Ryan Simpson
President & Chief Executive Officer

Ryan Simpson has been in hospital leadership roles for over 20 years and is currently Chief Executive Officer for HCA Healthcare/HealthONE's The Medical Center of Aurora (TMCA), including its Main Campus, North Campus, Centennial Medical Center and Spalding Rehabilitation Hospital. He has been with HealthONE since 2011, first as Chief Operating Officer at TMCA, before moving into the COO role at Swedish Medical Center in January 2017. In October 2018, he returned to TMCA in the CEO role.

During his time at Swedish, he was instrumental in relocating Colorado's largest urology practice to the facility, resulting in a 40% increase in robotic surgeries. He led over $80 million in construction projects that included building a new hybrid OR, a cath lab expansion, and a surgical robotics OR expansion. He also led tactics that improved physician engagement to top-decile performance in HCA.

During his earlier time as COO at TMCA, Ryan led numerous development, construction and renovation projects across campuses totaling over $70 million. Among the projects were the renovation of TMCA's perioperative services, intensive care unit, emergency departments, Saddle Rock ER, and the establishment of a behavioral health campus.

Prior to joining HealthONE, Mr. Simpson served in HCA's Nashville market as Chief Operating Officer for The Sarah Cannon Cancer Center and TriStar Oncology Services. Prior to that, he was with Middle Tennessee Medical Center (MTMC) in the chief operations role. In addition to general hospital operations at MTMC, he led the planning, programming, and construction of a $300 million replacement facility. Prior to joining MTMC, he was with Baptist Health System of East Tennessee in Knoxville for nine years.

Upon graduating with a B.S. in Finance and Marketing from Birmingham-Southern College, he spent two years in the banking industry in Birmingham, Alabama before attending graduate school. Mr. Simpson received his MBA and a Masters in Health Administration from the University of Alabama at Birmingham. He is a Fellow in the American College of Healthcare Executives (FACHE) and is currently chairman of the Aurora (CO) Chamber of Commerce.


Hallie Woods, MBA
Chief Operating Officer

Hallie Woods is the Chief Operating Officer of HCA Healthcare/HealthONE's The Medical Center of Aurora (TMCA), including its Main Campus, North Campus, Centennial Medical Center (CMC) and Spalding Rehabilitation Hospital. Her responsibilities include overseeing the integrated operations of The Medical Center of Aurora and Spalding Rehabilitation Hospital and executive oversight over several hospital departments.

Ms. Woods' tenure with HCA Healthcare/HealthONE began in 2011 at Presbyterian/St. Luke's Medical Center where she served in various roles including Director of Radiology, Radiation Oncology, and Cardiovascular Services.

Ms. Woods joined The Medical Center of Aurora's team in April 2016 as the Associate Chief Operating Officer, a position that was part of HCA's Chief Operating Officer Development Program. Her responsibilities included oversight for the departments of Radiology, Pharmacy, Therapies, and Plant Operations. Ms. Woods was accepted into HCA Healthcare's COO Development Program in August 2016. Upon graduating from the Program the following May, she was promoted to Vice President of Operations.

Ms. Woods joined The Medical Center of Aurora's team in April 2016 as the Associate Chief Operating Officer. Her responsibilities included oversight for the departments of Radiology, Pharmacy, Therapies, and Facilities and Construction. She was promoted to Vice President of Operations in August 2017 after graduating from the COO Development Program.

In 2018, Ms. Woods took the role of lead executive over the Centennial Medical Center campus expansion project, which broke ground in March 2019. While at CMC, Ms. Woods worked with her team to bring new provider groups to the campus, collaborated with city leaders for growth opportunities, and led the $85 million capital construction project, which will eventually be the first full-service hospital in Centennial. She also sits on the Board of Directors of the South Metro Denver Chamber of Commerce.


Rachel Miles, MSN, RN, NEA-BC
Chief Nursing Officer

Rachel Miles is the top nursing executive overseeing The Medical Center of Aurora's five campuses, which include two freestanding ERs (Centennial Medical Plaza and Saddle Rock ER)l, TMCA's North Campus Behavioral Health and Wellness Center, Spalding Rehabilitation Hospital, and an array of services and programs including TMCA’s Level 2 Trauma Center and emergency services.

Rachel came to TMCA in January 2017 from Northeast Methodist Hospital, a 179-bed HCA facility in San Antonio, Texas, where she has served as Chief Nursing Officer since February 2014. Prior to her CNO role, Miles was the Vice President of Nursing for Methodist Healthcare, a 700-bed trauma center.

Rachel is a Registered Nurse, having received a Bachelor of Science in Nursing from the University of Central Florida (UCF) in Orlando and began her career in a medical ICU at Central Florida Regional, an HCA facility. She soon transferred to the hospital’s Cardiac ICU, where she spent three years focusing on recovering patients from bypass surgery and other cardiovascular procedures. Rachel went on to earn her master’s degree in Nursing Leadership and Management, graduating with honors in 2008 from UCF.

