Ottawa Hospital Research Institute

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Thrombosis / thromboembolism

The Ottawa Hospital’s Thrombosis Program is a centre of excellence in both clinical research and clinical care of thrombosis related illness. We are devoted to generating practice-changing knowledge in the areas of diagnosis, treatment and prevention of deep vein thrombosis and pulmonary embolism (venous thromboembolism).

Thrombosis Program’s Mission

The primary mission of the program is to energetically better the lives of patients with venous thromboembolic disease. This is accomplished through:

the design, conduct and dissemination of practice-changing clinical research
education of the next generation of leaders in Adult Thrombosis Medicine (expert clinicians, educators and researchers)
the delivery of quality cost-effective care to patients with venous thromboembolic disease in the Ottawa region

Thrombosis Program’s Vision

It is our vision to be world leaders in developing practice-changing knowledge generation in the areas of venous thromboembolism. Our group has a strongly established presence in the development of patient-oriented research on diagnostic algorithms for suspected deep vein thrombosis and suspected pulmonary embolism and cancer-associated thrombosis. We are growing an important research program on the management of anticoagulant-related bleeding complications. We also seek to be leaders in the next generation of experts in venous thromboembolism through our Area of Focussed Competency (AFC) Adult Thrombosis Medicine Fellowship (Clinical and Research Fellowship Programs). Finally, and importantly, we seek to deliver cost-effective quality care to patients with venous thromboembolism in the Ottawa region through the development of an Ottawa Regional Clinical Thrombosis Program with arms of the program including thromboembolism management, peri-operative anticoagulation and oral anticoagulation management.

