Delivering value and improving health

Board Members

The LHP Board of Managers develops and oversees the strategic direction of the network. The board oversees the work of the three board subcommittees and has final approval authority for all recommended actions put forth by the committees, including but not limited to, clinical integration program performance measures, contracts entered into on behalf of the network, data integration activities and population health services.

Chair: Gregory Saunders, M.D., LMG – Camas
Vice Chair: Albert Chaffin, M.D., Pediatric Associates of the NW

  • Jennifer Byrne, D.O., Columbia View Family Health
  • Joseph Frankhouse, M.D., LMG – Gastrointestinal Surgery
  • Greg Hallas, M.D., The Vancouver Clinic
  • Jon Hersen, FACHE, MHA, MBA, Hospital President, Legacy Salmon Creek Medical Center
  • Janis Howatt, M.D., Broadway Medical Clinic
  • Steve Mansberger, M.D., MPH, Glaucoma Associates and Consultation
  • Melinda Muller, M.D., Senior Vice President, Interim Chief Medical Officer, Legacy Health
  • Opher Nadler, M.D., Northwest Acute Care Specialists
  • Natasha Pereira, M.D., The Children's Clinic
  • Matthew Smith, M.D., Northwest Gastroenterology Clinic
  • Dan Tseng, M.D., Northwest Minimally Invasive Surgery
  • Damon Warhus, M.D., Women's Healthcare Associates
  • Beau Weill, M.D., Metropolitan Pediatrics

Jennifer Byrne, D.O.

Columbia View Family Health
Legacy Health Partners Board of Managers

Dr. Byrne received her bachelor’s degree from Yale University, New Haven, CT, and her medical degree from Oklahoma State University Center for Health Sciences in Tulsa, OK. She completed her internship at Eastmoreland Hospital, Portland, OR, in 2004 and her residency training at Swedish Medical Center, Seattle, WA, in 2006. Dr. Byrne is interested in preventive medicine, pediatrics and women’s health.


Albert Chaffin, M.D.

Chief Medical Officer, Pediatric Associates of the NW
Legacy Health Partners Board of Managers
Clinical Collaboration and Performance Improvement Committee Chair

Dr. Chaffin knew from a young age that he liked science so he set his heart on becoming a doctor in seventh grade. He never changed his mind and, from that point on, pursued his ultimate dream. After graduating from medical school, he wanted to explore the world beyond Ohio. So, he traveled to Portland, Oregon where he trained at OHSU in pediatrics. After joining PANW in 2009 he found that he loved a balance between patient care and administrative work. Through various avenues within his practice and Legacy Health Partners he has been able to contribute to quality improvement and strategic planning to improve health outcomes for his patients.


Joseph FrankhouseJoseph Frankhouse, M.D.

Legacy Good Samaritan Colorectal Cancer Center
Legacy Health Partners Board of Managers
Quality and Membership Committee Chair

Dr. Frankhouse is a general surgeon, specializing primarily in colon and rectal surgery. He grew up in Harrisburg, Pennsylvania, and graduated from Dartmouth with an engineering degree in 1985. He then went to Emory University for medical school and completed a surgical residency at LAC + USC Medical Center. He has previously been in two private practices, Surgical Associates, PC and the Colon and Rectal Clinic, PC, prior to joining Legacy Health in 2011. He practices primarily at Good Samaritan Hospital now. Dr. Frankhouse established a GI oncology conference, and has been actively involved in both specialty surgical care and in hospital leadership positions. He has served as section Chair for General Surgery, Quality Council Chair and is currently Chair for Department of Surgery.


Greg Hallas, M.D.

The Vancouver Clinic
Legacy Health Partners Board of Managers
Quality and Membership Committee Vice Chair

Dr. Hallas is a board-certified internal medicine physician with the Vancouver Clinic in Vancouver. He trained at Creighton University in Nebraska and has been practicing outpatient internal medicine in Washington since 1989. He served as the first medical staff president at Legacy Salmon Creek hospital. He is a fellow in the American College of Physicians and has recently joined the faculty of the Elson S. Floyd College of Medicine at Washington State University.



