WEDNESDAY, May 18 (HealthDay News) -- Although commonly used to treat heart disease, aspirin and simvastatin offer no benefit to patients suffering from pulmonary arterial hypertension, or PAH, a progressive disease characterized by increased blood pressure in the arteries of the lungs, according to new research.

In a study funded by the U.S. National Institutes of Health, researchers divided 65 patients into four groups: one receiving aspirin; one taking simvastatin; one receiving both drugs; and one in which patients received a placebo (or dummy pill).

"Surprisingly, we found no evidence that aspirin or simvastatin had beneficial clinical effects in this population," said Dr. Steven Kawut, study lead author and associate professor of medicine and epidemiology at the University of Pennsylvania School of Medicine.

After taking the assigned medication for six months, patients were asked to see how far they could walk in six minutes. The distance tended to be shorter in the simvastatin group, and no difference was seen between the aspirin and placebo patients.

Following these early results, the U.S. National Heart, Lung, and Blood Institute discontinued the study based on a recommendation from the Data and Safety Monitoring Board.

"The results of this study do not support the routine treatment of PAH with these medications," Kawut said in an American Thoracic Society news release.

The findings are scheduled to be presented Wednesday at the American Thoracic Society international conference in Denver.

PAH, which is incurable, causes shortness of breath, dizziness and fatigue, and can lead to heart failure and death.

The researchers concluded that both aspirin and simvastatin may be prescribed for usual clinical indications in patients with PAH, but should not be administered specifically to treat PAH.

"The findings show the importance of subjecting traditional cardiovascular therapies and drugs which appear effective in the laboratory to placebo-controlled [randomized clinical trials] in humans before recommending their use," Kawut said.

Research presented at meetings is considered preliminary until published in a peer-reviewed journal.

More information

The U.S. National Heart, Lung, and Blood Institute provides more information on treatments for pulmonary arterial hypertension.