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ASH Clinical Practice Guidelines on Venous Thromboembolism

ASH Guidelines on Use of Anticoagulation in Patients with COVID-19

In June 2020, ASH formed a multidisciplinary, international panel to develop guidelines on the use of anticoagulation in patients with COVID-19. The panel prioritized questions about the use of anticoagulation in critically and acutely ill patients.

The McMaster University GRADE Centre supported the guideline development process. In collaboration with experts on the guideline panel, the team conducted urgent systematic reviews of available evidence on the baseline risk of thrombosis in patients with COVID-19 and on the use of prophylactic versus higher intensity anticoagulation in patients who are acutely or critically ill.

On October 8, 2020, the panel agreed on the following recommendations. During October and November, these recommendations and a report of the guideline development process will undergo public review and ASH organizational review and approval, then will be submitted for publication within Blood Advances.

Critically Ill Patients

In patients with COVID-19 related critical illness who do not have confirmed or suspected venous thromboembolism, should we use prophylactic-intensity vs. intermediate-intensity vs. therapeutic-intensity anticoagulation?

Draft Recommendation

The ASH guideline panel suggests using prophylactic-intensity over intermediate-intensity or therapeutic-intensity anticoagulation in patients with COVID-19 related critical illness who do not have suspected or confirmed VTE (conditional recommendation based on very low certainty in the evidence about effects).

Remarks: An individualized assessment of the patient's risk of thrombosis and bleeding is important when deciding on anticoagulation intensity. Risk assessment models to estimate thrombotic and bleeding risk in hospitalized patients are available, but they have not been validated in patients with COVID-19. The panel acknowledges that higher-intensity anticoagulation may be preferred in patients judged to be at high thrombotic risk and low bleeding risk.

At present, there is no direct high quality evidence comparing different types of anticoagulants. The selection of a specific agent (e.g., low molecular weight heparin, unfractionated heparin, etc.) may be based on availability, resources required, familiarity, and the aim of minimizing PPE use or staff exposure to COVID-19 infected patients as well as patient-specific factors (e.g., renal function, history of heparin-induced thrombocytopenia, concerns about gastrointestinal tract absorption).

This recommendation does not apply to patients who require anticoagulation to prevent thrombosis of extracorporeal circuits such as those on extracorporeal membrane oxygenation or continuous renal replacement therapy.

View the evidence profiles and evidence-to-decision framework here.

Acutely Ill Patients

In patients with COVID-19 related acute illness who do not have confirmed or suspected venous thromboembolism, should we use prophylactic-intensity vs. intermediate-intensity vs. therapeutic-intensity anticoagulation?

Draft Recommendation

The ASH guideline panel suggests using prophylactic-intensity over intermediate-intensity or therapeutic-intensity anticoagulation in patients with COVID-19 related acute illness who do not have suspected or confirmed VTE (conditional recommendation based on very low certainty in the evidence about effects).

Remarks: An individualized assessment of the patient's risk of thrombosis and bleeding is important when deciding on anticoagulation intensity. Risk assessment models to estimate thrombotic and bleeding risk in hospitalized patients are available, but they have not been validated in patients with COVID-19. The panel acknowledges that higher-intensity anticoagulation may be preferred in patients judged to be at high thrombotic risk and low bleeding risk.

At present, there is no direct high quality evidence comparing different types of anticoagulants. The selection of a specific agent (e.g., low molecular weight heparin, unfractionated heparin, etc.) may be based on availability, resources required, familiarity, and the aim of minimizing PPE use or staff exposure to COVID-19 infected patients as well as patient-specific factors (e.g., renal function, history of heparin-induced thrombocytopenia).

View the evidence profiles and evidence-to-decision framework here.

Public Comment

ASH welcomes comments on the draft recommendations here. The deadline to comment is October 16, 2020.

Guideline Implementation Tools and Resources

Webinar

This webinar highlights the guideline recommendations along with the underlying evidence and rationale for the recommendations. A slide set is available from the webinar.

