VTE Guidelines
Maria G. Tanzi, PharmD
The American Society of Hematology (ASH) released guidelines for management of venous thromboembolism (VTE), with 28 recommendations focused on initial management of deep vein thrombosis (DVT) and pulmonary embolism (PE), secondary prevention of VTE events, and management of recurrent events.
Nancy L. Shapiro, PharmD, FCCP, BCACP, CACP, coordinator and clinical pharmacist in the Antithrombosis Clinic at the University of Illinois at Chicago Hospital and Health Sciences System, said clinic practitioners are used to seeing and incorporating ASH’s recommendations, especially since the last CHEST VTE guideline was released in 2016.
“We do use the ASH guideline in practice because ASH also released VTE guidelines in 2018, which focused on optimal management of anticoagulation, including recommendations on point-of-care testing, interval between testing, and adherence considerations for anticoagulants,” she said.
Following are select recommendations of the new guidelines. Clinicians can review the complete guidelines in the October 2 issue of Blood Advances (http://apha.us/2020VTEguidelines).
Primary treatment
The ASH guidelines recommend home treatment over the hospital setting for patients with uncomplicated DVTs and those with a PE with a low risk of complications.
Use of direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists for management of DVTs and PEs, but ASH does not suggest a preference for one DOAC over another. In selecting the most appropriate DOAC, clinicians should be guided by factors such as the dosing regimen (e.g., daily vs. twice daily), out-of-pocket costs, renal function, patient comorbidities, and concurrent medications, the guidelines advise.
The ASH guidelines also recommend a shorter over a longer course (i.e., 3–6 mo vs. 6–12 mo) of anticoagulation therapy for primary treatment of VTE. They note that most patients with a DVT or PE provoked by a temporary risk factor will discontinue anticoagulation therapy after completing primary treatment, whereas patients with a VTE event provoked by chronic risk factors and those with unprovoked VTEs may continue anticoagulation indefinitely for secondary prevention after completing the primary treatment course.
Secondary prevention
If treatment is continued for secondary prevention, the guidelines recommend an anticoagulant over aspirin. For warfarin, a target international normalized ratio (INR) between 2 and 3 is recommended over a lower INR range of 1.5 to 1.9. If a DOAC was used for primary treatment, the guidelines suggest using a standard- or lower-dose DOAC.
“This recommendation continues to allow for flexibility of the DOAC dosing based on patient-specific risk factors,” said Shapiro.
Treatment of recurrent events
For patients presenting with a new VTE event during therapeutic treatment with a vitamin K antagonist, the guidelines note that clinicians should determine if a potential underlying cause may be present. They also state that a DOAC may be a reasonable option for poor INR control.
“Often, clinicians are switching patients from warfarin to a DOAC when there is a treatment failure,” said Shapiro. But, she noted, it is important to consider whether there are underlying conditions, such as cancer, that are the potential cause of the breakthrough event.
“If the anticoagulation control with warfarin prior to the new VTE was not optimal, though, switching to a DOAC may be helpful,” Shapiro said.
This is especially true if adherence problems revolve around the inability to have regular INR monitoring because of work, transportation issues, or other barriers.
Additional considerations
The ASH guidelines also comment on management of patients with a VTE who have stable cardiovascular disease and are on aspirin therapy. They suggest suspending the aspirin therapy instead of continuing it for the duration of the anticoagulation.
“This recommendation is new and important because there is an ever-increasing role for clinical pharmacists, as medication experts, to evaluate whether aspirin therapy should be continued or not in patients that require anticoagulation,” said Shapiro. “This is an area that can be overlooked, and one that continues to deserve our attention to minimize the risk for bleeding.”