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Our Team

Thomas M. Hemmen, MD, PhD. 
Professor, UCSD Medical Center
Director, UCSD Stroke Center

Thomas Hemmen, MD, PhD, is a board-certified vascular neurologist. His expertise includes caring for patients with stroke, cerebrovascular diseases, and those who require neurological critical care. Dr. Hemmen directs the stroke center at UC San Diego Health and was instrumental in establishing the center as the first certified Stroke Center of Excellence in San Diego County.

As a professor at UC San Diego School of Medicine, he provides leadership and education to medical students, residents and fellows. Dr. Hemmen was the lead investigator for numerous clinical trials in cerebrovascular disease. He investigates the use of neuroprotection and reperfusion therapies after acute ischemic stroke, as well as stroke prevention, recovery and research in intracerebral hemorrhage. Dr. Hemmen leads the performance improvement program for stroke and is instrumental in providing oversight to create the best care delivery system for stroke patients possible.

Dr. Hemmen is Fellow of the American Heart Association and current President of the AHA Board in San Diego. He is involved in systems of care improvement throughout the greater San Diego region. He has authored publications in systems of care improvement for stroke and is highly collaborative in his approach to the engagement of all who participate in the care delivery for patients with stroke. 

He completed a neurology residency at New York-Presbyterian Hospital, The University Hospital of Columbia and Cornell, serving as chief resident. Dr. Hemmen completed at fellowship in stroke and vascular neurology at UC San Diego School of Medicine, and a fellowship in neurological intensive care at Philipp University of Marburg in Germany. He earned his medical degree from the Free University of Berlin. He is board-certified neurology and vascular neurology. 

Kunal Agrawal, MD.
Assistant Professor, UCSD Medical Center
Vascular Neurology Fellowship Program DIrector, UCSD Stroke Center 

Kunal Agrawal, MD is a board-certified neurologist specializing in vascular neurology and stroke treatment. He focuses on the spectrum of stroke care including stroke prevention, acute ischemic and hemorrhagic stroke, and post-acute stroke care.

Dr. Agrawal is faculty within the department of neurosciences at UC San Diego. His research focuses on post-acute stroke care as well as neurorehabilitation and post-stroke therapeutics. He has published several peer-reviewed articles and provides teaching and training for medical students, residents, and fellows in the treatment and management of cerebrovascular disease.

He completed a fellowship in vascular neurology at UC San Diego and residency training in neurology at The George Washington University in Washington, DC. Dr. Agrawal earned his medical degree from St. George's University, School of Medicine in Grenada, West Indies. He joined UC San Diego to become a part of furthering neurological care and has been working to establish a neurorehabilitation program at UC San Diego that would provide another dimension to the comprehensive care of diseases pertaining to vascular neurology.

In addition, Dr. Agrawal is a member of the American Heart Association/American Stroke Association and the American Academy of Neurology.



Brett C. Meyer, MD.

Professor, UCSD Medical Center
Co- Director, UCSD Stroke Center
Medical Director, UCSD Telemedicine

Brett C. Meyer, MD is a neurologist at UCSD Medical Center.  He is Board certified in Neurology, and subspecialty Board certified in Cerebrovascular diseases, by the American Board of Psychiatry and Neurology.  He specializes in acute cerebrovascular disease therapies and technological evaluation and treatment techniques.  Dr. Meyer completed his Neurology residency at the University of Florida in 2000, and a Cerebrovascular Fellowship at UCSD.  He joined the faculty in the Department of Neurology/Division of Neurosciences, and has since been Co- Director of the UCSD Stroke Center, and Director of the UCSD Stroke Telemedicine Initiative. 

Dr. Meyer was the Principal Investigator for an NIH funded clinical research trial assessing the use of telemedicine in acute stroke management consultations.  This 5 year trial assessed whether the use of telemedicine technologies can result in appropriate treatment decisions for acute stroke and assist with thrombolytic administrations.

