Meet Our Team

Brad S. Oriel, MD is a distinguished, board-certified vascular surgeon with more than a decade of surgical and endovascular experience coupled with a broad range of clinical and academic accomplishments.

He received his undergraduate degree in Neuroscience from Bates College in Lewiston, ME before pursuing his medical degree at the State University of New York at Buffalo Jacobs School of Medicine and Biomedical Sciences.  His postgraduate training at Tufts Medical Center in Boston, MA, included an internship and residency in general surgery.  Dr. Oriel then pursued a vascular surgery fellowship at Boston Medical Center, honing his expertise in complex vascular procedures and minimally invasive techniques.

Immediately prior to joining The Vascular Care Group, Dr. Oriel was a vascular surgeon with Middlesex Surgical Associates in Winchester, MA, and Chief of Vascular Surgery at Winchester Hospital.

Dr. Oriel has authored numerous peer-reviewed publications and has been the speaker for multiple local and national presentations. He is a member of professional organizations such as the Society for Vascular Surgery and the Vascular and Endovascular Surgery Society and has volunteered his time for medical trips to Guatemala.

Dr. Oriel is well-respected for his expertise, compassion, and innovative approach to patient care. Whether performing intricate vascular procedures or mentoring the next generation of surgeons, Dr. Oriel continues to make significant contributions to the advancement of vascular medicine and the well-being of his patients.

Dr. Swati Chaparala is a board-certified vascular surgeon with advanced training in both open and endovascular techniques. She brings a wealth of expertise to The Vascular Care Group, with clinical interests that include peripheral arterial disease, limb salvage, dialysis access, and complex aortic pathology.

Dr. Chaparala earned her medical degree from Northeast Ohio Medical University and completed her advanced training in vascular and endovascular surgery at the Mayo Clinic in Rochester, Minnesota. Immediately prior to joining The Vascular Care Group, she served as an Assistant Professor in the Division of Vascular Surgery at the University of Maryland School of Medicine, where she also led the medical student clerkship program in vascular surgery.

She has authored multiple peer-reviewed publications and presented her research at national and international vascular conferences. Dr. Chaparala is an active member of the Society for Vascular Surgery and the Alpha Omega Alpha Honor Medical Society. She is passionate about improving access to care and advancing the field through education and innovation.

In addition to her clinical work, Dr. Chaparala speaks Spanish at a working level, helping her communicate effectively with a diverse patient population. She is committed to delivering compassionate, patient-centered vascular care in a collaborative outpatient setting.

Dr. Allan I. Hoffman, MD, is a highly accomplished interventional radiologist and healthcare executive with over two decades of clinical and administrative leadership. He earned his MD magna cum laude in 1992, followed by internship in General Surgery, Radiology Residency and Vascular and Interventional Radiology Fellowship training at Brown University School of Medicine. He served as Chief Resident and Chief Fellow.

Dr. Hoffman has dedicated his career to advancing vascular care and interventional radiology (IR). He has been a practicing Interventional Radiologist at major institutions on the North Shore and in the Merrimack Valley. He served as Chief of Vascular and Interventional Radiology at Lowell General Hospital and North Shore Medical Center as well as Medical Director of Vein Specialists of the North Shore. 

A recognized leader in the field, Dr. Hoffman serves as President and Board Chair of Commonwealth Radiology Holdings, LLC, and previously led Commonwealth Radiology Associates as its president for over 18 years. Nationally, he chairs the Private Practice Advisory Council and co-chairs the Business Institute for the Society of Interventional Radiology. Elected a Fellow of the Society of Interventional Radiology in 2021, he is repeatedly recognized by his peers as a Boston Magazine “Top Doctor.”

Vascular & Interventional Radiologist

Dr. Gregg Franco brings a passion for minimally invasive medicine and a strong academic foundation to his work as a board-certified interventional and diagnostic radiologist at Commonwealth Radiology Associates (CRA). 

Since joining CRA in 2013, he has built a reputation for clinical excellence and collaborative care across northeastern Massachusetts.

Dr. Franco completed his medical training at Drexel University College of Medicine, followed by an internal medicine internship at Newark Beth Israel Medical Center and a diagnostic radiology residency at Boston Medical Center. He refined his subspecialty skills through a fellowship in vascular and interventional radiology at Emory University School of Medicine, earning board certification from the American Board of Radiology in 2011.

A respected voice in both his institution and the broader vascular and interventional radiology community, Dr. Franco is the Chief of Interventional Radiology at Lowell General Hospital, runs the Hepatobiliary multidisciplinary conference, elected member of medical executive committee and is an active member of two national committees for the Society of Interventional Radiology. 

He has been recognized with the Lowell General Hospital Outstanding Interdisciplinary Collaboration Award and holds academic appointments as a Clinical Assistant Professor at Tufts University School of Medicine and Adjunct Professor at multiple regional institutions.

Dr. Franco is part of the care team at the Tufts Medicine, Lowell General Hospital Vascular + Vein Center in Lowell, MA offering patient-centered vascular and interventional radiology care to the Merrimack Valley community. 

Interventional Cardiologist

Dr. Nathan Riddell is a board-certified interventional cardiologist with Merrimack Valley Cardiology Associates, serving patients in Lowell and the greater Merrimack Valley community. Driven by a belief in the power of personal connection, Dr. Riddell takes a tailored approach to patient care, recognizing that no two patients are alike and that the most meaningful outcomes come from understanding the full picture of a patient’s life and health goals.

Dr. Riddell earned his medical degree from St. George’s University School of Medicine and completed his internal medicine residency at UMass Memorial Medical Center, followed by fellowships at St. Elizabeth’s Medical Center with a focus on cardiovascular disease and interventional cardiology.

His clinical expertise spans a broad range of cardiovascular conditions, with particular experience in aortic stenosis, acute myocardial infarction, interventional cardiac procedures, vascular medicine, and peripheral vascular disease. Dr. Riddell is affiliated with Lowell General Hospital and Tufts Medical Center.

Dr. Riddell also serves as part of the interventional care team at the Tufts Medicine, Lowell General Hospital Vascular + Vein Center in Lowell, MA, where he collaborates with vascular and interventional specialists to deliver comprehensive, patient-centered care to the greater Merrimack Valley community.