Published on January 10, 2022

Contreras Appointed Chief of Staff at Henry Mayo Newhall Hospital

VALENCIA, CA (January 12, 2022) — Louie-Marc Contreras, MD, a trauma surgeon at Henry Mayo Newhall Hospital, has been elected Chief of Staff by the hospital’s medical staff. Prior to his appointment, Dr. Contreras served on the hospital’s Medical Executive Committee as Deputy Chief of Staff.

Dr. Contreras succeeds Don Nishiguchi, MD, an OB/GYN physician who served as Henry Mayo’s Chief of Staff for four years, from the beginning of 2018 to the end of 2021. Dr. Nishiguchi will now serve as Deputy Chief of Staff.

“At Henry Mayo, we are privileged to have fantastic physicians and surgeons to provide and direct care for our patient population.” Said Roger E. Seaver, Henry Mayo Newhall Hospital President and CEO. “We also have the commitment and support from physician leaders who provide time and talent to lead or participate in collaborative work with our clinical and support staff in the hospital. Dr. Contreras’ selection as Chief of Staff will continue the support needed to achieve transformational change and demonstrate the achievement as the ‘Healthcare Team of tomorrow.’”

Dr. Contreras, who has been with Henry Mayo since 2004, also leads the Louie-Marc G. Contreras MD Corp, a practice that focuses on general surgery, acute care surgery, trauma surgery, and minimally-invasive laparoscopic/robotic surgery. In his role as Chief of Staff, Dr. Contreras will lead Henry Mayo’s medical staff of about 500 physicians and will be a part of the Henry Mayo Newhall Hospital Board of Directors.

“I am very honored and proud to be a physician and part of the medical staff to be able to lead and navigate it through seas of opportunity and sometimes, turmoil,” said Dr. Contreras. “I look forward to collaborating with our medical staff leaders, administrative leaders, and board of directors in the service of the hospital, Santa Clarita Valley and Southern California.”

Henry Mayo’s Medical Executive Committee serves as the governing organization for the hospital medical staff by implementing policies of the medical staff, overseeing quality of care and making recommendations to hospital administration and its Board of Directors.

Dr. Contreras looks to focus on “transformational change with culture, caring, and collaboration,” and has a personal vision for Henry Mayo to become “The healthcare team of tomorrow.” “Together, medical staff and all services can create a healthcare team that we can only envision now as to what it could be and should be, the healthcare team of tomorrow," said Dr. Contreras.

Dr. Contreras began his training at The John Hopkins University where he earned Bachelor’s degrees in Philosophy and Biology. He continued at Loma Linda University where he received his Doctor of Medicine, and completed his Residency at the Charles R. Drew University of Medicine and Science. Dr. Contreras is completing his Masters in Business Administration at The Paul Mirage School of Business at UC Irvine.

Since joining the medical staff at Henry Mayo, Dr. Contreras has served on several committees including as Chairman of the Department of Surgery.

Physicians holding positions on the Henry Mayo Medical Executive Committee include Don Nishiguchi, MD., Deputy Chief of Staff, Maria Umali, M.D., Secretary, Mark Sender, M.D., Treasurer, Tracy Lawrence, M.D., Chairman, Administrative Services, Cecelia Hann, MD., Chair, Department of Surgery & Surgery Representative-Quality Performance Council, Balbir BrarM.D., Chair, Department of Medicine & Medicine Representative-Quality Performance Council, Robert Casey, M.D., Member at Large, Charanjit Saroa, M.D., Member at Large, and Peter Kim, M.D., Chair, CME/Library Committee.


ABOUT HENRY MAYO – Henry Mayo Newhall Hospital is a 357 bed not-for-profit acute care hospital serving the Santa Clarita Valley since 1975. The hospital recently opened a new patient tower that includes 90 private patient rooms and a new Center for Women and Newborns, also with all private rooms. Henry Mayo is an Advanced Primary Stroke Center and a STEMI Receiving Center. The hospital features state-of-the-art inpatient facilities, a neonatal intensive care unit, catheterization lab, infusion center, breast center and an outpatient surgery center. Additional services include cardiovascular, trauma, emergency, intensive care, neonatal intensive care, maternity, surgery, nursing, wound care, spine and joint, behavioral health, and acute rehab, as well as cancer, imaging, lab, digestive, respiratory services and physical and occupational therapies. Henry Mayo Newhall Hospital is located at 23845 McBean Parkway, Valencia, CA 91355-2083. For more information, visit or call 661.200.2000.