Management Of Infective Endocarditis Research Articles

Effects of Concomitant CABG on Outcomes in Veterans Who Require Surgery for Endocarditis.

Infective Endocarditis (IE) is a complicated disease frequently accompanied by coronary artery disease (CAD) though no clear guidelines exist for when concomitant revascularization should be undertaken once valve surgery is indicated. Data on this topic within the United States (US) Veteran population, who have unique healthcare needs when compared to the civilian population, is sparse. We investigated the impact of concomitant coronary artery bypass grafting (CABG) on morbidity and mortality in US Veterans requiring surgical management of IE. We identified 489 patients who underwent surgical management of IE between January 1 2010 and December 31 2020 at any of 43 Veterans Affairs (VA) cardiac surgery centers in the US. Patients were stratified based on who underwent concomitant CABG at the time of operation. Primary outcomes included the occurrence of postoperative myocardial infarction (MI), stroke, or mortality. Continuous variables were compared using independent t-tests or Mann Whitney U tests, and categorical variables were compared using the Chi square test. Cox proportional-hazard models were used to calculate risk for primary outcomes based on group. 61 patients (12.5%) underwent concomitant CABG for CAD. After adjusting for significant covariates, patients who underwent CABG had a higher long-term risk of MI (adjusted hazard ratios (aHR) 2.37, 95% CI: 1.29-4.35, p = 0.005) and higher risk of MI at 30-days (aHR 2.34, 95% CI: 1.06-5.19, p = 0.035). Concomitant CABG was not associated with long-term stroke or death, 30-day stroke or death, or perioperative complications. On sub-analysis of patients with moderate to severe CAD, rates of MI were higher in the CABG group at 30 days (25.9 vs. 3.4%, p = 0.016) and 1 year (33.3 vs. 3.4%, p = 0.004), though not long-term. The mean number of grafts was 1.51 ± 0.76, with only one graft performed in 65.6% (40/61) of patients. Concomitant CABG at the time of operation for IE was associated with increased risk of MI at 30-day and long-term, though most CABGs involved a low number of grafts. It was not associated with 30-day stroke or death, long term stroke or death, or perioperative complications. The optimal treatment of CAD noted during preoperative evaluation for veterans undergoing surgery for IE remains unclear.

Three-dimensional Transesophageal Echocardiography in Infective Endocarditis: What Does It Add?

Infective endocarditis (IE) diagnosis is based on a clinical suspicion supported by consistent microbiological and instrumental data. Evidence of involvement of cardiac valves (native or prosthetic) or prosthetic intracardiac material is a major diagnostic criterion of IE. Transthoracic echocardiography (TTE) is the initial technique of choice for the diagnosis while transesophageal echocardiography (TEE) is recommended in patients with an inconclusive or negative TTE, in patients with high suspicion of IE, as well as in patients with a positive TTE, in order to document local complications. Repeating TTE and/or TEE should be considered during follow-up of uncomplicated IE, in order to detect new silent complications and monitor vegetation size. In the setting of IE, the role of three-dimensional (3D) TEE is increasing; in fact, this technique has also been shown to be useful for the diagnosis of IE and its complications as it allows to obtain infinite planes and volumetric reconstructions. In this review, we will describe the usefulness of 3D-TEE and its added value in the management of IE.

Infective Endocarditis After Percutaneous Device Closure of Atrial Septal Defects: Incidence, Diagnosis, and Treatment. Case Report and Literature Review.

