Deep Venous Thrombosis

Educational Objectives

The goal of this program is to improve management of anticoagulation therapy for patients with deep venous thrombosis (DVT). After hearing about and assimilating this program, the clinician will be better able to:

1. List risk factors for recurrence of DVT.
2. Identify patients who may require long-term anticoagulation therapy after a DVT.

Summary

Anticoagulants after deep vein thrombosis (DVT): patients require initial anticoagulant treatment (ACT) for 3 to 6 mo; after this, reassess patients to decide whether to stop treatment or continue the ACT as secondary prevention; low-dose anticoagulants (eg, rivaroxaban 10 mg daily and apixaban 2.5 mg twice daily) have significantly lower bleeding rates, making long-term ACT feasible

Risk factors for DVT recurrence: influence the decision for secondary prevention; major transient risk factors (TRFs) and minor TRFs have a significantly lower risk for recurrent venous thromboembolism (VTE) compared with chronic persistent risk factors (CPRFs); CPRFs, eg, chronic immobility, chronic inflammatory conditions, antiphospholipid antibody syndrome (APS), confer a higher risk for recurrence than unprovoked VTEs; the risk for recurrent VTE with cancer-associated thrombosis is 3 times higher than with unprovoked VTE; TRFs have a ≈4.2% risk for recurrent VTE per patient-year; the risk for unprovoked VTE is 7.4%, and for CPRF is 9.7%; distal DVT vs proximal DVT — distal (calf) DVTs (have a risk for recurrence 50% of proximal DVT); elevated D-dimer is an important predictor; patients with unprovoked VTEs who have persistently elevated D-dimer levels after stopping initial ACT have a risk for recurrent VTE 2.5 times higher than those with a normal D-dimer

Risk of bleeding: the annualized risk of major bleeding on ACT is ≈2.1% based on data from warfarin use; direct oral anticoagulation (DOAC) has a risk ≈33% lower, even at therapeutic doses; prophylactic doses have a risk ≈50% lower; 12% of major bleeding events are fatal whereas 4% of recurrent VTEs are fatal; assessment — categorize patients as at low, intermediate, or high risk; risk calculators provided by, eg, the American Society of Hematology (ASH); for patients taking prolonged ACT, assess bleeding risk at every visit (eg, yearly); prolonged ACT is not typically needed for surgically provoked VTE; patients with nonsurgical (major or minor TRF) or unprovoked distal DVT are also more likely to have fatal bleeding events than recurrent VTE; for unprovoked proximal DVT or pulmonary embolism, there is a potential benefit to prolonged ACT; low- and intermediate-risk patients, in particular, are more likely to have a fatal recurrent VTE than major bleeding; for second unprovoked DVTs, there is a clear benefit to ACT; remember that the bleeding risks with DOACs are lower

Thrombophilia: all patients with thrombophilia, including factor V Leiden or prothrombin gene mutation, have an increased risk for initial VTE; only antithrombin 3 deficiency, protein C or S deficiency, and particularly APS, are associated with significantly higher rates of recurrent VTE; only these high-risk thrombophilias require long-term ACT; in triple-positive APS, warfarin is more likely to reduce recurrent thromboembolic events than DOACs; patients with CPRFs are at high risk for recurrent VTE events, so indefinite ACT is recommended; for isolated distal DVTs, consider stopping ACT; for initial unprovoked DVTs, continue ACT with low-dose DOACs for patients who are not at a high bleeding risk; for patients who prefer to avoid ACT, discuss the risk-benefit ratio and check for APS and D-dimer levels (recommend long-term ACT if test are positive); for recurrent unprovoked DVTs, use indefinite ACT; for cancer-associated thrombosis, continue ACT for ≥6 mo, until the cancer is in complete remission and there is no ongoing use of chemotherapy

Chronic deep venous disease: may require interventions, eg, iliac vein stenting or complex iliocaval reconstruction; stent patency rates for patients with chronic DVTs are low (≈73%); these patients tend to be in a slightly higher prothrombotic state and frequently experience recurrent thrombosis; these patients may require low molecular weight heparin (LMWH); a meta-analysis assessed patients with acute DVT taking low molecular weight heparin (LMWH) vs vitamin K antagonists (eg, warfarin); LMWH was associated with lower rates of venous ulceration, more thrombus resolution (recanalization), better venous competence, and lower rates of postthrombotic syndrome; LMWH has significant anti-inflammatory and antifibrinolytic mechanisms

Complex iliocaval reconstruction: the speaker uses a triple therapy protocol with ACT, aspirin, and clopidogrel for 1 to 3 mo based on the bleeding risk profile; patients are then transitioned to a DOAC and single antiplatelet therapy, with LMWH for the first 2 to 4 wk

Readings

Áinle FN, Kevane B. Which patients are at high risk of recurrent venous thromboembolism (deep vein thrombosis and pulmonary embolism)? Blood Advances. 2020 Nov 10;4(21):5595-606; Cushman M. Epidemiology and risk factors for venous thrombosis. Semin Hematol. 2007;44(2):62-69; Fahrni J, Husmann M, Gretener SB, et al. Assessing the risk of recurrent venous thromboembolism–a practical approach. Vascular health and risk management. 2015;11:451; McLendon K, Goyal A, Attia M. Deep venous thrombosis risk factors. [Updated 2022 Apr 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470215/; Sinescu C, Hostiuc M, Bartos D. Idiopathic venous thromboembolism and thrombophilia. Journal of Medicine and Life. 2011 Feb 15;4(1):57; Thaler J, Pabinger I, Ay C. Anticoagulant treatment of deep vein thrombosis and pulmonary embolism: the present state of the art. Frontiers in Cardiovascular Medicine. 2015 Jul 14;2:30.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Sharma is an advisor for Boston Scientific. The planning committee has nothing relevant to disclose.

Acknowledgements

Dr. Sharma was recorded at Kansas City Vascular Symposium 2022, held on April 29, 2022, in Kansas City, MO, and presented by the University of Kansas Medical Center. For information on upcoming CME opportunities from this presenter, please visit https://kumcce.ku.edu/kumc-ce. Audio Digest thanks the speakers and presenters for their cooperation in the produc­tion of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

IM700702

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.