Infective endocarditis in patients with rheumatic heart disease: a single-centre retrospective comparative study.

Aims: We reviewed the baseline characteristics and outcomes of patients with infective endocarditis (IE) and compared those with and without rheumatic heart disease (RHD).

Methods: We retrospectively reviewed patients ≥15 years with IE treated at Auckland City Hospital between January 2016 and December 2018 and excluded device-related IE and complex congenital heart disease. RHD status was based on echocardiographic features or previous history of rheumatic fever with valvular disease. Microbiologic and echocardiographic results, treatment modalities and complications were recorded. Demographics and outcomes were compared based on RHD status.

Results: There were 155 patients with IE. Twenty-two had RHD. The mean age at admission was 45 years for RHD patients, which was 19 years younger than for non-RHD patients. There were significantly more Pacific patients with RHD (55% vs 14%). Previous IE and prosthetic valve endocarditis (PVE) were more common in RHD patients (27% vs 5%, and 77% vs 29%, respectively). After a median follow-up of 29 months, there was no significant difference in all-cause mortality between the two groups. However, 25/155 patients (16%) had died from IE-related causes (septic or cardiogenic shock post cardiac surgery, or embolic complications), with a significantly higher mortality in patients with RHD (7/22 (32%) patients, HR: 2.5) on univariate analysis. On multivariable analysis, PVE, heart failure, Staphylococcus aureus infection, diabetes, stroke and cardiac abscess were all associated with increased mortality, whereas RHD was not independently associated with increased mortality.

Conclusions: In this retrospective single-centre audit, patients with RHD experienced IE at a younger age, had a higher incidence of prosthetic valve endocarditis and a prior history of IE. Although there was no difference in all-cause mortality, mortality in patients with RHD was almost exclusively secondary to complications of IE. This highlights the need for prevention strategies against endocarditis in the RHD population, including use of antibiotic prophylaxis¬, accessible dental health care and a high clinical suspicion for IE in RHD by healthcare providers.