Research News

	TOH pioneers innovative approach for treating lung blood clots in people with cancer March 26, 2025 - Two new research studies show how The Ottawa Hospital continues to lead the way in determining which cancer patients with a blood clot in their lung can safely recover at home and avoid hospitalization.
	Blood thinners can prevent vein blood clots in those with cancer, but results for artery clots are mixed March 13, 2025 - “Blood thinners are an effective tool for preventing vein blood clots in people with cancer. The fact they may also prevent artery clots in eligible patients with pancreatic cancer should encourage their use in that population."
	Dr. Deborah Siegal honoured for groundbreaking blood research February 25, 2025 - Dr. Deborah Siegal has been awarded the prestigious Joe Doupe Young Investigator Award from the Canadian Society for Clinical Investigation in recognition of her groundbreaking research on treatments for blood clots and blood transfusions.
Show more news stories
	Researchers at The Ottawa Hospital awarded 16 CIHR grants worth more than $8 million February 3, 2025 - Researchers at The Ottawa Hospital are leading 16 new projects funded by the Canadian Institutes of Health Research (CIHR) through the most recent operating grant competition.
	New Canada Research Chairs to advance regenerative medicine, thrombosis and stroke research at The Ottawa Hospital November 14, 2024 - The federal government announced a new round of Canada Research Chairs this week, including three based at The Ottawa Hospital.
	Honouring our top researchers of 2024 November 7, 2024 - Each year, The Ottawa Hospital and its Research Institute honour a small number of outstanding researchers for discoveries and innovations that are improving patient care at TOH and advancing science around the world.
	New scientist profile: Dr. Alexandre Tran aims to personalize blood clot prevention in trauma and critical care August 27, 2024 - Whether he’s preparing a trauma patient for surgery or caring for a patient in the intensive care unit, Dr. Alexandre Tran is thinking about how to keep them safe from life-threatening bleeds and blood clots.
	Researchers at The Ottawa Hospital awarded 14 CIHR grants worth more than $10 million July 18, 2024 - “Success at CIHR underscores the creativity, dedication and collaboration of our researchers and their teams. Funding for these innovative projects paves the way for groundbreaking advancement in biomedical sciences, improved patient care and progres
	Can AI predict major bleeds from blood thinners? May 28, 2024 - “More research is needed before we can use AI tools in the clinic to predict bleeding risk, but this proof-of-concept study shows they hold great promise.”
	New scientist profile: Dr. Yan Xu aims to better understand blood clots in racialized populations January 2, 2024 - “Our first step is to understand if there are ethnic and racial differences in the prevention and treatment of blood clots in Canada. And if so, what we can do about it.”
	What’s the best way to prevent blood clots after hip or knee replacement surgery in people with chronic kidney disease? December 15, 2023 - Surgery comes with a risk of blood clots, especially joint replacement surgery, so patients are given blood thinners to prevent clots from forming.
	Lifelong treatment with blood thinners is unlikely to have survival benefits for most patients with unexplained clots August 3, 2023 - More than 750,000 Canadians will have an unexplained vein blood clot, known as venous thrombosis. Guidelines suggest that these people take blood thinners for life to prevent a second clot, however, the tradeoffs between the benefits, risks and finan
	New scientist profile: Dr. Joseph Shaw investigates best way to “turn off” blood thinners March 16, 2023 - Thrombosis physician Dr. Joseph Shaw knows blood thinners are great for preventing blood clots. But sometimes people taking these drugs need to be able to form blood clots again, like before a surgery, or if they start bleeding in the brain or gut.
	Tools can identify which patients should stop taking blood thinners for unexplained blood clots November 30, 2022 - Over 750,000 Canadians will have an unexplained vein blood clot in their lifetime, known as venous thrombosis.
	Bench to bedside: the quest to prevent cancer from coming back after surgery October 20, 2022 - Researchers at The Ottawa Hospital have made another important step forward in their quest to find innovative ways to stop cancer from coming back after surgery. While surgery often provides the best option for removing all or most of a tumour, resea
