Endocarditis Postsurgical Risk Higher in Drug Addicts

Injection drug users who undergo surgery for infective endocarditis (IE) have a 10 times higher risk of reoperation or death following surgery compared to those who do not, according to a new study.

Researchers at the Cleveland Clinic (CC; OH, USA) conducted a study to evaluate the effect of active ongoing injection drug use (IDU) on outcomes after operation for IE. Of the 536 IE patients identified from the CC Infective Endocarditis and Cardiovascular Information registries surgically treated at the CC during the five-year study period, 41 (8%) were actively injected drugs. The primary outcome of the study was death or reoperation for IE.

The results showed that patients who injected drugs had poorer survival free of reoperation, with the risk of events varied with time; 90–180 days after surgery, injection drug abusers had 10 times the risk of death or reoperation for IE than the patients who did not inject drugs. Before or after that time, all patients appeared to have similar risk for death or reoperation. They also found that while in IDU-patients reoperation and death contributed equally to outcome, reoperation for IE was far less common among those that did not abuse drugs. The study was published in the September 2015 issue of the Annals of Thoracic Surgery.

“Injecting drugs into the bloodstream carries with it the potential for inadvertently introducing microorganisms which can settle on heart valves and cause IE,” said lead author Nabin Shrestha, MD, MPH. “Our hope is that this study can help patients with IDU and their doctors understand the magnitude of risk for endocarditis relapse during this time period and convince policy makers that IE treatment without adequately addressing the underlying addiction prevents achieving outcomes that should otherwise be attainable.”

IE is defined as an infection of the endocardial surface of the heart, which may include one or more heart valves, the mural endocardium, or a septal defect. Intracardiac effects include severe valvular insufficiency, which may lead to intractable congestive heart failure (CHF) and myocardial abscesses. Historically, the main risk factor for IE was rheumatic heart disease, but recent research has shown that other risk factors have gained prominence, such as IDU, prosthetic valve infection, degenerative valvular disease, and hemodialysis.

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