Sildenafil, a phosphodiesterase-5 inhibitor, had shown encouraging results in smaller studies and in animal models.
In this study, researchers looked at the drug’s effect on maximum exercise ability as assessed by peak oxygen consumption and on how far people could walk in six minutes, their clinical status and their heart structure and function. They found no benefit, says lead author Margaret Redfield, M.D., heart failure specialist and researcher at Mayo Clinic in Rochester, Minn.
“It was surprising and a disappointment, and it was contradictory to our hypothesis,” says
Dr. Redfield. “There are few options for help for these patients, and we hoped we would find something.”
When the heart does not pump blood well, heart failure symptoms such as shortness of breath, fatigue and weakness can result.