Long term follow up of prosthetic valve endocarditis: what characteristics identify patients who were treated successfully with antibiotics alone?

Management of Prosthetic Mitral Valve Infective Endocarditis in a Patient With Congenital Heart Disease

We present the case of an adult patient with Kartagener's syndrome, multiple prior sternotomies, and recurrent prosthetic valve endocarditis, a scenario without clear guidelines to direct management. Ultimately, the team elected for medical management given the high mortality risk associated with surgery; the patient responded to antibiotic therapy.

Clinical Features and Outcome of Infective Endocarditis in a University Hospital in Romania

Background and Objectives: Characterization of patients with endocarditis regarding demographic, clinical, biological and imagistic data, blood culture results and possible correlation between different etiologic factors and host status characteristics. Material and methods: This is a retrospective observational descriptive study conducted on patients older than 18 years admitted in the past 10 years, in the Cardiology Clinic of the Clinical County Emergency Hospital Oradea Romania, with clinical suspicion of bacterial endocarditis. Demographic data, clinical, paraclinical investigations and outcome were registered and analyzed. Results: 92 patients with definite infective endocarditis (IE) according to modified Duke criteria were included. The mean age of patients was 63.80 ± 13.45 years. A percent of 32.6% had health care associated invasive procedure performed in the 6 months before diagnosis of endocarditis. Charlson's comorbidity index number was 3.53 ± 2.029. Most common clinical symptoms and signs were: shortness of breath, cardiac murmur, fever. Sixty-six patients had native valve endocarditis, 26 patients had prosthetic valve endocarditis and one patient was with congenital heart disease. Blood cultures were positive in 61 patients. Among positive culture patient's staphylococcus group was the most frequently involved: Staphylococcus aureus (19.6%) and coagulase negative Staphylococcus (18.5%). Most frequent complications were heart failure, acute renal failure and embolic events. Conclusions: Staphylococcus aureus IE was associated with the presence of large vegetations, prosthetic valve endocarditis and intracardiac abscess. Coagulase negative Staphylococcus (CoNS) infection was associated with prosthetic valve dysfunction. Streptococcus gallolyticus etiology correlated with ischemic embolic stroke and the presence of large vegetations. Cardiovascular surgery was recommended in 67.4% of patients but was performed only on half of them. In hospital death occurred in 33.7% of patients and independent predictors of mortality were congestive heart failure and septic shock.

2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the valvular heart disease guideline provides recommendations for clinicians to diagnose and manage valvular heart disease as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to March 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected database relevant to this guideline. Structure: Many recommendations from the earlier valvular heart disease guidelines have been updated with new evidence and provides newer options for diagnosis and treatment of valvular heart disease. This summary includes only the recommendations from the full guideline which focus on diagnostic work-up, the timing and choice of surgical and catheter interventions, and recommendations for medical therapy. The reader is referred to the full guideline for graphical flow charts, text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in developing these guidelines.

A narrative review of early surgery versus conventional treatment for infective endocarditis: do we have an answer?

The most appropriate strategy and timing for surgery in infective endocarditis (IE) remains an argument of debate. Despite some authors promote the adoption of an early surgical approach (within 48 hours) to limit mortality and complications, no robust randomized trials are available on this argument and the evidence on this subject remain at the "expert opinion" level. Additionally, the different messages promulgated by the American and European guidelines contributed to fuel confusion regarding the relative priority of the surgical over medical therapy in IE. The European Society of Cardiology (ESC) guidelines individuates three level of urgency: emergency surgery, to be performed within 24 hours; urgent surgery, recommended within a few days; elective surgery to be performed after 1-2 weeks of antibiotic therapy. Urgent surgery is recommended for most cases of IE. In the American Heart Association (AHA)'s guidelines define early surgery as "during the initial hospitalization and before completion of a full course of antibiotics." Some of the available evidences showed that are no proven benefits in delaying surgery if a definite diagnosis of IE has been established. However, this argument is controversial across the literature and several factors including the center specific experience can play a role in decision-making. In this review the latest evidences on IE clinical and surgical characteristics along with the current studies on the adoption of an early surgical approach are analyzed to clarify whether enough evidence is available to inform an update of the guidelines.

