How beneficial are transcatheter aortic valve implantations, also known as TAVI procedures? They boost quality of life in a major way for at least 12 months in patients dealing with severe aortic stenosis, according to results from the German transcatheter aortic valve interventions registry. Researchers noted that patients themselves rated their lives as being significantly better after TAVI. But TAVI technology--made by Edwards Lifesciences ($EW), Medtronic ($MDT) and others--remains controversial. A recent Belgian study, for example, knocked widespread use of TAVI by concluding that evidence may not support the practice. The condition, where the heart's aortic valve narrows, is becoming common as the population ages. Release