Infective endocarditis (IE) is a rare disease that is difficult to diagnose, its treatment is complex and expensive, and mortality is high (around 20%). In the field of IE, the most recent changes are epidemiological and include an increased number of cases of IE in patients with prosthetic valves and intracardiac devices and in the population receiving health care, an increased number of cases of Staphylococcus aureus IE, and changes in antibiotic sensitivity patterns with a particular impact on vancomycin.1–3 Infective endocarditis requires prolonged hospitalization and resource-intensive treatment because antibiotic therapy, intensive care, and surgical treatment form part of the therapeutic approach.

Between 40% and 50% of patients require surgical treatment in the acute phase. In the year when IE is diagnosed, mortality is 30% with or without intervention. Mortality is high among certain groups, such as patients with prosthetic valves and especially those with intracranial hemorrhage.4

Early diagnosis and treatment can improve outcomes. Low suspicion of IE can delay effective treatment and increase mortality.5 In our experience, an appropriate therapeutic approach has a mean delay of 27 days when the patient is referred from another institution.

The treatment of IE is a paradigm of collaboration. Multidisciplinary teams (MDT) dedicated to IE have pioneered the organization of tertiary hospital care devoted to the disease.6,7 In the last decade, the International Collaboration in Endocarditis group has had a strong impact on understanding IE.8 The British Heart Valve Society has recommended the collaboration of specialists in valvular heart disease and IE9 and recent reports have supported this model.10

This article describes recommendations for the organization of an IE-MDT from the perspective of 30 years’ experience of the Working Group on Infective Endocarditis of the Hospital Clínic de Barcelona with the aim of making this experience useful to the Spanish National Health System.

Infective endocarditis is a medical-surgical disease in which surgical treatment is a part of the therapeutic process rather than a result of the failure of medical treatment. The care of patients with IE should be offered by an MDT comprising specialists with shared interests.

Since 1979, the organization and development of the Working Group on Infective Endocarditis of the Hospital Clínic de Barcelona has been paralleled by developments in infectious disease, cardiology, microbiology, pathology, and cardiovascular surgery services. Figure 1 shows the annual distribution of cases of IE at our hospital since 1979 (1256 patients). Basic achievements have included the establishment of a database dedicated to IE, the commencement of the cardiovascular surgery service in 1979, the creation of a cardiovascular tissue bank (cryopreserved heart valves and arteries) in 1989, the introduction of transesophageal echocardiography in 1991, and the establishment of an electronic medical records system accessible through the hospital intranet in 1999.

Figure 1.

Annual distribution of cases of endocarditis in the Hospital Clínic de Barcelona since 1979. ICD, intracardiac devices; IDU, intravenous drug users. *Pacemakers and defibrillators.

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Follow-up has been performed by specialists in infectious disease, cardiology, and cardiovascular surgery since 1986. The storage of pathogenic strains was organized at the microbiological biobank in 1993. The experimental endocarditis laboratory has been in operation since 1993, and the Working Group on Infective Endocarditis of the Hospital Clínic de Barcelona has maintained weekly meetings on IE since 1994.

The benefits of an MDT are undeniable. Infective endocarditis should be treated in tertiary centers with an experienced cardiovascular surgery service.6 An MDT should comprise:

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  A specialist in infectious diseases.

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  A microbiologist.

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  A specialist in valvular heart disease.

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  An echocardiologist with extensive experience in the interpretation of valvular disease.

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  A cardiovascular surgeon.

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  A specialist in pathology.

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  A specialist in outpatient parenteral antibiotic treatment (OPAT).

Tertiary hospitals also have the following services available: anesthesiology and resuscitation, diagnostic imaging, nuclear medicine, nephrology, neurology, neurosurgery, orthopedics and traumatology, and hemotherapy and blood management. The complexity of IE justifies the use of tertiary care.

Accumulated experience suggests the need for a home-care team for the management and follow-up of OPAT.11

The infectious disease service analyzes daily blood cultures at the hospital. If the results of blood cultures are positive, the action to be taken will be decided by consensus with the service that ordered the test.

