Management of infective endocarditis: challenges and perspectives

Antineutrophil Cytoplasmic Antibodies Associated With Infective Endocarditis

To determine the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in patients with infective endocarditis (IE) in internal medicine; and to compare clinical and biochemical features and outcome between patients exhibiting IE with and without ANCA.Fifty consecutive patients with IE underwent ANCA testing. The medical records of these patients were reviewed.Of the 50 patients with IE, 12 exhibited ANCA (24%). ANCA-positive patients with IE exhibited: longer duration between the onset of first symptoms and IE diagnosis (P = 0.02); and more frequently: weight loss (P = 0.017) and renal impairment (P = 0.08), lower levels of C-reactive protein (P = 0.0009) and serum albumin (P = 0.0032), involvement of both aortic and mitral valves (P = 0.009), and longer hospital stay (P = 0.016). Under multivariate analysis, significant factors for ANCA-associated IE were: longer hospital stay (P = 0.004), lower level of serum albumin (P = 0.02), and multiple valve involvement (P = 0.04). Mortality rate was 25% in ANCA patients; death was because of IE complications in all these patients.Our study identifies a high prevalence of ANCA in unselected patients with IE in internal medicine (24%). Our findings further underscore that ANCA may be associated with a subacute form of IE leading to multiple valve involvement and more frequent renal impairment. Because death was due to IE complications in all patients, our data suggest that aggressive therapy may be required to improve such patients' outcome.

Ross procedure is a safe treatment option for aortic valve endocarditis: Long-term follow-up of 42 patients

BACKGROUND

Aortic root replacement with a pulmonary autograft (Ross procedure) can be performed as a treatment of aortic valve endocarditis, avoiding prosthetic valve implantation in septic context. We sought to assess long-term outcomes of the Ross procedure in this indication.

METHODS

From April 1992 to March 2009, the intervention was performed in 42 patients (mean age 34 ± 8 years) suffering from an active or ancient aortic valve endocarditis. 36% of the patients had extensive perivalvular involvement, and surgery was urgent in 18 patients (43%). We performed a prospective clinical and echocardiographic follow-up of this population.

RESULTS

Median follow-up was 10 years (4-21 years). Overall survival at 10 and 15 years was respectively 87 ± 5% and 81 ± 8%. Perioperative mortality was 4.7% (2 patients) and no late cardiac death was reported. Eight patients (19%) underwent repeat surgery for autograft and/or homograft dysfunction at a median time of 8.4 years (3 months-18 years). Rate of recurrent endocarditis was low (7%-3 patients), including 1 in a context of persistent intravenous drug abuse. Clinical follow-up showed good functional status for all patients with NYHA ≤ II, and less than 25% of patients requiring cardiovascular medication. Late echocardiographic follow-up demonstrated well-functioning autograft and homograft, with only one severe aortic regurgitation, and one significant increase in pulmonary mean gradient.

CONCLUSION

The Ross procedure in aortic valve endocarditis is an interesting alternative to prosthetic valvular replacement in a selected population, with a high rate of survival free from any cardiovascular event or medication requirement.

Cardiothoracic surgical emergencies in the intensive care unit

Patients with cardiothoracic surgical emergencies are frequently admitted to the ICU, either prior to operative intervention or after surgery. Recognition and appropriate timing of operative intervention are key factors in improving outcomes. A collaborative team approach with the cardiothoracic service is imperative in managing this patient population.

Infective endocarditis in the military patient

Infective endocarditis (IE) is a potentially fatal cardiac infection associated with an inhospital mortality rate of up to 22%. Fifty per cent of IE cases develop in patients with no known history of valve disease. It is therefore important to remain vigilant to the possibility of the diagnosis in patients with a febrile illness and unknown source. From a military perspective, our patients are unique due to the breadth of pathogens they are exposed to, and blood-culture-negative IE is a risk. In particular, there should be awareness of Coxiella burnetii as a possible causative pathogen. In this review we incorporate the latest consensus from systematic reviews and publications identified by a literature search through Medline. We describe the diagnosis and management of IE with particular reference to the military population.

Aortico-Left Atrial Fistula: A Rare Complication of Bioprosthetic Aortic Valve Endocarditis Secondary to Enterococcus faecalis

Paravalvular aortic root abscess with intracardiac fistula formation is an exceedingly rare complication of infective endocarditis. This condition is even more rarely encountered in patients with bioprosthetic valve endocarditis. We report an unusual case of a 68-year-old Bosnian female with a bioprosthetic aortic valve, who developed an extensive aortic root abscess, complicated by an aortico-left atrial intracardiac fistula. This case illustrates that a high index of suspicion, prompt diagnosis by echocardiography, proper antibiotic therapy, and early surgical intervention are crucial to improving treatment outcomes for this rare condition.

Infective endocarditis in the Pacific: clinical characteristics, treatment and long-term outcomes

Introduction

Data on clinical characteristics and outcomes of infective endocarditis (IE) in the Pacific are scarce.

Methods

Retrospective hospital-based study in New Caledonia, a high-income country, on patients aged over 18 years with definite IE according to the modified Duke criteria (2005–2010).