Rachel and her husband, Mike, have one son and maintain a busy lifestyle, participating in a variety of sporting activities, while finding time to explore interesting destinations. Rachel is especially fond of running, cycling and CrossFit, and has completed eight half-marathons, one full marathon and a CrossFit competition.  Their family also includes two large dogs, Goose and Riley, and two cats.


Bryce Dehaven, CPA
Chief Financial Officer

Bryce Dehaven has nearly 30 years of financial leadership experience, with over 25 of those years in the HCA Healthcare system. Before joining the Medical Center of Aurora in July 2013, Bryce served as CFO at 3 other HCA Facilities in Independence, MI, San Jose, CA, and most recently at Orange Park Medical Center (OPMC), a 297-bed facility in Jacksonville, FL.

Bryce completed his undergraduate studies at the University of Arizona, and received his Master in Business Administration from the University of Colorado at Denver. He previously served on the American Cancer Society Board of Directors, and is currently a member of the Texas State Society of CPA’s. Locally, Bryce serves on the Aurora Health Access Board of Directors, a regional group focused on improving access to healthcare within the community of Aurora. 

Bryce has extensive experience in the field of behavioral health, most prominently as the Co-Founder of Psychiatric Solutions, Inc. Bryce and his wife, Susan have 3 children and reside in Greenwood Village, CO.


Dianne McCallister, MD, MBA
Chief Medical Officer

Dr. McCallister is a board certified Internal Medicine physician, with over 25 years of clinical experience. She received her M.D. at the University of Colorado and an MBA from Daniel’s College of Business at the University of Denver. She is a certified Patient Safety Officer, a Green Belt in Six Sigma Process Improvement Methodology and is certified as a facilitator of Rapid Improvement Process. With a family full of nurses and physicians, she possesses a strong belief that medicine is best practiced as a team sport, and approaches quality and safety initiatives with this in mind.

Dr. McCallister has been at The Medical Center of Aurora since May 2013 as the Chief Medical Officer and Patient Safety Officer. She initiated a comprehensive Physician Wellbeing and Engagement program at the hospital, which culminated in the facility being the first of four hospitals in the country to receive the Medicus Integra© Award from the Coalition for Physician Wellbeing. During her tenure, the Physician Satisfaction has had double digit increases in all metrics.

Prior to her time at Aurora, Dr. McCallister served at Centura Health, where she served as Chief Medical Officer and VP Patient Safety and Quality Systems for Porter Adventist Hospital where she pioneered a Physician Wellbeing program that again produced across the board increases in physician satisfaction and engagement.  Prior to joining Porter in 2005, she was the Medical Director and President of the Medical Staff for Parker Adventist Hospital, which she helped to open, and served as a PHO Medical Director while she practiced as a partner in large Internal Medicine groups in the Denver area. She served as Chief Medical Resident at Presbyterian/St. Luke’s Hospital and as an instructor in Internal Medicine for University of Colorado School of Medicine.

Dr. McCallister is a national expert in Physician Wellbeing, and was the co-founder of the Coalition for Physician Well-Being, a group that endeavors to support, engage and inspire physicians across the country, as well as educate institutions on structures to support Physician Well-Being. She leads the Development and Research Group that created the Medicus Integra© Award and serves on the Executive Committee for the Coalition. Dr. McCallister speaks nationally on structures and programs to support and improve Physician Wellbeing and Engagement, as well as on hospital recovery from mass-casualty events. She is on the National Physician Advisory Board for Med News Plus, an electronic Newsletter/CME Vehicle. 

She shares her passion for healthcare through her service on the board of Christian Living Communities and on the Board of a local PHO, HealthONE Physician Partners. Dr. McCallister was regular contributor to the 11:00am newscast on Denver Channel 7, where she has served as their medical expert for five years prior to starting at TMCA. In addition, she has served as faculty of the AMA’s Media in Medicine conferences, and as an Editor of the Journal for Healthcare Communications.

Dianne and her husband, Tom, live in the Denver Tech Center, and are an active part of the community. Dianne is involved in the local community as President of the Home Owner’s Association in her neighborhood. In her free time, she enjoys kayaking, reading and time with her family.


Lesley G. Rehak, MSN, RN, CCRN-CSC
Associate Chief Nursing Officer

Lesley Rehak is the Associate Chief Nursing Officer at The Medical Center of Aurora and Spalding Rehabilitation Hospital. Lesley has been a Registered Nurse for 20 years. She received her Diploma in Nursing from Western Pennsylvania Hospital School of Nursing, her Bachelors of Science in Nursing in from Pennsylvania State University, and her Masters of Science in Nursing Administration from Indiana University of Pennsylvania.

At TMCA, Lesley's responsibilities will include parts of inpatient services, driving the overall strategic plan for nursing services, helping drive the organization’s effort to achieve Magnet® re-designation in 2018, and daily nursing operations at all five TMCA campuses.

