In 2009, the most recent European Society of Cardiology guidelines defined infective endocarditis (IE) as an unusual disease for 3 reasons. First, in the last 30 years, the incidence of this disease and its associated mortality have remained unchanged despite clear advances in diagnosis and treatment. Second, IE is a highly heterogeneous entity with a wide spectrum of clinical manifestations that depend on the patient's underlying disease, the infecting microorganism, and the presence of local and remote complications. Hence, the management of these patients requires a multidisciplinary approach. Thirdly, given the lack of randomized studies, treatment guidelines are frequently based on expert opinions.1

Over the last few decades, the epidemiology of IE has changed in industrialized countries.2 The population at risk of infection are no longer young people with known rheumatic valvular heart disease and are now elderly people with no apparent valve disease.3 In addition, the mechanism of infection has also altered; a history of dental intervention before the onset symptoms has become anecdotal, while a substantial percentage of patients are infected by in-hospital procedures.4

Scientific publications on IE by Spanish hospitals in the last 20 years (1994-2013) has been considerable and continues to increase both in terms of the number and quality of the studies, allowing the current epidemiology of IE in Spain to be determined with considerable accuracy.

No population-wide studies of IE in Spain have been published, and consequently the national incidence of this disease is unknown. However, it is not unreasonable to assume that the situation should differ little from that of France, where population-wide observational studies are regularly conducted. These studies show that the incidence of IE is low but is slowly increasing: the age- and sex-standardized estimate was 2.4 episodes per 100 000 inhabitants/year in 1991,5 3.1 in 1999 (95% confidence interval [95%CI], 2.8-3.5),6 and 3.4 in 2008 (95%CI, 3.1-3.7).7 Although these figures describe the incidence in the general population, it is highest among men aged 75-79 years (19.4 episodes per 100 000 inhabitants/year).7

Table 1 shows the causes of IE in 4 contemporary Spanish series.8–11 Streptococci and staphylococci species are the 2 most frequent groups of causal microorganisms (approximately two-thirds of all episodes), followed by Enterococcus species, which cause approximately 10% of all cases.

Because of the marked epidemiologic changes in IE in recent years,2 infection due to methicillin-resistant Staphylococcus aureus strains is increasingly frequent, hampering the medical treatment of these patients.12 Furthermore, population aging is increasing the number of infections due to bovis13 and Enterococcus.14 Finally, although Q fever IE is infrequent (3% of all cases), Spanish groups have made a noteworthy contribution to our understanding of this entity.15

The spectrum of heart diseases predisposing patients to endocarditis has changed in the last few decades. Evidence of these changes in Europe was reported in the Euro Heart Survey,16 which found that degenerative heart diseases were the most frequent predisposing valvular heart conditions and that, in contrast, the number of patients with endocarditis and no previously known heart disease had increased considerably. In Spain, several studies have shown similar results. Castillo et al.3 reported 228 patients studied between 1987 and 2009: the incidence of predisposing rheumatic valvular heart disease and congenital heart diseases fell significantly, mitral valve prolapse was the most common heart disease, and the proportion of patients with no predisposing heart disease increased significantly (from 25% to 57% in recent years). The incidence of late prosthetic endocarditis has increased more than that of early prosthetic endocarditis.17 This trend was confirmed by a Spanish study indicating a fall in early prosthetic endocarditis from 0.94% between 1970 and 1986 to 0.34% between 1987 and 2003.18 However, Alonso-Valle et al.19 report no change in the incidence of early and late prosthetic endocarditis between 1986 and 2005. The incidence of pacemaker endocarditis and other device endocarditis has increased markedly,20 representing approximately 3% of cases in the series from Hospital Vall d’Hebron.

Without doubt, the most difficult issue in the management of patients with IE is deciding on the indications and timing of surgery. On the one hand, surgery would be indicated to prevent death or severe complications; on the other hand, surgery in the acute phase of the disease entails a high level of risk. Therefore, surgery should be performed in patients with clear indications and in the absence of comorbidities or severe complications that might seriously limit their chances of survival. In principle, age is not considered a contraindication to surgery, if required. In Spain, a large study has recently been published that reports surgical outcomes in octogenarian patients with IE.30 The European Society of Cardiology guidelines1 specify which patients should be considered for surgery and propose the optimal timing of interventions. Recently, the Society of Thoracic Surgeons have also published guidelines on the surgical management of endocarditis.46 However, despite this systematization, each case of endocarditis is a specific entity, involving multiple variables and should be; decision-making on surgery and its timing should therefore be individually tailored.