Results

51 patients were included: 31 (60.8%) men; median age of 52.4 years (IQR 33.0–70.0). Left-sided IE accounted for 47 (92.2%) patients: native valve IE in 34 (66.7%) and prosthetic valve IE in 13 (25.5%). The main underlying heart disease included: rheumatic valve disease in 19 (37.3%), degenerative heart valve disease in 12 (23.5%) and congenital heart disease in 6 (11.8%). Significant comorbidities (Charlson's score >3) were observed in 20 (38.7%) patients. Infection was community acquired in 43 (84.3%) patients. Leading pathogens included Staphylococcus aureus in 16 (31.4%) and Streptococcus spp in 15 (29.4%) patients. Complications were noted in 33 patients (64.7%) and 24 (47.1%) were admitted to the intensive care unit. Cardiac surgery was eventually performed in 22 of 40 (55.0%) patients with a theoretical indication. None underwent emergent cardiac surgery (ie, first 24 h); 2 (3.9%) were operated within 7 days; and 20 (39.2%) beyond 7 days. 11 (21.6%) patients died in hospital and 21 (42.9%) were dead after a median follow-up of 28.8 months (IQR 4.6–51.2). Two (3.9%) were lost to follow-up.

Conclusions

In New Caledonia, IE afflicts relatively young patients with rheumatic heart disease, and carries high complication and mortality rates. Access to heart surgery remains relatively limited in this remote archipelago.

Association of mean platelet volume level with in-hospital major adverse events in infective endocarditis

We hypothesised that increased on-admission and follow-up mean platelet volume (MPV) levels would correlate with adverse outcomes in patients with infective endocarditis (IE). A total of 108 consecutive patients were grouped into two according to median MPV level (≤ 8.6 and > 8.6 fL). Patients with MPV level of > 8.6 fL had a significantly higher rate of end-stage renal disease, Staphylococcus aureus infection, higher CRP levels, embolic events and in-hospital mortality compared to patients with MPV levels ≤ 8.6 fL. In multivariable Cox regression analysis, previous history of IE, S. aureus infection, end-stage renal disease, depressed LVEF, early surgical intervention, vegetation size ≥ 10 mm, presence of perivalvular abscess, higher on-admission platelet count, CRP and MPV levels emerged as independent predictors of in-hospital unfavourable outcomes. Patients with embolic events and in-hospital mortality revealed an incremental trend for MPV levels compared to patients without any adverse events. Our study results suggest that both on-admission and follow-up MPV levels may be a simple and available biomarker for risk stratification of IE patients.

Clinical features, microbiology and surgical outcomes of infective endocarditis: a 13-year study from a UK tertiary cardiothoracic referral centre

BACKGROUND

Infective endocarditis (IE) causes substantial morbidity and mortality. Patient and pathogen profiles, as well as microbiological and operative strategies, continue to evolve. The impact of these changes requires evaluation to inform optimum management and identify individuals at high risk of early mortality.

AIM

Identification of clinical and microbiological features, and surgical outcomes, among patients presenting to a UK tertiary cardiothoracic centre for surgical management of IE between 1998 and 2010.

DESIGN

Retrospective observational cohort study.

METHODS

Clinical, biochemical, microbiological and echocardiographic data were identified from clinical records. Principal outcomes were all-cause 28-day mortality and duration of post-operative admission.

RESULTS

Patients (n = 336) were predominantly male (75.0%); median age 52 years (IQR = 41-67). Most cases involved the aortic (56.0%) or mitral (53.9%) valves. Microbiological diagnoses, obtained in 288 (85.7%) patients, included streptococci (45.2%); staphylococci (34.5%); Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella (HACEK) organisms (3.0%); and fungi (1.8%); 11.3% had polymicrobial infection. Valve replacement in 308 (91.7%) patients included mechanical prostheses (69.8%), xenografts (24.0%) and homografts (6.2%). Early mortality was 12.2%, but fell progressively during the study (P = 0.02), as did median duration of post-operative admission (33.5 to 10.5 days; P = 0.0003). Multivariable analysis showed previous cardiothoracic surgery (OR = 3.85, P = 0.03), neutrophil count (OR = 2.27, P = 0.05), albumin (OR = 0.94, P = 0.04) and urea (OR = 2.63, P < 0.001) predicted early mortality.

CONCLUSIONS

This study demonstrates reduced post-operative early mortality and duration of hospital admission for IE patients over the past 13 years. Biomarkers (previous cardiothoracic surgery, neutrophil count, albumin and urea), predictive of early post-operative mortality, require prospective evaluation to refine algorithms, further improve outcomes and reduce healthcare costs associated with IE.

Prospective comparison of infective endocarditis in Khon Kaen, Thailand and Rennes, France

Prospectively collected, contemporary data are lacking on how the features of infective endocarditis (IE) vary according to region. We, therefore, compared IE in Rennes, France and Khon Kaen, Thailand. Fifty-eight patients with confirmed IE were enrolled at each site during 2011 and 2012 using a common protocol. Compared with French patients, Thais had a lower median age (47 versus 70 years old; P < 0.001) and reported more animal contact (86% versus 21%; P < 0.001). There were more zoonotic infections among Thai than France patients (6 and 1 cases; P = 0.017) and fewer staphylococcal infections (4 versus 15 cases; P = 0.011). Underlying rheumatic heart disease was more prevalent in Thai than in French patients (31% and 4%; P = 0.001), whereas prosthetic heart valves were less prevalent (9% and 35%; P = 0.001). Our data strengthen previous observations that IE in the tropics has distinctive demographic characteristics, risk factors, and etiologies and underscore the need for improved prevention and control strategies.

