Role of echocardiography in the diagnosis and management of infective endocarditis

Radionuclide Imaging of Infective Endocarditis

Infective endocarditis (IE) is associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management. Due to difficulties in the diagnosis, a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data is used. Imaging, including echocardiography, molecular imaging techniques, and coronary CT angiography (CTA) is central to detect infections involving heart valves and implanted cardiovascular devices, also allowing for early detection of septic emboli and metastatic. This article describes the main clinical application of white blood cell SPECT/CT and [¹⁸F]FDG-PET/CT and CTA in IE and infections associated with cardiovascular implantable electronic devices.

Three-Dimensional Transesophageal Echocardiography in the Diagnosis and Treatment of Mitral Prosthetic Valve Endocarditis—A Narrative Review

Despite advances in diagnosis, imaging methods, and medical and surgical interventions, prosthetic valve endocarditis (PVE) remains an extremely serious and potentially fatal complication of heart valve surgery. Characteristic changes of PVE are more difficult to detect by transthoracic echocardiography (TTE) than those involving the native valve. We reviewed advances in transesophageal echocardiography (TEE) in the diagnosis of PVE. Three-dimensional (3D) TEE is becoming an increasingly available imaging method combined with two-dimensional TEE. It contributes to faster and more accurate diagnosis of PVE, assessment of PVE-related complications, monitoring effectiveness of antibiotic treatment, and determining optimal time for surgery, sometimes even before or without previous TTE. In this article, we present advances in the treatment of patients with mitral PVE due to 3D TEE application.

Missed case of fever of unknown origin during COVID-19 pandemic: patent ductus arteriosus endarteritis

A 40-year-old woman presented with fever of unknown origin (FUO) for 2 months. Without a definitive diagnosis and having received multiple empirical antibiotics from outside without relief, she was referred to our centre. Cardiac auscultation was remarkable for a grade 3/6 continuous murmur in the upper left sternal border. Echocardiogram revealed a patent ductus arteriosus (PDA) and a 5×7 mm mobile vegetation at the pulmonary artery bifurcation. Blood culture grew Streptococcus mutans. Embolisation of the vegetation to the pulmonary circulation occurred after the start of intravenous antibiotics resulting in fever relapse. Antibiotics were continued for 6 weeks and the fever settled. She underwent device closure of PDA after 12 weeks and is currently doing fine. Infective endocarditis/endarteritis is an important differential in a patient of FUO. A thorough clinical examination is important in every case of FUO, gives an important lead into diagnosis and guides appropriate investigations to confirm it.

Comparative Value of Cardiac CT and Transesophageal Echocardiography in Infective Endocarditis: A Systematic Review and Meta-Analysis

PURPOSE

To assess the comparative diagnostic accuracy of cardiac CT and transesophageal echocardiography (TEE) in the detection of valvular and perivalvular complications in infective endocarditis.

MATERIALS AND METHODS

PubMed and Embase databases were systematically searched until July 2019 for original articles published in English. Studies were included if (a) they used CT and/or TEE as an index test, (b) data were provided as infective endocarditis valvular complications (classified as abscess or pseudoaneurysm, vegetation, leaflet perforation, and paravalvular leakage), and (c) they used surgical findings as the reference standard.

RESULTS

Eight studies fulfilled the inclusion criteria. The sensitivity was higher for CT than TEE for abscess or pseudoaneurysm detection, 78% (95% confidence interval [CI]: 70%, 85%) (112 of 142) versus 69% (95% CI: 62%, 76%) (94 of 135) (P = .052) and increased to 87% (95% CI: 78%, 93%) (70 of 79) when restricted to multiphase CT studies, the difference being significant (P = .04). The sensitivity was significantly higher for TEE than CT for vegetation detection, 94% (95% CI: 92%, 96%) (363 of 383) versus 64% (95% CI: 57%, 70%) (151 of 237) (P < .001) and leaflet perforation detection, 81% (95% CI: 71%, 88%) (74 of 91) versus 41% (95% CI: 25%, 59%) (14 of 35) (P = .02).The sensitivity for paravalvular leakage was 69% (95% CI: 58%, 79%) (56 of 80) versus 44% (95% CI: 30%, 59%) (21 of 48) for TEE and CT, respectively (P = .27).

CONCLUSION

CT performs better than TEE in the detection of abscess or pseudoaneurysm whereas TEE gives superior results for vegetation detection, leaflet perforation, and paravalvular leakage.Supplemental material is available for this article.© RSNA, 2020.

