A photo of James S. Tweddell.

Executive Co-Director, Heart Institute

Director, Cardiothoracic Surgery, Heart Institute

Professor, UC Department of Surgery


Board Certified

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My Biography & Research


Dr. Tweddell leads the Heart Institute’s surgical team providing unparalleled surgical care and innovation for our patients and their families. Over the last 20 years, he built the pediatric cardiothoracic surgery program at the Medical College of Wisconsin, where he held the S. Bert Litwin Chair for Cardiothoracic Surgery position, served as medical director of pediatric cardiothoracic surgery at Children’s Hospital of Wisconsin and professor and chief for the Division of Cardiothoracic Surgery. Dr. Tweddell has an extensive list of vital research contributions, having authored more than 125 peer reviewed articles, published numerous books, chapters, invited reviews and editorials, and serving on multiple editorial boards and national committees.

Dr. Tweddell is the elite surgeon of his generation and has earned a worldwide reputation for outstanding clinical results based on team contributions to his outcomes. He decreased mortality following the Norwood procedure through the use of venous saturation monitoring and afterload reduction. In addition, Dr. Tweddell reduced interstage mortality of a single ventricle patient through the development of a home monitoring program.

Clinical Interests

Surgical emphases include congenital heart surgery in neonates, infants, children, teenagers and adults. Heart transplantation and mechanical circulatory support.

Research Interests

Developing reliable and reproducible evidence-based perioperative management strategies to improve survival and developmental outcomes; novel monitoring techniques such as continuous venous oximetry and near infrared spectroscopy. 

Academic Affiliation

Professor, UC Department of Surgery


Heart, Heart Failure, Cardiothoracic Surgery, Lung Transplant, Heart, Cardiothoracic Surgery

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A New Kind of Clot Blocker

A New Kind of Clot Blocker

Joseph S. Palumbo, MD, James S. Tweddell, MD6/30/2019

My Locations

My Education

MD: University of Cincinnati, Cincinnati, OH, 1985.

Residency: Intern and Second Year Resident in General Surgery, New York Medical Center, New York, NY, 1987.

Residency: Research Fellow in Cardiothoracic Surgery, Washington University Medical Center, St. Louis, MO, 1989.

Residency: Senior Resident and Chief Resident in General Surgery, Washington University Medical Center, St. Louis, MO, 1991.

Residency: Resident in Cardiothoracic Surgery, Washington University Medical Center, St. Louis, MO, 1993.

Fellowship: Fellow in Pediatric Cardiothoracic Surgery, Washington University Medical Center, St. Louis, MO, 1993.

My Publications

Timing of Fontan Completion in Children with Functionally Univentricular Hearts and Isomerism: The Impact of Age, Weight, and Pre-Fontan Arterial Oxygen Saturation. Loomba, RS; Frommelt, PC; Anderson, RH; Flores, S; Tweddell, JS. Pediatric Cardiology. 2019; 40:753-761.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2019 Update on Outcomes and Quality. Jacobs, JP; Mayer, JE; Pasquali, SK; Hill, KD; Overman, DM; St. Louis, JD; Kumar, SR; Backer, CL; Tweddell, JS; Dearani, JA; et al. Annals of Thoracic Surgery. 2019; 107:691-704.

Atrioventricular block after congenital heart surgery: Analysis from the Pediatric Cardiac Critical Care Consortium. Romer, AJ; Tabbutt, S; Etheridge, SP; Fischbach, P; Ghanayem, NS; Reddy, VM; Sahulee, R; Tanel, RE; Tweddell, JS; Gaies, M; et al. Journal of Thoracic and Cardiovascular Surgery. 2019; 157:1168-1177.e2.

Sequence of refusals for donor quality, organ utilization, and survival after lung transplantation. Singh, E; Schecter, M; Towe, C; Rizwan, R; III, RB; Tweddell, J; Hossain, MM; Morales, D; Zafar, F. Journal of Heart and Lung Transplantation. 2019; 38:35-42.

Power of a Learning Network in Congenital Heart Disease. Anderson, JB; Brown, DW; Lihn, S; Mangeot, C; Bates, KE; Van Bergen, AH; Rudd, NA; Hanke, S; Tweddell, J; Lannon, C. World Journal for Pediatric and Congenital Hearth Surgery. 2019; 10:66-71.

How Small Is Too Small? Decision-Making and Management of the Small Aortic Root in the Setting of Interrupted Aortic Arch. Riggs, KW; Tweddell, JS. Seminars in Thoracic and Cardiovascular Surgery: Pediatric Cardiac Surgery Annual. 2019; 22:21-26.

Transposition of the Great Arteries and the Arterial Switch Operation. Benscoter, A; Ryan, A; Tweddell, JS. In: Ungerleider RM; Nelson K; Cooper DS; Meliones J; Jacobs J, Ed. Critical Heart Disease in Infants and Children. Philadelphia: Elsevier; 2018.

Porcine Small Intestinal Submucosa May Be a Suitable Material for Norwood Arch Reconstruction. Jacobsen, RM; Mitchell, ME; Woods, RK; Loomba, RS; Tweddell, JS. Annals of Thoracic Surgery. 2018; 106:1847-1852.

The Norwood Stage 1 procedure-conduct of perfusion: 2017 Survey results from NPC-QIC member institutions. Reagor, JA; Clingan, S; Kulat, BT; Matte, GS; Voss, J; Tweddell, JS. Perfusion (United Kingdom). 2018; 33:667-678.

Antithrombotic therapy management of adult and pediatric cardiac surgery patients. Kreuziger, LB; Karkouti, K; Tweddell, J; Massicotte, MP. Journal of Thrombosis and Haemostasis. 2018; 16:2133-2146.