Nuclear medicine in diagnosis of prosthetic valve endocarditis: an update

Over the past decades cardiovascular disease management has been substantially improved by the increasing introduction of medical devices as prosthetic valves. The yearly rate of infective endocarditis (IE) in patient with a prosthetic valve is approximately 3 cases per 1,000 patients. The fatality rate of prosthetic valve endocarditis (PVE) remains stable over the years, in part due to the aging of the population. The diagnostic value of echocardiography in diagnosis is operator-dependent and its sensitivity can decrease in presence of intracardiac devices and valvular prosthesis. The modified Duke criteria are considered the gold standard for diagnosing IE; their sensibility is 80%, but in clinical practice their diagnostic accuracy in PVE is lower, resulting inconclusively in nearly 30% of cases. In the last years, these new imaging modalities have gained an increasing attention because they make it possible to diagnose an IE earlier than the structural alterations occurring. Several studies have been conducted in order to assess the diagnostic accuracy of various nuclear medicine techniques in diagnosis of PVE. We performed a review of the literature to assess the available evidence on the role of nuclear medicine techniques in the diagnosis of PVE.

Infective endocarditis in northeastern Thailand

Despite rigorous diagnostic testing, the cause of infective endocarditis was identified for just 60 (45.5%) of 132 patients admitted to hospitals in Khon Kaen, Thailand, during January 2010–July 2012. Most pathogens identified were Viridans streptococci and zoonotic bacteria species, as found in other resource-limited countries where underlying rheumatic heart disease is common.

Aspergillus flavus endocarditis of the native mitral valve in a bone marrow transplant patient

Patient: Male, 36

Final Diagnosis: Aspergillus flavus endocarditis

Symptoms: Malaise • fatigue and dyspnea

Medication: —

Clinical Procedure: Mitral vale replacemnet

Specialty: Cardiology

Infective Endocarditis Presenting as Acute Renal Failure and Unusual Complications

Infective endocarditis can be a diagnostic challenge. Few cases have so far reported infective endocarditis presenting as renal failure. Pseudoaneurysms of the mitral-aortic intervalvular fibrosa and splenic abscess are rare complications of infective endocarditis. We herein report a case of an 80-year-old man admitted due to anorexia, malaise, edema of the legs and renal failure. A progressive degradation of the patient's renal function was documented and hemodialysis was started. Blood cultures revealed the presence of Enterococcus faecalis, and the patient was treated with ampicillin and gentamicin. The transesophageal echocardiogram findings showed pseudoaneurysms of the mitral-aortic intervalvular fibrosa and in the aortic root wall. Due to abdominal pain, an abdominal CT scan was performed and showed a cystic lesion compatible with splenic abscess. The patient received 6 weeks of antibiotic treatment. There was progressive clinical improvement and regression of the splenic abscess, but no recovery of the renal function. This report illustrates an unusual clinical presentation of infective endocarditis with unusual complications that were successfully treated with antibiotics.

Comparison of species identification of endocarditis associated viridans streptococci using rnpB genotyping and 2 MALDI-TOF systems

Streptococcus spp. are important causes of infective endocarditis but challenging in species identification. This study compared identification based on sequence determination of the rnpB gene with 2 systems of matrix-assisted laser desorption ionization-time of flight mass spectrometry, MALDI Biotyper (Bruker) and VITEK MS IVD (bioMérieux). Blood culture isolates of viridans streptococci from 63 patients with infective endocarditis were tested. The 3 methods showed full agreement for all 36 isolates identified in the Anginosus, Bovis, and Mutans groups or identified as Streptococcus cristatus, Streptococcus gordonii, or Streptococcus sanguinis. None of the methods could reliably identify the 23 isolates to the species level when designated as Streptococcus mitis, Streptococcus oralis, or Streptococcus tigurinus. In 7 isolates classified to the Mitis group, the rnpB sequences deviated strikingly from all reference sequences, and additional analysis of sodA and groEL genes indicated the occurrence of yet unidentified Streptococcus spp.

Infective endocarditis in the Lao PDR: clinical characteristics and outcomes in a developing country

INTRODUCTION

Data on infective endocarditis (IE) in Southeast Asia are scarce.

OBJECTIVES

To describe the clinical epidemiology of IE in Lao PDR, a lower middle-income country.

METHODS

A single centre retrospective study at Mahosot Hospital, Vientiane. Patients aged over 1year of age admitted 2006-2012 to Mahosot Hospital with definite or possible IE by modified Duke criteria were included.

RESULTS

Thirty-six patients fulfilled the inclusion criteria; 33 (91.7%) had left-sided IE. Eleven (30.6%) had definite IE and 25 (69.4%) possible left-sided IE. Median age was 25years old [IQR 18-42]. Fifteen patients (41.7%) were males. Underlying heart diseases included: rheumatic valve disease in 12 (33.3%), congenital heart disease in 7 (19.4%), degenerative valve disease in 3 (8.3%), and of unknown origin in 14 (38.9%) patients. Native valve IE was present in 30 patients (83.3%), and prosthetic valve IE in 6 patients (16.7%). The most frequent pathogens were Streptococcus spp. in 7 (19.4%). Blood cultures were negative in 22 patients (61.1%). Complications included: heart failure in 11 (30.6%), severe valve regurgitation in 7 (19.4%); neurological event in 7 (19.4%); septic shock or severe sepsis in 5 (13.9%); and cardiogenic shock in 3 patients (8.3%). No patient underwent heart surgery. Fourteen (38.9%) had died by follow-up after a median of 2.1years [IQR 1-3.2]; and 3 (8.3%) were lost to follow-up.

CONCLUSIONS

Infective endocarditis, a disease especially of young adults and mainly caused by Streptococcus spp., was associated with rheumatic heart disease and had high mortality in Laos.

