Inhaled Iloprost to Treat Severe Pulmonary Hypertension
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What is the problem and what is known about it so far?
Pulmonary hypertension (high blood pressure in the arteries that go to the lungs) can produce disabling shortness of breath and often causes death. It can occur on its own (primary pulmonary hypertension) but is usually the result of an underlying lung disease, such as scleroderma (secondary pulmonary hypertension). No proven therapies for pulmonary hypertension are known, but the drug prostacyclin has shown some promise in patients with this condition. Unfortunately, the side effects of prostacyclin and the need to give it intravenously limit its usefulness. Aerosolized iloprost is a form of prostacyclin that patients can inhale. Reports on a few patients have suggested improvement in patients with pulmonary hypertension after they inhaled iloprost.
Why did the researchers do this particular study?
They wanted to find out whether inhaled iloprost might really offer benefit as therapy for patients with severe pulmonary hypertension.
Who was studied?
Nineteen patients with primary or secondary pulmonary hypertension who were doing poorly despite maximum usual therapy. Patients were cared for at six German teaching hospitals.
How was the study done?
All 19 patients inhaled iloprost 6 to 12 times daily for 3 months. The researchers measured the degree to which shortness of breath limited patients' activities by observing how far patients could walk in 6 minutes, both at the beginning of the study and again after 3 months of treatment. They also performed special tests of blood flow to the lungs and heart function by inserting catheters into the patients' lung vessels.
What did the researchers find?
Only 12 of the 19 patients had the special catheter tests; only 8 patients completed the 6-minute walk test at baseline, and 9 completed that test after 3 months of treatment. The tests of heart function showed improvement after 3 months. The distance patients could walk in 6 minutes improved an average of 148 meters, an increase of nearly 100% compared to how far they could walk before treatment. Four patients died before completing 3 months of treatment. Of the remaining 15 patients, 8 stopped taking iloprost after about 1 year because they got lung transplants, 1 patient switched to intravenous prostacyclin, and another 3 died after the end of the 3-month study period. Seven patients continued to receive iloprost at the time that the researchers completed this report.
What were the limitations of the study?
The study did not include a control group of patients who received only usual therapy. Therefore, although study patients appeared to improve with inhaled iloprost, it is uncertain whether they did significantly better than patients who received only usual therapy would have done.
What are the implications of the study?
Inhaled iloprost may offer a new treatment option for people with pulmonary hypertension. However, larger studies with control groups are needed.
Article and Author Information
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The summary below is from the full report titled “Inhaled Iloprost To Treat Severe Pulmonary Hypertension. An Uncontrolled Trial.”. It is in the 21 March 2000 issue of Annals of Internal Medicine (volume 132, pages 435-443). The authors are H. Olschewski, H.A. Ghofrani, T. Schmehl, J. Winkler, H. Wilkens, M.M. Höper, J. Behr, F.-X. Kleber, and W. Seeger, for the German PPH Study Group.
- Copyright ©2004 by the American College of Physicians
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