Infective endocarditis: diagnosis and management

Epidemiology, microbiology, and outcomes of infective endocarditis in a tertiary center in Jordan

BACKGROUND

Infective endocarditis (IE) is a relatively rare but serious and life-threatening disease with substantial mortality and morbidity despite progress in diagnostic and treatment techniques. The aim of this study is to investigate the epidemiology, clinical characteristics, microbiological profile, and outcomes of IE patients in a tertiary care facility in Jordan, the Jordan University Hospital (JUH).

METHODS

This is a retrospective case series study which was conducted at JUH. A total of 23 patients with either definite or possible IE according to the Modified Duke Criteria were included in the study. Medical records were reviewed, and relevant information was collected. Descriptive data analysis was performed.

RESULTS

Our study identified a total of 23 patients with infective endocarditis; 65.2% were males, with a mean age of 40.4 years. The majority of patients had an underlying cardiac disease (60.9%), with the most common being congenital heart diseases (17.4%). The most commonly affected valves were the left-side heart valves, with the mitral valve (52.2%) being the most common followed by the aortic valve (34.8%). The most common organism detected in blood culture was Streptococcus viridans (21.7%) followed by methicillin-resistant Staphylococcus aureus. The most common complications among the patients were heart failure and septic shock, and the mortality rate among the patients was 13%.

CONCLUSION

In patients with endocarditis, Streptococcus viridans is the most common culture-positive bacteria at JUH. One third of our patients needed surgical intervention and the mortality rate was 13%.

Infectious native valve endocarditis by Streptococcus agalactiae species: Case report of pathogen identification only through metagenomic sequencing technology

INTRODUCTION

Streptococcus agalactiae is a common pathogen in infective endocarditis, but the positive rate of traditional blood culture diagnosis is not high. It is challenging to obtain a good outcome in the absence of pathogen information for patients with infectious endocarditis.

PATIENT CONCERNS AND DIAGNOSIS

Here, we report the case of a patient with infective endocarditis caused by S. agalactiae. The initial manifestations of this patient were coma, urinary incontinence, and fecal incontinence and had no history of heart disease or infectious diseases before admission.

INTERVENTIONS AND OUTCOMES

When the blood culture was negative 3 consecutive times, the pathogen S. agalactiae was diagnosed in a timely and accurate manner by metagenome sequencing. Eventually, the patient was discharged following surgery and antibiotic treatment.

CONCLUSIONS

For IE patients with infective endocarditis, metagenome sequencing is a valuable and selective tool for rapid, sensitive, and accurate pathogen detection, especially when the blood culture is negative.

ACR Appropriateness Criteria® Infective Endocarditis

Infective endocarditis can involve a normal, abnormal, or prosthetic cardiac valve. The diagnosis is typically made clinically with persistently positive blood cultures, characteristic signs and symptoms, and echocardiographic evidence of valvular vegetations or valvular complications such as abscess, dehiscence, or new regurgitation. Imaging plays an important role in the initial diagnosis of infective endocarditis, identifying complications, prognostication, and informing the next steps in therapy. This document outlines the initial imaging appropriateness of a patient with suspected infective endocarditis and for additional imaging in a patient with known or suspected infective endocarditis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

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.

Mitral valve repair in infective endocarditis is not inferior to valve replacement: results from a Spanish nationwide prospective registry

INTRODUCTION

Infective endocarditis (IE) still carries high morbidity and mortality and frequently requires surgery. The benefit of mitral valve repair (MVr) in the setting of IE is yet to be proven. The goal of this study was to assess the results of MVr in patients with IE after a minimum follow-up of 1 year.

METHODS

This study is based on a Spanish nationwide prospective registry that included patients operated on for native mitral valve IE. The collaborating Institutions pooled their pre-, peri-, and postoperative data into the database of the GAMES group [Grupo de Apoyo al Manejo de la EndocarditiS (Group for support and management of infective endocarditis)].

RESULTS

Data from 27 hospitals were recorded and 3524 cases of active IE identified between 2008 and 2016. There were 1513 cases of mitral IE, of which 898 involved native valves. Of these, 437 patients underwent surgical treatment, and 369 completed the 1-year follow-up. The valve was repaired in 68 cases (18.4%). Preoperative groups were comparable (EuroSCORE MVr 7.7 vs MVR 8.0; p = ns). Mortality in the repair group was inferior to that in the replacement group (16.2% vs 27.2%, p = 0.058). At 1 year, mortality remained higher in the replacement group: 3.7% vs 2.9%. Relapse of the infection was slightly more frequent in the repair group (7.1% vs 3.7%; p = ns), although this did not lead to higher rates of reintervention (MVr/MVR: 2.9% vs 4.9%).