	Dr. Marc Carrier recognized as one of top blood clot researchers in Canada July 13, 2022 - Dr. Marc Carrier has received a major honour recognizing his outstanding contributions to advancing blood and blood vessel care in both in Canada and around the world.
	Researchers at The Ottawa Hospital awarded 18 CIHR grants worth more than $11 million February 5, 2022 - These projects will advance science and improve health in areas such as tuberculosis, blood disease, prostate cancer, heart disease, muscle repair, sleep apnea, brain cancer, medical imaging, virtual care, prehab, intellectual disability, sarcoma, CA
	Helping patients and saving money: Drug that prevents blood clots in cancer patients is cost-effective January 6, 2022 - People with cancer are four to seven times more likely to have a blood clot than the general population.
	Tiny clots in the lung put patients at risk of future blood clots December 16, 2021 - A study led by Drs. Grégoire Le Gal and Marc Carrier found that tiny clots in the lungs are not as harmless as previously thought, and in most cases should be treated with blood thinners.
	Study establishes bleeding risk with long-term use of blood thinners for life-threatening clots October 20, 2021 - A new systematic review and meta-analysis now provides the best data yet on the long-term risks and consequences of bleeding with different blood thinners.
	Full-dose blood thinners help moderately ill COVID-19 patients August 23, 2021 - Two Canadian-led studies published in the New England Journal of Medicine show that full-dose blood thinners help moderately ill hospitalized COVID-19 patients, but not critically ill patients.
	Researchers at The Ottawa Hospital awarded eight grants worth $5 million from the Canadian Institutes of Health Research August 10, 2021 - These projects will advance science and improve health in areas such as cancer immunotherapy, orthopedic surgery, long-term care, neuromuscular disease, blood clots, vascular disease, aging, kidney disease and Inuit health.
	Plasma exchange may help treat rare blood clots related to vaccines August 6, 2021 - Canadian researchers have published the first study of plasma exchange as a possible treatment for rare blood clots related to certain COVID-19 vaccines.
	New Scientist profile: Dr. Miriam Kimpton aims to prevent blood clots in patients with rare blood cancer April 30, 2021 - Dr. Miriam Kimpton’s research centers on myeloproliferative neoplasms, a rare form of chronic blood cancer
	Blood thinners help keep hospitalized COVID-19 patients out of ICU February 17, 2021 - Full-dose blood thinners reduced the need for mechanical ventilation and transfer to the ICU in moderately ill patients hospitalized with COVID-19, according to interim results from an international clinical trial.
	New scientist profile: Dr. Tzu-Fei Wang aims to guide blood clot care for cancer patients February 17, 2021 - When hematologist Dr. Tzu-Fei Wang is deciding on the best way to treat a patient’s blood clot, she’ll ask whether they are taking any other medications. A quick check of an online database confirms whether these medications interact poorly with any
	New scientist profile: Dr. Deborah Siegal aims to enhance care for people taking blood thinners January 29, 2021 - Hematologist Dr. Deborah Siegal knows that blood thinners save lives by preventing strokes and blood clots in the veins. Unfortunately, these medications come with a risk of bleeding which can be fatal. Dr. Siegal wants to find out how to best manage
	Preventing dangerous blood clots in COVID-19 patients June 26, 2020 - Drs. Lana Castellucci, Marc Carrier and colleagues are contributing to an international clinical trial to find out whether a high dose of blood thinner can prevent dangerous blood clots in hospitalized COVID-19 patients.
	Ottawa doctor recognized as one of the top blood vessel researchers in Canada January 23, 2020 - Dr. Philip Wells has received a major honour recognizing his outstanding contributions to advancing care in blood and blood vessel sciences both in Canada and around the world.
	Researchers awarded $1.6M to improve care for cardiovascular disease November 13, 2019 - The Heart and Stroke Foundation of Canada has awarded $1.6M to researchers at The Ottawa Hospital, affiliated with the University of Ottawa.