Methicillin-Resistant Staphylococcus aureus Prosthetic Valve Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management

Staphylococcus aureus prosthetic valve endocarditis (PVE) remains among the most morbid bacterial infections, with mortality estimates ranging from 40% to 80%. The proportion of PVE cases due to methicillin-resistant Staphylococcus aureus (MRSA) has grown in recent decades, to account for more than 15% of cases of S. aureus PVE and 6% of all cases of PVE. Because no large studies or clinical trials for PVE have been published, most guidelines on the diagnosis and management of MRSA PVE rely upon expert opinion and data from animal models or related conditions (e.g., coagulase-negative Staphylococcus infection). We performed a review of the literature on MRSA PVE to summarize data on pathogenic mechanisms and updates in epidemiology and therapeutic management and to inform diagnostic strategies and priority areas where additional clinical and laboratory data will be particularly useful to guide therapy. Major updates discussed in this review include novel diagnostics, indications for surgical management, the utility of aminoglycosides in medical therapy, and a review of newer antistaphylococcal agents used for the management of MRSA PVE.

Prosthetic valve endocarditis - A trouble or a challenge?

Prosthetic valve endocarditis (PVE) represents a rare and serious complication of valve replacement associated with high morbidity and mortality, which significantly differs from native valve endocarditis (NVE). There are two major problems: establishing diagnosis and treatment of PVE. Diagnosis in PVE is challenging and often requires several imaging methods besides standard microbiological analyzes. Transesophageal echocardiographic examination remains the widely used imaging technique in PVE diagnosis, but additional techniques such as computed tomography (CT) and ¹⁸F-fluodeoxyglucose positron emission tomography/CT are often necessary. Persistent fever, embolic complications, valve dehiscence, intracardial abscess, heart failure, as well as staphylococcal and fungal PVE require surgical treatment to avoid lethal outcome. The introduction of transcatheter valve implantations and devices significantly complicated the approach - diagnostic and therapeutic to PVE patients. Despite constantly increasing knowledge regarding pathogenesis and treatment of PVE, the optimal therapy remains a matter of debate. Additional studies are necessary to define therapeutic strategies for this potentially fatal complication.

Endocarditis after interventional repair of the mitral valve: Review of a dilemma

BACKGROUND

The MitraClip procedure can be an alternative treatment option for patients with high surgical risk for whom surgical treatment is contraindicated. Patients with prosthetic material have an increased risk for infective endocarditis.

HYPOTHESIS

Incidence, treatment and outcome of patients with endocarditis after interventional mitral valve repair are not known.

METHODS

We searched for articles using PubMed using the terms "interventional mitral valve repair", "mitraclip" and "endocarditis". We have also searched for case reports in major congresses. Furthermore, we report two cases.

RESULTS

Four cases of IE after MitraClip were found in addition to our cases. The leading cause is a bacterial infection, typically with staphylococcal bacteria. Approximately two thirds of these patients underwent surgery. Short-term outcome seems to be reasonable for these patients. During the early postoperative period and if Staphylococcus aureus can be cultivated mortality seems to be significantly elevated.

CONCLUSION

IE after MitraClip procedure is a dilemma. While surgical bail-out seems to be the favorable treatment option, patients were rejected conventional surgery in first place due to their high operative risk. Best treatment recommendation must be made on an individual basis. Predisposing factors should be conscientiously addressed prior to the procedure.

Surgical Versus Medical Therapy for Prosthetic Valve Endocarditis: A Meta-Analysis of 32 Studies

Prosthetic valve endocarditis (PVE) is associated with significant morbidity, and the optimal treatment strategy has not been clearly defined. A systematic review and meta-analysis of 32 studies comparing valve reoperation and medical therapy was performed; it included 2,636 patients, with a mean follow-up of 22 months. A valve reoperation was associated with a lower risk of 30-day mortality, greater survival at follow-up, and a similar rate of PVE recurrence. Prospective studies are warranted to confirm these findings and to clarify clinical decision-making regarding the timing and necessity of a valve reoperation, as opposed to treatment with medical therapy alone.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Late postoperative prosthetic pulmonary valve endocarditis in a 13-year-old girl with repaired tetralogy of fallot

Prosthetic pulmonary valve endocarditis has infrequently been described outside large cohort reviews, which have typically focused on infections of the left-sided heart valves. Hence, the pathogenesis, clinical presentation, and management principles of prosthetic pulmonary valve endocarditis have not been well differentiated from those of infected aortic and mitral valves. More patients with repaired tetralogy of Fallot are reaching adulthood and will need pulmonary valve implantation. Consequently, a focus on this infrequent but serious cardiac infection is needed, to learn what characteristics might distinguish it from infections of left-sided heart valves. We report the case of a 13-year-old girl with repaired tetralogy of Fallot who presented with fever and nonspecific symptoms. The patient initially failed to meet the Duke criteria for endocarditis but was then found to have endocarditis of her prosthetic pulmonary valve. We explanted the valve and replaced it with a pulmonary homograft, after which the patient had no infectious sequelae. In addition to presenting the patient's case, we review the literature on surgically inserted prosthetic pulmonary valves and discuss the primary management concerns when those valves become infected with endocarditis.

