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Review: Diagnosis and Management of Infective Endocarditis in People Who Inject Drugs

Key findings

  • An understudied consequence of the opioid epidemic has been a precipitous increase in the incidence of drug use–associated infective endocarditis (DUA-IE)
  • In this review, a multidisciplinary group of physicians at Massachusetts General Hospital discuss what's known about optimal management of this condition
  • Parenteral antibiotics are the standard medical therapy for DUA-IE, but interactions with medications for opioid use disorder, antidepressants, and antipsychotics are important considerations
  • The limited evidence base leaves physicians in the realm of expert opinion, especially about indications for surgery and choice of prosthesis
  • DUA-IE is best managed with a multidisciplinary approach that includes treatment of substance use disorder; decisions that involve consideration of medical futility versus utility may require consultation with a hospital ethics committee

Drug overdoses are getting most of the attention during the U.S. opioid epidemic, but the increased rate of drug use–associated infective endocarditis (DUA-IE) also deserves attention. The proportion of hospital admissions for DUA-IE nearly doubled between 2005 to 2016, and the most marked rise was among patients ages 15 to 34 years old.

In the Journal of the American College of CardiologyThoralf Sundt, MD, chief of the Cardiac Surgery Division and co-director of the Corrigan Minehan Heart Center at Massachusetts General Hospital, Evin Yucel, MD, a noninvasive cardiologist at the center, and colleagues recently reviewed the state-of-the-art management of patients with DUA-IE.

This extensive review discusses the epidemiology, microbiology, and outcomes of DUA-IE; diagnosis; medical and surgical treatment along with percutaneous mechanical aspiration as an alternative to surgery; nuanced care for people who inject drugs that includes principles of trauma-informed care, and what cardiologists should know about substance use disorder.

Medical Treatment

Although oral antibiotics may be the agent of choice in certain circumstances, parenteral antibiotics are the standard therapy for DUA-IE. Patients with IE often receive six weeks of antibiotics, but guidelines support an abbreviated course for certain scenarios of right-sided IE, which is more common in DUA-IE.

It's not uncommon for patients with DUA-IE to want to leave the hospital early, and there are perceived risks of discharging these patients to a home setting with an indwelling line. However, several recent studies have shown people who inject drugs can successfully complete parenteral antimicrobial therapy as part of routine outpatient care.

Medication interactions are an important consideration:

  • Concurrent use of rifampin with either buprenorphine or methadone may lead to reduced levels of the latter agents, thus requiring higher doses of these medications for opioid use disorder
  • Linezolid increases the risk of serotonin syndrome in the setting of opioid use
  • Administration of fluoroquinolone or azoles can cause QTc prolongation, as can several classes of antidepressants and antipsychotics when used in combination with methadone

Initial Surgery

A recent meta-analysis published in BMC Infectious Diseases examined long-term outcomes of cardiac surgery for DUA-IE. It concluded people who inject drugs are at 47% greater risk of death and more than twice the hazard of reoperation compared with the general population, with 40% mortality five years after surgery.

Active endocarditis, emergency intervention, dialysis, liver disease, enterococcal infections, lung disease, prosthetic valve endocarditis, aortic valve disease, and multivalve disease are predictors of increased short-term mortality after surgery for DUA-IE. A paper in the Journal of Cardiac Surgery presents the STOP score, a tool for predicting operative morbidity and mortality in individual patients with DUA-IE.

The 2015 American Heart Association (AHA) guidelines on managing IE (published in Circulation) suggest avoiding surgery in people who inject drugs because of the risk of prosthetic infection. The 2020 joint guidelines of the American College of Cardiology (ACC) and AHA on valvular heart disease (published in JACC) provide only limited guidance. They do say valve repair is preferable to valve replacement when feasible (as is usually the case in younger patients).

When valve replacement is necessary, although the guidelines suggest mechanical valves, patients with DUA-IE often cope with adverse social circumstances, so compliance with an anticoagulation regimen can be challenging. Therefore in practice, bioprosthetic valves are commonly implanted in this patient population.

Reoperation

For patients with recurrent IE who are continuing to inject drugs, there are no absolute contraindications to surgery. As part of decision-making about reoperation, the ACC/AHA guidelines include a Class I recommendation to consult with experts in addiction medicine about the patient's long-term ability to refrain from drug use.

Decisions that involve consideration of medical futility versus utility are often challenging, especially when patients with recurrent DUA-IE have already received prosthetic valves or multiple reoperations. Engaging the hospital ethics committee may be helpful.

Multidisciplinary Care Is Crucial

A multidisciplinary team can help address bias and facilitate the provision of equitable, individualized care for DUA-IE. Such a team ideally includes experts in cardiology, cardiac surgery, addiction medicine, infectious diseases, case management, social work, and psychiatry. Multiple institutions, including Mass General, now use this model.

The team should provide patients with appropriate social, psychological, and financial support as early as possible.

Learn more about the Division of Cardiac Surgery

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