“I am very excited to have been selected for the ACNO role at The Medical Center of Aurora and Spalding Rehabilitation Hospital,” says Lesley. “I look forward to working with the executive team, employees and physicians who make TMCA the amazing hospital that it is.”


Cindy Meyer, MSSW
Chief Operating Officer, Behavioral Health Services

Cindy Meyer is the Chief Operating Officer of Behavioral Health Services at TMCA’s Behavioral Health and Wellness Center. In her role Meyer leads operations at TMCA’s behavioral health campus as well as behavioral health services across the HealthONE system. Under Meyer’s leadership, TMCA plans to expand their behavioral health services into the Centennial area and has future plans to add a number of new services across the Denver market.

Cindy previously served in the role of Chief Administrative Officer of Behavioral Health Services where she led significant program development and improvement in care for behavioral health patients, including the expansion of services to include an inpatient adolescent program and numerous partial hospitalization and outpatient programs and services. Meyer also led an important initiative to engage the Aurora community through partnering with Aurora Public Schools for consultative services and engaging in the development of a pilot program to integrate behavioral health services more into the community’s primary care physician offices.

Cindy came to TMCA in early 2016 from a leadership role as a Regional Vice President of behavioral health services in HCA’s Capital Division. In her role as RVP, Meyer oversaw the operations of 340 psychiatric beds in over 11 HCA hospitals and was instrumental in developing new services for patients in numerous communities. The programs that Meyer oversaw received multiple awards and recognitions from their communities.


Katie Weihe
Vice President, Human Resources

Katie Weihe joined The Medical Center of Aurora and Spalding Rehabilitation Hospital as Vice President of Human Resources in May 2018. Prior to this, Katie worked as the Human Resources Director for the Sales and Marketing Teams in the West Division of Comcast. She has worked in Human Resources her entire career, having held positions in HealthONE and the Colorado Department of Transportation. She has vast experience in all HR-related functions including employee relations, compensation, talent development, and training. 

Katie received a Bachelor of Arts in Communications from the University of Colorado and a Master’s of Science in Management with an emphasis in Human Resources from Regis University. She graduated as a member of the Alpha Sigma Nu Jesuit honor society. Katie also has her Professional of Human Resources certification and is a member of the Society of Human Resources Management. She is Prosci Change Management Certified and is an Insights Discovery Practitioner. 

Katie, the mother of two rambunctious boys, lives in Aurora with her husband Matt and their dog Rufus. She is an avid runner who participates in many races throughout the year. Katie enjoys the outdoors and spending time with her family. 


Erika Kaye, MBA, MS, CCC-SLP
Vice President, Operations

Erika is the Vice President of Operations for TMCA and Spalding Rehabilitation Hospitals. Prior to joining the TMCA / Spalding family, Erika worked at Swedish Medical Center since 2006 with an ever increasing scope of oversight. In her roles at Swedish, Erika oversaw services to include Therapies, Wound Care, Swedish Acute Rehab and opened the very first Burn Unit in HealthONE.  This project was one of the most successful new program launches in every aspect imaginable from design and construction, to quality of care and critical care integration. Since joining our team in the fall of 2017, Erika has been over implementing the Microvascular Hand Clinic and Spalding Day Rehab, and has operational oversight of the Oncology service line, EVS, FNS, Security and Labor Management.

Erika is a Speech Language Pathologist by background who has had extensive Business Development experience to include opening a mobile Speech service in North Carolina. Erika also wrote and taught an on-line course in swallowing disorders. She has a Bachelor of Arts and a Master’s of Science from the University of Redlands, as well as a Master’s of Business Administration-Healthcare Management from Western Governor’s University.

A native to Colorado, Erika and her husband have twin boys and a daughter. She loves to bake, read and hike and in recent years has taken up tap dancing.


Alexandra Hoffman
Vice President, Business Development

Alexandra Hoffman is the Vice President of Business Development for The Medical Center of Aurora and Spalding Rehabilitation Hospital. Ms. Hoffman came to TMCA/Spalding from HCA Healthcare/HealthONE's Continental Division where she served in the Director of Business Development role, supporting HealthONE's Denver, CO and Wichita, KS markets.

Ms. Hoffman joined HealthONE's Continental Division team in 2017. During her tenure there, she made significant contributions to HealthONE and the Continental Division's Business Development team. She led the establishment of the Division's first rural employed physician practice in Fairplay, CO, a unique public-private partnership. She also assisted in the development and regional expansion of the HealthONE footprint. Ms. Hoffman served as executive sponsor for HealthONE's Surgical Robotics Service Line, leading to 23% year-over-year volume growth. She comes to TMCA with expertise in strategic affiliations, physician alignment and investment, and service line growth.

Ms. Hoffman graduated from Virginia Tech and earned her Master's in Healthcare Administration from Virginia Commonwealth University's Medical College of Virginia. She is an active member of the Denver Chamber of Commerce and is currently part of the Leadership Aurora Development Program through the Aurora Chamber of Commerce.