Infective endocarditis (IE) on atrial septal defect (ASD) closure devices, while extremely rare, has been reported to be more frequent early after the procedure. We describe a case of late IE after percutaneous closure of patent foramen ovale (PFO). We also performed a literature review on this subject. We reviewed a total of 42,365 patients who were treated with percutaneous devices: 13,916 for ostium secundum (OS) (32%), 24,726 for PFO (58%) and 3,723 for OS+PFO (8%). Among these patients, we identified 50 cases of IE after atrial septal defect device closure (0.001%). In contrast to previous reports, nearly 66% of IE in this setting occurred late, after at least 6 months from the procedure (33/50 patients). A statistical analysis clearly showed that the mean time from the procedure to IE increased in the last five years, probably associated with a change in antiplatelet therapy after ASD closure. Management of IE on an ASD occluder should always be discussed in the setting of a multidisciplinary heart team that includes a cardiologist, cardiac surgeon, and anesthetist. While surgical strategies gave excellent results, conservative management might be considered in cases of small IE vegetations and for patients in good general condition. However, in these cases, the patient must be closely observed with repeated blood and instrumental tests.

Multimodality Imaging Diagnosis in Infective Endocarditis.

Imaging is an important tool in the diagnosis and management of infective endocarditis (IE). Echocardiography is an essential examination, especially in native valve endocarditis (NVE), but its diagnostic accuracy is reduced in prosthetic valve endocarditis (PVE). The diagnostic ability is superior for transoesophageal echocardiography (TEE), but a negative test cannot exclude PVE. Both transthoracic echocardiography (TTE) and TEE can provide normal or inconclusive findings in up to 30% of cases, especially in patients with prosthetic devices. New advanced non-invasive imaging tests are increasingly used in the diagnosis of IE. Nuclear medicine imaging techniques have demonstrated their superiority over TEE for the diagnosis of PVE and cardiac implantable electronic device infective endocarditis (CIED-IE). Cardiac computed tomography angiography imaging is useful in PVE cases with inconclusive TTE and TEE investigations and for the evaluation of paravalvular complications. In the present review, imaging tools are described with their values and limitations for improving diagnosis in NVE, PVE and CIED-IE. Current knowledge about multimodality imaging approaches in IE and imaging methods to assess the local and distant complications of IE is also reviewed. Furthermore, a potential diagnostic work-up for different clinical scenarios is described. However, further studies are essential for refining diagnostic and management approaches in infective endocarditis, addressing limitations and optimizing advanced imaging techniques across different clinical scenarios.

ESC guidelines 2023 on the management of endocarditis : What is new?

In August 2023 the new European guidelines on the management of infective endocarditis were published by the European Society of Cardiology (ESC). Numerous recommendations were revised and supplemented by new ones. This review article outlines the essential modifications of the current ESC guidelines focusing on the prevention including antibiotic prophylaxis, the role of the endocarditis team, the revision of the diagnostic criteria, the paradigm shift towards oral antibiotic treatment, the timing and the indications for surgical treatment as well as the relevance of infections of cardiovascular implantable electronic devices.

Trends of Infective Endocarditis at Two Teaching Hospitals: A 12-Year Retrospective Cohort Study in Rio de Janeiro, Brazil.

Despite advances in diagnosis and treatment, the incidence and mortality of infective endocarditis (IE) have increased in recent decades. Studies on the risk factors for mortality in endocarditis in Latin America are scarce. This retrospective cohort study included 240 patients diagnosed with IE according to the modified Duke criteria who were admitted to two university hospitals in Rio de Janeiro, Brazil from January 2009 to June 2021. Poisson regression analysis was performed for trend tests. The multivariate Cox proportional hazards model was used to estimate the hazard ratio (HR) of predictors of in-hospital mortality. The median age was 55 years (IQR: 39-66 years), 57% were male, and 41% had a Charlson comorbidity index (CCI) score > 3. Healthcare-associated infective endocarditis (54%), left-sided native valve IE (77.5%), and staphylococcal IE (26%) predominated. Overall, in-hospital mortality was 45.8%, and mortality was significantly higher in the following patients: aged ≥ 60 years (53%), CCI score ≥ 3 (60%), healthcare-associated infective endocarditis (HAIE) (53%), left-sided IE (51%), and enterococcal IE (67%). Poisson regression analysis showed no trend in in-hospital mortality per year. The adjusted multivariate model determined that age ≥ 60 years was an independent risk factor for in-hospital mortality (HR = 1.9; 95% CI 1.2-3.1; p = 0.008). In this 12-year retrospective cohort, there was no evidence of an improvement in survival in patients with IE. Since older age is a risk factor for mortality, consensus is needed for the management of IE in this group of patients.

