Surgical decision-making in aortic prosthetic valve endocarditis: the influence of electrocardiogram-gated computed tomography

Bacteraemia with gram-positive bacteria-when and how do I need to look for endocarditis?

BACKGROUND

Patients with bacteraemia caused by gram-positive bacteria are at risk for infective endocarditis (IE). Because IE needs long antibiotic treatment and sometimes heart valve surgery, it is very important to identify patients with IE.

OBJECTIVES

In this narrative review we present and discuss how to determine which investigations to detect IE that are needed in individual patients with gram-positive bacteraemia.

SOURCES

Published original studies and previous reviews in English, within the relevant field are used.

CONTENT

First, the different qualities of the bacteraemia in relation to IE risk are discussed. The risk for IE in bacteraemia is related to the species of the bacterium but also to monomicrobial bacteraemia and the number of positive cultures. Second, patient-related factors for IE risk in bacteraemia are presented. Next, the risk stratification systems to determine the risk for IE in gram-positive bacteraemia caused by Staphylococcus aureus, viridans streptococci, and Enterococcus faecalis are presented and their use is discussed. In the last part of the review, an account for the different modalities of IE-investigations is given. The main focus is on echocardiography, which is the cornerstone of IE-investigations. Furthermore, 18F-fluorodesoxyglucose positron emission tomography/computed tomography and cardiac computed tomography are presented and their use is also discussed. A brief account for investigations used to identify embolic phenomena in IE is also given. Finally, we present a flowchart suggesting which investigations to perform in relation to IE in patients with gram-positive bacteraemia.

IMPLICATIONS

For the individual patient as well as the healthcare system, it is important both to diagnose IE and to decide when to stop looking for IE. This review might be helpful in finding that balance.

Imaging of Cardiac Infections: A Comprehensive Review and Investigation Flowchart for Diagnostic Workup

Infections of the cardiovascular system may present with nonspecific symptoms, and it is common for patients to undergo multiple investigations to arrive at the diagnosis. Echocardiography is central to the diagnosis of endocarditis and pericarditis. However, cardiac computed tomography (CT) and magnetic resonance imaging also play an additive role in these diagnoses; in fact, magnetic resonance imaging is central to the diagnosis of myocarditis. Functional imaging (fluorine-18 fluorodeoxyglucose-positron emission tomography/CT and radiolabeled white blood cell single-photon emission computed tomography/CT) is useful in the diagnosis in prosthesis-related and disseminated infection. This pictorial review will detail the most commonly encountered cardiovascular bacterial and viral infections, including coronavirus disease-2019, in clinical practice and provide an evidence basis for the selection of each imaging modality in the investigation of native tissues and common prostheses.

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.

The role of cardiac computed tomography in the diagnosis of prosthetic valve endocarditis - A comparison with transthoracic and transesophageal echocardiography and intra-operative findings

BACKGROUND

Infective endocarditis is one of the most severe complications after prosthetic valve implantation and an accurate diagnosis is a clinical challenge. The purpose was to assess the diagnostic usefulness of cardiac computed tomography (CT) in valvular and perivalvular complications in patients with prosthetic valve endocarditis (PVE) and to compare CT results with transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) and intraoperative findings.

METHODS

The retrospective study included 44 consecutive patients with PVE who underwent cardiac surgery. The mean age was 59.6 ± 12.9 years, 33 (75 %) were males. The presence of vegetations, abscess/pseudoaneurysm, paravalvular leakage (PVL) and inflammatory infiltration were evaluated by TTE, TEE and CT prior to surgery and the results were compared with intraoperative findings.

RESULTS

Endocarditis affected 47 valves (26 mechanical, 21 biological) in 44 patients. PVE most often affected the aortic valve (n = 36), followed by the mitral valve (n = 9) and the pulmonary valve (n = 2). In the per-valve analysis, the sensitivity of TTE, TEE and CT in diagnosing vegetations was 65 %, 91 % and 96 %; abscess 44 %, 77 % and 89 %; paravalvular leakage 90 %, 100 % and 70 %; inflammatory infiltration 39 %, 56 % and 78 %, respectively. The combination of CT and echocardiography allowed the detection of abscesses/pseudoaneurysms and inflammatory infiltration in all cases except one.

CONCLUSION

CT was superior to echocardiography in the diagnosis of paravalvular abscesses, vegetations and inflammatory infiltration. Echocardiography had a higher diagnostic value to CT in the evaluation of paravalvular leakage. Cardiac CT combined with echocardiography improves the diagnostic accuracy of PVE and both modalities should be performed.

