scholarly journals Analysis of the Genotype and Virulence of Staphylococcus epidermidis Isolates from Patients with Infective Endocarditis

2008 ◽  
Vol 76 (11) ◽  
pp. 5127-5132 ◽  
Author(s):  
Alastair B. Monk ◽  
Sam Boundy ◽  
Vivian H. Chu ◽  
Jill C. Bettinger ◽  
Jaime R. Robles ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Heart Valves ◽  
Prosthetic Valve Endocarditis ◽  
Bloodstream Infections ◽  
Prosthetic Heart Valves ◽  
Native Valve ◽  
Prosthetic Devices ◽  
C Elegans ◽  
Prosthetic Valves ◽  
Kaplan Meier

ABSTRACT Staphylococcus epidermidis is one of the most common causes of infections of prosthetic heart valves (prosthetic valve endocarditis [PVE]) and an increasingly common cause of infections of native heart valves (native valve endocarditis [NVE]). While S. epidermidis typically causes indolent infections of prosthetic devices, including prosthetic valves and intravascular catheters, S. epidermidis NVE is a virulent infection associated with valve destruction and high mortality. In order to see if the differences in the course of infection were due to characteristics of the infecting organisms, we examined 31 S. epidermidis NVE and 65 PVE isolates, as well as 21 isolates from blood cultures (representing bloodstream infections [BSI]) and 28 isolates from nasal specimens or cultures considered to indicate skin carriage. Multilocus sequence typing showed both NVE and PVE isolates to have more unique sequence types (types not shared by the other groups; 74 and 71%, respectively) than either BSI isolates (10%) or skin isolates (42%). Thirty NVE, 16 PVE, and a total of 9 of the nasal, skin, and BSI isolates were tested for virulence in Caenorhabditis elegans. Twenty-one (70%) of the 30 NVE isolates killed at least 50% of the worms by day 5, compared to 1 (6%) of 16 PVE isolates and 1 (11%) of 9 nasal, skin, or BSI isolates. In addition, the C. elegans survival rate as assessed by log rank analyses of Kaplan-Meier survival curves was significantly lower for NVE isolates than for each other group of isolates (P < 0.0001). There was no correlation between the production of poly-β(1-6)-N-acetylglucosamine exopolysaccharide and virulence in worms. This study is the first analysis suggesting that S. epidermidis isolates from patients with NVE constitute a more virulent subset within this species.

scholarly journals 18F-FDG PET/CT in Infective Endocarditis: Indications and Approaches for Standardization

2021 ◽  
Vol 23 (9) ◽  
Author(s):  
D. ten Hove ◽  
R.H.J.A. Slart ◽  
B. Sinha ◽  
A.W.J.M. Glaudemans ◽  
R.P.J. Budde
Keyword(s):  
Infective Endocarditis ◽  
Fdg Pet ◽  
Prosthetic Valve Endocarditis ◽  
Cardiac Device ◽  
Native Valve ◽  
Prosthetic Valves ◽  
Cardiac Devices ◽  
Pet Ct ◽  
Fdg Pet Ct ◽  
Disseminated Disease

Abstract Purpose of Review Additional imaging modalities, such as FDG-PET/CT, have been included into the workup for patients with suspected infective endocarditis, according to major international guidelines published in 2015. The purpose of this review is to give an overview of FDG-PET/CT indications and standardized approaches in the setting of suspected infective endocarditis. Recent Findings There are two main indications for performing FDG-PET/CT in patients with suspected infective endocarditis: (i) detecting intracardiac infections and (ii) detection of (clinically silent) disseminated infectious disease. The diagnostic performance of FDG-PET/CT for intracardiac lesions depends on the presence of native valves, prosthetic valves, or implanted cardiac devices, with a sensitivity that is poor for native valve endocarditis and cardiac device-related lead infections, but much better for prosthetic valve endocarditis and cardiac device-related pocket infections. Specificity is high for all these indications. The detection of disseminated disease may also help establish the diagnosis and/or impact patient management. Summary Based on current evidence, FDG-PET/CT should be considered for detection of disseminated disease in suspected endocarditis. Absence of intracardiac lesions on FDG-PET/CT cannot rule out native valve endocarditis, but positive findings strongly support the diagnosis. For prosthetic valve endocarditis, standard use of FDG-PET/CT is recommended because of its high sensitivity and specificity. For implanted cardiac devices, FDG-PET/CT is also recommended, but should be evaluated with careful attention to clinical context, because its sensitivity is high for pocket infections, but low for lead infections. In patients with prosthetic valves with or without additional aortic prosthesis, combination with CTA should be considered. Optimal timing of FDG-PET/CT is important, both during clinical workup and technically (i.e., post tracer injection). In addition, procedural standardization is key and encompasses patient preparation, scan acquisition, reconstruction, subsequent analysis, and clinical interpretation. The recommendations discussed here will hopefully contribute to improved standardization and enhanced performance of FDG-PET/CT in the clinical management of patients with suspected infective endocarditis.

