Profile, presentation and outcomes of prosthetic valve endocarditis in a South African tertiary hospital: Insights from the Groote Schuur Hospital Infective Endocarditis Registry

Background. Prosthetic valve infective endocarditis (PVE) is associated with high morbidity and mortality. The prevalence of PVE in South African retrospective studies ranges between 13% and 17%. Objectives. To define the clinical profile and outcomes of patients with PVE, and compare them with those of native valve endocarditis (NVE) patients. Methods. We performed a prospective observational study of patients presenting or referred to Groote Schuur Hospital, Cape Town, with definite or possible infective endocarditis (IE) based on the 2015 European Society of Cardiology IE diagnostic criteria. Consenting adult patients who met the inclusion criteria were enrolled into the Groote Schuur Hospital Infective Endocarditis Registry, which was approved by the University of Cape Town Human Research Ethics Committee. This study is an analysis of the patients enrolled between 1 January 2017 and 31 December 2019. Results. During the study period, a total of 135 patients received a diagnosis of possible or definite IE (PVE n=18, NVE n=117). PVE therefore accounted for 13.3% of the overall IE cohort. PVE patients had a mean (standard deviation) age of 39.1 (14.6) years, and 56.6% were male. PVE occurred within 1 year of valve surgery in 50.0% of cases. Duke's modified diagnostic criteria for definite IE were met in 94.4% of the PVE cohort. Isolated aortic valve PVE was present in 33.3%, and a combination of aortic and mitral valve PVE in 66.6%. Tissue prosthetic valves were affected in 61.1% of cases. Of the PVE cases, 55.6% were healthcare associated. On transthoracic echocardiography, vegetations (61.1%), prosthetic valve regurgitation (44.4%) and abscesses (22.2%) were discovered. Staphylococcus and Streptococcus species accounted for 38.8% and 22.2% of PVE cases, respectively, and 27.8% of cases were blood culture negative. Valve surgery was performed in 38.7% of the PVE patients, and 55.6% of the patients died during the index hospitalisation. Secondary analysis indicated that the PVE patients were sicker than those with NVE, with a higher frequency of septic shock and atrioventricular block (22.2% v. 7%; p=0.02 and 27.8% v. 12%; p=0.04, respectively). In addition, in-hospital mortality was higher in PVE patients than NVE patients (55.6% v. 31.6%; p=0.04). Conclusions. PVE was uncommon, mainly affecting tissue prosthetic valves and prosthetic valves in the aortic position. Patients with PVE were sicker than those with NVE and had high in-hospital mortality.