Rationale for Intervention in DVT Treatment

Locally delivered thrombolysis, combined with anticoagulation, has been shown to result in positive patient outcomes with good safety and is supported as a proximal DVT treatment by major medical societies.

Patients treated interventionally in addition to anticoagulation show significantly better venous flow and reduced symptoms compared to anticoagulation alone.

The new 2008 American College of Chest Physicians (ACCP) Evidence-Based Clinical Practice Guidelines on Venous Thromboembolic (VTE) disease as published in the July, 2008 Supplement to the CHEST Journal now suggest the use of Pharmacomechanical Thrombolysis in certain cases. Download the complete 2008 VTE Guidelines here
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Conventional therapy for DVT (anticoagulation) has been associated with long-term disability following venous insufficiency. The literature notes the success of catheter-directed thrombolysis (CDT) in reducing thrombus burden with acceptable complication rates. This study evaluates use of CDT plus angioplasty and stenting in combination with anticoagulation therapy versus anticoagulation alone.

Fifty-one patients with ultrasound-confirmed iliofemoral DVT were given the choice of treatment with conventional therapy (anticoagulation alone) or intervention plus anticoagulation. Patients with chronic clot or contraindications for thrombolytic therapy were not offered the intervention option. All patients were on an anticoagulation regime for at least six months post-diagnosis. Urokinase and tPA were the lytics used in the intervention arm of the study. Standard techniques were used for CDT, with visualization of the clot performed at 12 and 24 hour intervals and thrombolysis continued until maximum lysis was achieved. PTA/stenting was performed if an underlying stenosis was observed.

Thirty-three patients entered the conventional therapy arm while 18 patients received intervention plus anticoagulation. Both groups were similar in their demographics and clinical characteristics. Ten of 18 patients in the intervention group had PTA and stent placement. Data showed significantly better venous patency for the intervention group at 30 days (83% versus 3% for anticoagulation alone) and 6 months (83% versus 24%). Long term symptom resolution was also significantly better for the intervention group (78% versus 30%). Life table analysis showed a similar patency trend for 1, 3 and 5 years.

The data shows intervention plus anticoagulation was more effective than anticoagulation alone in treatment of iliofemoral DVT. Data examined included venous patency rates and symptom resolution.
Reference: AbuRahma, AF, Perkins, SE, Wulu, JT and Ng, HK. Iliofemoral Deep Vein Thrombosis: Conventional Therapy Versus Lysis and Percutaneous Transluminal Angioplasty and Stenting. Ann Surg 2001; 233:752-760.   

A literature review was undertaken for randomized controlled clinical studies of the use of thrombolysis versus anticoagulation alone in treatment of acute DVT. Twelve studies totaling 668 patients were ultimately included in the data analysis. Not all studies contributed to the data analysis for any one variable. Any form of lytic therapy was considered. Results were denoted as early (< one month) or late (> six months). PTS was assessed between one and six years.

  • Early mortality showed no difference between treatment groups.
  • Early major bleeding episodes were significantly more likely to occur in the thrombolysis group.
  • Early venous patency was significantly better in the thrombolysis group.
  • Early and late measures of complete lysis of thrombus were significantly more likely in the thrombolysis group.
  • PTS occurrence was significantly less in the thrombolysis group.

Reference: Watson, LI and MP Armon. Thrombolysis for Acute Deep Vein Thrombosis (Review). The Cochrane Database of Systematic Reviews 2004;
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Sixty-three centers reported the results of catheter-directed thrombolysis (CDT) in 473 patients. All patients had confirmed DVT and were treated with the lytic urokinase. The catheterization technique was left to the institution’s clinicians. The popliteal vein was the most common access site. Iliofemoral DVT was diagnosed in 71% of the patients, with 25% showing femoral-popliteal DVT. Stents were placed to treat stenoses after CDT in 33% of the patients.

Catheter-directed lytic therapy duration was 48 hours on average. Complete lysis was achieved in 31% of cases, 50-99% lysis was achieved in 52% of cases and less than 50% lysis was achieved in 17%. The chronicity of the thrombus correlated significantly with lytic therapy success, with acute (<10 days) thrombus more successfully lysed than chronic thrombus. Major bleeding complications occurred in 11% of patients. Minor bleeding complications occurred in 16% of patients. Primary patency at one year follow-up was 60%. The degree of thrombus clearance was predictive of the one year patency rate.
Reference: Mewissen, MW, Seabrook, GR, et al. Catheter-directed Thrombolysis for Lower Extremity Deep Venous Thrombosis: Report of a National Multicenter Registry. Radiology 1999; 211:39-49.

“The Society of Interventional Radiology (SIR) considers the use of catheter-directed intrathrombus thrombolysis (CDT) as an adjunct to anticoagulant therapy to represent an acceptable initial treatment strategy for carefully selected patients with acute iliofemoral deep vein thrombosis (DVT)”. 

Treatment goals for acute DVT must include: prevention of pulmonary embolism and DVT propagation, provision of early symptom relief and prevention of post-thrombotic syndrome (PTS). The SIR believes CDT as an adjunct to anticoagulant therapy is an acceptable initial treatment for acute iliofemoral DVT.
Reference: Vedantham, S, Millward, SF, et al. Society of Interventional Radiology Position Statement: Treatment of Acute Iliofemoral Deep Venous Thrombosis with Use of Adjunctive Catheter-directed Intrathrombus Thrombolysis. J Vasc Interv Radiol 2006; 17:613-616.

Key Learnings:

  • Four major goals for therapy of DVT:
    • Prevent PE
    • Diminish the severity and duration of lower extremity symptoms
    • Minimize the risk of recurrent venous thrombosis
    • Prevent PTS
  • DVT has traditionally been managed with anticoagulation to decrease PE risk
  • Anticoagulation does not reduce outflow obstruction, especially in the iliofemoral segment, even with development of venous collaterals
  • Outflow obstruction and valvular insufficiency result in the greatest risk for development of PTS
  • Thrombolysis with anticoagulation, compared to anticoagulant therapy alone, shows significantly better lysis of thrombus, venous patency and symptom resolution, with less occurrence of PTS, in the treatment of DVT
  • Systemic thrombolysis has resulted in significant major bleeding complications
  • CDT as an adjunct to anticoagulant therapy has been shown to result in 83% complete or partial lysis of thrombus, with primary patency after one year of 60%
  • Acute thrombus is more successfully lysed with CDT than chronic thrombus
  • There is an 11% rate of major bleeding complications with CDT
  • The Society of Interventional Radiologists, based on clinical literature, supports CDT as an adjunct to anticoagulation in treating acute iliofemoral DVT