Infectious endocarditis is a highly morbid disease with approximately 43,000 cases per year in the United States. The modified Duke Criteria have poor sensitivity; however, advances in diagnostic imaging provide new tools for clinicians to make what can be an elusive diagnosis. There are a number of risk stratification calculators that can help guide providers in medical and surgical management. Patients who inject drugs pose unique challenges for the health care system as their addiction, which is often untreated, can lead to recurrent infections after valve replacement. There is a need to increase access to medication-assisted treatment for opioid use disorders in this population. Recent studies suggest that oral and depo antibiotics may be viable alternatives to conventional intravenous therapy. Additionally, shorter courses of antibiotic therapy are potentially equally efficacious in patients who are surgically managed. Given the complexities involved with their care, patients with endocarditis are best managed by multidisciplinary teams.
Infectious endocarditis (IE) is a disease process with significant in-hospital mortality ranging between 15% and 20%.1 This is as a result of a multitude of factors including patients’ preexisting comorbidities, illness acuity, delays in diagnosis, lack of or delays in surgical intervention, the need for coordination between multiple medical and surgical specialties, and lack of long-term follow-up. In addition to its significant morbidity, IE also incurs significant costs to health care delivery systems as a result of long lengths of stay and expensive diagnostic tests.1 The increasing number of patients who inject intravenous drugs and subsequently develop endocarditis also creates new ethical dilemmas for medical providers to address.2,3 All of this is complicated by a dearth of randomized controlled trials involving patients with endocarditis. For these reasons, navigating the care of an endocarditis patient from admission to discharge may be among the most challenging tasks today’s medical providers face. Although there is an existing American Heart Association (AHA) endocarditis guideline, this article will also include recent literature not addressed in the AHA review such as updates on the diagnosis, risk-stratification, and treatment of IE as well as the role of multidisciplinary endocarditis teams.
Diagnosis
The diagnosis of IE can be particularly challenging, especially in patients with negative blood cultures who comprise anywhere from 2% to 71% of all endocarditis cases.4 The Modified Duke Criteria have been used as the primary diagnostic criteria for endocarditis since their publication in 2000 (Table 1).5 The algorithm uses a combination of major microbiologic and echocardiographic findings as well as minor clinical and microbiological criteria to stratify patients as having definite, possible, or rejected endocarditis. Despite their widespread and long-standing use, the Duke Criteria have a reported sensitivity between 70% and 79%.6 As a result, the diagnosis of endocarditis cannot be made solely by these parameters and instead is made after considering a variety of clinical factors. The relative insensitivity of the Duke Criteria can be attributed to a number of factors, including culture-negative cases, which are most commonly the result of antibiotic administration before obtaining blood cultures. The yield of blood cultures increases with the number of cultures obtained with literature demonstrating that sensitivity increases from 73%-80% with 1 culture to 85%-98% with 3.7 Medical providers can help increase the likelihood of appropriately diagnosing endocarditis by ensuring prompt acquisition of 3 blood cultures prior to the initiation of antibiotics. Additionally, specific pathogens included in the Duke Criteria should alert physicians to their patients’ increased risk of endocarditis. Gram-positive pathogens such as Staphylococcus aureus, Enterococcus faecalis, and alpha-hemolytic streptococcus as well HACEK (Haemophilus spp., Aggregatibacter spp., Cardiobacterium spp., Eikinella corrodens, and Kingella kingae) organisms are strongly associated with IE.5 Prompt consultation with an infectious disease specialist can help guide further evaluation and, for some organisms, decrease mortality.8 In patients undergoing surgical valve repair or replacement for culture-negative endocarditis microbiologic diagnosis can be aided by the use of 16 S ribosomal RNA (rRNA) sequencing. This relatively novel testing uses polymerase chain reaction (PCR) to identify bacterial RNA from excised native valve tissue or prosthetic material. In patients with definite endocarditis and negative blood cultures, the sensitivity of 16 S rRNA sequencing is reported to be has high as 80% with a false-positive rate of only 3%.9
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-Sami El-Dalati, MDa, Daniel Cronin, MDb, Michael Shea, MDc, Richard Weinberg, MD, PhDc, James Riddell IV, MDa, Laraine Washer, MDa, Emily Shuman, MDa, James Burke, MDe, Sadhana Murali, MDe, Christopher Fagan, MDc, Twisha Patel, PharmDf, Kirra Ressler, PA-Cg, George Michael Deeb, MDg
