[Pulmonary arterial hypertension, a rare entity].

Pulmonary arterial hypertension (PAH) is a rare disease. It is characterized by the progressive remodeling of the small pulmonary arteries that lead to an elevation of the pulmonary vascular resistance and right ventricular dysfunction. Early diagnosis and prompt treatment avoid the deterioration of the patient's quality of life. Statistics show that there are 15 cases per million people worldwide, the majority comprised of young women, with an age at diagnosis of 30 to 40 years. At present, the exact processes that initiate the pathophysiologic changes observed in PAH are unknown; it is thought to be multifactorial. Diagnosis in PAH must be done in a step by step manner. Under the suspicion of pulmonary hypertension (PH), the first thing to do is confirm the diagnosis. The second step is to identify the specific etiology and lastly evaluate the severity by echocardiography, hemodynamic parameters, biomarkers and exercise capacity. PH treatment, particularly PAH, has evolved over the last 2 decades due to the advance in disease knowledge and the availability of agents that act on different pathways. Concerning surgical treatment, it is indicated in PAH when there is not an adequate response to medical treatment. In conclusion, PAH is recognized worldwide as a rare or infrequent disease. The countries that have a registry for the diagnostics, treatment, follow-up and prevalence of PH are mainly in Europe. With the exception of the United States and Canada, there are no registries in America. Recent years have shown an important advance in Latin America.