scholarly journals Imaging of Cardiac Valves by Computed Tomography

Scientifica ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Gudrun Feuchtner
Keyword(s):  
Computed Tomography ◽  
Heart Valves ◽  
Severe Aortic Stenosis ◽  
Multislice Ct ◽  
Valvular Disease ◽  
Special Focus ◽  
Prosthetic Heart Valves ◽  
Cardiac Valves ◽  
Effective Treatment Option ◽  
Prosthetic Valves

This paper describes “how to” examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, “how to” perform and optimize a multislice CT scan and “how to” interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease by CT, including prosthetic heart valves, is highlighted. The last part gives a guide “how to” use CT for planning of transcatheter aortic valve implantation (TAVI), an emerging effective treatment option for patients with severe aortic stenosis. A special focus is placed on clinical applications of cardiac CT in the context of valvular disease.

scholarly journals Platelet Suppression Therapy in Arterial Disease: Present Status

1977 ◽  
Author(s):  
J. A. Blakely
Keyword(s):  
Secondary Prevention ◽  
Heart Valves ◽  
Case Reports ◽  
Myocardial Infarct ◽  
Arterial Disease ◽  
Preliminary Evidence ◽  
Prosthetic Heart Valves ◽  
Prosthetic Valves ◽  
Survival Studies ◽  
Cerebral Ischemic

Arterial disease is a severe test of clinical trials methodology. Results to date have defined areas for further study, but clinical indications are not established. Dipyridamole reduces emboli from prosthetic heart valves but applicability to less thrombogenic valves is uncertain. Transient cerebral ischemic attacks are physiologically appropriate and there is preliminary evidence of reduced attacks with Sulfinpyrazone, none with Dipyridamole, and favorable case reports with Aspirin. Effects on stroke and death in patients presenting with TIA or stroke are under study. Sulfinpyrazone has failed to prolong patency time after peripheral vascular surgery. Administration of aspirin and of Sulfinpyrazone to elderly populations has shown no detectable benefit from Aspirin, and has suggested that Sulfinpyrazone should be further studied in patients recovered from thrombotic stroke. The greatest potential benefit may be secondary prevention of myocardial infarct, but to date efficacy has neither been demonstrated nor excluded. Studies in progress include: ASA and/or Sulfinpyrazone and TIA, stroke and death in patients with TIA; ASA with and without Dipyridamole in patients with TIA: Sulfinpyrazone and survival after recovery from thrombotic stroke; Secondary prevention of myocardial infarct with ASA, ASA or ASA + Dipyridamole, Sulfinpyrazone, and Clofibrate; Sulfinpyrazone, ASA, and ASA with anticoagulants and emboli from prosthetic valves. Platelet survival studies may permit selection of populations likely to benefit and assessment of adequacy of therapy.Hypotheses tested by clinical trial must be distinguished from hypotheses formulated from retrospective analysis, and methods must permit effects of treatment to be distinguished from differences in risk.

scholarly journals 1075. A Retrospective Comparison of Native Valve Endocarditis and Prosthetic Valve Endocarditis in a Large Tertiary Care Teaching Hospital From 2007 to 2015

