Associations between echocardiographic manifestations and bacterial species in patients with infective endocarditis: a cohort study.

BACKGROUND: The diagnosis of infective endocarditis (IE) is based on microbiological analyses and diagnostic imaging of cardiac manifestations. Echocardiography (ECHO) is preferred for visualization of IE-induced cardiac manifestations. We investigated associations between bacterial infections and IE manifestations diagnosed by ECHO. METHODS: In this cohort study, data from patients aged 18 years or above, with definite IE admitted at the Karolinska University Hospital between 2008 and 2017 were obtained from Swedish National Registry of Endocarditis. Bacteria registered as pathogen were primarily selected from positive blood culture and for patients with negative blood culture, bacteria found in culture or PCR from postoperative material was registered as pathogen. Patients with negative results from culture or PCR, and patients who did not undergo ECHO during hospital stay, were excluded. IE manifestations diagnosed by ECHO were obtained from the registry. Chi-squared test and two-sided Fisher's exact test was used for comparisons between categorical variables, and student's t test was used for continuous numerical variables. Multivariable analyses were performed using logistic regression. Secular trend analyses were performed using linear regression. Associations and the strength between the variables were estimated using odds ratios (ORs) with 95% confidence intervals (CIs). P < 0.05 was considered significant. RESULTS: The most common bacteria were Staphylococcus aureus (n = 239, 49%) and viridans group streptococci (n = 102, 21%). The most common manifestations were vegetation in the mitral (n = 195, 40%), aortic (n = 190, 39%), and tricuspid valves (n = 108, 22%). Associations were seen between aortic valve vegetations and Enterococcus faecalis among patients with native aortic valves, between mitral valve vegetations and streptococci of group B or viridans group, between tricuspid valve vegetations and S. aureus among patients with intravenous drug abuse, and between perivalvular abscesses as well as cardiovascular implantable electronic device (CIED)-associated IE and coagulase negative staphylococci (all P < 0.05). CONCLUSIONS: Associations were found between certain bacterial species and specific ECHO manifestations. Our study contributes to a better understanding of IE manifestations and their underlying bacterial etiology, which pathogens can cause severe infections and might require close follow-up and surgical treatment.

The value of a new cardiac magnetic resonance imaging protocol in Myocardial Infarction with Non-obstructive Coronary Arteries (MINOCA) - a case-control study using historical controls from a previous study with similar inclusion criteria.

BACKGROUND: Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) is common with a prevalence of 6% of all patients fulfilling the diagnosis of myocardial infarction. MINOCA should be considered a working diagnosis. Cardiac Magnetic Resonance (CMR) imaging has recently been suggested to be of great value to determine the cause behind MINOCA. The objectives of this paper are to describe the rationale behind the second Stockholm Myocardial Infarction with Normal Coronaries (SMINC-2) study and to discuss the protocol for investigation of MINOCA patients in the light of the recently published position paper from the European Society of Cardiology. METHODS: The SMINC-2 study is an open non-randomised study using historical controls for comparison. The primary aim is to prove that MINOCA patients investigated with the latest CMR imaging technique can achieve a diagnosis in 70% of all cases entirely by imaging. By including 150 patients we will have >80% chance to prove that the diagnostic accuracy can be improved by 20 absolute % with a p-value of less than 0.05 when compared with CMR imaging in the SMINC-1 study. Furthermore, in addition to invasive coronary angiography, coronary arteries are evaluated by computed tomography angiography to investigate coronary causes and questionnaires are used to describe Quality-of-Life (QoL). By January 1st 2017, 75 patients have been included. DISCUSSION: Whether CMR imaging can provide a diagnosis to an adequate proportion of MINOCA patients is unknown. Well-defined inclusion and exclusion criteria will be used to compare a MINOCA cohort from the population with an appropriate control group. Positive results are likely to influence future guidelines of the management of MINOCA. Furthermore, the study will give mechanistic insights into MINOCA in particular in patients with "true" myocardial infarction and describe QoL in this vulnerable group of patients. TRIAL REGISTRATION: Clinical Trials NCT02318498 .