However, consensus appears to exist on the 3 main situations in which surgery should be seriously considered during the active phase of the infection: heart failure secondary to valvular dysfunction caused by the endocarditis, persistent signs and symptoms of sepsis despite correct antibiotic treatment (often accompanied by severe valvular destruction or perivalvular abscesses), and fear that systemic embolism might develop in patients with large vegetations.47

Another controversial issue is the urgency of surgery. Guidelines refer to indications for emergent, urgent (in the first week of treatment), and elective treatment. However, scarce data in the literature support this type of recommendation. San Román et al.48 have designed a multicenter clinical trial to determine the role of early surgery. In the absence of evidence in the medical literature, it is undoubtedly advisable to treat all patients with IE, if possible, in centers equipped for cardiac surgery or in a position to consult with specialized centers following diagnosis.49 Thus, the indication and timing of interventions will be decided by expert teams, if possible, before the infection leads to severe complications that substantially worsen prognosis.

Despite undoubted advances in medical and surgical treatment, mortality from IE has remained practically unchanged over the last 20 years, which can be explained by the marked epidemiologic changes that have led to the current situation in which IE affects elderly people with a number of comorbidities.

In the Hospital Vall d’Hebron series of left valve IE treated between 2000 and 2011, in-hospital mortality was 29% (26% in native valve IE and 39% in prosthetic valve IE).8 The percentages were similar in the Andalusian series, with 30% crude mortality during the study period (26% between 1984 and 1995 and 32% between 1996 and 2006).11 Both studies guaranteed consecutive inclusion of all left valve IE episodes.

It is known that in-hospital or early mortality from IE largely depends on factors associated with the infection and its complications. Specifically, 30% of deaths are due to heart failure, 20% to neurologic complications, and 10% to uncontrolled infection.8 However, long-term mortality exclusively depends on the patient's underlying disease.

Numerous studies have assessed the multiple risk factors for death from IE. However, we cannot ignore the modifiable factors or attitudes that can alter the natural course of the disease. First, given the percentage of HAIE, antiseptic measures must be strictly followed before any invasive procedure, whether the presence of predisposing heart disease is known or not, because one-third of all IE episodes can be avoided.4 Second, diagnosis of these patients should be improved: those at-risk should be aware of their risk and attend their referral centers promptly if they develop fever of unknown etiology or constitutional syndrome. Third, after diagnosis, patients should be treated by multidisciplinary teams with experience in making decisions about this disease, given that they are seldom easy to make50,51 and that a multidisciplinary approach has clear and proven benefits.33,52 Finally, early identification of patients more likely to require surgery or at greater risk of death is feasible,53 which facilitates their early transfer to referral centers equipped for cardiac surgery.

Medical treatment of IE is based on endovenous antibiotic administration, usually for 4 to 6 weeks, which entails lengthy hospitalization. However, it is known that the risk of complications in stable patients with good general health is minimal after the first 2 weeks of antibiotic therapy, allowing treatment to be completed out of hospital. This strategy can also be used in patients with a favorable clinical course after very early valve replacement. In addition to cutting costs, ambulatory administration of antibiotics improves patients’ quality of life. Consequently, a growing percentage of patients with IE have been included in programs for out-of-hospital administration of antibiotics through day hospitals and hospital at-home units.54,55 In our experience at the Hospital Vall d’Hebron, approximately one-third of patients who survive infection complete their antibiotic treatment in this context.

In Spain, an industrialized country, IE is currently an infrequent disease occurring in elderly people with no known predisposing heart disease and often as a consequence of close contact with the health care system. Despite continuous advances in the medical and surgical treatment of IE, mortality has remained stable. However, there is clear room for improvement in preventing episodes of catheter-related bacteremia, early diagnosis of infection, and identifying those at greater risk of needing surgery or of in-hospital mortality, as well as in creating multidisciplinary teams with experience in the medical and surgical management of this disease.

None declared.