Overview of DVT

Deep Vein Thrombosis (DVT) is a blood disorder resulting from the formation of a blood clot (thrombus) inside a deep vein of the leg, commonly located in the calf or thigh. DVT occurs when the blood clot either partially or completely blocks the flow of blood in the vein. Patient symptoms include pain, swelling, and discoloration.

Approximately 600,000 new DVT cases are diagnosed each year in the United States with as many as 20 million patients having had a prior DVT. The majority of patients diagnosed with DVT are treated with medication therapy alone. While this therapy reduces the risk of fatal Pulmonary Embolism and further blood clot from forming, the underlying blood clot may remain and result in permanent vein damage and the development of Post Thrombotic Syndrome.

Use links at left or below to learn more about issues related to DVT and its treatment.

DVT/PE – A Significant National Health Problem

  • 2,000,000 cases of DVT/PE are estimated to occur annually in the US.
  • 600,000 patients are diagnosed with DVT/PE annually.
  • 200,000 people yearly die of pulmonary embolism (PE).
    • DVT/PE is the third leading cardiovascular killer behind heart attack and stroke.
    • DVT/PE causes more people to die annually than breast cancer and AIDS combined

DVT – Looking Beyond Pulmonary Embolism

While pulmonary embolism is the most emergent concern, comprehensive care for a patient with DVT should consider all three potential consequences of the thrombus burden:

1. Pulmonary Embolism (PE)

  • Prophylaxis with anticoagulants is very effective in preventing DVT/PE in patients at high risk.
  • Anticoagulation of patients with confirmed DVT stops the progression of thrombus, but…
  • Anticoagulants do not dissolve existing clot.
2. Quality of Life (QOL)
  • DVT is much more than just a swollen leg.  DVT Quality of Life patient scores are similar to patients with angina and chronic lung disease.
  • In about one-third of DVT patients receiving anticoagulation, QOL deteriorates when measured four months after anticoagulation is initiated.
    • Average QOL of all DVT patients on anticoagulation is poorer than population norms at four months.
3. Post Thrombotic Syndrome (PTS)
  • PTS is a common long-term complication of DVT that can affect as many as 60-70% of people who have had a DVT, and can develop within two months of developing DVT.
  • The socioeconomic and medical costs of managing patients with PTS and chronic venous disease are high.
    • The direct cost of treatment of chronic venous disease is thought to exceed $300 million yearly in the US, and it is estimated that 2 million workdays are lost annually as a result of leg ulcers.
    • In a Swedish study, the average overall direct medical cost of treatment of late complications of DVT was $4,659; venous ulcer development was the most costly complication.
Endovascular Treatment Rationale for Acute Proximal DVT
  • Quality of Life:  Stand-alone anticoagulant therapy does not provide immediate symptom relief.  Recent data demonstrates the significant impact of DVT on QOL in patients with proximal (above-the-knee) DVT.

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  • Longer-Term Symptoms and PTS:  Early removal of venous thrombus has demonstrated potential to eliminate venous obstruction, preserve valvular function, maintain late venous patency, and prevent PTS.

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  • Iliofemoral DVT:  Occluded iliac veins secondary to iliac vein compression syndrome (May-Thurner, where the right iliac artery compresses the left iliac vein) may require endovascular reconstruction.
    • O’Sullivan et al. demonstrated that comprehensive endovascular reconstruction, including thrombus removal, ballooning and stenting, appears to be safe and effective.

Endovascular Treatment Modalities

  • Catheter-directed thrombolysis (CDT) has demonstrated the potential to dissolve thrombus, prevent PTS, and offers distinct advantages compared with surgical venous thrombectomy, systemic thrombolysis, and anticoagulation alone.

    The main disadvantage of CDT is thought to be an increased risk of bleeding.

  • Isolated Thrombolysis™ using the Trellis® system may offer much more rapid recanalization with less thrombolytic drug and potentially fewer systemic complications through:
    • Isolation of the treatment area with dual balloons on the catheter.
    • More rapid pharmacokinetics due to dispersion of the lytic throughout the thrombus.