Infective endocarditis in Turkey: aetiology, clinical features, and analysis of risk factors for mortality in 325 cases

OBJECTIVE

In order to define the current characteristics of infective endocarditis (IE) in Turkey, we evaluated IE cases over a 14-year period in a tertiary referral hospital.

METHODS

All adult patients who were hospitalized in our hospital with a diagnosis of IE between 2000 and 2013 were included in the study. Modified Duke criteria were used for diagnosis. The Chi-square test, Student's t-test, Mann-Whitney U-test, Cox and logistic regression analysis were used for the statistical analysis.

RESULTS

There were 325 IE cases during the study period. The mean age of the patients was 47 years. Causative microorganisms were identified in 253 patients (77.8%) and included staphylococci (36%), streptococci (19%), enterococci (7%), and Brucella spp (5%). A streptococcal aetiology was associated with younger age (<40 years) (p=0.001), underlying chronic rheumatic heart disease (CRHD) (odds ratio (OR) 3.89) or a congenital heart defect (OR 4.04), community acquisition (OR 17.93), and native valve (OR 3.68). A staphylococcal aetiology was associated with healthcare acquisition (OR 2.26) or pacemaker lead-associated endocarditis (OR 6.63) and an admission creatinine level of >1.2mg/dl (OR 2.15). Older age (>50 year) (OR 3.93), patients with perivalvular abscess (OR 9.18), being on dialysis (OR 6.22), and late prosthetic valve endocarditis (OR 3.15) were independent risk factors for enterococcal IE. Independent risk factors for mortality in IE cases were the following: being on dialysis (hazard ratio (HR) 4.13), presence of coronary artery heart disease (HR 2.09), central nervous system emboli (HR 2.33), and congestive heart failure (HR 2.15). Higher haemoglobin (HR 0.87) and platelet (HR 0.996) levels and surgical interventions for IE (HR 0. 33) were found to be protective factors against mortality.

CONCLUSIONS

In Turkey, IE occurs in relatively young patients and Brucella spp should always be taken into consideration as a cause of this infection. We should first consider streptococci as the causative agents of IE in young patients, those with CRHD or congenital heart valve disease, and cases of community-acquired IE. Staphylococci should be considered first in the case of pacemaker lead IE, when there are high levels of creatinine, and in cases of healthcare-associated IE. Enterococci could be the most probable causative agent of IE particularly in patients aged >50 years, those on dialysis, those with late prosthetic valve IE, and those with a perivalvular abscess. The early diagnosis and treatment of IE before complications develop is crucial because the mortality rate is high among cases with serious complications. The prevention of bacteraemia with the measures available among chronic haemodialysis patients should be a priority because of the higher mortality rate of subsequent IE among this group of patients.

Health Care-Associated Infective Endocarditis: a Growing Entity that Can Be Prevented

Infective endocarditis (IE) continues to be a serious disease with a poor prognosis and high mortality. Neither incidence rates nor mortality have decreased in recent decades. Because of this, it is important to prevent IE in patients at risk. In the past, prevention of IE has focused on antimicrobial prophylaxis, mainly for dental procedures. However, recent major changes in epidemiology, the most significant being the growing frequency and high mortality rate of health care-associated valve endocarditis (HAIE), mean that preventive strategies against IE must also change. Since intravascular catheters are the most common source of bacteremia among patients with HAIE, significant efforts must be made to minimize the risk of catheter-related bloodstream infections. Measures for preventing the infection of prosthetic valves and cardiac implantable devices at the time of implantation also need to be implemented.

The role of FDG-PET/CT imaging in early detection of extra-cardiac complications of infective endocarditis

The exact incidence of extra-cardiac complications (ECC) in patients with infective endocarditis (IE) is unknown but presumed to be high. These patients, although mostly asymptomatic, may require a more aggressive therapeutic approach. (18)fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is used for the diagnosis of infections, but its role in the early diagnosis of IE complications is still unclear. This study aimed to evaluate the role of FDG-PET/CT in the early diagnosis of ECC in IE and its implications for medical management. We prospectively studied 40 consecutive patients with a confirmed diagnosis of IE (according to the modified Duke criteria) who underwent a whole body FDG-PET/CT study within 14 days from diagnosis. The FDG-PET/CT demonstrated ECC in 17 (42.5%) patients, while 8 (38.1%) of them were asymptomatic. The most frequent embolic sites were musculoskeletal and splenic. Owing to the FDG-PET/CT findings, treatment planning was modified in 14 (35%) patients. This included antibiotic treatment prolongation (27.5%), referral to surgical procedures (15%) and, most substantially, prevention of unnecessary device extraction (17.7%). According to our experiences, FDG-PET/CT imaging was useful in the detection of embolic and metastatic infections in IE. This clinical information had a significant diagnostic and therapeutic impact in managing IE disease.