Dr. Meyer was responsible for overseeing acute stroke teleconsultations at numerous remote spoke facilities through the STRokE DOC trial.  Dr. Meyer has implemented a visiting scholars’ program for telemedicine training at the Stroke Center, and has trained multiple fellows in the implementation, deployment, and clinical use of telemedicine technologies.  Graduating fellows have successfully implemented telemedicine techniques into clinical practices throughout the USA.

Dr. Meyer is also the Medical Director for the UCSD Department of Telemedicine. In this role, he is responsible for the development and implementation of numerous telemedicine initiatives for multiple specialties throughout the entire medical center and their spoke partnerships.

Dr. Meyer has presented at major academic meetings, and has been published in numerous journals including The New England Journal of Medicine, Lancet Neurology, Stroke, Neurology, The International Journal of Stroke and The Journal of Stroke and Cerebrovascular Diseases.  He has been on multiple national advisory boards for telemedicine, and is the co-author of two AHA policy publications on telemedicine implementation and recommendations for telemedicine use in systems of care. 

Dawn D. Meyer, PhD.

Assistant Clinical Professor, UCSD Medical Center
Faculty Member, UCSD Stroke Center 
BSN: Nicholls State University
MSN-Family Nurse Practitioner, University of Texas Health Science Center at Houston
PhD-Nursing, UCLA

Dawn Meyer, PhD joined the UC San Diego Department of Neurosciences in April 2010 as an assistant professor. She completed her Bachelor of Science in Nursing at Nicholls State University and began work as a staff/charge nurse at MD Anderson Cancer Center of Houston, Texas. She completed her Master of Science in Nursing with a Family Nurse Practitioner concentration at the University of Texas Health Science Center at Houston.

After her certification as a family nurse practitioner, she was recruited to the University of Texas Stroke Team with James Grotta, MD. During this time, she gained expertise in stroke care and become involved as a co-investigator in numerous clinical trails. In 2005, she was recruited to Sharp Healthcare of San Diego to become the Director of Stroke Certification. In 2010, she completed her PhD in Nursing at the University of California Los Angles.

Dr. Meyer is a nationally certified family nurse practitioner. Her research focuses on the use of antiplatelet loading in acute stroke with a particular emphasis on sex differences in response to stroke and antiplatelet treatment. The rLOAD study has provided a scientifically rigorous preclinical evaluation of a cost-effective and easily accessible intervention and has explored the role of estrogen in stroke outcome for the first time in a non-rodent model of stroke.

The outcomes of this study will serve the 795,000 people – and the 55,000 more women than men – who suffer acute stroke each year by filling a gap in knowledge related to the understanding of the specific antiplatelet dosing that is safe and may lead to decreased in stroke burden. In addition, the role of estrogen has been explored for its mediating effects of estrogen in stroke treatment modulation.



Royya Modir, MD.
Assistant Professor, UCSD Medical Center
Faculty Member, UCSD Stroke Center

Royya Modir, MD, is a board-certified neurologist specializing in vascular neurology and the treatment of stroke. Her focus is Cardioembolic stroke and treatment strategies for stroke prevention with an emphasis on lifestyle changes.

As assistant professor of neurosciences at UC San Diego, a designated Comprehensive Stroke Center and Stroke Net site, she acts as the site Principal Investigator for multiple trials.  Dr. Modir's research is focused on cerebrovascular disease, specifically cardioembolic and cryptogenic stroke, as well as the hyperacute management of stroke. She also provides teaching and training for medical students, residents and fellows in the treatment and management of cerebrovascular disease.

She has coauthored numerous articles and her work has been published in Frontiers in Neurology and Journal of Stroke and Cerebrovascular Diseases, among others.

During her medical training, Dr. Modir completed a fellowship in vascular neurology at University of California Los Angeles and her internship and residency at Jackson Memorial Hospital in Miami. She earned her medical degree from Universidad Central del Caribe in Puerto Rico and her undergraduate degree in biology and Spanish from Loyola Marymount University. She is board-certified in neurology and vascular neurology. 

