DVT Treatment
Blood-Thinning Drugs 

Blood clots (DVT) are initially treated with blood-thinning drugs (anticoagulants), most often unfractionated heparin (given through an intravenous line or IV), a low molecular weight heparin (injected), or fondaparinux (injected), given for at least 5 days (1). Warfarin (a blood thinner that is given as a pill) is used for long-term outpatient DVT treatment in most patients. Cancer patients and some patients who fail warfarin may be best treated with long-term administration of a low molecular weight heparin alone. Overall, blood-thinning drugs are generally given for at least 3-6 months in patients with DVT. Blood-thinning drugs are very effective in preventing Pulmonary Embolism (PE). 

Graduated Elastic Compression Stockings 

Patients with DVT should wear prescription elastic compression stockings on a daily basis, since several studies strongly suggest that their use can significantly reduce a DVT patient’s likelihood of developing the Post-Thrombotic Syndrome (2,3). 

Inferior Vena Cava Filters 

Certain patients who cannot receive blood-thinning drugs (because they might cause bleeding or because they failed) may undergo placement of a small metal “filter” device within the inferior vena cava (IVC) (the large vein in the abdomen that drains blood from the legs and lower body) to catch any blood clots which are moving towards the lungs. 

Pharmacomechanical Catheter-Directed Thrombolysis (PCDT) 

In addition to blood-thinning drugs, patients with DVT may also be treated using Pharmacomechanical Catheter-Directed Thrombolysis (PCDT), which refers to the delivery of a clot-busting drug directly into the blood clot through a specially designed catheter (plastic tube) or catheter-mounted device that may also break up the clot and/or remove the clot fragments. The immediate goals of PCDT are to rapidly eliminate the clot, preserve the leg’s circulation, and quickly reduce leg pain and swelling. 

Preliminary studies suggest that patients who have their blood clots treated with PCDT and related techniques may be less likely to develop Post-Thrombotic Syndrome (PTS) (4-7). However, because these procedures may involve more bleeding risks and hospital resource use, doctors do not agree on whether PCDT should be routinely used in DVT patients (8).  The ATTRACT Study is being performed to answer this important question. 

Several PCDT methods are available but two have sparked particular interest because they can often enable clot removal treatment to be completed in a single 2-hour procedure. In the ATTRACT Study, many patients will be treated with one of these two methods: 

“Powerpulse” refers to a method of using the AngioJet Rheolytic Thrombectomy System (MEDRAD Interventional - Possis, Minneapolis, MN) to treat DVT in a single procedure. With Powerpulse, the AngioJet catheter is first used to deliver and disperse a clot-busting drug directly into the blood clot by a powerful pulse-spray injection. The AngioJet is used to remove the softened thrombus fragments. 

“Isolated Thrombolysis” refers to use of the Trellis Peripheral Infusion System (Covidien - Bacchus, Santa Clara, CA) to treat DVT in a single procedure. This device delivers a clot-busting drug directly into the clot, and then spreads the drug within the clot using an oscillating wire. 

The AngioJet and Trellis devices are FDA-approved for the delivery of clot-busting drugs into the peripheral blood vessels. The AngioJet is also FDA-approved for the removal of blood clots from the pelvic and leg veins. The clot-busting drug (TPA) used for PCDT is FDA approved for the treatment of heart attacks and strokes, but is used “off-label” by physicians for the treatment of DVT.

References

1. Kearon C, Kahn SR, Agnelli G, Goldhaber S, Raskob GE, Comerota AJ.  Antithrombotic therapy for venous thromboembolic disease.  American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Ed).  Chest 2008; 133:454S-545S.

2. Prandoni P, Lensing AW, Prins MH, Frulla M, Marchiori A, Bernardi E, Tormene D, Mosena L, Pagnan A, Girolami. Below-knee elastic compression stockings to prevent the post-thrombotic syndrome. Ann Intern Med 2004; 141:249-256.

3. Brandjes DP, Buller HR, Heijboer, H, Huisman MV, de Rijk M, Jagt H, ten Cate JW. Randomized trial of effect of compression stockings in patients with symptomatic proximal-vein thrombosis. Lancet 1997; 349:759-762.

4. Grewal NK, Martinez JT, Andrews L, Comerota AJ.  Quantity of clot lysed after catheter-directed thrombolysis for iliofemoral deep venous thrombosis correlates with postthrombotic morbidity.  J Vasc Surg 2010; 51(5):1209-1214.

5. Comerota AJ, Throm RC, Mathias SD, Haughton S, Mewissen M.  Catheter-directed thrombolysis for iliofemoral deep venous thrombosis improves health-related quality of life. J Vasc Surg 2000; 32:130-137.

6. AbuRahma AF, Perkins SE, Wulua JT, Ng HK. Iliofemoral deep vein thrombosis: Conventional therapy versus lysis and percutaneous transluminal angioplasty and stenting. Ann Surg 2001; 233:752-760. 

7. Enden T, Haig Y, Klow N, et al.  Long-term outcome after additional catheter-directed thrombolysis versus standard treatment for acute iliofemoral deep vein thrombosis (the CaVenT study):  a randomised controlled trial.  Lancet Online December 13, 2011; DOI:10.1016/S0140-6736(11)61753-4.

8. Vedantham S, Rundback JR, Comerota AJ, Hunter DW, Meissner M, Hofmann LV, Horne M III, Gloviczki P, Andrews RT, Fan C, Hume K, Goldhaber SK, Tapson VF, Razavi MK, Min RJ.  Development of a research agenda for endovascular treatment of venous thromboembolism: proceedings from a multidisciplinary consensus panel.  J Vasc Interv Radiol 2005, 16:1567-1573.