Premier Health is searching for a new leader after announcing the planned retirement of its current president and CEO. Mike Riordan will step down in first quarter of 2027, according to the health system. Dayton-based Premier operates operates throughout Southwest Ohio. This includes Miami Valley Hospital and its North and South campuses, Atrium Medical Center, Upper Valley Medical Center, more than 130 outpatient and physician locations, CompuNet Clinical Laboratories and Fidelity Health Care.