CONCLUSION

MVr is an attractive option for specific patients with IE and does not seem to negatively impact on relapses.

Demonstration of infective endocarditis by cardiac CT and transoesophageal echocardiography: comparison with intra-operative findings

Aims

We aimed to compare imaging findings of infective endocarditis between computed tomography (CT) and transoesophageal echocardiography (TEE) using surgical inspection as a reference standard.

Methods and results

Forty-nine patients (aged 54 ± 17 years, 69% men) who underwent pre-operative CT and TEE for infective endocarditis were included. Twelve of these patients had prosthetic valve endocarditis. Imaging findings of infective endocarditis were classified as vegetation, leaflet perforation, abscess/pseudoaneurysm, and paravalvular leakage. Diagnostic performances of CT and TEE were evaluated using surgical inspection as a reference standard. Interobserver agreements for CT findings were obtained using Cohen's κ test. The detection rates of infective endocarditis per patient with CT and TEE were 93.9% (46/49) and 95.9% (47/49), respectively. In per-imaging analysis, the sensitivities of CT and TEE were not significantly different for both native and prosthetic valve infective endocarditis (sensitivity: vegetation, 100% in TEE and 90.9% in CT; leaflet perforation, 87.5% in TEE and 50.0% in CT; abscess/pseudoaneurysm, 40.0% in TEE and 60.0% in CT; paravalvular leakage, 100% in TEE and 50.0% in CT). Interobserver agreements for CT findings were substantial or excellent (0.79-0.88).

Conclusion

Cardiac CT can accurately demonstrate infective endocarditis in pre-operative patients with a similar diagnostic accuracy to TEE. The interobserver agreements for the CT findings of infective endocarditis were excellent.

Pseudomonas aeruginosa Invades Human Aortic Endothelial Cells and Induces Cell Damage in vitro

BACKGROUND

Cardiovascular diseases such as endocarditis are the second most common cause of death worldwide. Infective Endocarditis (IE) is the most severe infection of the heart associated with significant mortality and morbidity. The binding and invasion of Human Aortic Endothelial Cells (HAECs) by pathogenic microbes can play an important role in the pathogenesis of IE.

OBJECTIVE

Pseudomonas aeruginosa is an emerging pathogen that has been associated with IE. However, it is not known whether P. aeruginosa can bind and interact with HAECs. The aim of this study was to determine whether P. aeruginosa can bind and colonize HAECs.

METHODS

The invasion of HAECs by P. aeruginosa was assessed by gentamicin protection assay. Cytokine levels were determined by enzyme-linked Immunosorbent Assay (ELISA) kits. Cell damage was determined by Lactate Dehydrogenase (LDH) assay.

RESULTS

P. aeruginosa can bind and invade HAECs. Infection of HAECs with P. aeruginosa induces TNF-α IL-1β, IL-6 and IL-8 cytokine production leading to the generation of inflammatory milieu that can cause tissue damage as observed in human clinical cases of IE. We also observed that P. aeruginosa induces cell damage in HAECs.

CONCLUSION

In this study, we demonstrate for first time that P. aeruginosa can invade and survive inside HAECs. This cell culture model can be of immense importance to determine the efficacy of drug targets against IE.

Acute Haemophilus parainfluenzae endocarditis: a case report

Introduction

Numerous pathogens can cause infective endocarditis, including Haemophilus parainfluenzae. H. parainfluenzae is part of the H. aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae group that may cause about 3% of the total endocarditis cases, and is characterized by a subacute course and large vegetations.

Case presentation

Acute H. parainfluenzae endocarditis developed in a 54-year-old woman, with no underlying predisposing factors. The patient presented with fever of 3 days duration and a severe headache. Magnetic resonance imaging of the brain revealed multiple cerebral emboli with hemorrhagic foci. Upon suspicion of endocarditis, cardiac transesophageal ultrasonography was performed and revealed massive vegetations. The patient underwent emergency mitral valve replacement, and was further treated with ceftriaxone. Blood cultures grew H. parainfluenzae only after valve replacement, and a 6-week course of ceftriaxone was prescribed.

Conclusion

We underline the typical presentation of large vegetations in H. parainfluenzae endocarditis, which are associated with embolic phenomena and resulting severity. Although the majority of the few cases reported in the literature are subacute in progress, our case further underlines the possibility that H. parainfluenzae endocarditis may develop rapidly. Thus, awareness of the imaging characteristics of the pathogen may enhance early appropriate diagnosis and therapeutic response.