Infective and non-infective endocarditis in critically ill patients: a clinical-pathological study

The aims of this study are to estimate the incidence, the outcome and the associated risk factors of infective and non-infective endocarditis (IE and NIE, respectively) in intensive care unit (ICU) patients. We studied the post-mortem findings and the clinical data of the patients who died in our ICU between 1996 and 2010. Of the 765 reviewed autopsies, 21 patients (2.7%) presented cardiac vegetations. These cases consisted of 12 IEs and 9 NIEs. Three patients with IE had a mechanical prosthetic valve, and in 11 cases invasive devices had been used. Multiple peripheral embolisms were discovered at autopsy. In particular, the brain appeared to be more affected in patients with IE, while pulmonary embolisms were commonly associated with NIE. Blood cultures were positive in nine patients with IE. The imaging diagnostics (transthoracic and transesophageal echocardiography) which were seldom performed in both groups, proved to be of little help. As a consequence, an IE was correctly diagnosed before death in three patients (25%) and suspected in two other cases (17%), while a NIE was diagnosed before death in one patient alone. In conclusions, critically ill patients admitted to general ICUs, multiple factors related both to the underlying conditions and to performed procedures can facilitate the occurrence of IE and NIE making, at the same time, their diagnosis challenging. Many cases, in fact, are diagnosed only at autopsy. Yet again, post-mortem examination proves to be an invaluable tool for the evaluation of diagnostic accuracy in critical care.

My paper 10 years later: infective endocarditis in the intensive care unit

INTRODUCTION

Although the recent literature contains plenty of studies concerning all aspects of infective endocarditis (IE), very few focus on severe IE requiring admission to the ICU.

RESULTS

In 2004, we published a report on the clinical spectrum and prognostic factors in 228 consecutive critically ill patients with IE. Septic shock, neurological complications and immunocompromised state were independently associated with in-hospital mortality. Cardiac surgery during the acute phase of EI was associated with better survival. A lot of information has been accumulated during the past 10 years on management of IE. Although three sets of blood cultures allow the identification of about 90% of cases, culture-negative IE still remains a diagnostic challenge. Blood-polymerase chain reaction in valve tissue may yield a microbiologic diagnosis. New imaging techniques such as positron emission tomography computed tomography (PET-CT) have shown additive value in patients with an intracardiac device or valvular prosthesis. Systematic cerebral magnetic resonance imaging can lead to modification of therapeutic plans. The decision to operate and the timing of cardiac surgery should take into account the presence of congestive heart failure, neurological complications, renal failure and multiorgan dysfunction syndrome. In 2011 and 2013, we published the results of a multicentre prospective observational study of 198 ICU patients with left-sided IE and confirmed that cardiac surgery was associated with better outcome. The strongest independent predictor of post-operative mortality was the pre-operative multiorgan failure score. Neurological failure also represented a major determinant of mortality, regardless of the mechanism of neurological complication.

CONCLUSION

In the present paper, we propose algorithms to optimize the medico-surgical approach.

MRI visualization of Staphyloccocus aureus-induced infective endocarditis in mice

Infective endocarditis (IE) is a severe and often fatal disease, lacking a fast and reliable diagnostic procedure. The purpose of this study was to establish a mouse model of Staphylococcus aureus-induced IE and to develop a MRI technology to characterize and diagnose IE. To establish the mouse model of hematogenous IE, aortic valve damage was induced by placing a permanent catheter into right carotid artery. 24 h after surgery, mice were injected intravenously with either iron particle-labeled or unlabeled S. aureus (strain 6850). To distinguish the effect of IE from mere tissue injury or recruited macrophages, subgroups of mice received sham surgery prior to infection (n = 17), received surgery without infection (n = 8), or obtained additionally injection of free iron particles to label macrophages (n = 17). Cardiac MRI was performed 48 h after surgery using a self-gated ultra-short echo time (UTE) sequence (TR/TE, 5/0.31 ms; in-plane/slice, 0.125/1 mm; duration, 12∶08 min) to obtain high-resolution, artifact-free cinematographic images of the valves. After MRI, valves were either homogenized and plated on blood agar plates for determination of bacterial titers, or sectioned and stained for histology. In the animal model, both severity of the disease and mortality increased with bacterial numbers. Infection with 105 S. aureus bacteria reliably caused endocarditis with vegetations on the valves. Cinematographic UTE MRI visualised the aortic valve over the cardiac cycle and allowed for detection of bacterial vegetations, while mere tissue trauma or labeled macrophages were not detected. Iron labeling of S. aureus was not required for detection. MRI results were consistent with histology and microbial assessment. These data showed that S. aureus-induced IE in mice can be detected by MRI. The established mouse model allows for investigation of the pathophysiology of IE, testing of novel drugs and may serve for the development of a clinical diagnostic strategy.

Cardiac multidetector computed tomography in infective endocarditis: a pictorial essay

Objectives

The goals of this pictorial essay are: (1) to set out a multislice computed tomography (MSCT) imaging protocol to assess infective endocarditis (IE); (2) to give an MSCT overview of valvular and peri-valvular involvement during IE; (3) to give a CT overview of septic embolism and infectious pseudoaneurysms during IE.

Methods

MSCT acquisition protocols to assess IE are performed in two different phases: the first acquisition, under electrocardiography (ECG) gating, covers the cardiac structures during first-pass iodine injection; the second acquisition covers the thorax, abdomen, pelvic and cerebral regions.

Results

Valvular and peri-valvular lesions during IE are: vegetation—a hypodense, homogeneous, irregular mass on a valve or endocardial structure; perforation—a defect in the leaflet; valvular aneurysm—loss of the homogenous curvature of the leaflet; valvular thickening; peri-valvular abscess; pseudoaneurysm; fistula and disinsertion of a prosthetic valve. Extra-cardiac location could involve all organs.

Conclusions

MSCT can be considered as a useful complement in visualising the cardiac lesions of IE if echocardiography is inconclusive. MSCT is the only imaging modality that provides assessment of valvular and peri-valvular involvement, extra-cardiac lesions, and non-invasive evaluation of the coronary artery anatomy, simultaneously.

