For example, there is a condition known as portopulmonary hypertension that is result of
liver failure. When these individuals receive a
liver transplant, the pulmonary hypertension disappears suggesting that the failing liver is unable to clear some biochemical that leads to pulmonary artery hypertension.
http://www.medicinenet.com/pulmonary_hypertension/page3.htm
Also, I found this which relates pulmonary hypertension to liver disease:
http://www.ccjm.org/content/75/2/121.