopies (particularly bronchoscopy). This large study “suggests that several invasive nondental medical procedures are associated with a markedly increased risk for infective endocarditis,” the authors concluded.

The authors noted that the use of prophylactic antibiotics before procedures has been discouraged in recent years. They calculated that, based on the study, 476 patients undergoing high-risk medical procedures would need to receive antibiotics to prevent one case of infective endocarditis. If prophylactic antibiotics were more narrowly targeted at particularly high-risk procedures, the number needed to treat could be lower (83 for bronchoscopy, for example). These calculations are based on antibiotics providing perfect protection against infective endocarditis and so would not be entirely accurate in real-world practice, the authors cautioned.

The study results could also encourage improvement of aseptic measures before and during procedures, consideration of the costs and benefits of elective procedures for patients at high risk, and earlier identification of infective endocarditis after procedures, the study authors said.

An accompanying editorial comment cautioned that observational data do not prove causality but agreed that the study “reopens the debate on the role of invasive medical procedures as a trigger for infective endocarditis.” The editorialists recommended a response focused on infection avoidance. “At least for those procedures where sterility should be easy to achieve and maintain, the solution is more likely to lay with improved sterile technique, infection control procedures and identifying systematic approaches for reducing health care-associated bacteremia rather than necessarily advocating antibiotic prophylaxis,” they wrote.