Meet Our Physician Associates
Sierra Stouffer, PA-C
Sierra Stouffer, PA-C grew up in Bartlesville, Oklahoma, where she spent much of her time helping on the family farm or at her grandfather’s veterinary clinic—experiences that first sparked her interest in science and medicine.
​She earned her Bachelor’s degree in Biology from the University of Oklahoma and went on to complete her Master of Physician Assistant Studies at the University of Oklahoma Tulsa.
​Sierra is passionate about Cardiovascular Health and helping patients improve their quality of life through education, prevention, and evidence-based care. She believes that achieving optimal health begins with a trusting relationship between a patient and their provider.
Sierra strives to understand each patient as a whole person, listen to what matters most to them, and work together to create a practical treatment plan. Her goal is for every patient to leave their visit with confidence and understanding in their care plan.
Outside of work, Sierra enjoys spending time with her husband and their many pets. She also loves watching reality TV and Netflix documentaries while working on a jigsaw puzzle. A lifelong gymnast, she has a background in both competing and coaching and continues to enjoy following college and elite gymnastics competitions.
Marianna Voola, PA-C
Marianna Voola, PA-C, is a Certified Physician Assistant specializing in Cardiology and committed to advancing patient quality of life through clinical expertise and compassionate, evidence-based care.
Marianna focuses on the management of complex peripheral vascular disease, cardiac rhythm disorders, and heart failure, often utilizing the newest research and guidelines for limb salvage and advanced wound healing.
She earned her Bachelor of Science from Oral Roberts University and later completed her Master of Physician Assistant Practice at Campbell University.
Her strong foundation is further enriched by her previous leadership experience in ophthalmology and her compassionate background as a Certified Nursing Assistant in Sweden, ensuring a culturally sensitive approach in every patient interaction.
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Marianna collaborates closely with her supervising physician, contributing actively to their shared mission of delivering cutting-edge, patient-centered cardiovascular care.
Summer Winger, PA-C
Summer Winger, PA-C, is originally from Grafton, Wisconsin, and brings over five years of frontline healthcare experience as a certified nursing assistant (CNA). While caring for patients during the COVID-19 pandemic, she witnessed the importance of compassion, advocacy, and continuity of care—experiences that inspired her to pursue a career as a physician assistant focused on long-term, patient-centered care.
She earned her Bachelor of Science in Biomedical Sciences from Marquette University in Milwaukee, followed by a Master’s degree in Physician Assistant Studies. Summer later practiced in cardiothoracic and vascular surgery, where she gained extensive experience in advanced cardiovascular care, perioperative management, and complex disease processes, strengthening her dedication to cardiovascular medicine.
Summer is especially passionate about caring for patients who require long-term cardiovascular management, with a focus on patient education, continuity of care, and building trusted relationships. Her background as a CNA allows her to combine empathy with evidence-based clinical decision-making.
Outside of work, Summer enjoys reading, painting, and spending time with her husband and their golden retriever. She is excited to continue her career at Tulsa Cardiovascular Center of Excellence, where she is committed to delivering compassionate, high-quality care to the community she now proudly calls home.