Current Challenges in the Management of Infective Endocarditis

Infective endocarditis is a relatively rare, but deadly cause of sepsis, with an overall mortality ranging from 20 to 25% in most series. Although the classic clinical classification into syndromes of acute or subacute endocarditis have not completely lost their usefulness, current clinical forms have changed according to the profound epidemiological changes observed in developed countries. In this review, we aim to address the changing epidemiology of endocarditis, several recent advances in the understanding of the pathophysiology of endocarditis and endocarditis-triggered sepsis, new useful diagnostic tools as well as current concepts in the medical and surgical management of this disease. Given its complexity, the management of infective endocarditis requires the close collaboration of multidisciplinary endocarditis teams that must decide on the diagnostic approach; the appropriate initial treatment in the critical phase; the detection of patients needing surgery and the timing of this intervention; and finally the accurate selection of patients for out-of-hospital treatment, either at home hospitalization or with oral antibiotic treatment.

Role of Cardiac CT in Infective Endocarditis: Current Evidence, Opportunities, and Challenges

Infective endocarditis (IE) can present with variable clinical and imaging findings and is associated with high morbidity and mortality. Substantial improvement of CT technology, most notably improved temporal and spatial resolution, has resulted in increased use of this modality in the evaluation of IE. The aim of this article is to review the potential role of cardiac CT in evaluating IE. Supplemental material is available for this article. © RSNA, 2021.

Endocarditis in Patients with Aortic Valve Prosthesis: Comparison between Surgical and Transcatheter Prosthesis

The interventional treatment of aortic stenosis is currently based on transcatheter aortic valve implantation/replacement (TAVI/TAVR) and surgical aortic valve replacement (SAVR). Prosthetic valve infective endocarditis (PVE) is the most worrisome complication after valve replacement, as it still carries high mortality and morbidity rate. Studies have not highlighted the differences in the occurrence of PVE in SAVR as opposed to TAVR, but the reported incidence rates are widely uneven. Literature portrays different microbiological profiles for SAVR and TAVR PVE: Staphylococcus, Enterococcus, and Streptococcus are the pathogens that are more frequently involved with differences regarding the timing from the date of the intervention. Imaging by means of transoesophageal echocardiography, and computed tomography (CT) Scan is essential in identifying vegetations, prosthesis dysfunction, dehiscence, periannular abscess, or aorto-ventricular discontinuity. In most cases, conservative medical treatment is not able to prevent fatal events and surgery represents the only viable option. The primary objectives of surgical treatment are radical debridement and the removal of infected tissues, the reconstruction of cardiac and aortic morphology, and the restoration of the aortic valve function. Different surgical options are discussed. Fast diagnosis, the adequacy of antibiotics treatment, and prompt interventions are essential in preventing the negative consequences of infective endocarditis (IE).

Diagnostic performance of cardiac computed tomography versus transesophageal echocardiography in infective endocarditis: A contemporary comparative meta-analysis

OBJECTIVE

To compare the diagnostic accuracy of transesophageal echocardiography (TEE) and cardiac computed tomography (CCT) in diagnosing infective endocarditis (IE).

BACKGROUND

TEE is a mainstay imaging modality for IE, while the use of CCT is becoming increasingly prevalent. Data directly comparing the diagnostic performance of these two imaging modalities for IE are limited.

METHODS

We conducted a systematic review and meta-analysis of published literature in Embase, PubMed and Cochrane databases through October 1, 2020 for studies comparing diagnostic performance of CCT and TEE for the diagnosis of IE in the same patient populations. A meta-analysis of diagnostic accuracy was performed using the bivariate model based on studies that used surgical pathology as a reference standard for defining endocarditis. From a total of 10 studies included in the meta-analysis, a total of 872 patients were evaluated.

RESULTS

The pooled sensitivities and specificities of TEE for detecting vegetations were 96% and 83% respectively, whereas for CCT, they were 85% and 84%, respectively. In the prosthetic valve sub-group, the pooled sensitivities and specificities of TEE for detecting vegetations were 89% and 74% respectively, whereas for CCT, they were 78% and 94%, with CCT being more specific than TEE (p < 0.05). The pooled sensitivities and specificities of TEE for detecting periannular complications were 70% and 96% respectively, whereas for CCT, they were 88% and 93%, respectively. CCT showed a trend (p = 0.06) towards higher sensitivity than TEE for detection of periannular complications. The pooled sensitivities and specificities of TEE for detecting leaflet perforation were 79% and 93% respectively, whereas for CCT, they were 48% and 93% respectively, with TEE being more sensitive (p < 0.05). The two modalities also showed comparable diagnostic performance for detecting fistulae, paravalvular leaks and prosthetic valve dehiscence.

CONCLUSION

In a contemporary comparative meta-analysis, TEE and CCT demonstrated both good diagnostic accuracy for detecting valvular involvement and complications of IE. TEE performed better for detecting leaflet defects, whereas CCT performed better in cases of prosthetic valve involvement, and showed a trend towards improved detection of periannular complications. Appropriate, complementary use of both TEE and CCT in a multimodality imaging approach in clinical practice may achieve the highest diagnostic performance.