Predictors of In-hospital Adverse Events in Patients with Prosthetic Valve Infective Endocarditis

BACKGROUND

We aimed to study patients with prosthetic valve endocarditis (PVE) and analyse factors associated with in-hospital adverse events.

METHODS

A review of all patients who underwent echocardiography at a local university hospital with definite PVE (modified Duke's criteria) was performed. Adverse events of in-hospital mortality and redo valve surgery were identified.

RESULTS

There were 23 patients with PVE (median age 53 years (IQR:38-66), 12 males (52%)). Twelve adverse events occurred including seven (30%) in-hospital mortalities and five (21%) redo valve surgery. Factors associated with in-hospital mortality include Staphylococcus aureus-PVE (86% vs 31%, p=0.027), presence of shock (86% vs 19%, p=0.005) and intensive care unit admission (72% vs 19%, p=0.026). Factors associated with the need for redo valve surgery include a younger median age (37 vs 61 years, p=0.012), longer median length of stay (58 vs 17 days, p=0.004), history of intravenous drug abuse (IVDA) (60% vs 6%, p=0.021) and right-sided valvular involvement (40% vs 0%, p=0.040). Using a composite endpoint of both outcomes, factors associated with in-hospital adverse events were a history of IVDA (36% vs 0%, p=0.037) and presence of shock (64% vs 17%, p=0.036).

CONCLUSION

PVE carries a high risk of poor clinical outcome in terms of in-hospital mortality and the need for redo surgery.

Management strategies and outcome for prosthetic valve endocarditis

The aim of this study was to assess the impact of an operative protocol with a multidisciplinary approach on the outcome of patients with prosthetic valve endocarditis (PVE). A formal policy for the care of PVE was introduced at our hospital in 2003 in which patients were referred to and managed by a preexisting team involving a cardiologist, a specialist in infectious diseases, and a cardiac surgeon. All patients underwent transesophageal echocardiography as soon as clinical suspicion of PVE arose. If high-risk conditions such as heart failure, ring abscess, conditions associated with impending malfunctioning of the prosthesis, or vegetations at high risk for systemic embolization were found during the initial multidisciplinary evaluation (performed within 12 hours of admission), patients were operated on within 48 hours. Stable patients were evaluated weekly by the multidisciplinary team, and on-treatment surgery was performed whenever high-risk conditions developed or when there was persistent fever/bacteremia after 1 week of adequate antibiotic therapy. Comparing the period 2003 through 2009 with 1996 through 2002 (when a multidisciplinary policy was not followed), patients with PVE were more numerous (61 vs 38), older (mean age 68.3 vs 63.1, p = 0.01), and had more co-morbidities (mean Charlson index 3.15 vs 2.42, p = 0.03). The most frequent causative organisms were Staphylococci in both periods. In the second period, fewer patients had delayed diagnosis (39% vs 71%, p = 0.03), heart failure (20% vs 45%, p = 0.01), abscess (20% vs 39%, p = 0.04), culture-negative infective endocarditis (11% vs 29%, p = 0.03), and worsened renal function (21% vs 42%, p = 0.04). A significant reduction in in-hospital mortality (53% to 23%, p = 0.04) and 3-year mortality (60% to 28%, p = 0.001) was observed, driven by the increased number of patients successfully treated with medical therapy alone (44% vs 16%, p = 0.04). In conclusion, formalized, collaborative management led to significant improvement in PVE-related mortality.

DNA persistence and relapses questions on the treatment strategies of Enterococcus infections of prosthetic valves

We used amplification of the 16S rRNA gene followed by sequencing to evaluate the persistence of bacterial DNA in explanted heart valve tissue as part of the routine work of a clinical microbiology laboratory, and we analyzed the role of this persistence in the relapses observed in our center. We enrolled 286 patients treated for infective endocarditis (IE) who had valve replacement surgery and were diagnosed according to the modified Duke's criteria described by Li et al. from a total of 579 IE cases treated in our center. The patients were grouped based on the infecting bacteria, and we considered the 4 most common bacterial genus associated with IE separately (144 were caused by Streptococcus spp., 52 by Enterococcus spp., 58 by Staphylococcus aureus and 32 by coagulase-negative Staphylococcus). Based on our cohort, the risk of relapse in patients with enterococcal prosthetic valve infections treated with antibiotics alone was 11%. Bacterial DNA is cleared over time, but this might be a very slow process, especially with Enterococcus spp. Based on a comprehensive review of the literature performed on Medline, most reports still advise combined treatment with penicillin and an aminoglycoside for as long as 4-6 weeks, but there has been no consensus for the treatment of enterococcal infection of prostheses in IE patients.