Unusual Infectious Metastases Secondary to Acupuncture Induced MSSA Septicemia

We describe a rare case of methicillin-sensitive staphylococcus aureus (MSSA) septicemia with metastatic spread leading to pulmonary septic emboli, sub-capsular perinephric renal abscess, prostatic abscess, and intramuscular calf and gluteal abscess in a 48-year-old male with uncontrolled diabetes mellitus (Hemoglobin A1c of 15.2). The patient developed right lower extremity pain after a session of acupuncture followed by a three-week history of fevers, chills, abdominal pain, left flank pain, and urinary retention. Evaluation was negative for endocarditis, intracardiac shunt, intravenous drug usage, or immunodeficiency.

Antibiotic Prophylaxis and Incidence of Endocarditis Before and After the 2007 AHA Recommendations

BACKGROUND

The American Heart Association updated its recommendations for antibiotic prophylaxis (AP) to prevent infective endocarditis (IE) in 2007, advising that AP cease for those at moderate risk of IE, but continue for those at high risk.

OBJECTIVES

The authors sought to quantify any change in AP prescribing and IE incidence.

METHODS

High-risk, moderate-risk, and unknown/low-risk individuals with linked prescription and Medicare or commercial health care data were identified in the Truven Health MarketScan databases from May 2003 through August 2015 (198,522,665 enrollee-years of data). AP prescribing and IE incidence were evaluated by Poisson model analysis.

RESULTS

By August 2015, the 2007 recommendation change was associated with a significant 64% (95% confidence interval [CI]: 59% to 68%) estimated fall in AP prescribing for moderate-risk individuals and a 20% (95% CI: 4% to 32%) estimated fall for those at high risk. Over the same period, there was a barely significant 75% (95% CI: 3% to 200%) estimated increase in IE incidence among moderate-risk individuals and a significant 177% estimated increase (95% CI: 66% to 361%) among those at high risk. In unknown/low-risk individuals, there was a significant 52% (95% CI: 46% to 58%) estimated fall in AP prescribing, but no significant increase in IE incidence.

CONCLUSIONS

AP prescribing fell among all IE risk groups, particularly those at moderate risk. Concurrently, there was a significant increase in IE incidence among high-risk individuals, a borderline significant increase in moderate-risk individuals, and no change for those at low/unknown risk. Although these data do not establish a cause-effect relationship between AP reduction and IE increase, the fall in AP prescribing in those at high risk is of concern and, coupled with the borderline increase in IE incidence among those at moderate risk, warrants further investigation.

Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism

Embolism from the heart or the thoracic aorta often leads to clinically significant morbidity and mortality due to transient ischemic attack, stroke or occlusion of peripheral arteries. Transthoracic and transesophageal echocardiography are the key diagnostic modalities for evaluation, diagnosis, and management of stroke, systemic and pulmonary embolism. This document provides comprehensive American Society of Echocardiography guidelines on the use of echocardiography for evaluation of cardiac sources of embolism. It describes general mechanisms of stroke and systemic embolism; the specific role of cardiac and aortic sources in stroke, and systemic and pulmonary embolism; the role of echocardiography in evaluation, diagnosis, and management of cardiac and aortic sources of emboli including the incremental value of contrast and 3D echocardiography; and a brief description of alternative imaging techniques and their role in the evaluation of cardiac sources of emboli. Specific guidelines are provided for each category of embolic sources including the left atrium and left atrial appendage, left ventricle, heart valves, cardiac tumors, and thoracic aorta. In addition, there are recommendation regarding pulmonary embolism, and embolism related to cardiovascular surgery and percutaneous procedures. The guidelines also include a dedicated section on cardiac sources of embolism in pediatric populations.

Surgical Treatment of Aortic Prosthetic Valve Endocarditis: A 20-Year Single-Center Experience

BACKGROUND

Despite progress in diagnostic methods and treatment, aortic prosthetic valve endocarditis (PVE) remains a life-threatening disease. We report the outcome of all operations for aortic PVE performed at our institution over the past 20 years.

METHODS

Eighty-seven operations performed in 84 patients between 1993 and 2013 were included in this retrospective study. An aortic homograft was used in 56 (64%) cases, a mechanical prosthesis was used in 20 (23%) cases, and a bioprosthesis was used in 11 (13%) cases. Early and late complications and mortality were compared between the first and second decades of our experience. Predictors of mortality were identified with Cox regression. Mean follow-up was 5.5 years (range 0-17 years).

