Introduction
One of the specific natures of pulmonary arterial hypertension (PAH) is the remodeling of small pulmonary vessels which is characterized by increases in pulmonary arterial pressure (PAP) and pulmonary vascular resistance [1]. PAH is a pathophysiological state defined by an increase in mean PAP (mPAP) ≥ 25 mmHg during rest confirmed by right heart catheterization (RHC) [1] and [2]