Valvular Heart Disease

Corresponding Author

“An imbalance between rich and poor is the oldest and most fatal ailment of all republics.”

—Plutarch

The extent to which valvular heart disease affects the population’s health varies across countries. The trends of cardiovascular disease burdens have been well documented in countries with varying socioeconomic developments.^1,2 There has been an overall downward trend in the burden of cardiovascular diseases across the world that is inversely related to socioeconomic development indices. Poverty, overpopulation, pollution, and unhealthy dietary habits with adoption of western Standard American Diet are some of the driving factors for increased rates of cardiovascular diseases in countries with lower socioeconomic status. As in many chronic diseases, valvular heart disease management requires disease awareness, screening tools and facilities for diagnosis, proper follow-up, and ultimately access to modern medications and advanced surgical/interventional therapies. The unevenness in the availability of these 4 prerequisites for improved outcomes results in disparate outcomes.

In the analysis by Hibino et al³ in this issue of JACC: Advances, a multinational World Health Organization database spanning almost 20 years of self-reported disease prevalence and outcomes of valvular heart disease from 42 middle-income and 51 high-income countries noted an increase in overall crude mortality rate of valvular heart disease and decreasing rates of age standardized mortality rates in high-income countries while constant rates in the middle-income countries. A granular analysis reveals that even in middle-income countries there was a steady decline in rheumatic heart disease mortality (diseases of the young), while the mortality from disease of the old (mitral regurgitation, aortic stenosis, and infective endocarditis [IE]) was on the rise. This is not surprising given that with economic growth, one expects an increase in life expectancy and thus emergence of age-related degenerative diseases, and better treatments for the young with early use of antibiotics for management and prevention of rheumatic heart disease. On the other hand, this report astutely detects the signal for increased rates of endocarditis-related mortality in the young in the high-income countries staring in the late aughts reflecting the emergence of the epidemic of drug use disorders mainly in the United States.

Growing burden of non-rheumatic valvular diseases mainly aortic stenosis and mitral regurgitation has been observed in high-income countries.^2,4 The escalating rates could be explained by increased life expectancy, the lack of competing causes of mortality in an aging population, and improved disease surveillance with wide spread use of echocardiography. For instance, the increased prevalence of mitral regurgitation in the elderly may be a consequence of aggressive deployment of revascularization therapies and improved survival of patients with ischemic and nonischemic left ventricular dysfunction. This allows for continuous negative left ventricular remodeling and emergence of mitral regurgitation. On the positive side, the rate of mortality due to aortic stenosis in individuals >80 years of age after the year 2015 plateaued in middle-income countries and decreased in high-income countries. This is an interesting finding that coincides with transcatheter aortic valve interventions particularly in the frail and elderly. Some of the latter group may have up to that point been provided with palliative care.

There is a significant global increase in the overall burden of IE irrespective of the socioeconomic status, especially in the younger age group <39 years.^1,2 This can be attributed to multiple causes, implementation of modified duke criteria which is more inclusive, ongoing opioid epidemic and associated intravenous drug usage and burgeoning employment of cardiac devices and prosthetic heart valves hence narrowing the gaps across developed and developing nations. The unrestrained antibiotic use has also contributed to antibiotic resistance bacteria which predisposes to IE. Strategies for improved prevention and control risk factors for IE are important to curb this rate of increase.

The divergence in prevalence of rheumatic heart disease across countries based on sociodemographic index has been well described. There is a trend of increasing age in rheumatic heart diseases in high-income countries when compared with low- and middle-income countries which can be associated with increased disease density.⁵ Verma and colleagues also reported a decrease in crude mortality rate due to rheumatic valvular disease in middle-income countries and a constant trend in high-income countries. This finding should be interpreted with caution. Recent study by Li and colleagues projected an increase in the age standardized prevalence rate of rheumatic heart disease (RHD) by 2030 in high-income countries. The decreasing awareness of RHD prevention among physicians and limited follow-up for compliance of penicillin treatment could be the potential etiology calling for extensive interventions to improve prevention and treatment of the RHD across the world.⁶

This important study adds to our holistic and global understanding of valvular heart disease at the population levels under different socioeconomic regimes and at different positions up the modernization ladder. A competing pull and tug picture emerges where benefits from modern medical and technological contributions may be attenuated under resourced health systems, emergence of substance abuse epidemic in “developed countries,” and an aging population surviving some previously fatal conditions.

Finally, this report serves as a benchmark for policymakers and reminds us of the importance of improved disease awareness, enhanced screening and diagnostic modalities, and proper periodic follow-up. Such improvements coupled with judicial use of modern therapies can bend the mortality curve of valvular heart disease in the coming decades. Controlling health care cost and making valve care more widely affordable and accessible can extend the anticipated benefits to more patients across the globe.

Funding support and author disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.