RESULTS

Nine patients (10%) died within 30 days, and severe perioperative complications occurred in 36 patients (41%). Overall cumulative survival was 80% at 5 years and 65% at 10 years. Four (12.9%) of the patients treated with mechanical or biological prostheses had a recurrent episode of endocarditis, compared with none of the patients treated with homografts (p = 0.006). During the second decade, 30-day mortality was lower (3.6% versus 22%; p = 0.007) and 5-year cumulative survival was higher (88% versus 66%; p = 0.027). Age, preoperative serum creatinine, and severe perioperative complications were independent predictors of mortality during follow-up.

CONCLUSIONS

Aortic PVE is associated with a high rate of early complications and substantial early mortality. Patients who survive the immediate postoperative period have satisfactory long-term survival. The risk of recurrent endocarditis is low, especially in patients treated with homografts. The results have improved during the past decade.

Streptococcus constellatus community acquired pneumonia with subsequent isolated pulmonic valve endocarditis and abscess formation in a structurally normal heart

Pulmonic valve infective endocarditis in isolation is a rare clinical entity. The formation of an abscess in the right ventricular outflow tract as a consequence of vegetations affecting the pulmonic valve in a structurally normal heart is extremely rare and has not been reported. We report a case of isolated pulmonic valve endocarditis complicated by a regional abscess formed within the right ventricular outflow tract caused by Streptococcus Constellatus (S. Constellatus), a member of the Streptococcus Milleri group in a young male whose risk factor was alcohol abuse and he was treated medically, a comprehensive literature review on the subject is also reported. Our case is the first reported in literature with infective endocarditis caused by S. Constellatus affecting the pulmonic valve, and the first with pulmonic valve endocarditis and perivalvular abscess formation in a structurally normal heart.

Transesophageal echocardiography: a complementary view of the heart

Transesophageal echocardiography has been widely used as a diagnostic tool during the past two decades to detect cardiac abnormalities that are not visible or poorly visible with transthoracic echocardiography. At present, transesophageal echocardiography is a cornerstone of modern diagnosis of several cardiac diseases, providing diagnostic, prognostic and therapeutic information. In this review, the present status of transesophageal echocardiography not only as a diagnostic tool, underlining its effects on clinical decision making, but also as a monitoring adjunct for many interventional cardiac procedures is examined.

Imaging of the aortic valve with MRI and CT angiography

The aortic valve may be affected by a wide range of congenital and acquired diseases. Echocardiography is the main non-invasive imaging technique for assessing patho-anatomical alterations of the aortic valve and adjacent structures and in many cases is sufficient to establish a diagnosis and/or guide treatment decisions. Recent technological advances in magnetic resonance imaging (MRI) and multidetector computed tomography (MDCT) have enabled these techniques to play a complimentary role in certain clinical scenarios and as such can be useful problem-solving tools. Radiologists should be familiar with the indications, advantages, and limitations of MRI and MDCT in order to advise and direct an appropriate imaging strategy depending upon the clinical scenario. This article reviews the role of MRI and MDCT angiography for assessment of the aortic valve including relevant anatomy, scan acquisition protocols, and post-processing methods. An approach to interpretation and the key imaging features of commonly encountered aortic valvular diseases are discussed.

Current trends in the management of cardiac implantable electronic device (CIED) infections

Cardiac implantable electronic device (CIED) infections are an emerging clinical problem. A growing number of dedicated and high quality clinical studies are currently being generated. We here review the most recent advances in the diagnosis and treatment of patients with CIED infection including intracardiac lead endocarditis. We discuss the current etiology and risk factors, and appraise the major diagnostic issues, describing our center's therapeutic approach. We also address the management of CIED infection complications.

Appropriate use of echocardiography in managing Staphylococcus aureus bacteremia

Staphylococcus aureus bacteremia (SAB) is increasing, both in the community and in healthcare settings. Accurate and timely diagnosis of underlying infective endocarditis (IE) is critical for optimal management of SAB cases as it has significant management and prognostic implications. Reported prevalence of IE in patients with SAB varies depending on the study population, and ranges from 10 to 30%. As clinical presentation of IE can be nonspecific, echocardiography is usually recommended in SAB cases to 'rule out' IE. Due to its poor sensitivity (<50%), especially for diagnosing prosthetic valve IE, transthoracic echocardiography is considered inadequate in this setting and clinicians have to rely on transesophageal echocardiography (TEE) to confirm or exclude endocarditis in SAB cases. Although some experts recommend TEE in all patients presenting with SAB, it is believed that the use of TEE could be guided by individual patient risk factors, mode of acquisition of SAB and clinical presentation. In this article, published data regarding the use of TEE in the SAB population are reviewed and a simplified algorithm to guide use of TEE in SAB cases is proposed.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

