Deep Vein Thrombosis



Deep Vein Thrombosis


Robert R. Attaran, MD, FACC, FASE, FSCAI, RPVI






Key Points



  • Venous thromboembolism is a common and sometimes devastating condition.


  • In some cases, mechanical thrombus removal can be beneficial.


  • The rate of recurrent DVT is high.


  • Optimal duration of anticoagulation for DVT is controversial.


  • Treatment of post-thrombotic syndrome should ideally address both venous obstruction and reflux.


I. Venous Thromboembolism

Venous thromboembolism (VTE) (deep vein thrombosis [DVT] and pulmonary embolism [PE]) is a common cause of mortality, morbidity, and loss of quality of life, particularly due to postthrombotic syndrome (PTS). This is a chronic condition of the leg that can result in pain, swelling, discoloration, and even ulceration, which occurs in at least 30% after DVT.1 Rarely limb loss can occur through phlegmasia cerulean dolens. There are over 250,000 cases of VTE per annum in the United States alone.2 Venous thrombosis is initiated by a combination of vessel injury, inflammation, hypercoagulability, and stasis. A first occurrence of VTE dramatically increases the risk of a subsequent one.


II. Venous Thromboembolism and Risk of Subsequent Recurrent Venous Thromboembolism

In a prospective cohort study, 355 patients with a first episode of DVT were followed for 8 years. Recurrent VTE occurred at 17.5% after 2 years and 24.6% after 5 years. PTS was reported in 22.8% after 2 years and 28% after 5 years.3 The same investigators in a larger prospective cohort study of 1626 patients with VTE reported a recurrence of 11% at 1 year, 19.6% at 3 years, and 29.1% at 5 years.4 Anticoagulation is effective at lowering recurrences but carries an increased risk of bleeding.5




III. Pharmacological Treatment



  • A. Anticoagulation Parenteral anticoagulation with a heparinoid followed by oral anticoagulation has been the mainstay of treatment for acute DVT. Anticoagulants help prevent thrombus propagation and embolization. Both vitamin K antagonists (VKAs) and non-vitamin K oral anticoagulants which are the novel oral anticoagulants (NOACs) have been used. An advantage of NOACs is the steady anticoagulation they provide (without the need for routine monitoring). They may also result in less intracranial bleeding than VKAs, although possibly more gastrointestinal bleeds as shown in some studies.6,7


  • B. American College of Chest Physician Guidelines



    • 1. The required duration for anticoagulant therapy in DVT has been a contentious issue with significant variability in practice pattern. Some patients are maintained on
      anticoagulation for years. The 2016 American College of Chest Physician Guidelines8 made the following recommendations for anticoagulation in DVT:



      • In patients with proximal DVT or PE, 3 months of anticoagulant therapy are recommended (Grade 1B). NOACs are preferred over VKAs.


      • In proximal DVT or PE provoked by surgery or a transient risk factor, 3 months of anticoagulant therapy are recommended (Grade 1B).


      • In proximal DVT of the leg or PE and cancer (“cancer-associated thrombosis”), low-molecular-weight heparin is recommended over oral anticoagulants. Anticoagulation should be extended beyond 3 months in those without a high bleed risk (Grade 1B).


      • In unprovoked first proximal DVT or PE with low-moderate bleed risk, extended anticoagulant therapy beyond 3 months is suggested (Grade 2B).

      In a second unprovoked proximal DVT or PE, extended anticoagulant therapy beyond 3 months is recommended with low bleed risk (Grade 1B) and moderate bleed risk (Grade 2B).


    • 2. While anticoagulants prevent thrombus propagation, thrombolytics directly eliminate thrombus. One of the troublesome sequelae of DVT is PTS. DVT can acutely lead to elevated limb venous pressures and diminished venous outflow leading to inflammation, fibrosis, and valvular damage. This is particularly a concern if the DVT involves the venous outflow at the common femoral vein or even more proximal level (iliac vein or IVC). Thrombolysis can relieve the obstruction more rapidly than mere anticoagulation. A Cochrane review of randomized trials comparing thrombolysis against anticoagulation identified 17 trials (n = 1103). Thrombolysis reduced rates of PTS by a third and leg ulceration approximately a half, but there were more instances of bleeding (RR 2.23; 95% CI 1.41-3.52, P = .0006). There was no difference in mortality.9


  • C. Catheter-Directed Therapy



    • 1. Systemic thrombolysis for DVT carries a significant bleed risk and has largely been superseded by catheter-directed therapy (CDT). With CDT, lower doses of thrombolytics are required and are often administered over a longer period. In addition to the availability of simple perfusion catheters, some available devices have a mechanical component that can help disrupt the thrombus.10,11


    • 2. Two of the devices currently used for mechanical thrombectomy in the United States are AngioJet (Boston Scientific, Marlborough, MA) and EKOS (BTG, West Conshohocken, PA). AngioJet is a pharmacomechanical thrombectomy catheter.12 Multiple high-velocity saline jets through orifices at the tip create a low-pressure zone using the Venturi-Bernoulli effect, resulting in dissociation of thrombus which is concurrently removed by suction. The power pulse function allows for local infusion of a thrombolytic agent (eg, 12-25 mg tissue plasminogen activator), while the suction function is stopped to prevent removal of the lytic.12,13 With the AngioJet catheter tip positioned within the thrombus, power pulse lytic infusion can be run for approximately 90 minutes before the thrombectomy mode is reactivated and the tip manipulated up and down to retrieve thrombus.14 The larger caliber AngioJet ZelanteDVT catheter (8F) is capable of removing thrombus more quickly.