The Role of Multimodality Imaging in Patients with Congenital Heart Disease and Infective Endocarditis.

Infective endocarditis (IE) represents an important medical challenge, particularly in patients with congenital heart diseases (CHD). Its early and accurate diagnosis is crucial for effective management to improve patient outcomes. Multimodality imaging is emerging as a powerful tool in the diagnosis and management of IE in CHD patients, offering a comprehensive and integrated approach that enhances diagnostic accuracy and guides therapeutic strategies. This review illustrates the utilities of each single multimodality imaging, including transthoracic and transoesophageal echocardiography, cardiac computed tomography (CCT), cardiovascular magnetic resonance imaging (CMR), and nuclear imaging modalities, in the diagnosis of IE in CHD patients. These imaging techniques provide crucial information about valvular and intracardiac structures, vegetation size and location, abscess formation, and associated complications, helping clinicians make timely and informed decisions. However, each one does have limitations that influence its applicability.

Comparison of dalbavancin with standard of care in the management of infective endocarditis: efficacy, safety, and cost analysis

ObjectivesDue to its long half-life, dalbavancin offers benefits for long-duration treatments, especially osteoarticular and infective endocarditis (IE). We evaluated the efficacy and costs of IE treatment, comparing dalbavancin with standard of care (SOC). MethodsRetrospective multicenter cohort study of adult patients with Gram-positive cocci definite IE. Dalbavancin was used as a sequential therapy before discharge. Efficacy was a combined variable of clinical cure and absence of recurrence in 12-month follow-up. Length of hospital stay and the associated costs were analyzed in both groups of treatment. ResultsTwenty-two patients received dalbavancin and 47 SOC. The efficacy was similar between the groups (dalbavancin 18 [72%] vs SOC 44 [94%], P = 0.198). Hospital stay was shorter in the dalbavancin group (dalbavancin 22 days [16-34] vs SOC 37 days [23-49], P = 0.001), especially in those with E. faecalis IE (dalbavancin 30 days [20-36] vs SOC 65 days [46-74], P <0.001). A reduction of cost was observed between both groups (dalbavancin, 12,206 € [8998-17,283] vs SOC 16,249 € [11,496-22,367], P = 0.032). ConclusionDalbavancin could be a safe and effective option in the sequential treatment of patients with IE. Also, a cost reduction was detected, due to a significant shortness of hospital stay.

Impact of the COVID-19 Pandemic on Infective Endocarditis Management and Outcomes: Analysis of a National Clinical Database

COVID-19 has widely affected health care delivery, but its impact on the management of infective endocarditis (IE), including valve surgery, is uncertain. We compared the national trends in admissions, demographics, and outcomes of IE before and after COVID-19 onset, using a national sample of IE admissions between 2016 and 2022 from the Vizient Clinical Database. The pre-COVID-19 and post-COVID-19 time periods were separated by the start of the second quarter of 2020, the time during which the COVID-19 pandemic was declared. For all admissions and for admissions involving valve surgery, pre-COVID-19 versus post-COVID-19 baseline characteristics and outcomes were compared using 2-sample t tests or chi-square tests. Propensity score-matched cohorts were similarly compared. Before COVID-19, there were 82,867 overall and 11,337 valve-related surgical admissions, and after COVID-19, there were 45,672 overall and 6,322 valve-related surgical admissions. In the matched analysis for all admissions, the in-hospital mortality increased from 11.4% to 12.4% after COVID-19 onset (p <0.001); in-hospital stroke (4.9% vs 6.0%, p <0.001), myocardial infarction (1.3% vs 1.4%, p=0.03), and aspiration pneumonia (1.8% vs 2.4%, p <0.001) also increased, whereas other complications remained stable. In the matched analysis of surgical admissions, there was decreased in-hospital mortality (7.7% vs 6.7%, p=0.03) and intensive care unit stay (8.5 ± 12.5 vs 8.0 ± 12.6 days, p=0.04); other outcomes remained stable. In conclusion, patients admitted with IE after COVID-19 were more medically complex with worsened outcomes and mortality, whereas patients who underwent valve surgery had stable outcomes and improved mortality despite the pandemic.

