(Image source: medicaldesign.com) According to a study commissioned by Medtronic, Inc. (NYSE:MDT) and conducted by the University of Michigan, the non-surgical implemented heart valves produced by Medtronic which are used to delay open heart surgery for children who suffer from congenital heart defects has a huge success rate. According to the study, the valves showed no signs of narrowing, significant leakage or stenosis. Congenital heart defects affect about 1 million children in the U.S. According to Reuters, more than 6,000 patients have received the implanted valves.