Troy A. Villarreal - President and Chief Executive Officer
Troy A. Villarreal joined Medical City in October of 2013, and has more than 19 years of experience in healthcare. Prior to his arrival at Medical City, he served as CEO of The Medical Center of Plano.
Villarreal has a strong history of community service. He is a member of the Board of Directors of the Dallas / Fort Worth Hospital Council, a member of the Fort Worth Stock Show Syndicate and also serves on the Board of Directors of Cancer Care Services. Additionally, Villarreal has served in the past on the Boards of the Fort Worth Public Library Foundation and North Dallas Chamber of Commerce.
Villarreal is a Fellow in the American College of Healthcare Executives. He earned his BS in Psychology from Texas A&M University in 1989 and his MHA and MBA from the University of Houston-Clear Lake, Texas in 1994. Mr. Villarreal is married and has four children.
Charles Gressle - Chief Operating Officer
Charles Gressle, a healthcare executive with more than 16 years of experience, is Medical City's Chief Operating Officer. He joined Medical City in August of 2012.
Gressle has served as a Senior Vice President in the HCA Continental Division where he led the strategy, business development and growth agenda for the three markets of Denver, Oklahoma City and Wichita. Gressle served in an instrumental role that resulted in tremendous growth and expansion in the Denver Market. Prior to that, he served as the Chief Operating Officer at The Woman’s Hospital of Texas where he contributed to significant volume growth, quality improvements, patient satisfaction and greater employee engagement. Gressle also completed a $78 million dollar tower expansion and facilitated the Division’s Women’s Growth Initiative moving the system to #1 in market share in Houston.
Gressle received his undergraduate degree in chemistry and economics from the University of North Carolina at Chapel Hill and his masters in business administration from Wake Forest University.
Carol Gregory - Senior Vice President & Chief Nursing Officer
Registered Nurse Carol Gregory’s prior leadership roles include critical care clinician, director of education, assistant director of nursing, vice president of hospital operations, and chief nursing officer and vice president of patient care at The Medical Center of Aurora and Centennial Medical Plaza, in Aurora, Colorado.
Gregory is active in several professional organizations, including the American College of Healthcare Executives (ACHE), the American Organization of Nurse Executives (AONE) and the Association of periOperative Registered Nurses (AORN). Her career achievements include being named a 2008 Finalist for the Colorado Nightingale Award for Excellence in Human Caring and a 2008 and 2010 Nominee for the Denver Business Journal Outstanding Women in Business Award.
Gregory received her Bachelor of Science in Nursing from the University of Michigan, her Master of Science in Nursing from Wayne State University and a Master of Business Administration from the University of Denver.
Mark Atchley - Chief Financial Officer
Mark Atchley joined Medical City after serving as senior vice president and CFO at Medical Center of Plano, where he oversaw all financial management and registration functions, health information management, case management, scheduling and information services. Atchley is an experienced financial executive with a demonstrated record of developing and implementing creative business solutions for more than 27 years. He has also held executive financial positions at Hospital Corporation of America (HCA), Encon International and Chapman Companies.
A graduate of Abilene Christian University with a degree in accounting, Atchley brings experience in financial management disciplines including treasury, national and worldwide tax planning, and administration and payroll.
Keith Zimmerman - Chief Executive Officer, Medical City Children’s Hospital
Prior to joining Medical City, Keith Zimmerman was the system vice president of business development for OhioHealth, a complex system of hospitals, ambulatory centers and surgery centers that account for nearly 2,500 licensed beds and more than 2,300 physicians in its network. During his tenure, Zimmerman led several multi-million dollar growth strategies, including the approval and development of a freestanding emergency department and a comprehensive outpatient cardiovascular diagnostic center. He also led advanced process improvement initiatives, successfully restructuring and aligning physician services and systems to optimize organizational performance.
Prior to his role as system vice president for OhioHealth, Zimmerman served as the organization’s vice president for physician partnerships for three years. Leading the strategic recommendations for growth, Zimmerman worked closely with large physician groups on major projects including acquisitions and joint ventures.
Zimmerman holds a Master’s of Business Administration in Health Care Management from Regis University in Denver, along with an undergraduate degree in business administration from the University of Louisiana.
Mark Hébert, M.D. - Chief Medical Officer
Mark Hébert has more than 30 years of physician insight and expertise as an active member of Medical City. Before becoming chief medical officer, he was a staff anesthesiologist at Medical City and a medical director of the hospital’s Ambulatory Surgery Center (ASC).
During his tenure as an anesthesiologist, Hébert was elected to medical staff president and chairman for the department of surgery, and served in numerous hospital committees including the Physician Wellness Committee, Pharmacy and Therapeutics Committee, Meditech Advisory Committee, Quality Improvement Committee and the Privileges and Credentials Committee.
Hébert received his medical degree from Southwestern Medical School in Dallas, and completed his residency training at Parkland. He is also a member of the Ambulatory Surgery Centers’ governing board and medical executive committee.
Jamie Youssef - Senior Vice President & Chief Development Officer
Jamie Youssef is Medical City’s Senior Vice President and Chief Development Officer. He joined Medical City in 2011, and has more than 11 years of experience in healthcare in hospital leadership and physician practice operations. Prior to joining HCA, Jamie served as Vice President of Integrated Healthcare Strategies in Columbus, Ohio, and Director of Operations at OhioHealth Practice Management Services.
As Medical City’s Senior Vice President and Chief Development Officer, Jamie is responsible for the overall direction, strategic planning, and business development for all service lines at Medical City.
Jamie received his Masters of Healthcare Administration from The Ohio State University.