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S322-S322
Author(s):  
Hoi Yee Annie Lo ◽  
Anahita Mostaghim ◽  
Nancy Khardori
Keyword(s):  
Risk Factors ◽  
High Risk ◽  
Aortic Valve ◽  
Teaching Hospital ◽  
Prosthetic Valve ◽  
Prosthetic Valve Endocarditis ◽  
Native Valve ◽  
Prosthetic Valves ◽  
Dental Procedures ◽  
History Of

Abstract Background Studies comparing native valve and prosthetic valve endocarditis (NVE and PVE) have mixed findings on the risk factors and outcomes between the two cohorts. This retrospective review of infective endocarditis (IE) at a teaching hospital in the United States aims to compare the clinical and microbiological features between NVE and PVE. Methods Patients were retrospectively identified from 2007 to 2015 using appropriate IE-related ICD-9 codes. Cases that met definite Modified Duke Criteria for IE were further classified as either PVE or NVE, and were reviewed for epidemiology, causative organism(s), affected valves and associations, risk factors, dental procedures in the past 6 months, and 30-day mortality. Results A total of 363 admissions met criteria for definite endocarditis, with 261 NVE cases and 59 PVE cases. Forty-three cases that were either associated with an infection involving both native and prosthetic valves or intracardiac devices were omitted from this study. Most risk factors, such as hemodialysis and intravenous drug use, did not show any significant difference amongst the two groups. IE involving the aortic valve as well as a previous history of IE were more likely to be seen in PVE (both P &lt; 0.0001). Dental procedures done in the preceding 6 months before IE admission were more likely to be associated with PVE than NVE (P = 0.0043). PVE showed a higher likelihood of 30-day mortality compared with NVE (P = 0.067). The causative organisms of PVE were more likely to be caused by common gut pathogens such as Klebsiella and Enterobacter species. Conclusion PVE cases had a significantly higher chance of involving the aortic valve as well as having a history of IE. PVE cases were also significantly more likely to be associated with a dental procedure done in the preceding 6 months than with the NVE cases. This implies that patients with prosthetic valves, who are currently covered under the 2007 AHA guidelines to receive prophylaxis prior to dental procedures, are still at a high risk of developing PVE. It may be prudent to reconsider adding a post-procedure dose of antibiotics, instead of a single preprocedure dose, to extend the protection of this high-risk population with prosthetic valves. Furthermore, PVE cases showed higher rates of 30-day mortality compared with NVE with near significance, which is likely multifactorial. Disclosures All authors: No reported disclosures.

scholarly journals Analysis of leaflet flutter in biological prosthetic heart valves using PIV measurements

2019 ◽  
Vol 42 ◽  
pp. e41746
Author(s):  
Artur Henrique de Freitas Avelar ◽  
Mairon Assis Guimaris Eller Stófel ◽  
Glenda Dias Vieira ◽  
Jean Andrade Canestri ◽  
Rudolf Huebner
Keyword(s):  
High Speed ◽  
Heart Valves ◽  
Particle Image ◽  
Prosthetic Heart Valves ◽  
Shear Stresses ◽  
Lower Velocity ◽  
Piv Measurements ◽  
Prosthetic Valves ◽  
Image Velocimetry ◽  
Experimental Bench

The use of biological prosthetic valves has increased considerably in recent decades since they have several advantages over mechanical ones, but they still possess the great disadvantage of having a relatively short lifetime. An understudied phenomenon is the flutter effect that causes oscillations in the cusps, which is associated with regurgitation, calcification and fatigue, which can reduce even more the lifetime of bioproteses. In an experimental bench that simulates the cardiac flow, the behavior of a porcine and a bovine pericardium valves was recorded by a high-speed camera to quantify the oscillations of the cusps and an experiment using particle image velocimetry was conducted to study the velocity profiles and shear stresses and their relations with flutter. Results showed that the pericardial valve has lower values of frequencies and amplitudes compared to the porcine valve. Lower velocity values were found in the cusps that did not have flutter, but no relationship was observed between shear stress values and leaflet vibrations. These results may assist in future projects of biological prosthetic valves that have less flutter and longer lifespan.