Main Messages

• MSCT provides assessment of coronary anatomy, cardiac and extra-cardiac lesions.

• MSCT represents an alternative to echocardiography during IE.

• Surgical valve replacement is usually required if vegetation is >10 mm.

• Peri-valvular extension (abscesses, pseudoaneurysm and fistulae) required surgical treatment.

Long-term clinical outcome of major adverse cardiac events in survivors of infective endocarditis: a nationwide population-based study

BACKGROUND

Substantial infective endocarditis (IE)-related morbidity and mortality may occur even after successful treatment. However, no previous study has explored long-term hard end points (ie, stroke, myocardial infarction, heart failure, cardiovascular death) in addition to all-cause mortality in IE survivors.

METHODS AND RESULTS

A nationwide population-based cohort study was conducted among IE survivors identified with the use of the Taiwan National Health Insurance Research Database during 2000 to 2009. IE survivors were defined as those who survived after discharge from first hospitalization with a diagnosis of IE. A total of 10 116 IE survivors were identified. IE survivors were matched to control subjects without IE at a 1:1 ratio through the use of propensity scores. The primary outcomes were stroke, myocardial infarction, readmission for heart failure, and sudden cardiac death or ventricular arrhythmia. The secondary outcomes were repeat IE and all-cause mortality. Compared with the matched cohort, IE survivors had higher risks of ischemic stroke (adjusted hazard ratio [aHR], 1.59; 95% confidence interval [CI], 1.40-1.80), hemorrhagic stroke (aHR, 2.37; 95% CI, 1.90-2.96), myocardial infarction (aHR, 1.44; 95% CI, 1.17-1.79), readmission for heart failure (aHR, 2.24; 95% CI, 2.05-2.43), sudden death or ventricular arrhythmia (aHR, 1.69; 95% CI, 1.44-1.98), and all-cause death (aHR, 2.27; 95% CI, 2.14-2.40). Risk factors for repeat IE were older age, male sex, drug abuse, and valvular replacement after an initial episode of IE.

CONCLUSION

Despite treatment, the risk of long-term major adverse cardiac events was substantially increased in IE survivors.

Severe infective endocarditis with systemic embolism due to community associated methicillin-resistant Staphylococcus aureus ST630

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are increasingly causing infective endocarditis over the past decade. Here we report a healthy man who developed a severe acute infective endocarditis with systemic embolism caused by CA-MRSA. The strain was recovered from repeated blood cultures and was characterized using molecular detection and genotyping. The S. aureus isolate was typed as ST630 SCCmecV with spa-type t4549, agrI/IV and was PVL-negative. This is the only case report, to our knowledge, of CA-MRSA infective endocarditis in China. This case highlights the emergence and geographical spread of life-threatening CA-MRSA infection within China.

Biodegradable materials for surgical management of infective endocarditis: new solution or a dead end street?

Background

One third of patients with infective endocarditis will require operative intervention. Given the superiority of valve repair over valve replacement in many indications other than endocarditis, there has been increasing interest and an increasing number of reports of excellent results of valve repair in acute infective endocarditis. The theoretically ideal material for valve repair in this setting is non-permanent, “vanishing” material, not at risk of seeding or colonization. The goal of this contribution is to review currently available data on biodegradable materials for valve repair in infective endocarditis.

Discussion

Rigorous electronic and manual literature searches were conducted to identify reports of biodegradable materials for valve repair in infective endocarditis. Articles were identified in electronic database searches of Medline, Embase and the Cochrane Library, using a predetermined search strategy. 49 manuscripts were included in the review. Prosthetic materials needed for valve repair can be summarized into annuloplasty rings to remodel the mitral or tricuspid annulus, and patch materials to replace resected valvar tissue. The commercially available biodegradable annuloplasty ring has shown interesting clinical results in a single-center experience; however further data is required for validation and longer follow-up. Unmodified extra-cellular matrix patches, such as small intestinal submucosa, have had promising initial experimental and clinical results in non-infected valve repair, although in valve repair for endocarditis has been reported in only one patient, and concerns have been raised regarding their mechanical stability in an infected field.

Summary

These evolving biodegradable devices offer the potential for valve repair with degradable materials replaced with autologous tissue, which could further improve the results of valve repair for infective endocarditis. This is an evolving field with promising experimental or initial clinical results, however long-term outcomes are lacking and further data is necessary to validate this theoretically interesting approach to infective endocarditis.

Cardiac mass with calcification forming pulmonary atresia in utero; a case of fetal endocarditis

Fetal intracardiac mass with calcification is very rare and not well reported. The authors treated a patient with a cardiac mass presumed to be infective endocarditis in the tricuspid valve and pulmonary valve positions with postcalcification echocardiographic shadow forming pulmonary atresia. Although postnatal consecutive blood cultures for bacterial and fungal pathogens tested negative, serial follow-up echocardiograms and surgical findings suggested infective endocarditis. This report describes a very rare case of presumed fetal infective endocarditis presenting as a calcified mass, which was successfully treated by partial resection without significant morbidity.

D-dimer level predicts in-hospital mortality in patients with infective endocarditis: a prospective single-centre study

BACKGROUND

Increased circulating D-dimer levels have been correlated with adverse outcomes in various clinical conditions. To our knowledge, the association of on-admission D-dimer and in-hospital mortality in infective endocarditis (IE) has not been investigated. We hypothesized that increased on-admission D-dimer levels would correlate with adverse outcomes when prospectively studied in patients with IE.

