Diagnostic imaging in infective endocarditis: a contemporary perspective

Role of echocardiography in the diagnosis and clinical management of infective endocarditis

Infective endocarditis (IE) is a deadly disease, constituting both diagnostic and treatment challenges. A positive outcome requires rapid and accurate diagnosis, and for that, echocardiography unequivocally remains the cornerstone. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have complementary roles and have been markedly improved during the last decades. The transthoracic modality is the recommended first-line approach but may only be sufficient in patients where the probability of IE is low and/or with clear acoustic windows, especially in patients with right-sided IE. The transesophageal modality is superior to TTE in most aspects and is recommended for all other patients. Both TTE and TEE may delineate vegetation location and size, assess for paravalvular extension of infection, and have the added advantage of defining the hemodynamic effects of valvular or device infection. However, echocardiography still has significant limitations, and novel imaging techniques are increasingly being exploited to improve diagnostic potential. Cardiac computed tomography (CT) performs better than TEE in the detection of abscess or pseudoaneurysm, while magnetic resonance imaging (MRI) has limited value in the diagnostic phase of IE but adds knowledge to the evaluation of extracardiac events. Nuclear molecular techniques are evolving as key supplementary methods in difficult-to-diagnose cases. Although newer imaging modalities are undergoing preliminary evaluation and multimodal imaging will play an increasing role in IE, echocardiography will continue to be pivotal in patients with IE for the foreseeable future.

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.

The role of imaging in infective endocarditis

Infective endocarditis (IE) poses a large diagnostic and therapeutical challenge. An early diagnosis is necessary for a positive outcome. Echocardiography is initial diagnostic method when there is a possibility of IE presence. TTE and TEE are useful in detection, accurate localisation and estimation of vegetation size, and also in detection of paravalvular spreading of infection. In certain situations, there is a need for usage of complementary methods like CCT and nuclear techniques. This article will outline advantages and limitations of certain diagnostic methods in diagnosis of IE.

Etiology, clinical characteristics, and outcome of infective endocarditis: 10-year experience from a tertiary care center in Pakistan

This study was conducted to assess the clinical characteristics, causative agents, complications, and outcomes of infective endocarditis (IE) among patients presenting to our tertiary care center over the last decade. This retrospective cohort study included all adult patients admitted to the Aga Khan University Hospital with the diagnosis of IE over a ten-year period from 2010 to 2020.  Outcomes variables included complications during hospitalization, surgical intervention, mortality, and length of stay. We identified a total of 305 cases out of which 176 (58%) were males and 129 (42%) were females. The mean age of the patients was 46.9±18.8 years. 95 (31%) had prosthetic valves in place. Staphylococcus aureus was isolated in 54 (39%) patients followed by coagulase-negative Staphylococcus in 23 (17%). Echocardiography revealed vegetations and abscesses in 236 (77%) and 4 (1%) patients, respectively. The most common valvular complication was mitral valve regurgitation found in 26 (9%) patients, followed by tricuspid valve regurgitation in 13 (4%) patients and aortic valve regurgitation in 11 (3%) patients. Furthermore, 81 (27%) patients suffered from heart failure and 66 (22%) from a stroke during hospitalization. The mean hospital length of stay was 10.4 ± 10.6 days. 64 (21%) patients required surgical repair and the overall mortality rate was 25%. Prosthetic valve endocarditis (OR = 3.74, 95% CI = 2.15-6.50, p<0.001), chronic kidney disease (OR = 2.51, 95% CI = 1.15-5.47, p=0.036), previous stroke (OR = 2.42, 95% CI = 1.18-4.96, p=0.026), and ischemic heart disease (OR = 3.04, 95% CI = 1.50-6.16, p=0.003) were significantly associated with an increased risk of mortality. In conclusion, our study provided valuable data on the clinical characteristics and outcomes of patients with IE in a developing country. S. aureus was the most common causative agent. Heart failure and stroke were the most common complications. The presence of prosthetic valves, history of chronic kidney disease, ischemic heart disease and previous stroke were associated with a significantly increased risk of mortality. Surgical management was not associated with improved outcomes.

Epidemiology of infective endocarditis: novel aspects in the twenty-first century

INTRODUCTION

The epidemiology of infective endocarditis (IE) in this millennium has changed with emergence of new risk factors and reemergence of others. This, coupled with modifications in national guidelines in the setting of a pandemic, prompted an address of the topic.

AREAS COVERED

Our goal is to provide a contemporary review of IE epidemiology considering changing incidence of rheumatic heart disease (RHD), cardiac device implantation, and injection drug use (IDU), with SARS-CoV-2 pandemic as the backdrop.

METHODS

PubMed and Google Scholar were used to identify studies of interest.

EXPERT OPINION

Our experience over the past two decades verifies the notion that there is not one 'textbook' profile of IE. Multiple factors have dramatically impacted IE epidemiology, and these factors differ, based, in part on geography. RHD has declined in many areas of the world, whereas implanted cardiovascular devices-related IE has grown exponentially. Perhaps the most influential, at least in areas of the United States, is injection drug use complicating the opioid epidemic. Healthy younger individuals contracting a potentially life-threatening infection has been tragic. In the past year, epidemiological changes due to the COVID-19 pandemic have also occurred. No doubt, changes will characterize IE in the future and serial review of the topic is warranted.