Become Familiar with VTE Treatment and Anticoagulation Management

Health-System Edition, September 2021, Volume 10, Issue 5

Pharmacists should stay knowledgeable about recommendations and evidence related to therapies.

The American College of Chest Physicians (CHEST) has been developing and publishing guidelines related to venous thromboembolism (VTE) management for more than 30 years.

These clinical practice recommendations guide clinicians and physicians through the prophylaxis and treatment of VTE by covering aspects from initial management through secondary prevention and risk reduction of postthrombotic syndrome.

CHEST's most recent publication, the 10th edition of the Antithrombotic Guideline, contains updated recommendations on 12 topics that were in the ninth edition and addresses 3 new topics.1,2 These new guidelines also contain 4 new guidance statements that did not appear in the ninth edition (2012) or first update (2016), and 8 statements have been substantially modified in recent years because of new evidence.1-3

VTE Overview

VTE is a common condition in which a blood clot forms in a vein, dislodges, and then travels in the blood.4,5 It is the third-leading vascular diagnosis after heart attack and stroke, affecting more than 900,000 Americans each year, and is associated with considerable morbidity and mortality.6 There are 2 types.4,6,7

Deep vein thrombosis (DVT) is the result of thrombus formation in a deep vein, most commonly in the lower extremities. Pulmonary embolism (PE) occurs when a thrombus dislodges from a vein and travels to the heart and then to a lung, completely or partially occluding the pulmonary artery or its branches.

The most common triggers for VTE are cancer, hip or leg fracture, hospitalization, immobilization, and surgery. In women, pregnancy and the use of hormones such as estrogen or oral contraceptives for menopause symptoms can also play a role.4,7

Certain groups are at higher risk for clotting, including individuals older than 40 years, with risk doubling each subsequent decade; people with antiphospholipid antibody syndrome, cancer, polycythemia vera, or autoimmune disorders such as lupus; and those who are obese or overweight.7 Genetic causes of excessive blood clotting are also important. Inherited traits such as antithrombin deficiency, factor V Leiden, or protein C or S deficiency can contribute to a hypercoagulable state.7

Guidelines

The mainstay of therapy for VTE is anti-coagulation, provided there is no contraindication. Following initial anticoagulation, patients with DVT or PE usually continue anticoagulation for a period to prevent embolism, future recurrences, and thrombosis-related death.5,6

In the CHEST guidelines, treatment recommendations are graded as strong (grade 1) and weak (grade 2) based on the level of high-quality (grade A), medium-quality (grade B), or low-quality (grade C) evidence.

The 13 strong recommendations in the 10th edition include the following:

  • In patients with acute DVT of the leg, guidelines recommend against the use of an inferior vena cava (IVC) filter in addition to anticoagulants.
  • In patients with acute isolated distal DVT of the leg managed with anticoagulation, the recommendation is to use the same anticoagulant regimen as for patients with acute proximal DVT.
  • In patients with cerebral venous sinus thrombosis, the recommendation is to use anticoagulation therapy for at least the treatment phase (first 3 months) over no anticoagulant therapy.
  • In patients with thrombosis and antiphospholipid syndrome being treated with anticoagulant therapy, adjusted-dose vitamin K antagonists are recommended over direct oral anticoagulant therapy.

Recommendations that are unchanged but now supported by better evidence include discouragement of IVC filter use in anticoagulated patients, discouragement of thrombolytic therapy in PE patients who are not hypotensive or deteriorating on anticoagulation, and encouragement of indefinite anticoagulant therapy after a first unprovoked PE.2,3

New evidence also led to several changes, including the use of novel oral anticoagulants (NOACs). NOACs are recommended over vitamin K antagonists (VKAs) for the treatment of VTE in patients without cancer. Low-molecular-weight heparin is still the preferred long-term treatment for cancer and VTE, but it is no longer suggested to use VKAs over NOACs in these patients.2,3

Clinicians often ask which NOAC is preferred, and these guidelines state that individual patients may favor selection of one NOAC over another in patients without or with cancer or may favor selection of a NOAC or VKA in patients with cancer. The guidelines did not express an overall preference for one NOAC over another or for either a NOAC or VKA in patients with cancer because indirect comparisons have not shown convincingly varying outcomes with different NOACs. NOACs have not been compared with VKA in a broad spectrum of patients with VTE and cancer, and there are no direct comparison trials of different NOACs.2,3,8

Another notable change in the 10th edition is that, based on a new low-risk-of-bias study, graduated compression stockings are not routinely used to prevent postthrombotic syndrome.3

Conclusion

VTE treatment and anticoagulation management are common in clinical practice. Pharmacists should be up-to-date with the recommendations and evidence around therapies and knowledgeable about the newest evidence related to VTE management. Although there is still uncertainty related to limited disease and special patient populations, the newest recommendations serve as a guide to therapy.

Joanna Lewis, PharmD, MBA, is the 340B compliance coordinator at Baptist Health in Jacksonville, Florida.

REFERENCES

1. CHEST releases new guidelines for antithrombotic therapy in VTE disease. News release. American College of Chest Physicians. August 3, 2021. Accessed August 13, 2021. https://www.chestnet.org/Newsroom/Press-Releases/2021/08/CHEST-releases-new-guidelines-for-antithrombotic-therapy-for-VTE-disease

2. Kearon C, Akl EA, Ornelas J, et al. Antithrombotic therapy for VTE disease: CHEST guideline and expert panel report. Chest. 2016;149(2):315-352. doi:10.1016/j.chest.2015.11.02

3. Stevens SM, Woller SC, Baumann Kreuzinger L, et al. Antithrombotic therapy for VTE disease: second update of the CHEST Guideline and Expert Panel Report – executive summary. Chest. Published online July 31, 2021. doi:10.1016/j.chest.2021.07.056

4. Data and statistics on venous thromboembolism. CDC. Updated February 7, 2020. Updated February 7, 2020. Accessed August 23, 2021. https://www.cdc.gov/ncbddd/dvt/data.html

5. Kearon C. Natural history of venous thromboembolism. Circulation. 2003;107(suppl 1):I22-130. doi:10.1161/01.CIR.0000078464.82671.78

6. Philippe HM. Overview of venous thromboembolism. Am J Manag Care. 2017;23 (suppl 20):S376-S382.

7. Anderson FA Jr, Spencer FA. Risk factors for venous thromboembolism. Circulation. 2003;107(suppl 1):I9-I16. doi:10.1161/01.CIR.0000078469.07362.E6

8. Schulman S, Kearon C, Kakkar AK, et al; RE-MEDY Trial Investigators; RE-SONATE Trial Investigators. Extended use of dabigatran, warfarin, or placebo in venous thromboembolism. N Engl J Med. 2013;368(8):709-718. doi:10.1056/NEJMoa1113697