Jon Hersen, FACHE, MHA, MBA

President of Legacy Salmon Creek Medical Center
Legacy Health Partners Board of Managers

Jon Hersen was appointed president of Legacy Salmon Creek Medical Center in fall 2019. He previously served as Legacy vice president of care transformation, a role in which he was responsible for positioning the organization to thrive in a value-based health care environment that aligns care transformation with financial sustainability. In that capacity, he oversaw and coordinated all Legacy activities and initiatives aimed at accomplishing this vision. Hersen holds a bachelor's of science degree in health policy administration from Penn State University and an MBA and MHA from the University of Pittsburgh. He is a member of the MHA program faculty at Pacific University. He joined Legacy in 2004 as a financial analyst for Legacy Medical Group. Since then he’s served as director of Legacy Inpatient Medicine Service, primary care clinics and multispecialty clinics. In 2010, he became acting vice president of Information Systems and Services with overall responsibility for the systemwide implementation of Epic electronic health record. He also served as interim chief operating officer for Health Share of Oregon.


Janis Howatt, M.D. 

The Broadway Medical Clinic
Legacy Health Partners Board of Managers
Clinical Collaboration and Practice Improvement Committee Member

Dr. Howatt is Board Certified in Internal Medicine and has been in practicing at The Broadway Medical Clinic in North East Portland since 1996, combining hospital and outpatient medicine for the first decade of practicing. She earned a Bachelor of Arts degree in Biology from Westmont College in Santa Barbara, California then worked in clinical research in the Department of Gastroenterology at Oregon Health Sciences University before attending The Medical College of Pennsylvania in Philadelphia. She completed her Internal Medicine Residency training at Providence Portland Medical Center. She is a native Oregonian, born at Legacy Emanuel Medical Center, where her mother had trained as a Registered Nurse.


Steve Mansberger, M.D., MPH

Glaucoma Associates and Consultation
Legacy Health Partners Board of Managers

Dr. Mansberger is a board-certified ophthalmologist, who subspecializes in glaucoma and cataract surgery at Legacy Devers Eye Institute. Dr. Mansberger joined Devers in 1999, and now is Chief of Legacy Devers and Director of the Glaucoma Service. He has served on many Legacy committees. His research interests include glaucoma treatment and detection, ophthalmic epidemiology, and telemedicine. He has been honored with the Senior Achievement Award from the American Academy of Ophthalmology, Portland’s Top Doctors, and Best Doctors in America list since 2007. The National Eye Institute has continuously funded his research since 1999. He has published over 200 manuscripts. He has several patents and copyrights in glaucoma and diabetic retinopathy adherence. He is on the Editorial Boards of Journal of Glaucoma and American Journal of Ophthalmology.

Melinda Muller, M.D., FACP

Senior Vice President, Interim Chief Medical Officer, Legacy Health
Legacy Health Partners Board of Managers

Dr. Muller has served as a general internal medicine fellow, a chief resident in internal medicine and a resident and intern in internal medicine for Legacy Portland Hospitals. Dr. Muller is board certified by the American Board of Internal Medicine. She has served as Clinical Assistant Professor of Medicine at OHSU. She most recently served as Clinical Vice President, Care Transformation, and also was Clinical Vice President for Primary Care. A native Oregonian, Dr. Muller graduated with a medical degree from Oregon Health & Science University’s School of Medicine in 1996. Before that she received a bachelor’s of science (as a valedictorian) in medical technology from OHSU and a bachelor’s of arts in general studies math/science and pre-medical technology from Southern Oregon State College (now University) in Ashland. Her clinical interests include AIDS and HIV, gay and lesbian issues, preventive medicine and women's health. In the community, she volunteered for 10 years at the Outside In Transgender Clinic until it closed. She also has volunteered at other local clinics, as well as helping with the Oregon AIDS Hotline. Dr. Muller was named Healthcare Professional of the Year by the Oregon Association of Hospitals and Health Systems in 2010. In 2010, she also received the “Outstanding Young Physician Award” from the Oregon chapter of the American College of Physicians. She has also has been recognized by the National Committee for Quality Assurance (NCQA) and the American Diabetes Association (ADA) for providing quality care to her patients with diabetes. Dr. Muller has been practicing outpatient medicine at Legacy Good Samaritan’s Internal Medicine Clinic since 1996.


Opher Nadler

Opher Nadler, M.D.

Northwest Acute Care Specialists
Legacy Health Partners Board of Managers

Dr. Nadler is board-certified in pediatrics and pediatric emergency medicine. A specialist in pediatric emergency medicine, Dr. Nadler joined Northwest Acute Care Specialists and Legacy Health in 2009. Dr. Nadler serves as the medical director for pediatric emergency services for Randall Children’s Hospital at Legacy Emanuel and Legacy Health. Dr. Nadler also serves as quality co-chair for Randall Children’s Hospital, is on the board of directors for Northwest Acute Care Specialists and the board of trustees for the Randall Children’s Hospital Foundation. Born in Minneapolis and raised in Israel, Dr. Nadler is a graduate of University of Minnesota. After receiving his medical doctorate from Sackler School of Medicine in Tel-Aviv, Dr. Nadler completed a pediatric residency program at University of Minnesota followed by a pediatric emergency fellowship at Children’s Hospitals and Clinics of Minnesota. 


