Thromboprophylaxis is the most important patient safety strategy in patients admitted to the hospital. Pulmonary embolism remains the leading cause of preventable in-hospital death.
The risk of venous thrombosis in patients admitted to the hospital depends on medical versus surgical admission and, among surgical patients, the type of surgery.
Evaluating venous thromboembolic risk factors within these patient groups helps further stratify the thrombotic risk.
Bleeding risk and possible contraindication to antithrombotic agents must be assessed before instituting thromboprophylaxis.
Although national and international thromboprophylaxis guidelines have repeatedly recommended thromboprophylaxis of patients admitted to the hospital, only 40% to 50% of medical patients and 60% to 75% of surgical patients receive adequate thromboprophylaxis.
Computer-based decision systems and preprinted orders are most effective in optimizing physician adherence to thromboprophylaxis guidelines. Periodic audits by pharmacists or other health professionals reinforce the consistent use of venous thromboembolism prophylaxis.
Venous thromboembolism (VTE) prophylaxis consists of pharmacologic and nonpharmacologic measures to diminish the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE).
DVT of the leg is the development of a blood clot in one of the major deep veins in the leg or thigh, which leads to impaired venous blood flow, usually causing leg swelling and pain.
PE is a consequence of thrombus formation in distal veins, most commonly those of the deep venous system of the lower extremities. Thrombus formation in the venous system occurs as a result of venous stasis, trauma, and hypercoagulability. About 51% of deep venous thrombi will embolize to the pulmonary vasculature, resulting in a PE.
History and exam
Key diagnostic factors
- previous VTE, thrombophilia, malignancy, postoperative setting, trauma, and indwelling central catheter
- chronic medical conditions, paresis, increasing age, obesity, estrogen-containing birth control pills and hormone replacement therapy, varicose veins, pregnancy and up to 6 week postpartum, first-degree relative with a history of VTE, extended travel, and admission to intensive care
- previous VTE (deep vein thrombosis [DVT] and/or pulmonary embolism [PE])
- postoperative setting
- indwelling central catheter (upper or lower extremity)
- myeloproliferative diseases
- congestive heart failure
- chronic obstructive pulmonary disease
- inflammatory bowel disease
- neurologic disease with extremity paresis
- increasing age
- estrogen-containing birth control pills, hormone replacement therapy (HRT), and androgen deprivation therapy
- history of varicose veins
- extended travel
- lower leg immobility
- first-degree relative with a history of VTE
- admission to intensive care
1st investigations to order
- serum creatinine
Investigations to consider
- serum antiplatelet factor 4 antibodies
all at-risk patients
Nathalie Routhier, MD, MSc, FRCPC
University of Montreal
NR declares that she has no competing interests.
Vicky Tagalakis, MD, FRCPC, MSC
General Internal Medicine Program Director
McGill University Division of Internal Medicine
Centre for Clinical Epidemiology of the Lady Davis Institute for Medical Research
Jewish General Hospital
VT declares that she has received an investigator-initiated grant from Sanofi-Aventis. She has also received consultancy fees from and given lectures sponsored by Bristol-Myers Squibb, Pfizer, Sanofi-Aventis, and Servier. VT is an author of references cited in this topic.
Department of Medicine
Hôpital du Sacré-Coeur de Montréal
University of Montreal
FZ declares that she has no competing interests.
Dr Nathalie Routhier, Dr Vicky Tagalakis and Dr Farah Zarka would like to gratefully acknowledge Dr Vincent Bouchard-Dechêne and Dr Adi J. Klil-Drori, previous contributors to this topic.
VBD and AJKD declare no competing interests.
Andrew Parfitt, MBBS, FFAEM
Associate Medical Director
Consultant Emergency Medicine
Guy's and St Thomas' NHS Foundation Trust
Clinical Lead and Consultant
Accident Emergency Medicine
St Thomas' Hospital
AP declares that he has no competing interests.
Sudeep Shivakumar, MD
University of Ottawa
Ottawa Health Research Institute
SS declares that he has no competing interests.
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