Right-sided infective endocarditis: characterization and prognosis
Authors: Bernardo M , Moreira I , Carvalho C , Carvalho P , Monteiro J , Guimaraes J , Silva Carvalho S , Moreira J I 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Right-sided infective endocarditis (RIE) involves native/prosthetic valves and any intracardiac devices present in the right cavities. It's caused by the seeding of any of these structures by bacterial or, less commonly, fungal organisms. It's commonly associated with intravenous drug use, intracardiac devices and central venous catheters, all of which became more prevalent over the past 20 years.

Purpose
We aimed to characterize the patients with right-sided infective endocarditis, including device endocarditis, admitted to our center and compare them with patients admitted with left-sided infective endocarditis (LIE).

Methods
We performed a retrospective study of a group of patients (pts) with infective endocarditis (IE) admitted to our center from 2000 to 2020. Pts were categorized with right-sided endocarditis when presented with endocarditis of the native/prosthetic valves right-sided and intracardiac devices. We considered, as composite endpoint, deaths, embolic events and recurrence of endocarditis in a medium follow-up of 37.4 ± 46.0 months.

Results
A total of 160 pts (106 males, mean age 66,3 ± 16 years) with the diagnosis of IE were included. 32 pts had RIE (11 with involvement of tricuspid valve and 23 with device involvement) and 126 had LIE (100 of native valve and 26 of prosthetic valve). We had 56 (15.5%) pts referred to surgery during hospitalization and 27 (7.5%) died during hospitalization. Compared with LIE, most of the pts with RIE were males (84% versus 61%, p= 0,015). The mean age was similar between the groups (p= 0,584). Pts with RIE had a lesser prevalence of known valvular heart disease (48% versus 21%, p= 0,007). Concerning complications of endocarditis, pts with RIE had less prevalence of fistula (18% versus 0%, p= 0,021). During hospitalization, the proportion of pts undergoing surgery was significantly less in patients with RIE (31% vs 61%, p=0,001). Considering the subgroup of patients with device endocarditis, 14 patients undergo device extraction (8 percutaneous and 6 surgical extraction). During a mean follow-up duration of 37.4 ± 46.0months, pts with the diagnosis of RIE had better outcomes for the composite endpoint (61% vs 33%, p=0.003). Even when we considered the events during the hospitalization (namely embolic events or death), this subgroup had fewer events (83% vs 63%, p=0.034). In a multivariate regression analysis, after adjusting for all the confounders (previous cardiac failure, development of severe valvular regurgitation, presence of fistula/perforation and development of abscess), RIE was an independent predictor of less prevalence of the composite endpoint (HR 0.38; 95% CI: 0.19-0.79).

Conclusions
RIE was associated with a better outcome, when considering death, embolic events, or recurrence of endocarditis. The patients with right-sided endocarditis were also less frequently submitted to surgery compared to others.