An overview of infective endocarditis in the context of COVID-19 pneumonia.

Infective endocarditis (IE) in the context of coronavirus disease (COVID-19) is an emerging clinical entity. If not identified timeously, it is associated with high morbidity and mortality. Herein, we provide an overview of the literature supported by a clinical vignette, and highlight the importance of early recognition and management of IE in the context of COVID-19 infection.

Multidisciplinary Teams for the Management of Infective Endocarditis: A Systematic Review and Meta-analysis.

The management of infective endocarditis (IE) is complex owing to a high burden of morbidity and mortality. Recent guidelines recommend dedicated multidisciplinary teams (MDTs) for the management of IE. The aim of this systematic review and meta-analysis was to evaluate and summarize the effect of MDT management on patient outcomes. A systematic review was performed and, where feasible, results were meta-analyzed; otherwise, results were summarized narratively. Data extraction and quality assessment were performed in duplicate. Restricted maximum likelihood random effects models were used to calculate unadjusted risk ratios and 95% CIs. Screening of 2343 studies based on title and abstract yielded 60 full-text reviews; 18 studies were summarized narratively, of which 15 were included in a meta-analysis of short-term mortality. Meta-analysis resulted in a risk ratio of 0.61 (95% CI, .47-.78; I2 = 62%) for mortality in favor of a dedicated MDT as compared with usual care. Length of stay was variable, with 55% (10/18) of studies reporting an increased length of stay. Most studies (16/18, 88.9%) reported a decreased time to surgery and an increased rate of surgery (13/18, 73%). No studies reported on patient-reported outcomes. This is the first systematic review and meta-analysis to assess the impact of MDT management on IE. The sum of evidence demonstrated a significant association between MDTs and improved short-term mortality. Further research is needed to evaluate benefits of virtual MDT care, cost-effectiveness, and the impact on patient-reported outcomes and long-term mortality.

Infective Endocarditis After Transcatheter Versus Surgical Aortic Valve Replacement.

Scarce data are available comparing infective endocarditis (IE) following surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). This study aimed to compare the clinical presentation, microbiological profile, management, and outcomes of IE after SAVR versus TAVR. Data were collected from the "Infectious Endocarditis after TAVR International" (enrollment from 2005 to 2020) and the "International Collaboration on Endocarditis" (enrollment from 2000 to 2012) registries. Only patients with an IE affecting the aortic valve prosthesis were included. A 1:1 paired matching approach was used to compare patients with TAVR and SAVR. A total of 1688 patients were included. Of them, 602 (35.7%) had a surgical bioprosthesis (SB), 666 (39.5%) a mechanical prosthesis, 70 (4.2%) a homograft, and 350 (20.7%) a transcatheter heart valve. In the SAVR versus TAVR matched population, the rate of new moderate or severe aortic regurgitation was higher in the SB group (43.4% vs 13.5%; P < .001), and fewer vegetations were diagnosed in the SB group (62.5% vs 82%; P < .001). Patients with an SB had a higher rate of perivalvular extension (47.9% vs 27%; P < .001) and Staphylococcus aureus was less common in this group (13.4% vs 22%; P = .033). Despite a higher rate of surgery in patients with SB (44.4% vs 27.3%; P < .001), 1-year mortality was similar (SB: 46.5%; TAVR: 44.8%; log-rank P = .697). Clinical presentation, type of causative microorganism, and treatment differed between patients with an IE located on SB compared with TAVR. Despite these differences, both groups exhibited high and similar mortality at 1-year follow-up.