Risk factors of mid-term mortality of patients with infective endocarditis

In-hospital and long-term mortality of infective endocarditis (IE) are well noted, but the studies for mid-term (90-day) mortality of IE is still limited. We determine the mid-term mortality rate of IE and its significant predictors. Seventy patients with IE were hospitalised at St. Luke's International Hospital between January 1996 and March 2009, of whom 62 consecutive patients could be followed up for 90 days after diagnosis. We then calculated Kaplan-Meier (KM) estimates and performed time-to-event analysis. The mean (standard deviation, SD) age was 66.6 (15.3) years. Thirty-five patients (56%) were male. Blood cultures were positive in 87%. Causative microorganisms were: viridans group streptococci (23%), β-streptococci (16%), Staphylococcus aureus (15%), including methicillin-resistant S. aureus (MRSA) (5%). Thirty-three cases (53%) had at least one complication such as heart failure (34%), central nervous system (CNS) complication (29%) or emboli peripheral to CNS (6%). KM estimates (95% CI) of the 90-day mortality was 14.5% (7.8-25%). In multiple regression analysis using the Cox proportional hazards model, hazard ratios of at least one complication for the 90-day mortality was 8.2 (1.4-155). Mid-term mortality of IE continues to be high and the presence of at least one complication may be considered as an independent risk factor of mid-term mortality.

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.

Thrombosis of mechanical mitral valve prosthesis

Obstruction of mechanical valve prostheses is a rare but potentially lethal complication following valve replacement surgery. Identifying the etiology and differentiation between thrombus, pannus, and vegetation obstructing the valve prosthesis can pose a diagnostic challenge. We report a patient who had an acute cerebral hemorrhage, developed a progressive mass lesion obstructing his mechanical mitral valve, and discuss contemporary diagnostic and management strategies.

Active infectious endocarditis: postoperative outcome

OBJECTIVE

Many changes have occurred in the natural history and the management of active infectious endocarditis (AIE) in recent years. Therefore, the records of patients admitted in a tertiary care specialized hospital presenting with the Duke criteria were reviewed.

METHODS

Adults operated on to treat AIE were included during a 3-year period. Patients presenting with AIE associated with a pacemaker were not included. Bacteriologic investigations included blood cultures, intraoperative samplings (including polymerase chain reaction), and serologies. Clinical and bacteriologic factors associated with hospital mortality were studied by univariate regression analysis (p < 0.05).

RESULTS

Ninety-eight of 164 patients (60%) admitted with the diagnosis of AIE underwent valvular surgery. The duration between the beginning of AIE and surgery was 23 +/- 16 (mean +/- standard deviation) days. Only 45 patients had a previous history of valvular disease. Seventy-two patients presented with aortic and 41 with mitral valve AIE. Fifty suffered from embolic events. Streptococcus species were responsible in 64 cases (23 were Streptococcus bovis) and Staphylococcus species in 24 cases. Death occurred postoperatively in 19 patients. The factors associated with fatal outcome were preoperative hemodynamic instability, age, Parsonnet and Simplified Acute Physiology Score II scores, diabetes mellitus, preexisting valvulopathy, antiarrhythmic treatment, hypoalbuminemia, renal dysfunction, duration of extracorporeal circulation, and red cell allogeneic transfusions. The type of bacteria did not influence mortality. The mean intensive care unit and hospital stays were 10 and 39 days, respectively. Eleven patients suffered from neurologic sequelae; 2 years later, 2 of them presented with severe deficit and 1 had died.

CONCLUSIONS

AIE necessitating cardiac surgery should be considered as a severe and resource-consuming disease.

Current State of Intraoperative Echocardiography

Intraoperative use of echocardiography is becoming more prevalent and is now considered an essential part of modern cardiac surgery. Echocardiography can be performed intraoperatively using transesophageal, epicardial or epiaortic, and substernal approaches. These techniques have a variety of applications in evaluating myocardial and valvular function, assessing aortic atheroma, and determining adequacy of various kinds of repair and reconstruction. Future applications will most likely involve more compact equipment, the implementation of epicardial and transesophageal real-time three-dimensional echocardiography, and better use of provocative methods of intraoperative testing.

Infective Endocarditis in Adults with Congenital Heart Disease

Although modern medicine has improved survival in congenital heart disease dramatically, the long-term course carries a risk of late complications. The incidence of infective endocarditis in adults with congenital heart disease is more than 10 times higher than that of the normal population. Identification of the high-risk groups, a high diagnostic alert, and no random prescription of antibiotics to these patients are important issues to health care providers. There is also a need for a structured education of patients on preventive measures and symptoms of infective endocarditis.