  • ASH Guidelines on Use of Anticoagulation in Patients with COVID-19 Webinar
    Powerpoint | PDF

Guideline Panel

  • Pantep Angchaisuksiri, MD (Ramathibodi Hospital, Mahidol University, Bangkok, Thailand)
  • Clifton Blair (Union, New Jersey) / Patient Representative
  • Adam Cuker, MD, MS (University of Pennsylvania) / Clinical Co-chair
  • Kathryn E. Dane, PharmD (Johns Hopkins Hospital)
  • Jennifer Davila, MD (Children's Hospital at Montefiore)
  • Maria DeSancho, MD, MSc (Weill Cornell Medicine)
  • David L. Diuguid, MD (Columbia University)
  • Daniel Griffin, MD, PhD (Columbia University and ProHealth Care, New Hyde Park, NY)
  • Susan R. Kahn, MD, MSc (McGill University)
  • Frederikus A. Klok, MD, PhD (Leiden University Medical Center Einthoven Laboratory)
  • Alfred Ian Lee, MD, PhD (Yale School of Medicine)
  • Reem Mustafa, MBBS, PhD, MPH (University of Kansas) / Methodology Co-chair
  • Ignacio Neumann, MD, MS (Pontifica Universidad Católica de Chile, Santiago, Chile)
  • Ashok Pai, MD (Kaiser Permanente, Oakland Medical Center)
  • Menaka Pai, MD, MSc (McMaster University) / Ex Officio, Guideline Oversight Subcommittee
  • Marc Righini, MD (University of Geneva, Switzerland)
  • Kristen M. Sanfilippo, MD, MPHS (Washington University in St. Louis)
  • Holger Schünemann, MD, PhD (McMaster University) / Methodology Co-chair
  • Deborah Siegal, MD, MSc (McMaster University)
  • Mike Skara (Cottage Grove, Indiana) / Patient Representative
  • Kamshad Touri (Ontario, Canada) / Patient Representative
  • Eric K. Tseng, MD, MSc (St. Michael's Hospital, Toronto) / Writer

Methods Team

  • Elie A. Akl, MD, PhD, MPH (American University of Beirut)
  • Romina Brignardello-Petersen, PhD, MSc, DDS (McMaster University)
  • Reem Mustafa, MBBS, PhD, MPH (University of Kansas)
  • Ignacio Neumann, MD, MS (Pontifica Universidad Católica de Chile, Santiago, Chile)
  • Robby Nieuwlaat, PhD, MSc (McMaster University)
  • Holger Schünemann, MD, PhD (McMaster University)
  • Karla Solo, MSc (McMaster University)
  • Adrienne Stevens, MSc, PhD (Cochrane Canada)
  • Wojtek Wiercioch, MSc (McMaster University)

Systematic Review Team

  • Reyad Al Jabiri (University of Jordan)
  • Yazan Al Jabiri, MD (Lincoln Medical Center)
  • Elie A. Akl, MD, PhD, MPH (American University of Beirut)
  • Antonio Bognanni, MD (McMaster University)
  • Imad Bouakl, MD (American University of Beirut)
  • Mary Ellene Boulos, BSc, MSc (McMaster University)
  • Emma Cain, HBSc (McMaster University)
  • Matthew Chan, MD (McMaster University)
  • Rana Charide, BS, MPH (Clinical Research Institute, American University of Beirut, Beirut, Lebanon)
  • Andrea J. Darzi, MD, MPH (McMaster University)
  • Karin Dearness, BSc, MLS (St. Joseph’s Healthcare, Hamilton, Ontario)
  • Philipp Kolb, MBA, BHSc (McMaster University)
  • Luis Enrique Colunga Lozano, MD, MSc (Universidad de Guadalajara, México)
  • Razan Mansour, MD (King Hussein Cancer Center, Amman, Jordan)
  • Gian Paolo Morgano, MSc (McMaster University)
  • Rami Z. Morsi, MD (University of Chicago)
  • Giovanna Muti-Schünemann, MD (McMaster University)
  • Robby Nieuwlaat, PhD, MSc (McMaster University)
  • Atefeh Noori, MSc (McMaster University)
  • Thomas Piggott, MD, MSc, CCFP, FRCPC (Labrador-Grenfell Health, Labrador, Canada)
  • Yuan Qiu, BHSc (McMaster University)
  • Yetiani Maria Roldan Benitez, MD (McMaster University)
  • Holger Schünemann, MD, PhD (McMaster University)
  • Finn Schünemann, MD (Albert-Ludwigs University, Freiburg, Germany)
  • Karla Solo, MSc (McMaster University)
  • Adrienne Stevens, MSc, PhD (Cochrane Canada)
  • Matthew Ventresca, MSc, MBA, CHE (McMaster University)
  • Wojtek Wiercioch, MSc (McMaster University)