Diagnostic imaging in infective endocarditis: a contemporary perspective

INTRODUCTION

Infective endocarditis (IE) remains a diagnostic challenge. Prompt diagnosis is essential for accurate risk stratification and appropriate therapeutic decisions and surgical management. In recent years, the use of multimodal imaging has had a transformative effect on the diagnostic approach of IE in selected patients.

AREAS COVERED

This review assesses published literature on different imaging modalities for the diagnosis of IE published between 1 January 2009 and 1 February 2020. We illustrate the diagnostic approach to IE with three clinical cases.

EXPERT OPINION

Novel approaches to imaging for cardiac and extracardiac complications improve and individualize diagnosis, management, and prognosis in patients with suspected IE. The use of multimodal imaging should be guided by a multidisciplinary group of medical providers that includes infectious disease specialists, radiologists, cardiologists, and cardiothoracic surgeons.

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.

Prosthetic valve endocarditis: A challenging complication of prosthetic valves

Background

This study aims to evaluate the surgical outcomes of prosthetic valve endocarditis.

Methods

A total of 21 patients (6 males, 15 females; mean age 58.9±12.6 years; range, 33 to 79 years) who were surgically treated for prosthetic valve endocarditis between January 2013 and January 2018 were retrospectively analyzed. Surgical indications included persistent fever for more than seven days after antibiotherapy, congestive heart failure refractory to medical treatment, vegetations larger than 1 cm on echocardiography, the presence of fungal endocarditis, severe valvular leak and valvular dysfunction, and staphylococcal prosthetic valve endocarditis.

Results

Five patients had previous aortic valve replacement and three of the aortic prostheses were re-replaced. Two patients had coexisting native mitral valve endocarditis and double valve replacement was done. Thirteen patients had previous mitral valve replacement and 12 of the mitral prostheses were re-replaced. One patient had coexisting native aortic valve endocarditis and double valve re-replacement was done. Three patients had previous aortic valve replacement + mitral valve replacement. Mitral valve endocarditis was diagnosed in two patients and these patients had only mitral valve re-replacement. The other patient had double valve endocarditis, and double valve replacement was done. The mean time from the first operation to the development of endocarditis was 7.3±5.7 years. Of five lost patients, two died from multiple organ failure, one from low cardiac output, one from pneumonia, and one from respiratory failure.

Conclusion

Radical resection of the infected tissues is critical to achieve favorable surgical outcomes. Single valve replacement of the infected valve may be preferred in patients having previous double valve replacement. Mechanical valves or bioprostheses can be used for re-replacement procedures.

Value of cardiac computed tomography angiography in pre-operative assessment of infective endocarditis

Background

Substantial development of cardiac computed tomography angiography (CTA) technology in the last decade has commanded to increase usage of this modality for assessing infective endocarditis (IE). The objective of this study is to evaluate the sensitivity and specificity of preoperative cardiac CTA imaging as opposed to transthoracic echocardiography (TTE) in the assessment of complications associated to IE, with comparison to surgical findings.

Methods

Among 52 patients with surgically proven IE in our database, 24 underwent contrast-enhanced ECG cardiac CTA and were included in the study and all of them also underwent TTE.

Results

For the detection of pseudoaneurysm/abscess in both native and prosthetic valves, cardiac CTA demonstrated significantly higher sensitivity (91.5% vs. 15.8%, p < 0.0001) with similar specificity (81.25). Cardiac CTA demonstrated similar sensitivity and specificity in identifying vegetation and valvular dehiscence in all patients.

Conclusions

Preoperative cardiac CTA can be seen as complementary to TTE in assessing complications such as pseudoaneurysm or abscess of the patients with IE.

The usefulness of cardiac CT in the diagnosis of perivalvular complications in patients with infective endocarditis

Objectives

The aim of the study was to compare the usefulness of cardiac CT to transthoracic (TTE) and transesophageal (TEE) echocardiography in the diagnosis of infective endocarditis (IE) and perivalvular complications using surgical inspection as the gold standard.

Material and methods

Fifty-three consecutive patients (42 men, mean age 58.3 ± 12.5) with IE requiring surgical procedures were enrolled in the study. All patients underwent preoperative TTE, TEE, and CT. The presence of vegetations, perivalvular abscess/pseudoaneurysm, leaflet perforation, inflammatory infiltration, and prosthesis dehiscence was assessed.

