Catheter-directed thrombolysis (CDT) is an endovascular approach to the treatment of acute iliofemoral deep vein thrombosis. It involves the administration of a lytic agent directly into a thrombus.
Indications
- precise diagnosis of iliofemoral deep vein thrombosis
- first episode of acute iliofemoral DVT
- symptomatic patients
- onset of symptoms <14 days
- low bleed risk
- ambulatory patients with good functional capacity and acceptable life expectancy
- phlegmasia cerulea dolens
Contraindications
- cerebral disease
- previous ipsilateral DVT
- uncontrolled hypertension
- bleeding disorders
- isolated femoral-popliteal deep vein thrombosis should be managed with conventional anticoagulation therapy
Procedure
Ultrasound-guided micropuncture technique of a deep vein of the lower limb is performed, usually the popliteal vein. There are a wide range of catheters and they usually have multiple holes employing a pulse-spray technique of the thrombolytic agent.
Recombinant tissue plasminogen activator (rt-PA) is the thrombolytic agent of choice, it has a half-life of 3-5 minutes and 90% first-pass elimination in the liver. This results in targeted activation of plasminogen on the clot with the intent to dissolve fibrin. Doses range between 1-2 mg/hr up to a total dose of 30 mg. Heparin is used to maintain venous patency.
Successful catheter-directed thrombolysis results in a patent vein on venogram, spontaneous outflow of injected contrast, and disappearance of venous collaterals.
Complications
So far studies have shown no mortality or pulmonary embolism associated with catheter-directed thrombolysis. Major bleeding rates are 1-2% while minor bleeding was found to be <25%.