Isolated angiitis of the CNS and bacterial endocarditis: similarities and differences

Both isolated angiitis of the central nervous system (IAN) and bacterial endocarditis (BE) may present with similar clinical and auxiliary findings. The differentiation is extremely important because of the different treatment regimens. We compared the findings of six patients with biopsy-proven IAN with the data of six patients with BE. Patients with IAN were younger (27-62 years) and presented with multiple strokes (n = 4), intracerebral hemorrhage (n = 1), epileptic seizures (n = 2), or encephalopathy (n = 1). All IAN patients had pathologic cerebrospinal fluid (CSF) findings (pleocytosis n = 5; protein elevation n = 4), and angiography revealed multilocular stenoses in two cases while digital subtraction angiography was normal in four. BE patients (32-77 years) presented multiple (n = 3) or single ischemic strokes (n = 2) or encephalopathy and headache (n = 2). While all patients showed inflammatory serum findings (C-reactive protein n = 6, leucocytosis n = 4), CSF-pleocytosis was present in two cases only. Angiography revealed a vasculitic pattern in two patients. The diagnosis of BE was established based on transesophageal echocardiography and blood cultures. Leptomeningeal and brain biopsies performed in two cases were normal. Both IAN and BE may present multiple strokes and encephalopathy. The frequency of a vasculitic pattern in angiography is similar in both conditions. While inflammatory serum findings are the rule in BE, pathologic CSF findings were present in all IAN patients. Transesophageal echocardiography and blood cultures should be performed in order to diagnose or exclude BE. Without brain biopsy, immunosuppressive therapy may be dangerous in suspected IAN.

Multislice computed tomography in infective endocarditis: comparison with transesophageal echocardiography and intraoperative findings

OBJECTIVES

The aim of this study was to assess the value of multislice computed tomography (CT) for the assessment of valvular abnormalities in patients with infective endocarditis (IE) in comparison with transesophageal echocardiography (TEE) and intraoperative findings.

BACKGROUND

Multislice CT has recently shown promising data regarding valvular imaging in a 4-dimensional fashion.

METHODS

Thirty-seven consecutive patients with clinically suspected IE were examined with TEE and 64-slice CT or dual-source CT. Twenty-nine patients had definite IE and underwent surgery.

RESULTS

The diagnostic performance of CT for the detection of evident valvular abnormalities for IE compared with TEE was: sensitivity 97%, specificity 88%, positive predictive value (PPV) 97%, and negative predictive value (NPV) 88% on a per-patient basis (n = 37; excellent intermodality agreement kappa = 0.84). CT correctly identified 26 of 27 (96%) patients with valvular vegetations and 9 of 9 (100%) patients with abscesses/pseudoaneurysms compared with the intraoperative specimen. On a per-valve-based analysis, diagnostic accuracy for the detection of vegetations and abscesses/pseudoaneurysms compared with surgery was: sensitivity 96%, specificity 97%, PPV 96%, NPV 97%, and sensitivity 100%, specificity 100%, PPV 100%, NPV 100%, respectively, without significant differences as compared with TEE. Vegetation size measurements by CT correlated (r = 0.95; p <0.001) with TEE (mean 7.6 +/- 5.6 mm). The mobility of vegetations was accurately diagnosed in 21 of 22 (96%) patients with CT, but all of 4 leaflet perforations (<or=2 mm) were missed. CT provided more accurate anatomic information regarding perivalvular extent of abscess/pseudoaneurysms than TEE.

CONCLUSIONS

Multislice CT shows good results in detecting valvular abnormalities in IE and could be applied in pre-operative planning and exclusion of coronary artery disease before surgery.

A young adult patient with septic pulmonary emboli of undetermined origin

A 25-year-old male who had no significant medical history presented abrupt onset of high-grade fever and chills without noticeable trigger. The patient sought for medical attention for subsequently developed dyspnea and chest pain. Radiological examinations revealed bilateral lung peripheral multiple opacities, some of which were cavitating, suggesting of septic pulmonary emboli (SPE). Isolation of Staphylococcus aureus in blood and sputum culture confirmed the diagnosis. Extensive examinations disclosed neither underlying immunocompromising conditions nor infectious foci, which are usually notable in patients with SPE. The present patient illustrates that there are patients with SPE in whom underlying conditions or infectious foci are difficult to determine, and that suspicion of the disease based on characteristic radiological findings is critical for appropriate management in those patients.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.