Jim Houser has stepped down as chief executive of Nashville-based Saint Thomas Health Services, a victory for physician leaders who had questioned his leadership. But it remains to be seen whether a shift at the top softens potential budget cuts that have some doctors concerned about the future of its four hospitals. In casting no-confidence votes against Houser's leadership less than two weeks ago, medical staff leaders at three of those hospitals raised concerns about how proposed budget cuts and a move to a more centralized management could affect patient care.