Kettering Medical Center has contracted exclusively with a group of surgeons to perform valve and other specialized heart surgeries at the hospital, a move that limits patient choice but hospital officials say ensures good patient care. "It's really important for a hospital to have a group of cardiothoracic surgeons who's available all the time," said Walter Sackett, the hospital's vice president of clinical services. "The idea is to have the same people involved in these highly technical procedures over and over again." Sackett said the three-year exclusive contract, put in place about a year ago, creates a coordinated approach to cardiac care that benefits patients. Hospital staffers become accustomed to working with the same group of surgeons, another plus for patient care, he said.