Overview of the Process

The treatment process of patients with IE is complex and involves several steps that commence when there is diagnostic suspicion of IE. The initial index of suspicion should be high, since the diagnosis of IE is often delayed due to the non-specificity of the symptoms.5 The initial step is to contact the infectious disease service, once there is clinical suspicion of IE or when blood culture results are positive from samples sent to the microbiology laboratory for various reasons. Once there is suspicion of IE and the criteria for IE have been confirmed, the cardiology and cardiovascular surgery services are contacted to form a consensus on which antibiotic and cardiological therapy to administer and to establish the indications for and timing of surgical intervention if applicable. Figure 2 shows this process.

Figure 2.

Care process of patients with infective endocarditis admitted to hospital with a cardiovascular surgery service. HACEK, Haemophilus parainfluenzae, H. aphrophilus, H. paraphrophilus, H. influenzae, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae, and K. denitrificans; ICU, intensive care unit; IE, infective endocarditis; OPAT, outpatient parenteral antibiotic therapy; TEE, transesophageal echocardiography, TTE, transthoracic echocardiography.

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Given that the process of treating IE is complex and involves an MDT, each case must be reviewed and policies for common action established. It is therefore recommended that the medical-surgical team hold weekly meetings to discuss patients who have been admitted, patients referred from other institutions, and patients attended in the emergency department. This meeting should confirm medical-surgical decisions and assess patients for OPAT. The team should also oversee the quality control process and analyze the postmortem study of any patients who died.

The care of patients with IE is often difficult and complex in hospitals without a dedicated cardiovascular surgery service. Interhospital collaboration is essential in order to facilitate patient transfer under the best possible clinical conditions.

Overview of the Process

When a patient has suspected IE in a secondary hospital, the diagnosis and treatment should be confirmed by contacting the tertiary hospital and sending imaging (echocardiography, computed tomography) and microbiological materials. It is important to clearly establish the criteria for patient transfer. Figure 3 shows the basic steps in this process.

Figure 3.

Care process of patients with infectious endocarditis in a hospital without cardiovascular surgery service. aInfectious diseases, cardiology or cardiac surgery. bEchocardiography, abdominal ultrasound, cranial/body computed tomography, cranial magnetic resonance imaging.

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It is recommended that physicians from the referring hospitals attend the weekly meeting, if possible, to present the cases and any imaging material. The MDT should share the endocarditis protocols with the physicians from the referring hospitals and should guarantee the continuing education of its physicians. The microbiology service of the referring hospital should store the strains of isolated microorganisms and send them to the reference laboratory for additional analysis.

It is recommended that indications for transferal are comprehensive. Table 1 shows the basic indications to consider a transfer to a referral center.

Table 1.

Criteria for the Transfer of Patients From Hospitals Without Cardiovascular Surgery

1. Patients with unstable hemodynamics (inotropic support, mechanical ventilation)

2. Severe valvular regurgitation (clinical and echocardiographic criteria)

3. Prosthetic endocarditis

4. Intracardiac device endocarditis (pacemakers, defibrillators, resynchronizers)

5. Extravalvular complications (abscesses, fistulas)

6. Persistent sepsis (positive blood cultures > 7 days)

7. Stroke

8. Recurrent embolism

9. Residual large vegetations (> 10 mm)

10. Aggressive or difficult to treat microorganisms (eg, Staphylococcus aureus, Gram-negative bacilli, fungi, culture-negative endocarditis)

The diagnosis and treatment of IE based on modified Duke criteria.12 The results of blood cultures should be obtained before antibiotics are administered. Echocardiographic examination should be performed within the first 48h. Patients with complicated IE on a native valve, artificial heart valve, or intracardiac prosthetic device should be admitted to the cardiology service and other patients with IE should be admitted to the infectious disease or internal medicine services. Patients with heart failure, septic shock, neurological disease, or conduction abnormalities should be admitted to intensive or intermediate care units. The treatment of IE is guided by good practice based on the clinical experience and judgment of the MDT and by the implementation of the approved recommendations of scientific societies.1

The severity of IE raises ethical problems in certain subgroups, such as patients with cancer, human immunodeficiency virus infection, or advanced liver cirrhosis. The MDT plays a key role in determining the benefits of surgical treatment in these subgroups of patients.

