Acute Venous Thrombosis: Thrombus Removal With Adjunctive Catheter-Directed Thrombolysis

Activase, the study drug, is a fibrinolytic drug that is indicated for use in acute myocardial infarction, acute ischemic stroke, and acute massive pulmonary embolism in adults. Previous studies have established the ability of rt-PA to lyse venous thrombus in patients with deep vein thrombosis (DVT), and suggest that successful rt-PA mediated thrombolysis can prevent the post-thrombotic syndrome (PTS), a morbid, late complication of DVT that occurs in nearly 50% of patients.

rt-PA is delivered directly into venous thrombus using a catheter/device which is embedded within the thrombus by a physician under imaging guidance. This method of rt-PA delivery, pharmacomechanical catheter-directed intrathrombus thrombolysis (PCDT),is thought to be safer, more effective, and more efficient than previous methods. The question of whether PCDT using rt-PA improves long-term DVT patient outcomes with acceptable risk and cost has not yet been addressed.

The rationale for performing the ATTRACT Trial is based upon:

• the major burden of PTS on DVT patients and the U.S. healthcare system
• the association between rapid clot lysis and prevention of PTS
• the proven ability of rt-PA to dissolve venous thrombus in proximal DVT
• recent advances in CDT methods which may lower bleeding risk
• the major clinical controversy on whether CDT should be routinely used for first-line DVT therapy

Inclusion criteria

• Symptomatic proximal DVT involving the iliac, common femoral, and/or femoral vein.

Exclusion criteria

• Age less than 16 years or greater than 75 years.
• Symptom duration > 14 days for the DVT episode in the index leg (i.e., non-acute DVT).
• In the index leg: established PTS, or previous symptomatic DVT within the last 2 years.
• In the contralateral (non-index) leg: symptomatic acute DVT a) involving the iliac and/or common femoral vein; or b) for which thrombolysis is planned as part of the initial therapy.
• Limb-threatening circulatory compromise.
• Pulmonary embolism with hemodynamic compromise (i.e., hypotension).
• Inability to tolerate PCDT procedure due to severe dyspnea or acute systemic illness.
• Allergy, hypersensitivity, or thrombocytopenia from heparin, rt-PA, or iodinated contrast, except for mild-moderate contrast allergies for which steroid pre-medication can be used.
• Hemoglobin < 9.0 mg/dl, INR > 1.6 before warfarin was started, or platelets < 100,000/ml.
• Moderate renal impairment in diabetic patients (estimated glomerular filtration rate [GFR] < 60 ml/min) or severe renal impairment in non-diabetic patients (estimated GFR < 30 ml/min).
• Active bleeding, recent (< 3 mo) GI bleeding, severe liver dysfunction, bleeding diathesis.
• Recent (< 3 mo) internal eye surgery or hemorrhagic retinopathy; recent (< 10 days) major surgery, cataract surgery, trauma, cardiopulmonary resuscitation, obstetrical delivery, or other invasive procedure.
• History of stroke or intracranial/intraspinal bleed, tumor, vascular malformation, aneurysm.
• Active cancer (metastatic, progressive, or treated within the last 6 months). Exception: patients with non-melanoma primary skin cancers are eligible to participate in the study.
• Severe hypertension on repeated readings (systolic > 180 mmHg or diastolic > 105 mmHg).
• Pregnant (positive pregnancy test, women of childbearing potential must be tested).
• Recently (< 1 mo) had thrombolysis or is participating in another investigational drug study.
• Use of a thienopyridine antiplatelet drug (except clopidogrel) in the last 5 days.
• Life expectancy < 2 years or chronic non-ambulatory status.
• Inability to provide informed consent or to comply with study assessments (e.g. due to cognitive impairment or geographic distance).