How to Use These Guidelines

ASH guidelines are primarily intended to help clinicians make decisions about diagnostic and treatment alternatives. Other purposes are to inform policy, education and advocacy, and to state future research needs. They may also be used by patients. These guidelines are not intended to serve or be construed as a standard of care. Clinicians must make decisions on the basis of the clinical presentation of each individual patient, ideally through a shared process that considers the patient’s values and preferences with respect to the anticipated outcomes of the chosen option. Decisions may be constrained by the realities of a specific clinical setting and local resources, including but not limited to institutional policies, time limitations, or availability of treatments. These guidelines may not include all appropriate methods of care for the clinical scenarios described. As science advances and new evidence becomes available, recommendations may become outdated. Following these guidelines cannot guarantee successful outcomes. ASH does not warrant or guarantee any products described in these guidelines.

Statements about the underlying values and preferences as well as qualifying remarks accompanying each recommendation are its integral parts and serve to facilitate more accurate interpretation. They should never be omitted when quoting or translating recommendations from these guidelines. Implementation of the guidelines will be facilitated by the evidence-to-decision frameworks and summary of findings tables linked above and by other implementation tools linked below.

For more information, see Izcovich et al. A user guide to the American Society of Hematology clinical practice guidelines. Blood Adv (2020) 4 (9): 2095-2110. https://doi.org/10.1182/bloodadvances.2020001755.

Publication Information

These guidelines are informed by living systematic reviews of available evidence, i.e., monthly literature searches and, as needed, updates to estimates for the baseline risk of thrombosis or the effects of anticoagulation. If and when estimates change, the guideline panel will reconvene to consider changes to these recommendations.

The recommendations published on this page and within the ASH guidelines app will be updated when their status changes, i.e., from draft to final to updated.

Suggested citation for this page: Adam Cuker, Eric K. Tseng, Robby Nieuwlaat, Pantep Angchaisuksiri, Clifton Blair, Kathryn E. Dane, Jennifer Davila, Maria DeSancho, David L. Diuguid, Daniel Griffin, Susan R. Kahn, Frederikus A. Klok, Alfred Ian Lee, Ignacio Neumann, Ashok Pai, Menaka Pai, Marc Righini, Kristen M. Sanfilippo, Deborah Siegal, Mike Skara, Kamshad Touri, Elie A. Akl, Imad Bouakl, Mary Ellene Boulos, Romina Brignardello-Petersen, Rana Charide, Matthew Chan, Karin Dearness, Andrea J. Darzi, Philipp Kolb, Luis E. Colunga-Lozano, Razan Mansour, Gian Paolo Morgano, Rami Z. Morsi, Atefeh Noori, Thomas Piggott, Yuan Qiu, Yetiani Roldan, Finn Schünemann, Adrienne Stevens, Karla Solo, Matthew Ventresca, Wojtek Wiercioch, Reem A. Mustafa, and Holger J. Schünemann. ASH 2020 guidelines on the use of anticoagulation in patients with COVID-19: Draft recommendations. Washington, DC: American Society of Hematology. Published October 8, 2020. http://www.hematology.org/COVIDguidelines.

All content on this page and within the ASH guidelines app is copyrighted 2020 by the American Society of Hematology. None of the content may be published or distributed by any other individual or organization without permission from ASH.

Published Guidelines

Coming Soon

  • VTE in Latin America adaptation
  • Cancer
  • Thrombophilia

Public Comment

All are welcome to comment on draft recommendations, including physicians, patients, caregivers, and members of the public.

Review Draft Guidelines

ASH Webinar

This webinar highlights recommendations along with underlying evidence and rationale for the recommendations for the ASH Guidelines on Use of Anticoagulation in Patients with COVID-19 .

Watch webinar

user guide to Guidelines 

Learn how patients, clinicians, policymakers, researchers, and others may interpret and apply guideline information.

Learn more