A deep vein thrombosis (DVT) is a solid blood clot deep inside the veins of the muscles, usually occurring in the leg or arm. It causes intense swelling, heaviness, and pain.
While the standard treatment is prescribing blood-thinning medication, sometimes blood thinners aren't enough, or the clot is too large and dangerous. In these cases, interventional radiologists use image guidance to access the vein and physically clear the blockage without open surgery.
About this scan
Will it be painful?
The area where the catheter is inserted is completely numbed with local anesthetic, and you will be sedated, so you should not feel sharp pain during the treatment. You may feel a sensation of pressure when the catheter is inserted or when a balloon is inflated inside the vein.
What are the risks?
Because this procedure involves blood vessels and sometimes potent clot-busting drugs, the primary risk is bleeding.
- Bleeding at the puncture site or, rarely, internal bleeding.
- Bruising and soreness at the catheter insertion site.
- In rare cases, a piece of the clot can break off during the procedure and travel to the lungs.
- Contrast dye used during the X-rays can cause an allergic reaction or affect kidney function.
Before your appointment
Common Indications for DVT Treatment
Your doctor may recommend this interventional procedure if you have:
- Severe, sudden swelling and throbbing pain in an arm or leg that does not improve with medication.
- A very large clot that completely blocks blood flow, threatening the limb.
- A high risk of permanent vein damage, known as post-thrombotic syndrome (PTS), which causes chronic pain, swelling, and skin ulcers.
- A clot that poses a high risk of breaking loose and traveling to your lungs (a pulmonary embolism).
Do I need to prepare?
- Fasting: You must not eat or drink for 6 to 8 hours before the procedure because you will receive sedation.
- Medications: Discuss all your medications with the doctor. You may need to adjust your blood thinners immediately prior to the procedure.
- Hospital Stay: Be prepared for an overnight stay in the hospital, especially if clot-busting medications (thrombolysis) are used, as you will need close monitoring.
During the scan
What happens during the procedure?
- You will be given intravenous sedation to keep you relaxed and sleepy, and the skin over the entry site (usually behind the knee, in the groin, or the neck) will be numbed.
- Using live X-ray and ultrasound pictures, the doctor places a small, flexible tube (catheter) into the vein.
- Thrombolysis: The doctor may inject "clot-busting" medication directly into the clot to dissolve it over several hours or a day.
- Thrombectomy: The doctor may use a tiny mechanical tool or a gentle vacuum on the end of the catheter to physically break up and suck the clot out of your body.
- Angioplasty and Stenting: Once the clot is cleared, the vein may still be narrow. A tiny balloon is often inflated to stretch the vein wide open, and a metal mesh tube (a stent) is permanently placed to keep the vessel propped open and ensure smooth blood flow.
How long does it take?
Procedure time and admission vary. If infusion thrombolysis is used, repeat imaging assesses residual clot and flow, but complete clot removal is not guaranteed and treatment may be stopped early for bleeding or limited benefit.
Safety and special situations
What are the important limitations and safety checks?
Interventional radiology is minimally invasive, but it is not risk-free and is not automatically safer or more effective than surgery, endoscopy, medicines, or observation for every patient. Technical success does not always produce symptom relief or cure disease, and repeat treatment or another approach may be needed. Suitability depends on anatomy, disease severity, comorbidities, imaging, local expertise, and the alternatives available.
Risks vary by procedure and may include pain, bleeding, infection, contrast reaction, kidney injury, radiation exposure, vessel or organ injury, clotting, device movement or blockage, sedation complications, treatment failure, and an unplanned operation or admission. Tissue sampling can be nondiagnostic and requires pathology; tumor treatments require oncology follow-up. The consent discussion should cover the patient-specific benefits, material risks, alternatives, and what happens if the procedure cannot be completed.
Preparation is individualized. Give the team a complete list of anticoagulants, antiplatelet drugs, diabetes medicines, supplements, allergies, kidney problems, pregnancy possibility, and prior contrast reactions. Do not stop a blood thinner or diabetes medicine on your own: the procedural team and prescribing clinician must balance bleeding against thrombosis or metabolic risk and provide exact written instructions. Fasting, laboratory tests, antibiotics, sedation, escort, admission, and aftercare differ by procedure.
Sources and summary
Sources and further reading
Conclusion
Catheter-directed treatment may relieve severe symptoms and restore flow in carefully selected patients with extensive, recent DVT, but it increases bleeding risk and does not reliably prevent post-thrombotic syndrome for everyone. Anticoagulation remains foundational unless contraindicated.