Results

We analyzed 71 affected valves (58 native, 13 prosthetic). Intraoperative assessment revealed 11 abscesses/pseudoaneurysms. Sensitivity and specificity of echocardiography (TTE + TEE) and CT were 63%, 90% and 81%, 90%, respectively. The combination of CT and echocardiography allowed diagnosing all abscesses/pseudoaneurysms. Inflammatory infiltration was found intraoperatively in 15 patients. Sensitivity and specificity of TEE and CT were 53%, 94% and 46%, 100%, respectively. Intraoperative assessment revealed leaflet perforation in 16 patients. Sensitivity and specificity of TEE and CT were 75%, 79% and 43%, 89%. The sensitivity of the combination of TTE + TEE + CT was 81%. Perivalvular leakage was found in eight patients with a prosthetic valve. Sensitivity and specificity of echocardiography and CT were 100%, 100% and 88%, 100%, respectively. TEE showed higher sensitivity (97%) than CT (89%) in the diagnosis of vegetations.

Conclusions

The combination of TTE, TEE, and CT increased the sensitivity for the detection of valvular and perivalvular complications of IE.

Key Points

• CT is a useful modality in the diagnosis of IE and its local complications in addition to echocardiography.

• For the detection of abscesses and pseudoaneurysms, CT is superior to echocardiography. Combining these two modalities can increase the sensitivity of diagnosing abscess/pseudoaneurysm up to 100%.

• Adding CT to TEE increases the sensitivity for detection of inflammatory infiltrate. CT is not superior to echocardiography in diagnosing vegetations, valvular leaflet perforations, and perivalvular leaks, but it can be a useful tool when echocardiography is indeterminate.

Role of preoperative cardiac CT in the evaluation of infective endocarditis: comparison with transesophageal echocardiography and surgical findings

Background

Significant improvement of computed tomography (CT) technology in the last decade has led to more use of this modality for evaluating infective endocarditis (IE) especially since the introduction of high resolution electrocardiogram (ECG) synchronized multiphasic (4D) acquisition. While there are a number of reports on the accuracy and value of 4D CT for evaluation of IE, there is no published data regarding the performance of single-phase ECG gated CT for assessment of IE. The purpose of this study is to evaluate the sensitivity and specificity of preoperative single-phase ECG-gated CT imaging versus transesophageal echocardiography (TEE) in the assessment of complications related to IE, with comparison to surgical findings.

Methods

Among 899 patients with surgically proven IE in our database, 122 underwent contrast-enhanced ECG cardiac CT and were included in the study; 84 of these patients also underwent TEE.

Results

Overall, there was no significant difference between CT and TEE in the identification of pseudoaneurysm/abscess and dehiscence. For the detection of pseudoaneurysm/abscess in prosthetic valves, CT demonstrated higher sensitivity (81% vs. 64%) and specificity (75% vs. 33%) in patients with mechanical aortic valves; TEE demonstrated marginally higher sensitivity (72% vs. 63%) and specificity (80% vs. 73%) in patients with bioprosthetic aortic valves, although the differences are not statistically significant. TEE demonstrated significantly higher sensitivity (85% vs. 16%) in identifying vegetation in all patients (P<0.0001), including patients with prosthetic valves (sensitivity, 78% vs. 19%). The combined imaging findings of CT and TEE demonstrated improved sensitivity in identifying pseudoaneurysm/abscess and slightly improved detection of prosthesis dehiscence.

Conclusions

Preoperative single-phase gated CT can be seen as complementary to TEE in assessing complications of suspected IE or may be substituted for TEE when vegetation or dehiscence is depicted on transthoracic echocardiography and the patient has a contraindication to TEE.

S. aureus endocarditis: Clinical aspects and experimental approaches

Infective endocarditis (IE) is a life-threatening disease, caused by septic vegetations and inflammatory foci on the surface of the endothelium and the valves. Due to its complex and often indecisive presentation the mortality rate is still about 30%. Most frequently bacterial microorganisms entering the bloodstream are the underlying origin of the intracardiac infection. While the disease was primarily restricted to younger patients suffering from rheumatic heart streptococci infections, new at risk categories for Staphylococcus (S.) aureus infections arose over the last years. Rising patient age, increasing drug resistance, intensive treatment conditions such as renal hemodialysis, immunosuppression and long term indwelling central venous catheters but also the application of modern cardiac device implants and valve prosthesis have led to emerging incidences of S. aureus IE in health care settings and community. The aetiologic change has impact on the pathophysiology of IE, the clinical presentation and the overall patient management. Despite intensive research on appropriate in vitro and in vivo models of IE and gained knowledge about the fundamental mechanisms in the formation of bacterial vegetations and extracardiac complications, improved understanding of relevant bacterial virulence factors and triggered host immune responses is required to help developing novel antipathogenic treatment strategies and pathogen specific diagnostic markers. In this review, we summarize and discuss the two main areas affected by the changing patient demographics and provide first, recent knowledge about the pathogenic strategies of S. aureus in the induction of IE, including available experimental models of IE used to study host-pathogen interactions and diagnostic and therapeutic targets. In a second focus we present diagnostic (imaging) regimens for patients with S. aureus IE according to current guidelines as well as treatment strategies and surgical recommendations.