Do all patients with prosthetic valve endocarditis need surgery?

A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was 'do all patients with prosthetic valve endocarditis need surgery?' Seventeen papers were found using the reported search that represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. These studies compared the outcome and survival between surgically and non-surgically treated patients with prosthetic valve endocarditis. Of these studies, two were prospective observational studies and the rest were retrospective studies. The results of most of these papers were in accordance with the guidelines of the American College of Cardiology and American Heart association. These studies showed that unless a patient is not a surgical candidate, an operation is the treatment of choice in prosthetic valve endocarditis. Surgery should be performed as soon as possible, particularly in haemodynamically unstable patients and those who develop complications such as heart failure, valvular dysfunction, regurgitation/obstruction, dehiscence and annular abscess. In addition to the above indications and cardiac/valvularrelated complications of prosthetic valve endocarditis, infection with Staphylococcus aureus plays an important role in the outcome, and the presence of this micro-organism should be considered an urgent surgical indication in the treatment of prosthetic valve endocarditis. Surgery should be performed before the development of any cerebral or other complications. In contrast, in stable patients with other micro-organisms, particularly those with organisms sensitive to antibiotic treatment who have no structural valvular damage or cardiac complications, surgery can be postponed. The option of surgical intervention can also be revisited if there is a change in response to the treatment. This option is reserved for selected patients only and we conclude that as soon as the diagnosis of prosthetic valve endocarditis is made, cardiac surgeons should be involved.

Prosthetic valve endocarditis: management strategies and prognosis: A ten-year analysis in a tertiary care centre in Tunisia

BACKGROUND

Prosthetic valve endocarditis (PVE) is a rare and serious complication after heart valve replacement; its optimal management strategy, though, still needs to be defined.

OBJECTIVE

To study the clinical, microbiological and echocardiographic characteristics of PVE and to analyse the influence of the adopted therapeutic strategy (medical or surgical) on short- and midterm outcome in a tertiary care centre in a developing country (Tunisia).

METHODS

All cases of PVE treated in our institution between 1997 and 2006 were retrospectively analysed according to the modified DUKE criteria.

RESULTS

A total of 48 PVE episodes were diagnosed (30 men and 18 women), mean age was 37.93 years. Twenty-eight patients (58.33%) were exclusively medically treated, whereas 20 (41.66%) were treated by a combined surgical and medical strategy. Indications for surgery were haemodynamic deterioration in eight patients (40%), annular abscess in six (30%) and persisting sepsis in six (30%). In comparison with those from the medical group, operated patients had a longer delay to diagnosis (p=0.025), were more frequently in heart failure (p=0.04) and experienced more early complications (p=0.011); they also more frequently had prosthetic dehiscence (p=0.015), annular abscesses (p=0.039) and vegetations >10 mm (p=0.008). Conversely, no differences were found between the groups in terms of age, sex, or nature of involved organisms. In-hospital mortality for the medical group was 14.28% and for the surgical group 35% (p=0.09).

CONCLUSION

PVE is a very serious condition carrying high mortality rates regardless of the adopted strategy. Our study demonstrates that, in selected patients, medical treatment could be a successful and acceptable approach. (Neth Heart J 2009;17: 56-60.).

Prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is associated with a high mortality during the early and midterm follow-up despite diagnostic and therapeutic improvements; its incidence is increasing and reaches 20-30% of all infective endocarditis episodes. In this review, changes in epidemiology, microbiology, diagnosis and therapy that have evolved in the past few years are analyzed. Staphylococci (both Staphylococcus aureus and coagulase-negative Staphylococcus) have emerged as the most common cause of PVE and are associated with a severe prognosis. Moreover, diagnosis may often be difficult because of its complications and extracardiac manifestations; thus, a comprehensive assessment of the clinical, echocardiographic and laboratory data must be performed. Early PVE, comorbidity, severe heart failure and new prosthetic dehiscence are predictors of mortality. Therapy is not indicated by evidence-based recommendations but mostly on identification of the high-risk conditions. A PVE is a common indication for surgery, whereas medical treatment alone may be achieved in a few instances. Systematic prophylaxis should be used to prevent this severe complication of cardiac valve replacement.