	Milestone study will help doctors treat life threatening blood clots October 22, 2019 - Faizan Khan’s research will influence how doctors around the world treat venous thrombosis, the third-deadliest cardiovascular disease. This is a remarkable achievement for a PhD candidate in the early stages of his career.
	Study establishes long-term risks and consequences of leg vein clot recurrence July 31, 2019 - Over 750,000 Canadians will have an unexplained vein blood clot in their lifetime, known as venous thrombosis. A collaborative study led by Dr. Marc Rodger and Faizan Khan now provides the best data yet on the long-term risks and consequences of recu
	The Ottawa Hospital awarded 13 grants worth $11.2 million from Canadian Institutes of Health Research July 26, 2019 - Researchers at The Ottawa Hospital have been awarded 13 grants worth a total of $11.2 million from the Canadian Institutes of Health Research (CIHR). The new projects focus on areas such as cancer immunotherapy, hepatitis C infection, blood clots, ar
	Preventing blood clots from coming back March 1, 2019 - Dr. Marc Carrier and his colleagues pooled data from more than 22,000 patients around the world to compare the effectiveness of multiple blood thinners to treat venous thromboembolism.
	Research could help people with cancer avoid life-threatening blood clots February 20, 2019 - In September 2018, Harold Black had trouble catching his breath while singing in his church choir. It turned out he had a life-threatening blood clot – a condition that is more common in people with cancer, like Harold. Today, people with cancer have
	Researchers to advance science and improve health with new CIHR funding February 14, 2019 - Researchers at The Ottawa Hospital, affiliated with the University of Ottawa, are playing a lead role in nine new projects funded by the Canadian Institutes of Health Research (CIHR). These projects will advance science and improve health in areas su
	Drug dramatically reduces risk of dangerous blood clots in cancer patients December 4, 2018 - A Canadian clinical trial published in the New England Journal of Medicine provides the first approach for safely preventing blood clots (or venous thromboembolism) in people with cancer. About half of people newly diagnosed with a solid cancer coul
	Aspirin as good as blood thinner for preventing blood clots after hip and knee replacement surgery April 6, 2018 - Drs. Paul Kim, Wade Gofton, Phil Wells, Marc Rodger, Marc Carrier and Doug Coyle co-authored a study in the New England Journal of Medicine that found aspirin to be just as good as the blood thinner rivaroxaban for preventing blood clots after a hip
	Midwife’s question inspires study on best blood clot treatment July 11, 2017 - Midwife Elizabeth Fraser wanted to know how to reduce her risk of blood clots during pregnancy, and inspired a study that could help others with her rare condition. Elizabeth Fraser jokes that she had one of the world’s most-planned pregnancies.
	The Ottawa Hospital awarded 18 research grants from the Canadian Institutes of Health Research, worth $10.7 million May 19, 2017 - Eighteen research groups at The Ottawa Hospital, affiliated with the University of Ottawa, have been awarded nearly $11 million in the most recent project grant competition from the Canadian Institutes of Health Research (CIHR). This represents a suc
	Tattoo artist grateful to be off blood thinners thanks to made-in-Ottawa rule April 26, 2017 - Ottawa resident Sarah Rogers would have been taking blood thinners for life, if not for a rule that showed she was at low risk of having a second blood clot.
	New blood thinner better at preventing recurrent blood clots than aspirin March 18, 2017 - An international research team with prominent Canadian leadership has found that the blood thinner rivaroxaban is as safe as aspirin, and more effective at preventing recurrence of life-threatening blood clots in the legs and lungs, according to a
	“Invaluable” study confirms blood thinners don’t prevent recurrent pregnancy complications October 18, 2016 - Two years ago, Dr. Marc Rodger thought he had settled the debate about the use of blood thinners in pregnant women at high risk of developing blood clots. His trial of 292 women in five countries – the largest of its kind – definitely showed that t
	Study could reduce unnecessary cancer screening June 22, 2015 - Large clinical trial shows CT scanning does not improve cancer detection in people with unexplained blood clots A large clinical trial led by researchers at The Ottawa Hospital and the University of Ottawa has found that contrary to expectati