METHODS

In this prospective study, a total of 157 consecutive patients with the definite IE diagnosis met the inclusion criteria and underwent testing for on-admission D-dimer and CRP assays. The outcome measure was in-hospital death from any cause.

RESULTS

In-hospital mortality occurred in 40 (26%) patients. Increased levels of plasma D-dimer (5.1 ± 1.7 vs 1.9 ± 0.8, p<0.001), CRP [45(13-98) vs 12(5-28), p<0.001] were found in dead patients compared with those survived. In addition to S. aureus infection, increased leukocyte count, end-stage renal disease, LVEF<50%, vegetation size of >10mm, perivalvular abscess, on-admission D-dimer (HR: 1.32; 95% CI: 1.24-1.40; p<0.001) and CRP (HR: 1.18; 95% CI: 1.09-1.36; p=0.001) levels were significantly associated with in-hospital mortality. Furthermore, the sensitivity and specificity of D-dimer ≥ 4.2mg/L in predicting in-hospital death in IE were 86% and 85%, respectively. Moreover, the sensitivity and specificity of CRP levels ≥ 13.6 mg/L were 72% and 69%, respectively.

CONCLUSION

Our findings suggest that on-admission D-dimer level may be a simple, available and valuable biomarker that allows us to identify high-risk IE patients for in-hospital mortality. D-dimer ≥ 4.2mg/L, CRP ≥ 13.6 mg/L were independently associated with IE related in-hospital death.

Infective endocarditis in Rio de Janeiro, Brazil: a 5-year experience at two teaching hospitals

INTRODUCTION

Despite the recent advances in diagnosis and treatment, mortality rates due to infective endocarditis (IE) remain high if not aggressively treated with antibiotics, whether or not associated with surgery. Data on the prevalence, epidemiology and etiology of IE from developing countries remain scarce. The aim of this observational, prospective cohort study was to report a 5-year experience of IE at two teaching hospitals in Rio de Janeiro, Brazil.

MATERIAL AND METHODS

Demographical, anamnestic and microbiological characteristics of 71 IE patients were evaluated during the period of January 2009 to March 2013.

RESULTS

The mean age of the IE patients was 49.8 ± 2.4 years, of which 41 (57.7%) were males. The median time between the onset of symptoms and diagnosis of IE was 35.8 ± 4.8 days. A total of 31 (43.6%) cases of community-acquired infective endocarditis (CAIE) and 40 (56.3%) cases of healthcare-acquired infective endocarditis (HAIE) were observed. Staphylococcus aureus (30%) was the predominant cause of IE. Streptococcus spp. (45.1 %) was the predominant cause of the CAIE while S. aureus (32.5%) and Enterococcus spp. (27.2 %) were the main etiological agents of HAIE. For 64 (90.1 %) patients with native valve endocarditis, the mitral valve was the most commonly affected (48.3%). The main source of IE in this cohort was intravascular catheter. The tricuspid valve and renal chronic insufficiency were more frequent in patients with HAIE than CAIE (p = 0.001). The risk factors associated with in-hospital mortality rate (46.4%) in IE patients were: age over 45 (OR 3.4; 95% CI 1.03-11.24; p = 0.04) and chronic renal insufficiency (OR 38.3; 95% CI 3.2-449.4; p = 0.004).

CONCLUSIONS

At two main teaching hospitals in Brazil, Streptococcus spp. was the principal pathogen of CAIE while S. aureus and Enterococcus spp. were the most frequent causes of HAIE. IE remains a serious disease associated with high in-hospital mortality rate (46.6%); especially, in individuals over 45 years of age and with renal failure. Data suggest that early surgery may improve the outcome of IE patients.

Tropheryma whipplei endocarditis

Tropheryma whipplei endocarditis differs from classic Whipple disease, which primarily affects the gastrointestinal system. We diagnosed 28 cases of T. whipplei endocarditis in Marseille, France, and compared them with cases reported in the literature. Specimens were analyzed mostly by molecular and histologic techniques. Duke criteria were ineffective for diagnosis before heart valve analysis. The disease occurred in men 40-80 years of age, of whom 21 (75%) had arthralgia (75%); 9 (32%) had valvular disease and 11 (39%) had fever. Clinical manifestations were predominantly cardiologic. Treatment with doxycycline and hydroxychloroquine for at least 12 months was successful. The cases we diagnosed differed from those reported from Germany, in which arthralgias were less common and previous valve lesions more common. A strong geographic specificity for this disease is found mainly in eastern-central France, Switzerland, and Germany. T. whipplei endocarditis is an emerging clinical entity observed in middle-aged and older men with arthralgia.

The epidemiology and outcomes of infective endocarditis in a tertiary care hospital in Oman

OBJECTIVES

We undertook this study to describe the epidemiological and clinical features of infective endocarditis (IE) and to study the complications and management of IE in a tertiary care hospital in Oman.

METHODS

This is a retrospective study of 58 adult patients (>13 years of age) admitted to the Royal Hospital with IE from June 2006 to June 2011.

RESULTS

Of the 58 patients, 40 (69%) were males, and 18 (31%) were females (ratio 2.2). The median age was 43.6 years (range: 14-85). Forty-eight cases (82.7%) had native valves, nine patients (15.6%) had prosthetic valves, and one case (1.7%) had a pacemaker. The most commonly involved valves were mitral (33, 56.9%) and aortic (23, 39.7%). The blood cultures were positive in 47 (81%) patients, and the most commonly isolated organisms were Streptococci spp., which were found in 20 (34.5%) patients, and Staphylococci spp., which were found in 19 (32.8%) patients. The complication rate was 21%. A total of 15 (25.9%) patients underwent surgical intervention, and the in-hospital mortality rate was 27.6%.

