Breathing problems for almost 3 years

[aea71]

In October 2005 I went to the ER with a sharp pain in my upper back.  I was admitted for almost 2 weeks for low oxygen levels and discharged with shunting in my heart.  When I went to have it repaired, it could not be found.  I went to another hospital and was told I had shunting in my upper lungs and thought to have AVMs.  It turned out to be pulmonary nodules and could not be corrected.  Went to heart, lung, pulmonary, blood and liver doctor and still nothing.  The liver doctor thought I might have cirrhosis of the liver but my liver enzyme tests were relatively normal.  Beginning this year I went to a third hospital.  I saw a lung specialist who said it must be my liver because my o2 levels were 78% sitting; 69 standing and 93% when laying flat on my back.  I went to a liver doctor there and he too said it is my liver and recommends a transplant.  My ABG test was 49%.  They cannot fix the shunting as they are unable to find any AVMs.

Some past history - pituitary tumor removed surgically in 1979 and was taking steroid replacement from 1987 to 2002 when I stopped because of extreme weight gain.  I had no additional health problems until October 2005.

My question...could the steroids have caused liver damage or could stopping them have done damage?  Do you know of any other problems that would cause shunting in the upper lungs other than what I have already been checked for?  I have already had the transplant evaluation and meet with the surgeon in 2 weeks.  Please help.