Results

Study population

Between April 2022 and October 2024, 145 consecutive TOE examinations performed for suspected IE were screened. Twelve examinations were excluded because IE was not confirmed or because they were duplicate or repeat examinations relating to the same infective episode, leaving 133 unique confirmed clinical episodes of IE for the final analysis. Overall in-hospital mortality during the index admission was 11.3% (15/133).

Baseline characteristics

The mean age of the study population was 63.3 ± 17.7 years (median, 64 years; interquartile range, 52-79 years), and 88 patients (66.2%) were male. The age distribution of the study population is shown in Figure 1. Native valve IE accounted for 75.9% of cases, whereas prosthetic valve involvement was identified in approximately one-quarter of patients. The aortic valve was the most frequently affected cardiac structure (62.4%). Intravenous drug use was documented in 9.8% of cases, and no deaths occurred within this subgroup. CIED-related infection was identified in 21 patients (15.8%).

Figure 1: Demographics.Age, mean ± SD: 63.3 ± 17.7 years.

Microbiological findings

Staphylococcus aureus was the predominant causative organism, accounting for 30.8% of infections. Streptococcal species represented 25.6% of cases, while enterococci accounted for 15.0%. Oral-flora organisms were identified in 44 patients (33.1%), representing approximately one-third of all episodes. Culture-negative IE occurred in 12.0% of cases. The microbiological distribution is illustrated in Figure 2.

Figure 2: Microbiological distribution.Staphylococcus aureus was the most common organism (30.8%). Streptococci (25.6%) and enterococci (15.0%) reflect a substantial oral/gastrointestinal contribution. Culture-negative infective endocarditis occurred in 12.0% of cases.

Echocardiographic findings and management

TOE demonstrated that the aortic valve was the most commonly affected valve (62.4%), followed by the mitral valve. Multi-valve involvement was present in 14.3% of patients. Device-related IE accounted for 21 cases (15.8%).

Overall, 26 patients (19.5%) underwent an interventional procedure during the index admission, including 17 valve operations and nine device extractions. Among the valve procedures, aortic valve replacement was the most common operation (n = 10), followed by mitral valve replacement (n = 3), tricuspid valve replacement (n = 2), transcatheter aortic valve implantation (TAVI) (n = 1), and valve-in-valve TAVI (n = 1). The distribution of valve and structure involvement is illustrated in Figure 3. Clinical outcomes are summarised in Figure 4.

Figure 3: Valve/structure involvement.Multi-valve involvement occurred in 14.3% of patients. Surgical management was undertaken in 26 patients: 17 valve procedures and nine device extractions. In-hospital mortality was 11.3%.

Figure 4: Outcomes.Multi-valve involvement occurred in 14.3% of patients. Surgical management was undertaken in 26 patients: 17 valve procedures and nine device extractions. In-hospital mortality was 11.3%.

Association between dental exposure and oral-flora IE

Documented invasive dental procedures before the diagnosis of IE were identified in 26 patients (19.5%). Oral-flora organisms were isolated in 13 of these patients (50.0%), compared with 31 of 107 patients (28.8%) without documented dental exposure.

Patients with documented dental procedures had significantly higher odds of oral-flora IE than those without documented dental exposure (odds ratio, 2.47; 95% CI, 1.03-5.94; p = 0.040). Antibiotic prophylaxis was documented in 2 of 26 patients (7.7%). Among patients with documented dental procedures, prophylaxis status was not documented in 22 of 26 cases (84.6%). These findings are illustrated in Figure 5.

Figure 5: Association between documented dental exposure and oral-flora infective endocarditis.OR = 2.47 (95% CI: 1.03-5.94; p = 0.040).Oral-flora infective endocarditis occurred in 50.0% of patients with documented dental exposure, compared with 28.8% of patients without documented dental exposure.

Clinical outcomes

Overall in-hospital mortality was 11.3% (15/133). In-hospital mortality was defined as death occurring during the index hospital admission for IE. Prosthetic valve IE had the highest crude mortality (16.1%), although the CIs were wide. No deaths occurred among patients with intravenous drug use, while oral-flora IE was not associated with excess in-hospital mortality (11.4%). No demographic, microbiological, or echocardiographic variable was significantly associated with in-hospital mortality. Mortality across the principal clinical subgroups is illustrated in Figure 6.

Figure 6: In-hospital mortality.Overall in-hospital mortality was 11.3%, lower than that reported in most published series, reflecting strict in-hospital attribution.Prosthetic valve infective endocarditis had the highest crude mortality (16.1%), but the CIs were wide.No deaths occurred among patients with intravenous drug use (IVDU) (0/13), consistent with their younger age and right-sided disease.Oral-flora infective endocarditis was not associated with excess mortality (11.4%).