Dr. David J. Goldberg, a pediatric cardiologist at The Children's Hospital of Philadelphia who was the primary investigator, says all of the patients who took part in the study had earlier undergone the Fontan operation, a procedure that redirects venous blood directly to the pulmonary arteries, bypassing the heart.
It is the third operation in a series of surgeries for single-ventricle heart defects -- a life-threatening condition in which a child is born with severe underdevelopment of one of the pumping chambers of the heart, Goldberg says.
"Despite dramatically improved early operative success achieved over the past 20 years, morbidity and mortality are still a challenge for children who have undergone a Fontan operation," Goldberg said.
In this study, researchers randomized 28 children and young adults who had undergone the Fontan operation an average of 11 years earlier to receive either placebo or sildenafil three times a day for six weeks. After a six-week break from treatment, subjects were switched to the opposite treatment course.
The researchers also selected a relatively healthy pool of subjects without significant complications that they felt would have sufficient exercise capacity to complete the study.
The study, published in the journal Circulation, found significant improvements in exercise performance during treatment with sildenafil compared with placebo.
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