Candida Infectious Endocarditis and Implantable Cardiac Device Infections.

Intravascular diseases due to Candida species, including endocarditis and cardiac device-associated infections, are rare yet devastating manifestations of invasive candidiasis affecting an already vulnerable population. Despite their significant associated morbidity and mortality, limited prospective data exist to inform the optimal diagnostic and therapeutic approaches to these entities. Herein, we review the existing literature pertaining to the epidemiology, diagnosis, and management of infectious endocarditis, rhythm management device infections, and circulatory support device infections caused by Candida species and suggest areas for future research.

Differential response to antibiotic therapy in staphylococcal infective endocarditis: contribution of an ex vivo model.

Staphylococcal infective endocarditis (IE) remains a hard-to-treat infection with high mortality. Both the evaluation of new innovative therapies and research on alternative models mimicking human IE are therefore urgently needed to improve the prognosis of patients with diagnosed IE. Dalbavancin is a novel anti-staphylococcal lipoglycopeptide but there are limited data supporting its efficacy on biofilm infections. This antibiotic could be an alternative to current therapies for the medical treatment of IE but it needs to be further evaluated. Here we developed an original ex vivo model of Staphylococcus aureus IE on human heart valves and assessed biofilm formation on them. After validating the model, the efficacy of two antistaphylococcal antibiotics, vancomycin and dalbavancin, was compared by measuring and visualizing their respective ability to inhibit and eradicate late-formed biofilm. Determination of the minimum biofilm inhibitory (MbIC) and eradicating (MbEC) concentrations in our ex vivo model identified dalbavancin as a promising drug with much lower MbIC and MBEC than vancomycin (respectively <0.01 versus 28 mg/L and 0.03 versus 32 mg/L). These data highlight a strong bactericidal effect of dalbavancin, particularly on an infected heart valve compared with vancomycin. Dalbavancin could be a realistic alternative treatment for the management of staphylococcal IE.

Management of infectious endocarditis from the perspective of the Infectious Diseases specialist – a 2023 update

An increase in the number and the complexity of cardiac surgery has brought on a rise in the proportion of healthcare-associated Infectious Endocarditis (IE), and as a result, today S. aureus is the most common causative pathogen for this condition. Clinical suspicion for IE should be raised in front of a patient with predisposing risk factors, a new heart murmur and/or vasculitic/embolic events. The Duke Criteria have been long used to diagnose IE. However, they underwent several changes in order to improve their sensitivity in the diagnosis of Q-fever IE and to decrease the size of the possible IE group. Our primary goal is to enhance the knowledge regarding the diagnosis and treatment of infective endocarditis. In acute IE, prior to beginning antibiotic therapy, at least three sets of blood cultures must be taken, ideally from three distinct sites, as determining the etiologic agent is of highest importance. The diagnosis of IE cannot be made based just on a single positive blood culture. To diagnose subacute IE, three to five sets of blood cultures must be drawn over the course of 24 hours. Transthoracic echocardiography (TTE) remains the preferred investigation when the diagnosis of IE is suspected. Transesophageal echocardiography (TOE) is recommended when TTE is unremarkable but the suspicion is still high. A whole-body CT scan, an MRI, a cardiac CT, PET-CT, or radiolabeled leucocyte single-photon emission computed tomography may be helpful when TTE and TOE are inconclusive. Recommended empirical therapy for Native Valve Endocarditis (NVE) and late Prosthetic Valve Endocarditis (PVE) consists of IV Amoxicillin, Oxacillin and Gentamicin administered until blood culture results are available. If a patient is allergic to penicillin, IV Vancomycin and Gentamicin should be given. The recommended empirical antibiotic regimen for early PVE includes IV Vancomycin, Gentamicin, and Rifampin. Once the results of blood cultures are available, the treatment will depend on the isolated organism, its sensitivity to antibiotics, and whether it is an NVE or a PVE.