Researchers

Name	Scientific appointment	Diseases, conditions and populations of interest	Research and clinical approaches
Berardi, Philip MD, PhD, FRCPC	Clinician Investigator (CR)	Aging, Anemia, Bleeding disorders, Blood cancer, Cancer, COVID-19, Health equity, Health in older peoples, Sickle cell anemia, Thalassemia, Thrombosis / thromboembolism	Artificial intelligence and data science, Basic research, Bioinformatics, Biomarkers, Cancer biotherapeutics, Cell therapy, Epigenetics, Gene expression, Genetics, Genomics, Immunotherapy, Molecular and cellular biology, Stem cells, Translational research
Burger, Dylan PhD	Senior Scientist (ICD)	Aging, Diabetes, Heart disease, Hypertension, Kidney disease, Maternal and fetal health, Obesity, Thrombosis / thromboembolism, Type 1 diabetes, Vascular cognitive impairment, Vascular, heart and metabolic disease	Basic research, Biomarkers, Disease models, Exercise, Extracellular vesicles / exosomes, Imaging, Model organisms, Molecular and cellular biology, Pharmacology, Proteomics, Regenerative medicine, Stem cells, Transgenic/knockout models, Translational research
Carrier, Marc MD, MSc, FRCPC	Senior Scientist (ICD)	Cancer, Thrombosis / thromboembolism	Clinical research, Patient engagement
Castellucci, Lana MD, FRCPC, MSc	Scientist (ICD)	Thrombosis / thromboembolism	Clinical research, Clinical trials, Cohort studies, Critical care, Patient engagement, Systematic reviews, Transfusions
Duffett, Lisa MD	Associate Scientist (ICD)	Thrombosis / thromboembolism	Clinical research, Clinical trials, Epidemiology
Le Gal, Gregoire MD, PhD	Senior Scientist (ICD)	Thrombosis / thromboembolism	Clinical decision rules, Clinical research, Clinical trials, Epidemiology, Patient engagement, Peri-operative medicine
Rodger, Marc MD	Senior Scientist Affiliate (ACR)	Pregnancy, Thrombosis / thromboembolism, Women's health	Clinical decision rules, Clinical research, Clinical trials, Cohort studies, Epidemiology, Systematic reviews
Santos, Marlise MD (FRCPC), MSc, MPH	Clinician Investigator (NS)	Alzheimer's, Anxiety, Ataxia, Autoimmune disease, Autoimmune diseases of the nervous system, Blood cancer, Brain and neuromuscular disease, Brain cancer, Cancer, Concussion, Dementia, Depression, Global health, Head and neck cancer, Health equity, Health in disadvantaged peoples, Infectious disease, Intellectual disabilities, Multiple sclerosis, Parkinson's, Population health, Sickle cell anemia, Spinal cord injury, Stroke, Subarachnoid hemorrhage, Thrombosis / thromboembolism, Traumatic brain injury, Traumatic injuries, Vascular cognitive impairment, Vascular, heart and metabolic disease	Artificial intelligence and data science, Basic research, Behaviour, Biostatistics, Cancer biotherapeutics, Clinical decision rules, Clinical research, Clinical trials, Cohort studies, Critical care, Epidemiology, Health economics, Health research methods, Health services research, Health technology, Imaging, Patient safety, Pragmatic trials, Prevention, Public health, Qualitative methods, Quality Improvement, Shared decision making, Surgery, Surveys, Systematic reviews
Shaw, Joseph MD MSc FRCPC DRCPSC	Associate Scientist (ICD)	Cancer, Thrombosis / thromboembolism	Biomarkers, Clinical research, Epidemiology, Peri-operative medicine, Pharmacology
Sood, Manish MD, FRCPC, MSc	Senior Scientist (ICD)	Heart disease, Hypertension, Kidney disease, Population health, Thrombosis / thromboembolism	Cohort studies, Epidemiology, Health research methods, Health services research, Pharmacology, Prevention
Thavorn, Kednapa BPharm, MPharm, PhD	Senior Scientist (MIR)	Cancer, COVID-19, Diabetes, Gastrointestinal disease, Glaucoma, Global health, Health equity, Health in disadvantaged peoples, Health in older peoples, HIV, Immigrant and refugee health, Population health, Septic shock, Stroke, Thrombosis / thromboembolism, Vision	Clinical research, Cohort studies, Epidemiology, Health economics, Health research methods, Health services research, Knowledge translation and implementation research, Patient engagement, Pharmacy, Public health, Quality Improvement, Systematic reviews
Wang, Xiang Pharm.D, MSc, ACPR	Clinician Investigator (ICD)	Cancer, Heart disease, Population health, Stroke, Thrombosis / thromboembolism	Health services research
Wells, Philip MD, FRCPC, MSc	Senior Scientist (ICD)	Thrombosis / thromboembolism	Artificial intelligence and data science, Clinical research
Xu, Yan MD, FRCPC, MSc	Associate Scientist (ICD)	Health equity, Health in disadvantaged peoples, Population health, Thrombosis / thromboembolism	Epidemiology