Prosthetic Valve Endocarditis in a Multicenter Registry of Chinese Patients

We evaluated the clinical outcomes of prosthetic valve endocarditis in 2 major tertiary referral centers in Hong Kong. The study population comprised 80 consecutive Chinese patients who fulfilled the modified Duke criteria for prosthetic valve endocarditis from March 2000 to June 2007. The major clinical endpoints analyzed were hospital mortality, need for valve surgery, and relapse of prosthetic endocarditis. The mean age at presentation was 56 ± 13 years, with a slight male preponderance. There were 76 (95%) patients with involvement of a mechanical prosthesis; the majority (69%) had late prosthetic endocarditis. Major hospital complications occurred in 49 (61%) patients. The overall hospital mortality was 28% (22 patients). Thirty-four (42%) patients required valve surgery during index hospitalization, of whom 5 (15%) died due to uncontrolled sepsis. Factors associated with hospital mortality were older age at presentation, Staphylococcus aureus infection, embolic events, severe heart failure, valve surgery, and any major complication. On multivariate analysis, severe heart failure was the only independent predictor of hospital death. Among the 58 hospital survivors followed up for a mean of 48 ± 31 months, 6 (10%) developed late complications related to prosthetic valve endocarditis, with 5 documented cases of relapse.

The changing face of prosthetic valve endocarditis at a tertiary-care hospital: 1986-2005

INTRODUCTION AND OBJECTIVES

To investigate changes in the clinical characteristics, etiology and prognosis of prosthetic valve endocarditis at a tertiary-care hospital.

METHODS

Retrospective cohort study of all patients diagnosed with prosthetic valve endocarditis using modified Duke criteria between 1986 and 2005. The analysis covered two time periods: January 1986 to December 1995 (P1) and January 1996 to December 2005 (P2).

RESULTS

In total, 133 episodes of endocarditis occurred in 122 patients. Of these, 73 (54.9%) were diagnosed in P1 and 60 (45.1%) in P2, with incidences of 2.19% and 2.18%, respectively. The patients' mean age (SD) was 52.6+/-16.6 years in P1 and 66.2+/-11.5 years in P2 (P=.0001). Clinical characteristics were similar in the two study periods. The increase in Enterococcus infection was remarkable (12.5% in P2 vs. 4.9% in P1; relative risk [RR]=2.5; 95% confidence interval [CI], 0.7-9.6), as was the decrease in viridans group Streptococcus infection (12.5% in P2 vs. 31.1% in P1; RR=0.4; 95% CI, 0.2-0.9). Some 90.4% of patients (63/73) underwent surgery in P1, while 68.3% (41/60) underwent surgery in P2. The difference was significant (RR=0.8; 95% CI, 0.6-0.9). The in-hospital mortality rate was 28.8% in P1 and 30% in P2 (RR=1; 95% CI, 0.6-1.7).

CONCLUSIONS

Changes in the epidemiology and microbiological etiology of prosthetic valve endocarditis were observed over the 20-year study period. Diagnostic and therapeutic approaches also changed, but mortality remained high.

[Timing and indications for surgical intervention in infective endocarditis]

This paper reviews current knowledge on the indications for and timing of cardiac surgery in patients with infective endocarditis. The main indications for surgery are haemodynamic compromise, persisting infection, peripheral embolisation, large size of vegetations, large valvular and paravalvular damage and infections caused by certain microorganisms.

Swedish guidelines for diagnosis and treatment of infective endocarditis

Swedish guidelines for diagnosis and treatment of infective endocarditis (IE) by consensus of experts are based on clinical experience and reports from the literature. Recommendations are evidence based. For diagnosis 3 blood cultures should be drawn; chest X-ray, electrocardiogram, and echocardiography preferably transoesophageal should be carried out. Blood cultures should be kept for 5 d and precede intravenous antibiotic therapy. In patients with native valves and suspicion of staphylococcal aetiology, cloxacillin and gentamicin should be given as empirical treatment. If non-staphylococcal etiology is most probable, penicillin G and gentamicin treatment should be started. In patients with prosthetic valves treatment with vancomycin, gentamicin and rifampicin is recommended. Patients with blood culture negative IE are recommended penicillin G (changed to cefuroxime in treatment failure) and gentamicin for native valve IE and vancomycin, gentamicin and rifampicin for prosthetic valve IE, respectively. Isolates of viridans group streptococci and enterococci should be subtyped and MIC should be determined for penicillin G and aminoglycosides. Antibiotic treatment should be chosen according to sensitivity pattern given 2-6 weeks intravenously. Cardiac valve surgery should be considered early, especially in patients with left-sided IE and/or prosthetic heart valves. Absolute indications for surgery are severe heart failure, paravalvular abscess, lack of response to antibiotic therapy, unstable prosthesis and multiple embolies. Follow-up echocardiography should be performed on clinical indications.