    • 3. Trials



      • The EKOS device is an ultrasound-assisted lysis perfusion catheter. In vitro studies have demonstrated improved dispersion of tissue plasminogen activator into thrombus, when assisted by ultrasound.15 The EKOS catheter is advanced into the venous thrombus and activated, infusing thrombolytics. The device is typically run for up to 24 hours before removal.16


      • There are two randomized controlled trials comparing CDT with anticoagulation in DVT that merit discussion. In the TORPEDO trial 91 patients with proximal DVT received CDT in addition to anticoagulation, versus 92 patients who received anticoagulation only. The CDT devices included Trellis (Covidien, Plymouth, MN) and AngioJet (Boston Scientific, Marlborough, MA). Approximately 3rd of CDT patients also underwent venous balloon angioplasty and 3rd underwent venous stenting. The CDT group demonstrated significantly lower rates of recurrent VTE and PTS at 6 and 30 months.11 CaVenT was a Norwegian multicenter trial that enrolled patients with acute iliofemoral DVT. In the CDT group (n = 101), a catheter perfused intravenous alteplase, and the control group (n = 108) received anticoagulation only. With CDT, iliofemoral vein patency was significantly higher at 65.9% versus 47.4% in the control group (P = .012). CDT led to an absolute risk reduction of 14.4% (NNT = 7) in PTS by Villalta score, at 24 months.17 Five-year follow-up data of CaVenT continue to favor CDT over anticoagulation only.18


      • Sponsored by the National Institute of Health, the ATTRACT trial has evaluated pharmacomechanical CDT in proximal DVT, enrolling 692 patients. The primary end point is rate of PTS on follow-up. Enrollment has been completed, and the study is currently in the follow-up phase.



        • While there is some consensus that CDT should especially be considered for treating acute DVTs causing venous outflow obstruction (those involving the common femoral, iliac veins or IVC), more robust data are needed. The ATTRACT trial may help shed more light on this issue.


      • Saha et al19 have suggested the five-component “BLAST” mnemonic when assessing candidates for CDT. BLAST stands for Bleeding risk, Life expectancy, Anatomy of DVT, Severity of DVT, and Timing. Lysis is less desirable in thrombi that are older than 14 days, although some trials have included patients within 21 days.



        • We believe that iliac stenting for venous outflow obstruction should be performed in addition to CDT for DVT, as it may enhance subsequent venous patency rates.20


IV. Superficial Venous Thrombosis of the Legs



  • A. Presentation Frequently, “superficial venous thrombosis” is also referred to as “superficial thrombophlebitis,” signifying inflammation of superficial veins with thrombosis. It appears to be more common in older age, particularly in women.21 Patients typically present with tender, erythematous legs along the region of affected veins. It can sometimes be mistaken for cellulitis, although infection is frequently not present. The affected veins may feel firm to palpation. Over time, pigmentation can develop.



  • B. Etiologic Factors Associated or etiologic factors include varicose veins, immobility, hypercoagulable states, surgery, intravenous access, pregnancy, malignancy, and estrogen therapy.22 Karathanos23 followed 97 patients with superficial thrombosis and varicose veins for a mean period of 55 months. Thirteen had a recurrence. There were higher rates of prothrombin gene (G20210A) mutation and dyslipidemia in those with recurrence.


  • C. Clinical Diagnosis Although superficial thrombosis is a clinical diagnosis, it may coincide with DVT.24 It is therefore reasonable to consider venous duplex imaging to gauge its extent and to rule out deep vein involvement.


  • D. Treatment Superficial venous thrombosis has been treated in a number of ways including topical or oral nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, anticoagulants, and compression.25 There is some evidence to support the role of NSAIDs as well as some anticoagulants in reducing recurrence, thrombus extension, or DVT. A 2013 Cochrane review noted a paucity of randomized controlled data for treatment modalities in superficial venous thrombosis. Prophylactic dose fondaparinux for 6 weeks appeared to show benefit by reducing thrombus extension.26 It is our practice to ablate venous insufficiency and varicose veins in patients with a history of superficial venous thrombosis, particularly if more than one episode has occurred.


V. Isolated Below-the-Knee Deep Vein Thrombosis



  • A. History and Management



    • 1. The infrapopliteal deep veins include the paired peroneal, anterior tibial, and posterior tibial veins, as well the gastrocnemius and soleal veins. Significant anatomic variability can exist. Isolated below-the-knee DVT, also referred to as isolated distal deep vein thrombosis (IDDVT), denotes thrombosis in any of the deep veins without involvement of the popliteal vein. Thrombotic involvement of the popliteal vein (or above) is referred to as proximal DVT.


    • 2. The natural history of IDDVT is not clear, and therefore, its management is controversial. Between 23% and 59% of individuals diagnosed with DVT also have IDDVT.27 Few studies have evaluated the natural history of IDDVT without anticoagulation. The CALTHRO study followed 59 patients with IDDVT. No anticoagulation was administered. After one week, proximal thrombus extension occurred in 3.1%.28


  • B. Risks of Recurrence

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Feb 27, 2020 | Posted by in CARDIOLOGY | Comments Off on Deep Vein Thrombosis

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