CONCLUSIONS

Native-valve IE is the predominant type of endocarditis and is more of an acute disease. The prevalence of Staphylococci spp. IE is similar to that of Streptococci spp. IE, and its associated mortality remains high.

The relationship of the lipoprotein SsaB, manganese and superoxide dismutase in Streptococcus sanguinis virulence for endocarditis

Streptococcus sanguinis colonizes teeth and is an important cause of infective endocarditis. Our prior work showed that the lipoprotein SsaB is critical for S. sanguinis virulence for endocarditis and belongs to the LraI family of conserved metal transporters. In this study, we demonstrated that an ssaB mutant accumulates less manganese and iron than its parent. A mutant lacking the manganese-dependent superoxide dismutase, SodA, was significantly less virulent than wild-type in a rabbit model of endocarditis, but significantly more virulent than the ssaB mutant. Neither the ssaB nor the sodA mutation affected sensitivity to phagocytic killing or efficiency of heart valve colonization. Animal virulence results for all strains could be reproduced by growing bacteria in serum under physiological levels of O(2). SodA activity was reduced, but not eliminated in the ssaB mutant in serum and in rabbits. Growth of the ssaB mutant in serum was restored upon addition of Mn(2+) or removal of O(2). Antioxidant supplementation experiments suggested that superoxide and hydroxyl radicals were together responsible for the ssaB mutant's growth defect. We conclude that manganese accumulation mediated by the SsaB transport system imparts virulence by enabling cell growth in oxygen through SodA-dependent and independent mechanisms.

Evidence for steric regulation of fibrinogen binding to Staphylococcus aureus fibronectin-binding protein A (FnBPA)

The adjacent fibrinogen (Fg)- and fibronectin (Fn)-binding sites on Fn-binding protein A (FnBPA), a cell surface protein from Staphylococcus aureus, are implicated in the initiation and persistence of infection. FnBPA contains a single Fg-binding site (that also binds elastin) and multiple Fn-binding sites. Here, we solved the structure of the N2N3 domains containing the Fg-binding site of FnBPA in the apo form and in complex with a Fg peptide. The Fg binding mechanism is similar to that of homologous bacterial proteins but without the requirement for "latch" strand residues. We show that the Fg-binding sites and the most N-terminal Fn-binding sites are nonoverlapping but in close proximity. Although Fg and a subdomain of Fn can form a ternary complex on an FnBPA protein construct containing a Fg-binding site and single Fn-binding site, binding of intact Fn appears to inhibit Fg binding, suggesting steric regulation. Given the concentrations of Fn and Fg in the plasma, this mechanism might result in targeting of S. aureus to fibrin-rich thrombi or elastin-rich tissues.

Epidemiology of infective endocarditis in a large Belgian non-referral hospital

OBJECTIVES

Guidelines for diagnosis of infective endocarditis are largely based upon epidemiological studies in referral hospitals. Referral bias, however, might impair the validity of guidelines in non-referral hospitals. Recent studies in non-referral care centres on infective endocarditis are sparse. We conducted a retrospective epidemiological study on infective endocarditis in a large non-referral hospital in a Belgian city (Kortrijk).

METHODS

The medical record system was searched for all cases tagged with a putative diagnosis of infective endocarditis in the period 2003-2010. The cases that fulfilled the modified Duke criteria for probable or definite infective endocarditis were included.

RESULTS

Compared to referral centres, an older population with infective endocarditis, and fewer predisposing cardiac factors and catheter-related infective endocarditis is seen in our population. Our patients have fewer prosthetic valve endocarditis as well as fewer staphylococcal endocarditis. Our patients undergo less surgery, although mortality rate seems to be highly comparable with referral centres, with nosocomial infective endocarditis as an independent predictor of mortality.

CONCLUSION

The present study suggests that characteristics of infective endocarditis as well as associative factors might differ among non-referral hospitals and referral hospitals.

Infective endocarditis: prevention, diagnosis, and management

Infective endocarditis (IE) is among the most severe infectious disease, the prevention of which has not decreased its incidence. The age of patients and the rate of health care-associated IE have increased as a consequence of medical progress. The prevention strategies have been subjected to an important debate and nonspecific hygiene measures are now placed above the use of antibiotic prophylaxis. Indeed, the level of evidence of antibiotic prophylaxis efficiency is low and the indications of its prescription have been restricted in the recent international guidelines. In cases carrying a high suspicion of IE, efforts should be made to rapidly identify patients with a definite or highly probable diagnosis of IE and to find the causative pathogen to ensure that appropriate treatment, including urgent valvular surgery, begins promptly. Although echocardiography remains the main accurate imaging modality to identify endocardial lesions associated with IE, it can be negative or inconclusive especially in cases of prosthetic valve or other intracardiac devices. Recent studies demonstrated the diagnostic value of other imaging strategies including cardiac computed tomography (CT), positron emission tomography/CT, radiolabelled leukocyte single-photon emission CT/CT, and cerebral magnetic resonance imaging. Novel perspectives on the management of endocarditis are emerging and offer a hope for decreasing the rate of residual deaths by accelerating the processes of diagnosis, risk stratification, and instauration of antimicrobial therapy. Moreover, the rapid transfer of high-risk patients to specialized mediosurgical centres (IE team), the development of new surgical modalities, and close long-term follow-up are of crucial importance.