If one were to ask what lies within the heart of a person suffering from opioid addiction, a bacterial infection most likely isn’t the first answer that would come to mind. Infective Endocarditis (IE) is an infection of the heart valve and is one of several infectious diseases that intravenous (IV) drug users have an increased risk of acquiring. Buildup of bacteria in the heart can have severe effects on the heart’s ability to pump blood throughout the body (Figure 1). One of the causes of IE is the introduction of bacteria into the bloodstream which circulate and settle within the heart valve. Continuous IV drug use increases the risk of injecting impure substances through contaminated drugs or unsanitary needles into the blood, creating a predisposition for IE .
In recent years, there have been noticeable increases in the percentage of IE patients within the drug user population [2,3] (Figure 2). However, addressing the increasing rate of IE is a complex issue that is complicated by the limited treatment options available for these patients.
In the United States, the American Heart Association (AHA) provides publicly available guidelines for how physicians should care for patients with IE. Patients that are diagnosed at early stages of the infection are usually treated with antibiotics to clear the bacteria in their hearts. In the event of a more severe infection, antibiotics may not be sufficient, and valve replacement surgery is required. This is an open-heart procedure in which surgeons remove the infected valve and replace it with an artificial one. Unfortunately, treatment of IE in IV drug users is more complex than in other types of patients. For one, many treatment programs disqualify IV drug users from receiving IV catheters for at-home IV antibiotic therapy . This forces many IV drug users diagnosed for IE to be put on oral antibiotics, which may not be as effective . Additionally, due to the increased risk of IE recurrence after treatment, the AHA guidelines do not recommend artificial valve replacements for IV drug user patients with IE . Studies have shown that, in the long-term, IV drug users with IE that receive surgery have poorer outcomes  and are ten times more likely to die or require a second surgery after initial treatment of IE compared to non-drug users . The limited treatment options available for IV drug users perpetuates a cycle of IE, in which these patients are diagnosed, unable to receive sufficient care, and acquire IE again (Figure 3).
This continuing cycle of recurrent IE is an underlying problem of the overall opioid epidemic, so how can we break it? Current societal efforts are being made to break the cycle at three significant points: 1) reducing the risk of acquiring infectious diseases from IV drug usage, 2) identifying proper treatment strategies for IV drug users with IE, and 3) targeting the addictive nature of substance use disorder.
Infectious diseases in IV drug users are likely a result of re-using needles or using non-sterile needles. To address these practices, communities throughout the United States have begun to initiate Needle Exchange Programs (NEPs), which provide access to free sterile needles for IV drug users. The Consolidated Appropriations Act of 2016 (Division H, Sec. 520) provides NEPs with federal funding to run additional services such as education on cleaner injection practices, proper disposal of used syringes, and counseling. Currently, there are about 300 NEPs throughout the United States, with the majority in California, and this number continues to increase yearly . However, there is strong criticism of NEPs that claim that the presence of these centers may actually encourage IV drug usage . On the contrary, evidence demonstrates that communities with NEPs see significant decreases in infectious disease rates within the IV drug user population with minimal adverse effects to the nearby area . While NEPs have begun to gain traction in the United States, other countries have taken further steps by opening Safe Injection Sites (SISs). SISs are medical facilities that provide a clean, secluded environment for drug users to use recreational drugs with on-site medical personnel present for primary care. While there are no SISs open in the United States, several facilities in Canada, Europe, and Australia have reported significantly lower rates of infectious diseases and overdose mortality in areas near SISs . Most importantly, these programs did not increase rates of drug-related arrests, suggesting that SISs do not further encourage illicit behaviors. New York City, San Francisco, Philadelphia, and Seattle have all expressed interest in starting SISs but have faced opposition at the federal level . The federal Crack House Statute (21 USC § 856) prohibits the maintenance of any place for the knowing use of any controlled substances. However, evidence of the beneficial effects of NEPs and SISs, particularly in reducing rates of infectious diseases, provides a strong case for supporting these programs.
If NEPs and SISs are steps that can help limit the prevalence of IE in the future, how can we help current IE patients? With IE being such a complex disease, it is necessary for the development of interdisciplinary approaches to treatment. Dr. Arnold S. Bayer, a faculty member of the Division of Infectious Diseases at the Harbor-UCLA Medical Center, is part of the Rapid Response Endocarditis Service, a team of experts from multiple fields that aim to provide the best care for each individual IE patient. For the 50 to 75 IE patients Harbor-UCLA sees every year, this team of specialists, including cardiologists, cardiac surgeons, experts in infectious diseases, and social workers, discuss and create a well-rounded treatment plan for each individual case. Dr. Bayer says that this multidisciplinary system “obviates all the confusion of such a robust and complicated infection.” However, these kinds of teams are not common throughout the United States; the Harbor-UCLA program only started in 2014. Even so, Dr. Bayer states that the program has already had a noticeable impact on the physicians at Harbor-UCLA. “On a philosophical basis, it’s made a huge difference because we get educated. We learn a lot from the point of view of other services,” he says. Next year the medical center will conduct a five-year review to determine the long-term effects of this program on the patients. Knowing the impacts of this multi-faceted approach to treating IE, on both physicians and patients, will hopefully provide a stronger case for the creation of more interdisciplinary teams across the United States for treating IE.
In addition to proper treatment for IE as a standalone disease, it is critical that the underlying issue of IV drug users is addressed: substance use disorder (SUD). One of the main approaches to treating SUD according to the National Institute of Drug Abuse is via opioid substitution treatment . This therapeutic approach consists of giving patients opioid agonists, such as buprenorphine and methadone, that mimic the physiological responses to opioids to help wean patients off the drugs. The Center for Medicaid and CHIP Services suggests that a combination of both medication and psychosocial support, known as medication-assisted treatment (MAT), is the most effective way to address SUD . Support includes individual or group therapies, motivational incentives, and education. Though MAT is currently being implemented for IV drug users with IE, studies have shown that the quality of treatment has been subpar. A 2016 study demonstrated that despite having initial social work consultations, less than 25% of patients were receiving addiction or psychiatric sessions . On top of that, accessibility to MAT has been limited for all drug users, in part due to restrictions on facilities that can provide opioid agonists. While buprenorphine can be prescribed by any physician that receives specialized training, methadone is only offered at federally-approved locations . The same 2016 study reported that only 7.8% of patients were discharged with a plan for MAT . There is a pressing need to improve upon MAT strategies and properly address SUD in IE patients.
Within the growing opioid epidemic there lies a cycle of IV drug users being hospitalized for IE, receiving treatment, and then returning to the hospital for recurring symptoms. The expansion of programs to prevent the spread of infectious diseases via unsanitary injection practices and increased focus on providing treatment for SUD in IE patients may be steps towards really targeting the ‘heart’ of this destructive cycle.
Shuin (Sue) Park
Staff Writer, Signal to Noise Magazine
PhD Candidate, Department of Medicine/Division of Cardiology, UCLA
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