Related Resources

Thrombosis Fellowship at The Ottawa Hospital

The Ottawa Hospital Hematology and Thrombosis Clinic

Canadian Venous Thromboembolism Clinical Trials and Outcomes Research (CanVECTOR) Network

Clinical Trials

The following list of clinical trials is pulled from ClinicalTrials.gov using the search terms "(thrombosis OR thromboembolism OR pulmonary embolism)” and “Ottawa Hospital.” More advanced search options are available. If you find a clinical trial that interests you, you can bring the information to the next appointment with your care team and ask if you are eligible for the study. If so, they may be able to refer you to the study team. Visit ohri.ca/patients to learn more about participating in research and clinical trials.

Note that ClinicalTrials.gov is hosted by the U.S. National Library of Medicine and is only available in English. Please note that we cannot guarantee a response from the person listed in the ‘Contact’ column.

NCT	Title	Condition	Status	Contact
NCT05171049	A Study Comparing Abelacimab to Apixaban in the Treatment of Cancer-associated VTE (NCT05171049)	Venous Thromboembolism, Deep Venous Thrombosis, Pulmonary Embolism	RECRUITING
NCT05171075	A Study Comparing Abelacimab to Dalteparin in the Treatment of Gastrointestinal/Genitourinary Cancer and Associated VTE (NCT05171075)	Venous Thromboembolism, Deep Venous Thrombosis, Pulmonary Embolism	RECRUITING
NCT04263038	Clinical Surveillance vs. Anticoagulation for Low-risk Patients With Isolated Subsegmental Pulmonary Embolism (NCT04263038)	Pulmonary Embolism, Embolism, Embolism and Thrombosis, Lung Diseases, Cardiovascular Diseases, Respiratory Tract Diseases, Venous Thromboembolism, Anticoagulant-induced Bleeding, Bleeding	RECRUITING
NCT03266783	Comparison of Bleeding Risk Between Rivaroxaban and Apixaban for the Treatment of Acute Venous Thromboembolism (NCT03266783)	Venous Thromboembolism	RECRUITING
NCT06894576	Development of a Risk Stratification Score for Recurrent Venous Thromboembolism and Treatment-related Clinically Relevant Bleeding in Patients With Cancer-associated Thrombosis (NCT06894576)	Cancer-associated Thrombosis	RECRUITING
NCT03778502	DOAC in Unusual Site Venous Thrombosis (NCT03778502)	Splanchnic Vein Thrombosis, Cerebral Vein Thrombosis, Ovarian Vein Thrombosis, Renal Vein Thrombosis, Retinal Vein Thrombosis	RECRUITING
NCT03636295	Low INR to Minimize Bleeding with Mechanical Valves Trial (NCT03636295)	Bleeding Post-mechanical Valve Replacement, Thromboembolism Post-mechanical Valve Replacement	RECRUITING
NCT05029063	Primary Thromboprophylaxis in Patients With Malignancy and Central Venous Catheters (NCT05029063)	Venous Thromboembolism, Cancer	RECRUITING
NCT03559114	PROphylaxis for Venous ThromboEmbolism in Severe Traumatic Brain Injury (PROTEST) (NCT03559114)	Traumatic Brain Injury	RECRUITING
NCT04304651	Screening for Occult Malignancy in Patients with Unprovoked Venous Thromboembolism (NCT04304651)	Embolism and Thrombosis	RECRUITING
NCT06603870	Secondary Prevention of VTE in Patients With Cancer and Catheter-Related Upper Extremity Deep Vein Thrombosis (NCT06603870)	Venous Thromboembolism, Cancer, Upper Extremity Deep Vein Thrombosis, Catheter-Related Infections	RECRUITING	kdanovitch@ohri.ca
NCT04319627	Statins for Venous Event Reduction in Patients With Venous Thromboembolism (NCT04319627)	Venous Thromboembolism, Blood Clot, Post Thrombotic Syndrome	RECRUITING
NCT05255003	STrategies for Anticoagulation in Patients With thRombocytopenia and Cancer-associated Thrombosis (NCT05255003)	Cancer-associated Thrombosis, Thrombocytopenia	RECRUITING
NCT05920343	VTE Prevention With Rivaroxaban in Genitourinary Cancer Patients Receiving Systemic Therapy (NCT05920343)	Venous Thromboembolism, Urologic Cancer	RECRUITING

Publications

The following research publications are pulled from PubMed using the search terms "thrombosis OR thromboembolism OR pulmonary embolism" and "Ottawa Hospital", with publication date of 2020 or later. More advanced search options are available. Note that PubMed is hosted by the U.S. National Library of Medicine and is only available in English.

Association between anticoagulant-related bleeding and mortality in patients with hematological malignancies and cancer-associated venous thromboembolism.
2025-04-01

American Society of Hematology living guidelines on use of anticoagulation for thromboprophylaxis for patients with COVID-19: executive summary.
2025-03-25

How to deal with interference on heparin anti-Xa activity caused by oral factor FXa inhibitors: communication from the ISTH SSC Subcommittee on Control of Anticoagulation.
2025-03-07

Treatment and outcomes after on-treatment recurrent venous thromboembolism in patients with cancer: a post hoc analysis of the Hokusai venous thromboembolism cancer study.
2025-03-04

Association Between Anticoagulant-Related Bleeding and Mortality in Patients With Solid Tumors and Cancer-Associated Venous Thromboembolism.
2025-03-01

Comparison of Clinical Outcomes in Patients with Active Cancer Receiving Rivaroxaban or Low-Molecular-Weight Heparin: The OSCAR-UK Study.
2025-03-01

Efficacy and safety of extended duration postoperative thromboprophylaxis with low molecular weight heparin among subgroups of patients undergoing surgical resection of colorectal cancer: A post-hoc analysis of the PERIOP-01 trial.
2025-02-14

POCUS literature primer: key papers on aorta and deep vein thrombosis POCUS.
2025-02-04

Low-dose aspirin versus placebo in postpartum venous thromboembolism: a multi-national, pilot, randomised, placebo-controlled trial.
2025-02-01

An emergency medicine review: Multiple myeloma and its complications.
2025-02-01

View more on PubMed