The modern epidemiology of heart valve disease

### Learning objectives In this review, we will discuss the current knowledge of heart valve disease (HVD) epidemiology, how it has changed over time and possible future trends. There are large differences in HVD epidemiology between high-income and low-income countries and across different forms of HVD. The majority of morbidity and mortality attributable to HVD worldwide is due to rheumatic heart disease (RHD), which is most commonly seen in low-income countries. In high-income countries, the greatest burden of HVD referred to hospital is due to calcific aortic valve disease (CAVD). Although prevalence of HVD is low compared with coronary heart disease, the requirement for long-term follow-up, and significant investigation and treatment costs, means that the impact of HVD on healthcare systems is disproportionately large. The strong association between HVD and age, combined with the rapid ageing of populations worldwide, means that HVD has been described as the ‘next cardiac epidemic’.1 ### Current knowledge Acute rheumatic fever (ARF) occurs a number of weeks after Streptococcus pyogenes (group A streptococcus) infection, usually in children. ARF leads to valve inflammation through molecular mimicry between the streptococcal M protein and cardiac proteins such as myosin and vimentin, although it is likely that other mechanisms are also involved.2 The requirements for ARF to lead to chronic RHD are not yet fully established but are likely to be related to repeated episodes of often subclinical secondary infection, leading to progressive valve fibrosis and self-sustaining valve inflammation. Those with repeated infections are more likely to progress to chronic RHD, and extended antibiotic prophylaxis is recommended for those with a …