Pulmonary Hypertension and Liver Transplantation

Pulmonary hypertension (PH) is characterized by high blood pressure and affects the vessels that transport blood from the heart to the lungs. Due to the disease, these vessels, known as pulmonary arteries, become narrowed and thickened, making blood transport more difficult. In turn, the heart needs to work harder to pump blood, which weakens and enlarges the organ, and can lead to right heart failure.

There is no cure for pulmonary hypertension, but treatments can help ease disease symptoms, and improve life expectancy and life quality. One of the problems with treating pulmonary hypertension, however, is the lack of understanding about the disease. There are cases in which the reasons for the disease’s development are unknown, as well as cases in which pulmonary hypertension is a primary or a secondary disease.

Development of Pulmonary Hypertension by Liver Transplant Patients

People who are candidates for a liver transplant or those who recently underwent one are at risk of developing pulmonary hypertension. The study, “Severe pulmonary hypertension in liver transplant candidates,” documents that advanced liver disease with portal hypertension (increased blood pressure in the veins that enter the liver) is associated with pulmonary hypertension, caused by fixed pathological changes in the pulmonary vasculature. Moreover, according to the study’s findings, a liver transplant will not reverse the damage attributed to pulmonary hypertension.

Two common pulmonary vascular complications in patients with cirrhosis that can lead to pulmonary hypertension are hepatopulmonary syndrome and portopulmonary hypertension, as explained in the study “Pulmonary hypertension after liver transplantation: case presentation and review of the literature.” This study reports on a case of pulmonary hypertension that developed following a  liver transplantation.

According to the Pulmonary Hypertension Association, portopulmonary hypertension (POPH) is a type of pulmonary hypertension that can be the result of advanced liver disease. This disease has the same characteristic symptoms as those found in cases of pulmonary hypertension that are not associated with liver disease, and is a serious risk factor in those being considered for a liver transplant.

The liver is the largest organ in the body and it is responsible for numerous metabolic functions — breaking down fats, storing certain vitamins, making specific amino acids, converting glucose to glycogen, and maintaing blood glucose levels. Importantly,  the liver also filters the blood and removes harmful substances. Diseases that can lead to the need for a liver transplant include chronic viral hepatitis (hepatitis, B, C, and D), alcoholic liver disease, acute liver failure, autoimmune hepatitis, nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and hepatic tumors, as well as metabolic and genetic disorders.

Prognosis of Pulmonary Hypertension in Liver Transplant Patients

The first study mentioned, of 1,205 patients with end-stage liver disease who had a liver transplant, assessed the incidence and severity of pulmonary hypertension post-transplantation. According to its findings, the incidence of pulmonary hypertension in these people was 8.5% (102 patients), with mild pulmonary hypertension found in 6.72% of them (81 people), moderate pulmonary hypertension in 1.16% (14), and severe pulmonary hypertension in 0.58% (7). Mild and moderate pulmonary hypertension did not influence the outcome of transplant surgery, but severe disease considerably increased mortality rates — of 42% at nine months post-transplant and 71% at 36 months. “This experience supports the view that in most patients who have severe pulmonary hypertension associated with advanced liver disease, it … is associated with a very high perioperative mortality rate,” the researchers concluded.

Another study came to similar conclusions. “Pulmonary hypertension patients provide challenging issues to anesthesiology. The condition is more so when it is associated with liver transplant surgery. This situation is especially true when associated with portopulmonary hypertension (POPH), a subdivision of pulmonary hypertension. Understanding the disease process as well as treatment outcome is an important factor for intraoperative management of those patients. Though offering many challenges, mild-to-moderate pulmonary hypertension and POPH patients could be transplanted safely,” researchers wrote in the study, “Pulmonary hypertension in liver transplant.”