Inch by inch, two doctors working side by side in an operating room guide a long narrow tube through a patient's femoral artery, from his groin into his beating heart. They often look intently, not down at the 81-year-old patient, but up at a 60-inch monitor above him that's streaming pictures of his heart made from X-rays and sound waves. The big moment comes 40 minutes into the procedure at Morton Plant Hospital. Dr. Joshua Rovin unfurls from the catheter a metal stent containing a new aortic valve that is made partly out of a pig's heart and expands to the width of a quarter outside the catheter.
