Pulmonary veno-occlusive disease (PVOD) and/ or pulmonary capillary hemangiomatosis (PCH)
My doctor says I have PVOD. What is this?
As the name suggests PVOD involves the small veins of the lung circulation rather than the small arteries. The veins become blocked and the cause is generally unknown. Sometimes PVOD is associated with connective tissue disease, HIV infection, bone marrow transplantation and other rare conditions. On rare occasions PVOD has occurred in families and a few cases are associated with mutations in BMPR2. PVOD occurs about 10 times less often than IPAH/HPAH, which makes it a really rare disease. PVOD is somewhat different than PAH in that more men are affected, smoking exposure is higher, and a lower carbon monoxide diffusing capacity of the lung (DLCO) is seen.
Also, changes can be detected on high resolution CT scans that are suggestive of PVOD. These are sometimes described as “presence of centrilobular ground glass opacities,” although having this on your CT scan does not necessarily mean you have PVOD. A lung biopsy might possibly be necessary to distinguish PVOD f rom interstitial lung disease, for which there are treatments other than transplant. However, although a lung biopsy is the definitive diagnostic test for PVOD, such biopsies are dangerous for patients with PH. Currently, the best treatment for PVOD is lung transplant. Although some of the available PAH therapies may be helpful, they must be used with extreme caution. The patient must be carefully observed to avoid the risk of developing pulmonary edema (fluid in the lung). Clubbing of fingers might be present in PVOD.
My doctor says I have PCH. What is this?
Pulmonary capillary hemangiomatosis (PCH) is a disease of the lung capillaries or tiny vessels that are found between arteries and veins. The capillaries tend to overgrow a great extent in the lung tissue. This condition is extremely rare and some argue that it is not a separate disease but a different manifestation of PVOD or PAH. Chest x-rays and CT scans may show characteristic signs of disease (very similar to PVOD) and help in determining the best area of lung to biopsy for confirmation of the diagnosis. Unfortunately, open lung biopsy is required to accurately diagnose this condition also. These biopsies are dangerous for PH patients, but may be necessary in order to prevent endangering the patient with potentially harmful therapies. There is not yet an accepted drug treatment for this type of PH; prostanoids (like Flolan®) may be harmful; interferon has been tried, but still lacks a promising track record; lung transplantation is an option.