Why some DVT needs more than blood thinners
Anticoagulation — blood thinners such as apixaban, rivaroxaban, warfarin, or low molecular weight heparin — does two important things: it prevents new clot from forming and stops existing clot from growing. What it does not do is actively dissolve the clot already there. The body has to do that on its own, and with larger clots it often can’t finish the job.1
When clot remains in the deep veins, the vein and its valves can be permanently damaged. The result is post-thrombotic syndrome (PTS) — chronic leg swelling, heaviness, pain, skin discoloration, and in severe cases, non-healing venous ulcers. PTS develops in 25 to 50 percent of patients after iliofemoral DVT treated with anticoagulation alone.2 For acute iliofemoral DVT, limb-threatening clot, and complex venous disease, removing the clot directly can change the long-term outcome.
Two image-guided approaches
Modern DVT intervention typically uses one of two techniques — or a combination — chosen based on clot age, location, bleeding risk, and patient preference.
Catheter-directed thrombolysis (CDT)
A thin catheter is placed directly into the clot under image guidance. A clot-dissolving medication such as alteplase is delivered through the catheter over several hours, sometimes accelerated with ultrasound energy (EkoSonic / EKOS). Patients are observed in the hospital during the infusion, and follow-up imaging confirms clot resolution. CDT is well-suited to fresh, soft acute clot.
Mechanical suction thrombectomy
Large-bore catheter systems — including ClotTriever, FlowTriever (Inari), Penumbra Indigo, and AngioJet — physically aspirate or extract clot through a small access point. Many cases are completed in a single session with no thrombolytic medication, which is particularly valuable for patients with bleeding risk, recent surgery, or older clot less responsive to lytics. Pharmacomechanical thrombolysis combines both approaches.3
Complex venous disease — acute and chronic
Not every DVT is straightforward. Florida Interventional Specialists treats the full spectrum:
- Acute iliofemoral DVT with significant leg swelling, pain, or compromised venous outflow
- Phlegmasia cerulea dolens — limb-threatening DVT requiring urgent clot removal
- May-Thurner syndrome — anatomic compression of the left iliac vein, often missed on initial imaging. After clot removal, intravascular ultrasound (IVUS) confirms the underlying compression and a venous stent is placed to keep the vein open4
- Chronic iliofemoral occlusion — disabling leg swelling, venous claudication, skin changes, or non-healing venous ulcers from chronic post-thrombotic disease, sometimes years after the original DVT. Reconstruction with mechanical thrombectomy and stenting can restore meaningful function
- IVC thrombosis — clot extending into the inferior vena cava
- Upper extremity DVT, including Paget-Schroetter syndrome (effort thrombosis of the axillary-subclavian vein)
Who is a good candidate?
You may benefit from clot removal if you have acute iliofemoral DVT with significant symptoms, limb-threatening clot, suspected May-Thurner syndrome, or chronic iliofemoral occlusion causing disabling post-thrombotic syndrome. Candidacy is determined together with your hematology, vascular surgery, and primary care team based on clot age and location, bleeding risk, and your overall picture.
Who performs DVT thrombectomy
Image-guided DVT treatment is performed by interventional radiologists, vascular surgeons, and some interventional cardiologists. Long-term anticoagulation, hypercoagulability workup, and longitudinal management remain with hematology and your primary care team. Florida Interventional Specialists provides the procedural component of a coordinated complex-venous program in close partnership with referring teams across Tampa Bay.
References
- Stevens SM, Woller SC, Kreuziger LB, et al. Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report. Chest. 2021;160(6):e545–e608.
- Vedantham S, Goldhaber SZ, Julian JA, et al. Pharmacomechanical Catheter-Directed Thrombolysis for Deep-Vein Thrombosis (ATTRACT Trial). N Engl J Med. 2017;377(23):2240–2252.
- Dexter D, Kado H, Schor J, et al. Twelve-month outcomes from the multicenter ClotTriever Outcomes (CLOUT) Registry of mechanical thrombectomy for proximal lower-extremity deep vein thrombosis. J Vasc Surg Venous Lymphat Disord. 2024;12(2):101725.
- Mahnken AH, Thomson K, de Haan M, O’Sullivan GJ. CIRSE standards of practice guidelines on iliocaval stenting. Cardiovasc Intervent Radiol. 2014;37(4):889–897.
Frequently asked questions
Why would I need a procedure if I’m already on blood thinners?
Blood thinners stop new clots from forming and prevent existing clots from growing, but they don’t actively dissolve the clot already there — your body has to do that, and it often doesn’t finish the job in larger clots. For acute iliofemoral DVT, severe leg swelling, or limb-threatening clots, removing the clot directly can prevent long-term vein damage and reduce the risk of post-thrombotic syndrome.
What’s the difference between catheter-directed thrombolysis and mechanical thrombectomy?
CDT delivers a clot-dissolving medication directly into the clot over several hours, sometimes with ultrasound acceleration (EkoSonic). Mechanical thrombectomy uses a large-bore catheter system — ClotTriever, FlowTriever, Penumbra Indigo, or AngioJet — to physically aspirate or extract the clot in a single session, often without any clot-dissolving medication. The choice depends on clot age, location, bleeding risk, and patient factors.
What is May-Thurner syndrome and why does it matter?
May-Thurner syndrome is anatomic compression of the left common iliac vein by the right iliac artery, which can cause left-leg DVT — often in younger patients. It’s commonly missed on standard imaging. After clot removal, intravascular ultrasound confirms the compression and a venous stent is placed to keep the vein open and prevent recurrence.
Can chronic DVT be treated, or is it too late?
Yes. Complex chronic venous disease can often be treated even years after the original DVT. Patients with disabling leg swelling, venous claudication, skin changes, or non-healing venous ulcers from chronic iliofemoral occlusion may benefit from venous reconstruction with thrombectomy and stenting. Outcomes are best when patients are evaluated by a complex venous program rather than told nothing more can be done.
Will I still need anticoagulation afterward?
Yes. Anticoagulation continues after thrombectomy or thrombolysis to prevent recurrence and is managed by your hematology and primary care team. Duration depends on whether the DVT was provoked or unprovoked, your hypercoagulability evaluation, and other risk factors.
Who treats DVT?
Acute and chronic DVT is managed by a coordinated team — hematology and primary care for anticoagulation, vascular surgery and interventional radiology for clot removal and venous reconstruction, and sometimes interventional cardiology. Florida Interventional Specialists works alongside these teams.