Dr. Modir is a member of the American Heart Association/American Stroke Association.  She is heavily involved in community outreach and education throughout Southern California. 


Karen Rapp, RN, BSN, CCRC
Program Manager, UCSD Stroke Center

Karen Rapp joined the UCSD Stroke Center in 1991. As a research nurse, her first clinical trial was overseeing the NINDS tPA Stroke Trial at all hospitals in greater San Diego including UCSD Hillcrest, VAMC, Mercy Hospital (now Scripps Mercy), Sharp Memorial, Tri-City Medical Center, and Scripps Encinitas. This study led to the approval of tPA by the FDA, the first approved treatment of acute ischemic stroke within 3 hours of stroke onset.

Over her 25 plus years at UCSD, she has coordinated over 50 prevention and acute Phase I, II, III and IV stroke trials at the local site. In addition, Karen has overseen the UCSD Coordinating Center with both federally funded and pharmaceutical sponsored trials designing and writing protocols and study manuals, managing staff and clinical activities, developing databases, preparing reports for the FDA, and managing ongoing site recruitment activities. Karen was the Program Manager for the UCSD Stroke Center’s large NIH SPOTRIAS grant (2003 -2015), and currently oversees the San Diego effort for the NIH StrokeNet grant, a network of 25 regional coordinating centers across the US developed by the National Institutes of Health as a research pipeline for developing new treatments for stroke patients (2013 - present).

Karen graduated in 1989 from Loma Linda University with a BSN in nursing. She obtained her Critical Care Registered Nurse certification (CCRN) in 1991. Karen collaborated with the National Stroke Association from 1995-1998 acting as a consultant to hospitals around the country on how to set up their hospital system to treat acute stroke patients more efficiently and to augment their treatment options with clinical research. In 2000, Karen became certified in Clinical Research (CCRC). In 2001, Karen was honored by the UCSD Chancellor and named as the UCSD Exemplary Employee of the Year. In 2002, she was invited to participate on NINDS National Task steering committee in Washington, DC “Improving the Chain of Recovery for Stroke in your Community.” She has served on the American Heart Association and American Stroke Association Western States Affiliate Stroke Task Force seven different terms over her career and on the San Diego AHA/ASA Board of Directors from 2012-2014.

Lovella Hailey, MS, APRN, ANP-BC
Nurse Practitioner, UCSD Stroke Center 

Lovella Hailey was raised in North Carolina and obtained a Bachelor of Science in Nursing degree from the University of North Carolina at Chapel Hill in May of 2003.  She has experience working in a variety of inpatient healthcare settings as a travel nurse throughout the country including serving as a Primary Stroke Center program coordinator. Wanting to play a more integral role in direct patient care she completed a Master of Science Adult Nurse Practitioner Program from San Diego State University in 2010.  Lovella’s research interests include clinical trials that focus on innovative acute stroke treatment options for patients.

 “I believe communication is vital in providing exceptional patient care. As providers, we should collaborate with our patients and between multidisciplinary teams to offer a clear treatment plan while serving as an advocate for our patients.”

Lovella is Board Certified by the American Nurses Credentialing Center and licensed by the California Board of Nursing.

Melissa Mortin, MS, APRN, ANP-BC
Nurse Practitioner, UCSD Stroke Center 

Melissa Mortin completed her Bachelor of Science in Nursing degree from the University of Florida in April of 2004 and graduated Cum Laude and her Master of Science Adult Nurse Practitioner degree from San Diego State University in 2010. She has been a registered nurse since 2004 and has been Board Certified as an Adult Nurse Practitioner since 2010, receiving several honors and awards throughout both her academic and professional careers.  Melissa is passionate about helping patients and their families with their stroke care and understanding their treatment plan. She also enjoys participating as a sub-investigator in several UC San Diego Stroke Center research trials. 

Melissa is Board Certified by the American Nurses Credentialing Center and licensed by the California Board of Nursing.

Jennifer Kruse
Stroke Center Administrative Assistant