Prosthetic valve endocarditis: current approach and therapeutic options

Despite improvements in medical and surgical therapy, prosthetic valve endocarditis is still associated with a severe prognosis, and remains a diagnostic and therapeutic challenge. Diagnosis of prosthetic valve endocarditis is more difficult than that of the native valve endocarditis and the application of Duke criteria is less useful in this setting. Therapeutic strategies are not guided by evidence-based recommendations and are mainly based on a careful prognostic evaluation, which allows the identification of high-risk subgroups. Continuous effort have to be made to detect early this severe complication of valve replacement and to prevent it using systematic prophylaxis.

Infections associated with long-term prosthetic devices

The extensive and ever-increasing use of long-term prosthetic devices has improved quality of life and survival for many patients. Prosthetic device-related infection occurs infrequently but is associated with significant morbidity and mortality. Management is challenging, often requiring prolonged antimicrobial therapy and surgical intervention. Better understanding of the interaction between microorganisms, devices, and the host should improve the ability to manage device-related infections. This article reviews recent advances in the diagnosis and treatment of infections associated with indwelling medical devices, highlighting those associated with prosthetic joints, cerebrospinal fluid shunts, and prosthetic heart valves.

Infection of intravascular prostheses: how to treat other than surgery

Long-term antimicrobial therapy may be effective in some patients with intravascular prosthesis infection. However, this approach does not represent an alternative to surgery when this is feasible, but is merely the best opportunity for patients too ill to tolerate a re-intervention. Prosthetic valve endocarditis may be treated with antibiotic therapy alone in selected patients who are haemodynamically stable with non-staphylococcal infections and no para-valvular complications. In contrast, infections of pacemaker leads or other implantable cardiac devices require complete hardware removal, as infection recurrence always occurs, even after a seemingly effective initial treatment. Attempts to treat conservatively infections of abdominal aortic grafts can be successful in a few cases, provided the patient is stable, the pathogen has been identified, and antibiotic susceptibility has been demonstrated. Treatment requires at least 4-6 weeks and may be followed by a sequential oral regimen once the acute phase of the infection has subsided. The correct duration of this treatment is often unknown and relapses are common after treatment withdrawal. The availability of novel antibacterial and antifungal agents - showing fast microbicidal activity that includes biofilm micro-organisms - such as daptomycin and caspofungin, or having a wide antimicrobial spectrum, such as tigecycline, may increase the probability of long-standing suppression or even eradication of the infection in these particular subsets of inoperable patients. However, so far, very little experience is available on the efficacy and tolerability of these drugs in intravascular prosthesis infections. Controlled studies are lacking and difficult to plan. Well-designed prospective studies may help to establish guidelines and reach a multidisciplinary consensus on the optimal therapeutic approach, and are therefore awaited.

Medical versus surgical management of Staphylococcus aureus prosthetic valve endocarditis

PURPOSE

The study's purpose was to identify prognostic factors associated with mortality in Staphylococcus aureus prosthetic valve endocarditis and to determine whether these factors influenced decisions to treat medically versus surgically. We also analyzed whether there was a subset of patients who were cured with medical therapy alone.

SUBJECTS AND METHODS

A retrospective review of patients with S aureus prosthetic valve endocarditis was performed. Demographic and clinical data were collected from existing medical records. Severity of illness was classified using American Society of Anesthesiologists (ASA) score. Impact of treatment on in-hospital mortality was assessed using multiple logistic regression analysis.

RESULTS

Fifty-five patients met the Duke criteria for definite S aureus prosthetic valve endocarditis. Twenty-three patients were treated medically, and 32 patients had surgical intervention. Overall mortality was 36% (28% in the surgical group and 48% in the medical group). ASA score IV (P < .001) and older age (P = .014) were significant risk factors of mortality. Patients with ASA score IV (P = .037) and multiple prosthetic valves (P = .013) were less likely to undergo surgery. Medically treated patients were older compared with those in the surgical group (median age 66 vs 55 years, P = .04). All 4 patients aged less than 50 years in the medically treated group survived.

