RESUMEN
Pulmonary arterial hypertension (PAH) is a life-threatening and progressive disease characterized by pulmonary vascular remodeling that leads to increased pulmonary vascular resistance and pulmonary arterial pressure, most often resulting in right-sided heart failure. Originally considered to be a disorder of vasoconstriction and vasodilatation, it has become clear that the predominant characteristic of PAH is abnormal cellular proliferation leading to progressive obliteration of the pulmonary vasculature. Current PAH-specific therapies target one of three major pathways involved in development and progression of PAH: 1) The endothelin pathway targeted by the endothelin receptor antagonists (ERAs); 2) the prostacyclin pathway, targeted by prostacyclin analogs and 3) the nitric oxide (NO) pathway, targeted by the phosphodiesterase type 5 (PDE-5) inhibitors.