The erectile dysfunction drug sildenafil, commonly known as Viagra, boosts the heart's pumping ability in children and young adults who've had the Fontan operation to correct single-ventricle heart defects, researchers report.
In the Fontan operation, doctors direct venous blood directly to the pulmonary arteries, bypassing the heart. The procedure is the third surgery in staged reconstruction for children with single-ventricle defects, explained the researchers from the Children's Hospital of Philadelphia in a news release from the American Heart Association.
The study included 27 children and young adults who'd undergone the Fontan operation an average of 11 years earlier. The patients, average age 15, were given either a placebo or 20 milligrams of sildenafil three times daily for six weeks. That was followed by six weeks of no drug or placebo, and then the participants were switched to the opposite arm of the study for another six weeks.
Before and after each phase of the study, researchers assessed the participants' heart function and found significant improvements in the myocardial performance index during the sildenafil phase compared to the placebo phase. They also found that taking sildenafil improved diastolic performance and increased heart output, but the differences didn't reach statistical significance.
There was no difference in the average myocardial performance index improvement between the right ventricular dominant subgroup and the non-right ventricular dominant subgroup, indicating a benefit regardless of ventricular structure.
The findings suggest that improved ventricular performance associated with taking sildenafil may improve patients' exercise performance and quality of life, the researchers concluded.
The study was scheduled to be presented Tuesday at the American Heart Association's annual meeting in Orlando, Fla.