Polymicrobial native valve endocarditis due to Bacillus cereus and Cardiobacterium hominis

2021 ◽  
Vol 14 (12) ◽  
pp. e245417
Author(s):  
Sherin Meledathu ◽  
Rachel Denyer ◽  
Afsoon Roberts ◽  
Gary Simon
Keyword(s):  
Mitral Valve ◽  
Bacillus Cereus ◽  
Heart Valves ◽  
Medical Literature ◽  
Prosthetic Heart Valves ◽  
Beta Lactamase ◽  
Intravenous Drug Use ◽  
Native Valve ◽  
Invasive Infections ◽  
Cephalosporin Antibiotics

We present a case of polymicrobial subacute bacterial endocarditis and bacteremia with Bacillus cereus and Cardiobacterium hominis in a 72-year-old man with pre-existing mitral valve disease and prior mitral valve repair who presented with renal failure and glomerulonephritis. Bacillus is often a contaminant in blood cultures but has been rarely implicated in patients with invasive infections such as endocarditis. Intravenous drug use, prosthetic heart valves, valvular heart disease and venous catheters are the most frequently described risk factors for Bacillus bacteremia and endocarditis in the medical literature. Management is challenging as Bacillus is resistant to penicillin and cephalosporin antibiotics due to production of beta-lactamase. Polymicrobial endocarditis is uncommon and when it occurs typically involves Staphylococcal species. To our knowledge, this is the first reported case of polymicrobial endocarditis in which both Bacillus and a HACEK organism are implicated.

scholarly journals 155. A Case Series of Patients with Gemella Endocarditis

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S103-S104
Author(s):  
Abarna Ramanathan ◽  
Steven M Gordon ◽  
Nabin K Shrestha
Keyword(s):  
Heart Valves ◽  
Cleveland Clinic ◽  
Case Series ◽  
Prosthetic Valve Endocarditis ◽  
Blood Cultures ◽  
Valvular Regurgitation ◽  
Native Valve ◽  
Duke Criteria ◽  
Metastatic Infection ◽  
16S Rna

Abstract Background Gemella is a genus of gram-positive bacteria that thrives best at a high partial pressure of CO2 and is an unusual cause of infective endocarditis (IE). Methods We identified cases of Gemella IE in patients aged >18 years old, hospitalized at Cleveland Clinic between July 1, 2007 and January 1, 2017, by screening the Cleveland Clinic IE Registry. Gemella IE was defined as meeting modified Duke Criteria and having Gemella identified as the pathogen (by culture and/or 16S RNA sequencing from explanted valve tissue). Clinical features were obtained by manual chart review. Results A total of 13 cases of Gemella IE (G. haemolysans [6], G. morbillorum [3], G. sanguinis [2], and 2 undifferentiated species) were identified within the study period and accounted for <1% of all cases of IE. 9 were native valve IE and 4 were prosthetic valve endocarditis. Age varied from 20 to 86 years and 77% were male. The most common predisposing factors were pre-existing valvular disease (54%) and congenital heart disease (46%). 3 cases had dental manipulation within the prior 3 months, 3 had bioprosthetic valves, 2 had mechanical heart valves, and 2 were actively using intravenous recreational drugs. All cases were left-sided: 38% involved the aortic valve, 23% the mitral valve and 38% involved both. 69% had positive blood cultures, 38% had positive blood cultures and positive valve PCR, and 31% were identified based on positive valve PCR results only. Not one patient had positive valve cultures. 85% had significant valvular regurgitation and locally invasive disease occurred in 4 patients. Central nervous system emboli occurred in 3 cases and metastatic infection, in the form of lumbar diskitis, in one. All patients were treated surgically and the most commonly used anti-microbials were parenteral ceftriaxone and vancomycin, administered for a median duration of 42 days. All cases survived to hospital discharge and none relapsed over a median follow-up of 2.2 years. Conclusion Gemella species account for less than 1% of cases of IE, with G. haemolysans being the most common species. In a third of cases valve PCR provided the only means of diagnosis. It is effectively treated with surgery and antibiotics. Disclosures All authors: No reported disclosures.

