The following is a transcript of a report by medical editor Marilyn Brooks that first aired Aug. 8, 2007, on WTAE Channel 4 Action News at 5 p.m.

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People with a lethal high blood pressure in their lungs now have a new treatment option.

Doctors say the drug called Letairis is not only more convenient than other drugs they use for pulmonary hypertension, but it is less toxic.

Without treatment, pulmonary arterial hypertension (PAH) is usually fatal within three years. But the drugs used to treat it can be toxic to the liver.

That's what makes Letairis so important. It helps the patient without hurting the liver.

Taken once a day, Letairis dilates blood vessels. The cost is $3,940 a month, and $47,280 a year.

Carolyn Martin: "There are limitations but I figure I've had a very good life and whatever comes, it comes."

At 62, Martin is living on borrowed time. She has pulmonary arterial hypertension, a relatively rare but fatal disease.

Pressure rises in the pulmonary artery that connects the right side of the heart to the lungs. Shortness of breath and fatigue are constant companions.

Dr. Srinivas Murali, Allegheny General Hospital Cardiovascular Institute: "Right now, with these drugs, patients feel better. They do continue to progress, perhaps at a slower pace."

Pulmonary hypertension can stem from a genetic predisposition, result from HIV, sickle cell anemia and congenital heart disease or connective tissue diseases such as lupus and rheumatoid arthritis.

Martin's culprit is scleroderma.

Martin: "I listened to the alternatives -- one being a lung transplant, which I discounted."

The other alternative was medication.

Letairis is one of six or seven drugs that doctors now have to treat pulmonary arterial hypertension. All of them are expensive, running anywhere from $40,000 to $100,000 a year.

Some are all-day infusions. Others are oral drugs that increase the risk of birth defects and liver damage, which is exactly what happened to Martin. She took Tracleer and felt better, but Murali began to see liver function abnormalities.

Murali: "That prevented us from increasing the dose of the drug to a level where we could expect the maximum benefit."

It took nine months to regain normal liver enzymes. Letairis, approved in June, is not supposed to cause liver problems.

Martin began taking Letairis a week ago. If it works for her, she may be able to build up exercise tolerance so she will be able to do more and live a longer life.

Currently, an estimated 75,000 to 90,000 Americans have pulmonary hypertension. More than half of them are undiagnosed.