CONCLUSION

Mortality was generally higher in the medically treated patients with S aureus prosthetic valve endocarditis. Multivariable analysis showed that ASA class IV and bioprosthetic valves were independent predictors of mortality. A subset of medically treated patients characterized by age less than 50 years, ASA score III, and without cardiac, central nervous system, or systemic complications were cured without surgical intervention.

The use and effect of surgical therapy for prosthetic valve infective endocarditis: a propensity analysis of a multicenter, international cohort

BACKGROUND

Although surgical intervention is often used in the treatment of prosthetic valve infective endocarditis (PVIE), an understanding of its effect on survival has been limited by the biases of observational studies and lack of controlled trials.

METHODS

The International Collaboration on Endocarditis Merged Database is a large, multicenter, international registry of patients with definite endocarditis by Duke criteria, including 367 patients with PVIE. Clinical, microbiologic, and echocardiographic variables were analyzed to determine those factors associated with the use of surgery for PVIE. Logistic regression analysis was performed to create a propensity model of predictors of surgery use. Patients who underwent surgery during initial hospitalization were matched by propensity score with patients treated with medical therapy alone. Logistic regression analysis was performed to determine variables independently associated with inhospital mortality in this matched subset.

RESULTS

Surgical therapy for PVIE was performed in 148 (42%) of 367 patients. Inhospital mortality was similar for patients treated with surgery compared with those treated with medical therapy alone (25.0% vs 23.4%, P = .729). Surgical therapy was independently associated with patient age, microorganism, intracardiac abscess, and congestive heart failure. After adjustment for these determinants, inhospital mortality was predicted by brain embolization (OR 11.12, 95% CI 4.16-29.73) and Staphylococcus aureus infection (OR 3.67, 95% CI 1.29-9.74), with a trend toward benefit for surgery (OR 0.56, 95% CI 0.23-1.36).

CONCLUSIONS

Despite the frequent use of surgery for the treatment of PVIE, this condition continues to be associated with a high inhospital mortality rate in the contemporary era. After adjustment for factors related to surgical intervention, brain embolism and S aureus infection were independently associated with inhospital mortality and a trend toward a survival benefit of surgery was evident.

Human infective endocarditis caused by Streptococcus suis serotype 2

Human infective endocarditis due to Streptococcus suis occurs infrequently. The case of a 43-year-old male who sustained life-threatening infective endocarditis is reported. Since growth of S. suis on commonly used sheep blood agar plates resembles viridans streptococci, diagnosis of S. suis constitutes a diagnostic pitfall. Identification was accomplished by using molecular methods.

Prosthetic valve endocarditis: who needs surgery? A multicentre study of 104 cases

OBJECTIVES

To identify the prognostic markers of a bad outcome in a large population of 104 patients with prosthetic valve endocarditis (PVE), and to study the influence of medical versus surgical strategy on outcome in PVE and thus to identify patients for whom surgery may be beneficial.

DESIGN

Multicentre study.

METHODS AND RESULTS

Among 104 patients, 22 (21%) died in hospital. Factors associated with in-hospital death were severe co-morbidity (6% of survivors v 41% of those who died, p = 0.05), renal failure (28% v 45%, p = 0.05), moderate to severe regurgitation (22% v 54%, p = 0.006), staphylococcal infection (16% v 54%, p = 0.001), severe heart failure (22% v 64%, p = 0.001), and occurrence of any complication (60% v 90%, p = 0.05). By multivariate analysis, severe heart failure (odds ratio 5.5) and Staphylococcus aureus infection (odds ratio 6.1) were the only independent predictors of in-hospital death. Among 82 in-hospital survivors, 21 (26%) died during a 32 month follow up. A Cox proportional hazards model identified early PVE, co-morbidity, severe heart failure, staphylococcus infection, and new prosthetic dehiscence as independent predictors of long term mortality. Mortality was not significantly different between surgical and non-surgical patients (17% v 25%, respectively, not significant). However, both in-hospital and long term mortality were reduced by a surgical approach in high risk subgroups of patients with staphylococcal PVE and complicated PVE.

