Microplasmin Administered Via the Trellis-8 Infusion System for Treatment of Acute Iliofemoral DVT

Inclusion Criteria include: * Patients with radiographically-confirmed acute proximal DVT Exclusion Criteria include: * Isolated calf or popliteal vein DVT, based on duplex ultrasound * Thrombus involving the inferior vena cava (IVC) * Proximal (e.g. cranial) aspect of thrombus cannot be adequately assessed to level of the iliac veins or inferior vena cava, based on duplex ultrasound. * Cannot traverse the target vessel segment with guidewire * Symptomatic pulmonary embolism is present at time of presentation * Documented history of prior DVT in target extremity * History of anticoagulants administered for \> 30 days for undocumented/ unclear reason (e.g. for reasons other than presence of mechanical cardiac valve, atrial fibrillation, etc.) * Documented history of thrombophilic disorder, with diagnosis established via previous objective testing (e.g. familial screening for thrombophilia). * Cannot receive standard secondary prevention pharmacotherapy \[i.e. heparin or LMWH and vitamin K antagonists (VKA)\] due to contraindications to anticoagulation \[e.g. known bleeding diathesis, thrombocytopenia (platelets \< 100,000 mm3), heparin induced thrombocytopenia (HIT), known allergy to heparin or warfarin\] * Absolute contraindication to thrombolytic therapy * Previous central nervous system haemorrhage * Life expectancy less than 1 year, due to other comorbid condition. * Previous intervention in target limb to address venous thrombus. * Target limb has chronic venous insufficiency of C4 or greater severity * Acute or chronic symptomatic musculoskeletal condition in target limb (e.g. trauma, fracture, severe arthritis). * Documented patent foramen ovale or other right-to-left cardiac shunt. * Absolute contraindication to contrast media or renal insufficiency (baseline creatinine \>2.0 mg/dL).