by Phyllis Hanlon, Contributing Writer
People with liver disease can develop a type of pulmonary hypertension (PH – high blood pressure in the lungs) called portopulmonary hypertension (POPH). POPH involves increased blood pressure and resistance in the arteries of the lungs in people who also have high blood pressure in the veins of the liver (portal hypertension) due to their liver disease. If a person with liver disease needs a liver transplant, it is critical that they are screened for POPH, since moderate to severe POPH can lead to worse outcomes after the transplant. In fact, the American Association for the Study of Liver Disease (https://www.aasld.org/) and the International Liver Transplantation Society (https://ilts.org/) strongly recommend screening for POPH using an echocardiogram, as well as confirmation of POPH using right heart catheterization (RHC) before a patient undergoes liver transplantation. If POPH is present, proactive treatment may reduce the severity of the condition and lead to the possibility of POPH resolution after the transplant.
How often POPH occurs in patients preparing for liver transplant is still unknown. It is also unclear how any type of PH in addition to POPH might affect the outcome of surgery. Patients with liver disease can develop another type of PH other than POPH that is not caused by increased “resistance” in the lungs, but rather because the heart is pumping more blood per minute and the volume of blood is larger. It is important that doctors distinguish this type of PH related to liver disease from POPH. In order to learn more about POPH patient outcomes after liver transplant, researchers from the Mayo Clinic in Rochester, Minnesota, an accredited PH Care Center, and Mayo Clinic in Scottsdale, Arizona conducted a study assessing 300 patients who had liver transplants between January 2010 and December 2013 at the Rochester site. (https://www.ncbi.nlm.nih.gov/pubmed/28009757)
Michael J. Krowka, MD, senior author of the study, indicated that the biggest concern was what the outcomes might be for patients, with or without POPH, who had a mean pulmonary artery pressure (mPAP) of more than 35 mm Hg at the time of their liver transplant; the authors also wanted to understand why this was happening and how the condition could be managed if mPAP should rise during the operation.
Prior to the surgery, all patients were evaluated and 39 percent had PH from any cause, which is a common occurrence. Dr. Krowka pointed out though that the majority of these patients did not have POPH (the type with both increased blood pressure and resistance in the lungs). He reported that six patients in the study did have POPH and were treated with PAH-targeted therapies to try to bring their pulmonary pressures and resistance down. Three patients’ mPAP did not fall below 35 mm Hg at the time of the operation, however, they had normal pulmonary vascular resistance (PVR) at the time of operation and ultimately had a successful transplant.
When people who have been appropriately diagnosed with POPH begin PAH-targeted therapy before their transplant, their PVR can decrease by as much as 50 percent and increase their blood flow, the study authors pointed out. Improving the size and functioning of the right side of the heart by using targeted PAH therapy could be “…the most important factor in attaining successful outcomes.”
This study looked back at patient outcomes following liver transplantation from only one center, so the results may not apply to a wider population. However, the authors pointed out that the size of the study (300 patients) and the process of assessing and analyzing hemodynamics related to the lung led to better understanding and has prompted them to change the way they manage patients who qualify for liver transplantation.
Finally, the authors concluded that, based on their findings, liver transplantation in an expert center may be safe for certain patients with PH related to liver disease, provided they are managed carefully, with particular attention paid to the exact cause of PH, even if their mPAP is higher than 35 mm Hg.
Each PH patient is different. It is essential that you talk to your own doctor about what treatment options are best for you. For more information on finding a doctor or an accredited care center, visit https://www.phassociation.org/PHCareCenters/Patients.