CONCLUSIONS

Firstly, PVE not only carries a high in-hospital mortality risk but also is associated with high long term mortality and needs close follow up after the initial episode. Secondly, congestive heart failure, early PVE, staphylococcal infection, and complicated PVE are associated with a bad outcome. Thirdly, subgroups of patients could be identified for whom surgery is associated with a better outcome: patients with staphylococcal and complicated PVE. Early surgery is strongly recommended for these patients.

Bacteriological Outcome after Valve Surgery for Active Infective Endocarditis: Implications for Duration of Treatment after Surgery

BACKGROUND

There has been no systematic evaluation of outcome after surgery for infective endocarditis with respect to duration of antibiotic treatment.

METHODS

We performed a retrospective chart review of episodes of valve surgery for active infective endocarditis at Green Lane Hospital (Auckland, New Zealand) for 1963-1999. We recorded the duration of antibiotic treatment before and after valve surgery; the extent of infection at operation; Gram stain, culture, and histopathological testing results for valve samples; and the bacteriological outcome after surgery. The primary outcome measure was relapse, defined as endocarditis due to the same species within 1 year after surgery.

RESULTS

For the 358 patients in our study, the median duration of follow-up was 4.8 years. Thirty-two patients (9%) had 36 subsequent episodes of endocarditis. Relapse occurred after 3 (0.8%) of the operations (95% CI, 0.2%-2.0%). Relapse of infection was unrelated to the duration of antibiotic treatment before or after surgery, positive valve culture results, positive Gram stain results, or perivalvular infection. Since 1994, we have reduced the duration of antibiotic treatment by approximately 7 days for those with positive valve culture results and by approximately 14 days for those with negative valve culture results, without any increase in the number of relapses.

CONCLUSIONS

Relapse is an uncommon event following surgery for endocarditis. Commonly suggested indications for prolonging postoperative treatment are not associated with higher relapse rates, and their relevance is debatable. We conclude that it is unnecessary to continue treatment for patients with negative valve culture results for an arbitrary 4-6-week period after surgery. Two weeks of treatment appears to be sufficient, and, for those operated on near the end of the standard period of treatment, simply completing the planned course should suffice.

Infective endocarditis after transcatheter closure of a patent foramen ovale

Infection of devices for percutaneous transcatheter closure of atrial septal defects are exceedingly rare. Two cases of device-associated endocarditis have been reported, which were both operated on. We describe the successful treatment with antibiotics of a device-associated endocarditis.

Causative organisms of infective endocarditis according to host status

A prospective study of infective endocarditis (IE) was conducted between 1994 and 2000 in Marseilles, France, and included 170 definite cases diagnosed with the use of modified Duke criteria. Classification of IE based on the aetiological agent was related to epidemiological characteristics, including age, gender and the nature of the injured valve. Enterococci and Streptococcus bovis were identified more frequently in older subjects (p 0.02), and S. bovis was also associated with mitral valve infection (p 0.03). Streptococcus spp. were found to be associated with native valves (p < 10(-3)), whereas coagulase-negative staphylococci and Coxiella burnetii were associated with intracardiac prosthetic material (p < 0.05). S. bovis and Staphylococcus aureus were the predominant species associated with presumably healthy valves (p < 0.05), whereas oral streptococci caused IE exclusively in patients with previous valve damage. The basic host status of IE patients has been linked to specific microorganisms, and this may be of value when empirical treatment is needed in patients who have received previous antibiotic therapy and whose blood cultures are negative.

Long-term prognosis of early and late prosthetic valve endocarditis

A prospective series of 78 cases of prosthetic valve endocarditis (PVE) was studied (35 cases of early PVE and 43 cases of late PVE). The in-hospital mortality rate was significantly higher in patients with early PVE (31% vs 9%, p <0.01) because the onset of heart failure was more common in these patients (55% vs 37%, p <0.05). However, event-free survival at 4 years in survivors to the active phase was not different (74% and 82%, respectively).

Prognostic factors in 61 cases of Staphylococcus aureus prosthetic valve infective endocarditis from the International Collaboration on Endocarditis merged database

Staphylococcus aureus prosthetic valve infective endocarditis (SA-PVIE) is associated with a high mortality rate, but prognostic factors have not been clearly elucidated. The International Collaboration on Endocarditis merged database (ICE-MD) contained 2212 cases of definite infective endocarditis (as defined using the Duke criteria), 61 of which were SA-PVIE. Overall mortality rate was 47.5%, stroke was associated with an increased risk of death, and early valve replacement was not associated with a significant survival benefit in the whole population; however, patients who developed cardiac complications and underwent early valve replacement had the lowest mortality rate (28.6%).