But what of the Global South? We have now come to realize that PVD in the West represents perhaps <3% of the global burden of this disease. There are millions of patients with schistosomiasis, congenital heart disease, HIV, high-altitude exposure, COPD, and sickle cell disease who develop PVD. These subsets of PVD only have belatedly received basic science scrutiny or even clinical description. There is little recognition in many parts of the world that PVD even exists, and there are no training programs that can qualify physicians to subspecialize in PVD in order to correctly diagnose the condition. Very few such patients have been enrolled in registration trials of therapies; therefore, the response to therapy of most patients with PVD remains unknown. The centers that take care of these patients have no history of collaboration in clinical studies and often do not comply with International Conference on Harmonisation Good Clinical Practice guidelines. The currently available therapies for PAH have been priced so that the development cost of clinical trials can be amortized over a small western target population, which amounts to a high cost that is not affordable for most countries where the majority of the global PVD burden exists. Health-care disparities within these countries have meant that even when cheaper therapies like phosphodiesterase type 5 inhibitors are available, only the affluent urban population can possibly access them. There is almost no availability of therapies for which use is limited to PVD alone. Thus, millions of people with PVD continue to suffer and die without proper diagnosis, let alone treatment.