Current Views on Infective Endocarditis: Changing Epidemiology, Improving Diagnostic Tools and Centering the Patient for Up-to-Date Management

Infective endocarditis (IE) is a rare but potentially life-threatening disease, sometimes with longstanding sequels among surviving patients. The population at high risk of IE is represented by patients with underlying structural heart disease and/or intravascular prosthetic material. Taking into account the increasing number of intravascular and intracardiac procedures associated with device implantation, the number of patients at risk is growing too. If bacteremia develops, infected vegetation on the native/prosthetic valve or any intracardiac/intravascular device may occur as the final result of invading microorganisms/host immune system interaction. In the case of IE suspicion, all efforts must be focused on the diagnosis as IE can spread to almost any organ in the body. Unfortunately, the diagnosis of IE might be difficult and require a combination of clinical examination, microbiological assessment and echocardiographic evaluation. There is a need of novel microbiological and imaging techniques, especially in cases of blood culture-negative. In the last few years, the management of IE has changed. A multidisciplinary care team, including experts in infectious diseases, cardiology and cardiac surgery, namely, the Endocarditis Team, is highly recommended by the current guidelines.

Mitral Valve Endocarditis in Patient Awaiting TAVI: A Case Report

The current literature focuses on the risk of infective endocarditis (IE) following transcatheter aortic valve implantation (TAVI). However, the risk of IE in patients waiting for TAVI is not well-studied. We present a unique case of a patient waiting for TAVI with decompensated heart failure who was found to have a large mitral vegetation, and consider risk factors for the development of IE in this population. We report the case of an 85-year-old male with severe aortic stenosis and recurrent small bowel angiodysplasias, requiring frequent blood transfusions and intravenous iron. He presented to a peripheral hospital in decompensated heart failure. Transfer was arranged to our center to expedite TAVI, under the premise that worsening aortic stenosis precipitated his decompensated state. Prior to TAVI, an echocardiogram was done, and demonstrated a 30 × 18 mm mass on the mitral valve with anterior leaflet perforation and severe mitral regurgitation. The findings were consistent with IE, and the TAVI was cancelled. Despite antibiotic therapy, the patient unfortunately deteriorated and palliative care was provided. This case highlights the need for further research regarding the risk of IE in patients waiting for TAVI. Current literature focuses on the development and management of IE following TAVI. Clinicians must understand that TAVI candidates have multiple risk factors for IE, including valvular disease, age, and comorbidities. IE should be considered as a possible cause for decompensated heart failure in patients awaiting TAVI.

The Economic Burden of Infective Endocarditis due to Injection Drug Use in Australia: A Single Centre Study-University Hospital Geelong, Barwon Health, Victoria.

Injection drug use (IDU) is a well-recognized risk factor for infective endocarditis (IE). Associated complications from IDU result in significant morbidity and mortality with substantial cost implications. The aim of this study was to determine the cost burden associated with the management of IE due to IDU (IE-IDU). We used data collected prospectively on patients with a diagnosis of IE-IDU as part of the international collaboration on endocarditis (ICE). The cost of medical treatment was estimated based on diagnosis-related groups (DRG) and weighted inlier equivalent separation (WIES). There were 23 episodes from 21 patients in 12 years (2002 to 2014). The costing was done for 22 episodes due to data missing on 1 patient. The median age was 39 years. The gender distribution was equal. Heroin (71%) and methamphetamine (33%) were the most frequently used. 74% (17/23) required intensive care unit (ICU) admission. The median ICU length of stay (LOS) was 4 days (IQR (Interquartile range); 2 to 40 days) whilst median total hospital LOS was 40 days (IQR; 1 to 119 days). Twelve patients (52%) underwent valve replacement surgery. Mortality was 13% (3/23). The total medical cost for the 22 episodes is estimated at $1,628,359 Australian dollars (AUD). The median cost per episode was a median cost of $ 61363 AUD (IQR: $2806 to $266,357 AUD). We did not account for lost productivity and collateral costs attributed to concurrent morbidity. Within the limitations of this small retrospective study, we report that the management of infective endocarditis caused by injection drug use can be associated with significant financial cost.