Development of a Test Bank for Fluid Dynamic Analysis of Two Prosthetic Heart Valves Using Air as Working Fluid

2014 ◽  
Author(s):  
Luz M. Rivera ◽  
Ana I. Crispín ◽  
Nelson Escobar ◽  
Lina M. Hoyos ◽  
John Bustamante
Keyword(s):  
Dynamic Analysis ◽  
Heart Valves ◽  
Fluid Dynamic ◽  
Structural Characteristics ◽  
Working Fluid ◽  
Prosthetic Heart Valves ◽  
Pressure Gradients ◽  
Prosthetic Valves ◽  
Hemodynamic Performance ◽  
Clinical Conditions

This work presents the fluid dynamic analysis of the mechanical prosthetic heart valves: Björk Shiley and Sorin Bicarbon™. Analysis of prosthetic valves is currently done with viscous fluids that emulate the behavior of blood; however the developed test bank, wind tunnel, uses air as the working fluid. This working fluid differs from those currently being used due to its low density and viscosity properties, which provides greater sensitivity to small changes in geometry and valve design variations. These features permit to identify relevant changes to the patient’s hemodynamic system based on the effect of the implanted valve. Tests were performed by measuring the fluid-dynamics of both valves; the obtained results show accuracy with the valves’ performance under clinical conditions. The offset design of the Björk Shiley tilting disk gives the valve the ability to generate less blood trauma and increase laminar flow and the Sorin Bicarbon™ bileaflet has a larger orifice for better hemodynamic performance. Furthermore, the transversal pressure gradients and local effects such as turbulence and vortexes were also analyzed; and the obtained results are accurate according to the functionality, geometrical and structural characteristics of both valves at their real environment.

scholarly journals Role of Mitral Annulus Diastolic Geometry on Intraventricular Filling Dynamics

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Ikechukwu U. Okafor ◽  
Arvind Santhanakrishnan ◽  
Vrishank S. Raghav ◽  
Ajit P. Yoganathan
Keyword(s):  
Heart Valves ◽  
Cardiac Cycle ◽  
Vortical Structure ◽  
Mitral Annulus ◽  
Energy Dissipation Rate ◽  
Prosthetic Heart Valves ◽  
Prosthetic Devices ◽  
Geometric Changes ◽  
Ventricular Filling ◽  
Circular Design

The mitral valve (MV) is a bileaflet valve positioned between the left atrium and ventricle of the heart. The annulus of the MV has been observed to undergo geometric changes during the cardiac cycle, transforming from a saddle D-shape during systole to a flat (and less eccentric) D-shape during diastole. Prosthetic MV devices, including heart valves and annuloplasty rings, are designed based on these two configurations, with the circular design of some prosthetic heart valves (PHVs) being an approximation of the less eccentric, flat D-shape. Characterizing the effects of these geometrical variations on the filling efficiency of the left ventricle (LV) is required to understand why the flat D-shaped annulus is observed in the native MV during diastole in addition to optimizing the design of prosthetic devices. We hypothesize that the D-shaped annulus reduces energy loss during ventricular filling. An experimental left heart simulator (LHS) consisting of a flexible-walled LV physical model was used to characterize the filling efficiency of the two mitral annular geometries. The strength of the dominant vortical structure formed and the energy dissipation rate (EDR) of the measured fields, during the diastolic period of the cardiac cycle, were used as metrics to quantify the filling efficiency. Our results indicated that the O-shaped annulus generates a stronger (25% relative to the D-shaped annulus) vortical structure than that of the D-shaped annulus. It was also found that the O-shaped annulus resulted in higher EDR values throughout the diastolic period of the cardiac cycle. The results support the hypothesis that a D-shaped mitral annulus reduces dissipative energy losses in ventricular filling during diastole and in turn suggests that a symmetric stent design does not provide lower filling efficiency than an equivalent asymmetric design.

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