The liver is the largest solid organ in the body, and it has many jobs crucial for survival. It produces a substance called bile that breaks down fats for digestion; stores vitamins; makes proteins necessary for blood clotting and other important functions; and ensures stable levels of sugar in the blood.
Most importantly for this topic, the liver filters and removes harmful substances from the blood. If the liver becomes damaged or diseased, it can create problems throughout the rest of the body.
Damage to the liver over time can lead to a condition called cirrhosis, which refers to scarring of the liver tissue. The scarring impedes how much blood flows through the liver and impairs its function.
Cirrhosis is the most common cause of portal pulmonary hypertension, which is increased blood pressure in the portal veins that transport blood from the intestines to the liver.
This increased pressure causes blood to bypass the liver. As a result, the blood is not filtered by the liver, and chemicals and toxins are not removed from the blood. The blood vessels of the lungs are then exposed to potentially toxic substances that can damage the small arteries of the lungs and cause Group 1 PH (pulmonary arterial hypertension, or PAH).
Diagnosing PoPH or PH related to liver disease
Symptoms experienced by PoPH patients can include:
- Shortness of breath with activity.
- Increased fatigue.
- Swelling of the ankles, legs or abdomen.
- Chest discomfort or pain.
- Light-headedness and fainting.
PoPH is different from hepatopulmonary syndrome, another type of liver disease-associated abnormality of the pulmonary vessels. In contrast to PoPH, hepatopulmonary syndrome is characterized by widening of the pulmonary blood vessels and low oxygen levels in the blood.
The reason PoPH develops is unclear, but research has given us some clues. Patients with PoPH have a deficiency of prostacyclin (a substance that causes the blood vessels to relax), and an excess of endothelin1 (a substance that causes the blood vessels to constrict and the vessel walls to thicken).
In addition, women and those with autoimmune-related cirrhosis may be at increased risk of developing PoPH. Most patients diagnosed with PoPH are adults.
A specialist can diagnose PoPH when a patient has high blood pressure in the liver in addition to the usual signs of PAH. Doctors also may identify PoPH when people undergo tests to determine whether they are candidates for liver transplant.
Tests to diagnose PH
Any patients with chronic liver disease and shortness of breath, even if they aren’t considering transplant, should discuss with a specialist the possibility of getting an echocardiogram to screen for PH, followed by additional testing when indicated:
- Echocardiogram
- Pulmonary function tests
- Ventilation-perfusion (V/Q) scan
- Natriuretic peptide tests
- Right heart catheterization
Treatment options
Researchers are still studying treatment options for people with PoPH. Because people with PoPH have been excluded from most clinical trials for PH-specific drugs, doctors follow PAH treatment recommendations for PoPH gleaned from other PAH studies. There is hope that existing PH-specific treatments may be helpful. Small studies have described improvement in PoPH with drugs such as epoprostenol, treprostinil, bosentan, ambrisentan, macitentan and sildenafil.
- Targeted Therapies for Pulmonary Hypertension
Targeted medications for pulmonary hypertension are the result of years of research and development, including clinical trials with patients. These treatments work by addressing chemical imbalances in the lungs.
Diagnosis & treatment
- Supportive Medical Therapies for Pulmonary Hypertension
Supportive medical therapies that may be prescribed for pulmonary hypertension include supplemental oxygen, diuretics and blood thinners among others. Caution is advised for over-the-counter medications.
Diagnosis & treatment
- Group 1: Pulmonary Arterial Hypertension
Group 1 pulmonary hypertension is also known as pulmonary arterial hypertension. PAH occurs when the arteries in the lungs narrow and stiffen, leading to increased pressure in the lungs.
About PH
Liver transplant
The outcome for people with PoPH after liver transplant is unpredictable. The risk of complications and death from liver transplants increases with higher pressures in the pulmonary arteries.
For this reason, it is important to lower the pressure in the pulmonary arteries with PH-specific treatments before liver transplantation. If the pressure is high in the lungs during transplant, mortality during and after surgery is more likely.
However, limited but encouraging data suggest that carefully selected patients who respond to PH-specific therapy can undergo liver transplantation with excellent survival rates and in some cases improvement or complete resolution of PoPH. In all cases, the sooner a patient is tested, the sooner doctors can address or rule out problems like PoPH.
Additional Resources
Download or order a brochure
Information on PH and Liver Disease is one of a series of PH& brochures available to download as a PDF or to order as a printed brochure.
PH & Liver Disease
