The American Society of Hematology (ASH) recently released guidelines for managing venous thromboembolism (VTE) that were developed to help the medical community better prevent, diagnose, and treat this common complication. The guidelines included chapters on the optimal management of anticoagulation therapy and heparin-induced thrombocytopenia (HIT).

Anticoagulation Therapy

Anticoagulation therapy for VTE has long been the standard of care, but while the benefits are substantial, the risks and costs can be significant. Because of its complexity, clinicians confront numerous practical issues in optimizing the use of anticoagulant agents in this setting. The ASH guidelines, therefore, focus on the optimal management of anticoagulant drugs for preventing and treating VTE after anticoagulation therapy has been chosen.1

“This panel is looking at the optimal use of anticoagulant drugs for the treatment of venous thromboembolism,” said Daniel Witt, PharmD, of the University of Utah School of Pharmacy in Salt Lake City and chair of the panel on optimal management of VTE. “And even though anticoagulant drugs have been around a long time, the amount of evidence [that] is out there to inform clinicians is really pretty shocking.”

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On a webcast discussing the new guidelines, Dr Witt pointed out that several new medications “have come on the scene,” and that these new agents have to be incorporated into decision making. “How can clinicians be sure that they are using these drugs to help patients achieve the desired outcomes while minimizing the risk of any harms?” he asked.

Dr Witt believes that these guidelines target a broad audience, including both clinicians who occasionally prescribe anticoagulants and specialists. “I think it challenges the dogma that we generally take for granted: that there is all kinds of evidence to back things up,” he said. “But when you get in there and look at what’s available in the literature — that we feel relatively comfortable with — I think it’s going to be challenged by these guidelines.”

The panel agreed on 25 recommendations and 2 good practice statements. Overall, the recommendations put greater value on outcomes that relate to improving quality of life and preventing mortality, pulmonary embolism, deep vein thrombosis, major bleeding, and emergency department and/or hospital visits. Cost and cost effectiveness, impact on equity, acceptability, and feasibility were also taken into account.

Some of the key recommendations are:

  • In patients receiving maintenance therapy with vitamin K antagonists (VKAs), the panel recommends that patients use point-of-care international normalized ratio (INR) testing at home. Patient self-management of the dose is recommended over any other management approach.
  • The guideline panel suggests using an INR recall interval of 4 weeks or fewer for patients on VKA therapy following dose adjustment because of an out-of-target-range INR. The panel also suggests using a longer (6-12 weeks) INR recall interval compared with a shorter (4 weeks) interval during periods of stable INR control.
  • In obese patients receiving therapy with low molecular weight heparin (LMWH), the panel suggests that initial LMWH dose selection be made according to actual body weight rather than based on a fixed maximum daily dose.
  • In patients being treated with LMWH who either have renal dysfunction (creatinine clearance <30 mL/min) or are obese, the panel suggests against using anti-factor Xa concentration monitoring to guide LMWH dose adjustment.
  • When patients transition from using direct oral anticoagulants (DOACs) to using VKAs, the panel suggests overlapping DOAC and VKA therapy until the INR is within the therapeutic range, compared with the use of “bridging therapy” with LMWH or unfractionated heparin (UFH).
  • The panel recommends against using interventions (such as a daily lottery or digital reminders) to improve medication adherence.
  • In patients at low to moderate risk for recurrent VTE who require interruption of VKA therapy for invasive procedures, the panel recommends against periprocedural bridging with LMWH or UFH compared with interruption of VKA alone.

The 2 good practice statements included in the guideline refer to renal function monitoring. The ASH guideline panel agrees that good practice includes renal function monitoring every 6 to 12 months in patients with creatinine clearance of at least 50 mL/min who are receiving DOAC therapy. For those with creatinine clearance of less than 50 mL/min receiving DOAC therapy, good practice includes renal function monitoring approximately every 3 months.