PTGIS and portal hypertension: The endothelin-1 upsurge, endothelin receptor dysregulation, the rise of thromboxane-B1, interleukin-6, and serotonin could activate pulmonary artery vasoconstriction too [13-17] There is some evidence about prostacyclin synthase deficient, nitric oxide, and prostaglandin I2 lowering in patients with portal hypertension [18].