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Thomas Lee Ortel

Chief, Division of Hematology in the Department of Medicine
Medicine, Hematology
Duke Box 3422, Durham, NC 27710
0563 Stead Bldg, Durham, NC 27710

Overview


My research program investigates the molecular mechanisms whereby various congenital and acquired abnormalities result in ‘dysfunctional’ hemostasis (i.e., hemorrhage or thrombosis) to better understand the molecular mechanisms and interactions that are necessary for normal hemostasis. We are particularly interested in the mechanisms whereby antibodies and other inhibitors can interfere with normal hemostatic mechanisms. Several projects extensively overlap and focus on the assembly and function of procoagulant (e.g., factor X-ase and prothrombinase) and anticoagulant (e.g., activated protein C complex) phospholipid membrane-dependent complexes.

We utilize a variety of approaches in these studies. Monoclonal antibodies, single-chain variable domain fragments, polyclonal antibodies prepared from patients with factor VIII inhibitors, and site-specific mutagenesis have all been used to characterize structure-function relationships in coagulation factor VIII. Our laboratory has also extensively characterized anti-factor V antibodies, investigating autoantibodies as well as xenogenic antibodies developing after exposure to topical bovine thrombin preparations which contain trace amounts of contaminating bovine factor V. We have also characterized how antiphospholipid antibodies interfere with the activated protein C complex, a lipid-dependent natural anticoagulant complex that proteolytically inactivates factor Va and factor VIIIa.

Our current studies are focusing on two antibody-mediated thrombotic syndromes, heparin-induced thrombocytopenia and antiphospholipid antibody syndrome. First, we are initiating a large clinical trial investigating the incidence of clinically-significant heparin-induced thrombocytopenia in patients who develop anti-heparin/platelet factor 4 antibodies following cardiac bypass procedures. While these antibodies are commonly seen following cardiac bypass, the true incidence of thromboembolic complications related to these prothrombotic antibodies remains unknown. We are also collaborating with investigators in the Center for Human Genetics on a large, multi-center study exploring the genetics of familial antiphospholipid antibody syndrome. In addition, we have used a genomic strategy to investigate patients with antiphospholipid antibody syndrome and have identified a gene expression profile that appears to be unique to patients with this syndrome in contrast to patients with venous thromboembolism who do not have these autoantibodies.

We also participate in a variety of collaborative research efforts, both with individual investigators as well as participating in multi-center clinical research studies. For example, we are one of seventeen centers participating in the NIH-supported Transfusion Medicine/Hemostasis Network, and we are currently conducting a trial through this network to define the optimal dose of platelets for patients needing platelet transfusions for hypoproliferative thrombocytopenia. We are also part of a multi-center registry of patients with thrombotic thrombocytopenic purpura, and we are one of eight centers in the Hemostasis and Thrombosis Center pilot program sponsored by the Centers for Disease Control and Prevention. Participation in these registries and networks provides us with access to the patient populations that we study in the research laboratory.

Current Appointments & Affiliations


Chief, Division of Hematology in the Department of Medicine · 2013 - Present Medicine, Hematology, Medicine
Professor of Medicine · 2008 - Present Medicine, Hematology, Medicine
Professor of Pathology · 2008 - Present Pathology, Clinical Science Departments
Member of the Duke Cancer Institute · 2002 - Present Duke Cancer Institute, Institutes and Centers

In the News


Published February 14, 2025
The Hidden Risks of Floating in Space
Published August 27, 2015
Need 'bridging' if you stop warfarin temporarily?
Published June 23, 2015
Heart Patients Can Stop Blood Thinners When Undergoing Elective Surgery

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Recent Publications


Multimodal quality improvement project on reducing hospital perioperative thromboembolic events (Patient Safety Indicator-12).

Journal Article BMJ Open Qual · April 3, 2025 BACKGROUND: Venous thromboembolism (VTE), which includes both pulmonary embolism and deep vein thrombosis, is a common yet significant postoperative complication. Patient Safety Indicator (PSI)-12 was introduced by Centers for Medicare & Medicaid Services ... Full text Link to item Cite

An update on laboratory detection and interpretation of antiphospholipid antibodies for diagnosis of antiphospholipid syndrome: guidance from the ISTH-SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies.

Journal Article Journal of thrombosis and haemostasis : JTH · February 2025 Antiphospholipid syndrome (APS) diagnosis is dependent on the accurate detection and interpretation of antiphospholipid antibodies (aPL). Lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-beta2 glycoprotein I antibodies (aβ2GPI) remain t ... Full text Cite
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Recent Grants


CISA 2023 Clinical Contributing Task 2

ResearchInvestigator · Awarded by Centers for Disease Control and Prevention · 2023 - 2028

CISA 2023 Clinical Contributing Task 1

ResearchInvestigator · Awarded by Centers for Disease Control and Prevention · 2023 - 2028

U2C/TL1 NC KUH TRIO Professional Development Core

ResearchPrincipal Investigator · Awarded by University of North Carolina - Chapel Hill · 2023 - 2028

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Education, Training & Certifications


Indiana University at Indianapolis · 1985 M.D.
Indiana University at Bloomington · 1983 Ph.D.