Worldwide Epidemiology of Pulmonary Hypertension Associated With Left Heart Disease

Globally, around 1 in 2 patients with left heart disease (LHD) has pulmonary hypertension (PH). The prevalence of PH associated with heart failure, mitral regurgitation, aortic valve disease, hypertrophic cardiomyopathy, and cardiac amyloidosis has mainly been investigated in high-income countries, especially the United States and Europe, by transthoracic echocardiography without right heart catheterization confirmation. It is estimated that around 80% of patients with hypertrophic cardiomyopathy or cardiac amyloidosis, around 65% of patients with heart failure or mitral regurgitation, and around 40% of patients with aortic valve disease have PH. In contrast, data about PH associated with mitral stenosis and rheumatic heart disease are primarily from low-income countries. The prevalence is around 80% in mitral stenosis-as determined by right heart catheterization in candidates for surgery or balloon valvuloplasty-and around 45% in rheumatic heart disease based on transthoracic echocardiography screening. PH associated with LHD (PH-LHD) clinical trials have focused on PH secondary to heart failure and have most often been performed in the United States and Europe (sites from these countries in 53.3% and 43.3% of the trials, respectively). The heterogeneous epidemiology of PH-LHD may reflect actual differences in the frequency of the underlying types of LHD, but it may also be the consequence of detection and reporting biases. Regional health authority choices, diagnostic capacity, and socio-economic factors likely influence the selection of the sites of PH-LHD trials. Efforts are needed to better characterize the worldwide burden of PH-LHD and to conduct truly global clinical trials.