1994. The use of whole body PET scans in management of infective endocarditis

Abstract Background Whole-body 18F-FDG PET/CT (WBP) can have diagnostic utility in evaluating extracardiac sites of metastatic infection in patients with infective endocarditis (IE). However, the IE patient population that most benefits from this test is not certain. The purpose of this study is to investigate the clinical characteristics of patients with IE who had WBP performed and to evaluate how WBP results impacted management. Methods We performed a retrospective cohort study at a tertiary care center evaluating patients with suspected IE who were discussed at an internal multidisciplinary endocarditis conference between June 2018 and January 2022. Adult patients with suspected IE who also had a WBP during their inpatient stay were included. Patient demographics, IE risk factors, and WBP details were collected. Results 114 patients with suspected IE had a WBP out of 431 (26.5%). The majority (n=107, 93.9%) had definite or possible IE by mDuke criteria. Prosthetic valves and endocardial devices were present in 83 (72.8%) and 34 (29.8%) patients respectively. There were 67 (60.5%) patients with 2 or more days of bacteremia and 21 (22.1%) patients with over 7 days of bacteremia. Causative pathogens included S. aureus (n=26, 24.2%), Enterococcus (n=26, 24.2%), and Streptococcus species (n=24, 22.4%). Among the 70 (61.4%) patients with indications for cardiac surgery, 38 (54%) had cardiac surgery performed. Common WBP findings were bone/joint infections (n=18, 15.8%), pulmonary infection (n=32, 28.1%), and skin/soft tissue infection (n=15, 13.2%). WBP changed the management in 44.7% (n=51) of patients, including antibiotic change (n=11, 9.7%), source control procedure (n=12, 10.5%), and further workup of infectious or non-infectious findings (n=33, 29.0%). Six-month all-cause mortality was 25% and hospital readmission was 48.1%. Conclusion Many patients who underwent WBP had prolonged bacteremia, a history of cardiac prostheses, and had complicated IE with indications for cardiac surgery. WBP results changed treatment in some cases, but true clinical impact on morbidity and mortality is uncertain. We plan to do further research to compare outcomes between patients who get WBP and those who do not and to determine which patients may most benefit from this test. Disclosures All Authors: No reported disclosures.

Diffusion of amoxicillin into heart valves from infective endocarditis patients.

Amoxicillin is the drug of choice in the management of streptococcal and enterococcal infective endocarditis (IE) but little is known regarding amoxicillin diffusion into infected heart valves. Herein, we assessed amoxicillin valvular distribution and related pharmacokinetic/pharmacodynamic (PK/PD) target attainment in IE patients undergoing heart valve surgery. In this 2-year prospective study, patients with IE treated by continuous infusion of amoxicillin and undergoing a surgical valve replacement were included. Both amoxicillin plasma and tissue concentrations were measured the day of surgery. Amoxicillin concentration in plasma and crushed heart valves were measured by a validated liquid chromatography method coupled with ultra-violet and tandem mass spectrometry, respectively. MIC and MBC of amoxicillin were determined for all available isolates. The rate of achievement of PK/PD efficacy parameters were assessed. Twenty-two heart valves were removed from 20 patients. Bacterial aetiology was streptococcal (n = 17) and enterococcal (n = 3). Amoxicillin mean daily dose was 12 ± 3 g/24 h, mean plasma concentration was 29 ± 21 mg/L (n = 15), mean tissue concentration was 23 ± 15 mg/L (n = 22). Median diffusion rate was 62%. Patients reached a plasma concentration target >4XCMI (n = 13). Tissue concentrations were bactericidal for all streptococcal IE but not for enterococcal IE. Amoxicillin intravalvular measurements in IE treated patients showed significant penetration into the infectious site. These data are reassuring that in situ bactericidal concentrations can be largely achieved in the management of streptococcal IE and support the need for combination antibiotic therapy for enterococcal IE.