Association between Echocardiographic Findings and Causative Microorganisms in 731 Patients with Infective Endocarditis: Data from Iranian Registry of Infective Endocarditis

Context: Echocardiography has an important role in early diagnosis and management of infective endocarditis (IE). Our study aimed to investigate a relationship between cardiac lesions and causative pathogens for choosing the best antibiotic regimen as soon as possible. Subjects and Methods: From 2006 to 2018, all adult patients with a possible or definite diagnosis of IE based on the modified Duke criteria were enrolled in the Iranian Registry of IE at Shaheed Rajaei Institute. Transthoracic echocardiography and blood culture were performed for all patients, and three-dimensional transesophageal echocardiography was performed when deemed necessary based on the physician’s diagnosis. Statistical Analysis Used: ANOVA analysis. Results: The most common cardiac predisposing factors according to echocardiographic data were congenital heart disease (24.2%) and rheumatic heart disease (9.7%). Prosthetic valve endocarditis accounted for 16% of cases. Left-side valves were more infected than the right-side valves. It was found that 13.5% of patients had multivalvular IE and AV-MV IE was the most common. The most predominant cardiac lesion was vegetation (84.8%). Abscess formation was present in 8.8% ( n = 64), and dehiscence in 3.8% ( n = 28) of patients. We found no significant relationship between larger vegetation and embolic events or mortality. Patients with prosthetic valve IE were more likely to be infected by Coagulase-negative Staphylococci (CoNS) , Enterococcus , and Staphylococcus aureus ( S . aureus ) IE. S . aureus infected the tricuspid valve more than other pathogens. CoNS were the most prevalent pathogens causing abscess formation. Significant pulmonary hypertension (PH) was associated with left-side IE and the majority of patients with severe PH had aortic valve IE (78%). Severe PH in our study was associated with S . aureus (9%) and Enterococcus (9%) and. Pericardial effusion was present in 30% of the patients to some extent. Conclusions: Since some echocardiographic findings could be related to specific microorganisms, predicting the causative microorganism and initiation of a better antibiotic regimen based on echocardiographic data is possible in some circumstances.