Vascular issues can disrupt daily life with symptoms like pain, swelling, or fatigue, and may lead to serious complications if untreated. A quality vascular care team is essential with vascular surgeons and their skilled support teams diagnosing, treating, and managing these conditions. This helps restore health and improve quality of life through coordinated, expert care.
At APEX Vascular, patients are guided by a highly experienced team dedicated to personalized, high-quality vascular care. Using advanced surgical and minimally invasive options, education, and compassionate support, we empower you to make informed decisions and feel confident throughout your healthcare journey for optimal outcomes.
Meet Our East Tennessee Vascular Surgeons & Health Providers
At APEX Vascular, our experienced surgical team supports you with personalized, high-quality vascular care. We guide you through advanced surgical and minimally invasive options, educate you about your condition, and collaborate to create individualized treatment plans. This ensures that you feel empowered, respected, and confident throughout your healthcare journey.
Christopher Pollock, MD, FACS
Dr. Christopher Pollock earned his undergraduate degree from Vanderbilt University in Nashville before obtaining his medical degree from the University of Tennessee Health Science Center College of Medicine in Memphis. He completed his surgical residency at UTHSC and pursued a fellowship in vascular surgery at the University of Virginia in Charlottesville.
Since completing his fellowship in 2003, Dr. Pollock has delivered comprehensive vascular care throughout East Tennessee. He is actively involved in several professional organizations, including the Society for Vascular Surgery, the Southern Association of Vascular Surgery, and the Tennessee Medical Association.
Umashankar K. Ballehaninna MD, FSVS, RPVI
Also known as “Dr. B,” Dr. Umashankar K. Ballehaninna prioritizes a patient-centric approach in every aspect of care. He combines advanced minimally invasive and open surgical techniques to treat a wide range of vascular conditions, with a special focus on limb preservation and carotid artery disease.
Dr. B is committed to clear communication, empathy, and involving patients in every step of their treatment. He ensures that you understand your options and feel empowered in decision-making. He treats you like family, tailoring care plans to individual needs and striving to deliver the highest quality outcomes with compassion and respect.
Outside of work, Dr. Ballehaninna enjoys quality time with his family, engaging in road biking, road trips, music, and CrossFit.
George Michael Lodeiro, MD, RPVI
Dr. George Lodeiro began his medical education at East Tennessee State University and earned his medical degree from Ross University School of Medicine. He completed both his general surgery residency and vascular surgery fellowship at the University of Tennessee Medical Center in Knoxville.
Recognizing a critical need for advanced limb salvage care in the Knoxville area, Dr. Lodeiro joined APEX Vascular, the region’s leading center for cutting-edge limb salvage techniques. Fluent in Spanish, he is dedicated to patient-centered care, blending technical expertise with empathy.
Outside of work, Dr. Lodeiro enjoys fly fishing and spending time with his wife, Megan, and their daughters.
Amber Ridner, FNP-BC
Amber Ridner, FNP-BC, began her career with a Bachelor’s in Secondary Education from Louisiana State University, teaching science and math before transitioning to nursing. After moving to Tennessee, she earned her BSN from South College, where she was recognized as the Most Outstanding Nursing Student. She later completed her MSN in Family Medicine at the University of Tennessee.
Board-certified by the AANP, Amber has provided urgent and primary care in East Tennessee since 2012. She joined APEX Vascular in 2023, focusing on comprehensive, patient-centered vascular care. Amber lives in Knoxville with her husband and seven children and enjoys cooking, reading, and outdoor activities.
David Drum, PA-C
David Drum, PA-C, is an experienced physician assistant at APEX Vascular who began his PA career in 1988 after prior service in the U.S. Air Force and work as a paramedic. He earned his AAS in Surgeon Assistant from Cuyahoga Community College in Cleveland and obtained certification from the National Commission on Certification of Physician Assistants.
David spent 18 years with Oak Ridge Surgeons in general and peripheral vascular surgery before transitioning to MMC Wound Treatment Center. There he gained additional experience in:
- Sleep medicine
- Emergency care
- Wound management
He joined APEX Vascular in 2025, where he is known for his compassionate, relationship-focused care and strong commitment to vascular health. Outside of work, David enjoys aviation as a licensed pilot, gardening with his wife, and spending time with his four grandchildren.
Our Support Team
The APEX Vascular support team guides you through every stage of your vascular care journey by providing compassionate, personalized assistance, education, and expert procedures. From efficient operations to specialized treatments and a welcoming environment, they ensure that you feel informed, respected, and supported for the best possible outcomes.
Whether the team member is an executive, ultrasound tech, registered nurse, or medical assistant, everyone is united in making sure you have a voice in your own vascular care and treatment. At APEX Vascular, we believe in a family approach to medical care. We want you to ask us questions, and we promise to listen to you and lay out all of the solutions for you through a unique treatment plan.
At APEX Vascular, our experienced team provides personalized, high-quality care using advanced surgical and minimally invasive techniques. We educate and support you throughout your treatment so you can be confident that you’re making informed decisions. Our patient-centered approach ensures you receive care with the best possible health outcomes.
APEX Vascular is a vascular surgery and vein center with locations in Knoxville, Oak Ridge, Lenoir City, Sevierville, Crossville, Decatur, and Harrogate, TN. We are dedicated to delivering personalized, high-quality care that goes beyond medical treatment. Our exceptional vascular staff, boasting extensive experience in vascular surgery, works tirelessly to elevate the standards of patient care and contribute to your overall well-being. Visit us online or call us at 865-562-3232 to request an appointment today!