An institutional protocol ensures homogeneous treatment. The physician in charge of the patient must have the final responsibility, regardless of the opinion of the group. Medicolegal liability rests on the responsible physician.

It is of particular importance to present the treatment options and their risks. The patient's family or equivalent must be informed about the situation and the treatment decisions made clear when the patient is unable to make them. Table 2 shows the process that should be followed in the care of patients with IE.

Table 3 shows the list of signs and symptoms that should be monitored and tests and actions that must be performed during the treatment of a patient with IE.

Prevention is one of the most important aspects of IE.13 Clinical practice guidelines recommend antibiotic prophylaxis for patients with a previous episode of IE.1 Institutions and medical societies should disseminate information through informative brochures or via the Internet. Patient brochures about suspected IE and the need for dental checkup are prime educational materials for the general population. In order to prevent future episodes of IE, the patient and family should be provided with material on the disease, the procedures that can cause bacteremia, and the types of antibiotic prophylaxis.

The World Health Organization recommends education on hand-washing and compliance with protocols for zero bacteremia due to the risk of morbidity and mortality caused by venous catheter infections (including IE) in the hospital setting.

Between 40% and 50% of patients with IE will need surgical treatment.2,11 In our hospital, the indications for surgical treatment in the acute phase are heart failure, conduction abnormalities, periannular complications, and persistent sepsis despite antibiotic treatment for at least 1 week.

The most important issue is the timing of the indication for surgery. Early surgery refers to when IE is diagnosed and treated at admission. Critically ill patients in a life-threatening situation need emergency treatment within 24h of diagnosis.

Stable patients should be treated within at least 1 week to control the infectious process, although the best moment for intervention has yet to be established for this group of patients. Using propensity-based matching adjustment for survival bias and instrumental variable analysis, Lalani et al14 found that patients with IE receiving antibiotic treatment should undergo surgery within 4 weeks of admission, which is the expected duration of parenteral therapy. Recently, Kang et al15 suggested intervention within 48h for patients with severe valvular regurgitation who have embolisms and vegetations (> 10mm) although improved survival was not demonstrated in this small sample of patients. Although the final results of the 2008 prospective randomized study ENDOVAL 1 (Rationale, Design and Methods for the Early Surgery in Infective Endocarditis Study, NCT00624091) remain pending, early results suggest that early intervention should be performed within 1-2 weeks of beginning antibiotic treatment.

Indications for surgery should be confirmed in the weekly MDT meeting. Urgent cases or life-threatening emergencies should be individually addressed rather than formally reviewed. Each patient is stratified according to preoperative surgical risk.

The responsible physicians should follow up patients with IE who have undergone intervention. Patients should be followed up at 1, 3, and 12 months after intervention. Patients who have not undergone intervention should be followed up in medical outpatient consultations or at home after OPAT has been completed to assess possible recurrence and valvular dysfunction after the IE episode. Patients who have undergone intervention should be assessed in surgical outpatient consultations at 1, 3, and 12 months after intervention to follow-up cardiac and valvular function. Blood samples should be taken 48h after the completion of antibiotic treatment and at 1 and 3 months after discharge. The patient should be told that if they have fever they should go to hospital and should not take antibiotics to avoid false-negative results of blood cultures. The recurrence rate after the initial episode of IE is low (< 5%) and commonly occurs in the first 12 weeks. Infective endocarditis that develops after valve surgery is considered to be early IE if there is a new episode in the first 12 months and late IE if there is an episode after this period.

Infective endocarditis is a rare disease that has an impact on the community due to its morbidity and consumption of resources. The key element in the treatment process is the MDT, which attempts to reach an early diagnosis, standardize treatment criteria, and optimize results. The MDT should review local cases of IE, facilitate the transfer of patients from hospitals that do not have a cardiovascular surgery unit, and follow up patients with IE after the initial episode. The MDT should undertake educational activities aimed at patients, familar environment, and professional colleagues with little experience with the disease. The MDT should also audit their activity according to the criteria specified in Table 3.

None declared.