Although the pathogenic role of VEGF signaling pathways in impairing angiogenesis and promoting PAH is still under investigation, the above-mentioned experimental bench models provided critical insights into the pathogenic role of VEGFR blockade in the development of PAH by triggering histopathological structural changes responsible for the obliteration of small pulmonary vessels [20,21,84] (Table 1). This evidence concerns the gene KDR and pulmonary arterial hypertension.