Phenotype of vegetations: a retrospective echocardiographic analysis of patients with native valve endocarditis.
Authors: Rakhimov K , Zach V , Schoels M N , Frydas A , Schmidt W U H , Kemna C P , Pfaefflin F , Doehner W , Dreger H , Morris D A , Schneider-Reigbert M 
Published: January 2025

Abstract

Background
Echocardiography plays a central role in the diagnosis of infective endocarditis. Vegetations may present in various phenotypes depending on the bacterium involved and the immune state of the patient. Differentiation from thrombus and particularly non-bacterial thrombotic endocarditis (NBTE) in cancer patients can prove challenging. We sought to perform a retrospective morphologic echocardiographic analysis of vegetations and evaluate its association with the clinical and microbiological data in patients with native valve endocarditis.

Methods
We retrospectively included all patients from our tertiary referral center who were diagnosed with native valve endocarditis from 01/2019 until 12/2022. Baseline echocardiography was reviewed by two observers, vegetations were classified regarding their morphology. Clinical data was documented from chart analysis.

Results
A total of n=60 patients were included in this preliminary analysis, 44/60 (73,3%) were male, mean age was 68,2 years (±12,4). Blood cultures were positive in 55/60 (91.7%), the most common microorganisms identified being Staphylococcus aureus in 36.7%, viridans streptococci in 21.7%, enterococci in 20%, and other staphylococci species in 10%. Valves affected were mitral valve in 38.3%, aortic valve in 36.7%, tricuspid valve in 13.3%, and more than one valve in 10%. Cardioembolic events occurred in 24/60 (40%), most commonly cerebral stroke 18/24 (75%), splenic 4/24 (16.6%) and renal infarction 3/24 (12.5%). Charlson comorbidity index was 6.33 (±2.8). A total of 31/60 (51.6%) patients were operated. In-hospital mortality was 28.3%. A total of 14/60 (23%) patients had active malignant disease at the time of diagnosis of endocarditis. Eleven (18.3%) were additionally immunocompromised due to chemotherapy. Median vegetation size area was 0.79 cm² (0,47; 1,26), mean length was 12.4mm. It was classified as raceme in 20 (33%), filiform in 16 (27%), broad-based in 16 (27%), and broad-based with filiform foothills in eight (13%) patients (figure 1). There was no statistically significant association of morphology with outcome or the underlying microorganism (table 1).
Discussion: Endocarditis is a detrimental disease with high rates of morbidity and mortality, which was once again documented in this cohort. A quarter of the patients had active malignant disease. With port infection as common entry for bacteremia, and immunosuppression due to cancer itself and due to chemotherapy as predisposition, this group is particularly vulnerable. While NBTE must be on the list of differential diagnoses, probability for infective endocarditis is high if vegetations are present. In this retrospective analysis, we could show a diverse spectrum of echocardiographic morphology of vegetations ranging from broad-based to raceme configuration with no statistical association with underlying microorganism or outcome.
Table 1
Figure 1