Comparison of Clinical Characteristics and Prognosis in Patients with Right- and Left-sided Infective Endocarditis

Right-sided endocarditis (RSE) accounts for 5%-10% of all cases of infective endocarditis (IE) and frequently has different etiological, pathogenetic, and clinical presentations compared with left-sided endocarditis (LSE). The aims of this study were to evaluate the epidemiologic and clinical characteristics and prognosis of RSE patients and to compare them with those of LSE patients. This study's importance relates to the local understanding of RSE and LSE, since Israeli demographics are different compared to the Unites States and Europe with regard to intravenous drug abuse and rheumatic valvular disease prevalence.

A retrospective cohort study of 215 patients with infective endocarditis was performed. The primary outcome was in-hospital mortality. The secondary outcomes were duration of hospitalization, recurrent hospitalization, recurrent infective endocarditis, and one-year mortality.

Of the 215 patients in the study, 176 had LSE and 39 had RSE. The RSE patients were younger than the LSE patients (48.1±18.9 years versus 61.8±17.0 years, P<0.001). The most common pathogen in both groups was Staphylococcus aureus, which occurred more in the RSE group (51%) versus the LSE group (19%). In-hospital mortality was lower among patients with RSE (2.6% versus 17%, P<0.037).

Our study demonstrated an increasing percentage of RSE compared to LSE among patients with IE. Pacemaker lead infection has become the leading cause of RSE in intravenous drug users (IVDU), although less common in Southern Israel. The etiological and clinical differences between RSE and LSE are noteworthy. Patients with RSE have a better prognosis than those with LSE.