Natasha Pereira, M.D.

The Children's Clinic
Legacy Health Partners Board of Managers
Finance & Contracting Committee Vice Chair

Dr. Pereira graduated from the University Of Pennsylvania School Of Medicine in 1999. She completed her residency at the Children’s Hospital of Philadelphia and then spent two years at CHOP in the Emergency Department providing urgent care. Following residency, she moved to Portland where she worked in Washington before joining The Children’s Clinic in July 2009. She is board certified in Pediatrics and is a Fellow of the American Academy of Pediatrics. Dr. Pereira feels it is a privilege to be so intimately involved in the lives of her pediatric patients and just loves watching her patients grow.


Greg Saunders

Greg Saunders, M.D.

Legacy Medical Group­ – Camas
Legacy Health Partners Board of Managers Vice Chair

Dr. Saunders is board-certified in family medicine. Born and raised in Anchorage, Alaska, he completed his undergraduate degree and medical degree at the University of Washington in Seattle. He completed his residency in family medicine at the University of Wisconsin in Madison. Dr. Saunders practiced in Vancouver, Washington, for 10 years. In 2008, Dr. Saunders joined Legacy Medical Group–Fisher’s Landing as clinic site director and a primary care physician. In 2012, he became a regional primary care medical director for Legacy Health’s four primary care clinics associated with Legacy Salmon Creek Medical Center and served as co-director of Legacy Health’s emerging leadership program.


Matthew Smith, M.D.

Northwest Gastroenterology Clinic
Legacy Health Partners Board of Managers

Dr. Smith is a board-certified gastroenterologist in private practice at Northwest Gastroenterology Clinic since 2009 where he serves as Medical Director. He holds a BS in biology from the University of Oregon, a medical degree from Northwestern University School of Medicine, and completed his internship and residency at Virginia Mason Medical Center in Seattle, Washington. He received specialty training in gastroenterology at the University of New Mexico in Albuquerque. Dr. Smith has directed gastroenterology education for Legacy’s internal medicine residency program since 2010.



Dan Tseng, M.D.

Northwest Minimally Invasive Surgery
Legacy Health Partners Board of Managers
Clinical Collaboration and Performance Improvement Committee Vice Chair

Dr. Tseng is a general surgeon with special training in Advanced Laparoscopic Surgery. After residency at OHSU, he spent two additional years in advanced specialty training devoted solely to Laparoscopic Surgery. His interests are primarily in esophageal, general gastrointestinal, and solid organ surgery. He is a member of the Society for American Gastrointestinal Endoscopic Surgeons and Society for the Surgery of the Alimentary Tract.



Damon Warhus, M.D.

Women's Healthcare Associates
Legacy Health Partners Board of Managers
Finance & Contracting Committee Chair

Dr. Warhus attended the University of California, San Diego for medical school. He completed his residency training at Kaiser Medical Center in Santa Clara, California after which he moved to Portland and has been with Women’s Healthcare Associates, LLC ever since. He has served as President of WHA since 2010 and joined LHP on the Finance and Contracting Committee at its inception in 2015. Dr. Warhus chose OB/GYN for the variety and continuity it offered in being able to care for women throughout their lives. He enjoys helping each person understand their unique situation and options and appreciates being able to develop long-term relationships with patients and their families. His particular interests include minimally invasive surgery, including hysteroscopy and laparoscopic hysterectomy to treat or manage conditions such as abnormal bleeding, pelvic pain or endometriosis. He also has expertise in using ultrasound to diagnose and manage gynecological conditions and helps his colleagues do the same by serving as a designated gynecological ultrasound reader for WHA.


Beau Weill, M.D.

Metropolitan Pediatrics
Legacy Health Partners Board of Managers

Dr. Weill is a general pediatrician with Metropolitan Pediatrics at their Beaverton location. He grew up in San Mateo, California, and moved to San Diego for undergraduate studies. He worked researching breast cancer in Boston prior to attending medical school at Albany Medical College in Albany, New York. He then completed his residency in pediatrics at Oregon Health & Sciences University. He stayed on as Chief Resident and founded and led the Doernbecher Healthy Lifestyles Clinic for overweight and obese children. He transitioned to an attending role and adopted new roles in the residency program as an Associate Program Director and led the education of the residents in the general pediatrics practices. Dr. Weill currently serves on the executive committee at Metropolitan Pediatrics.