1
Indications & Contraindications
Primary Indications
- Acute iliofemoral DVT (<14 days, ideally <7 days) with significant functional impairment, limb-threatening phlegmasia cerulea dolens, or failure of anticoagulation
- Phlegmasia cerulea dolens — massive iliofemoral DVT with impending venous gangrene; emergent CDT/PMT indicated
- Acute DVT in anatomic May-Thurner syndrome (left iliac vein compression) — CDT to clear thrombus, then stenting
- Submassive or massive iliac vein thrombosis with good functional status and low bleeding risk
- DVT in younger patients (<50) with iliofemoral involvement — prevent post-thrombotic syndrome
DVT Classification for Intervention
- Femoral-popliteal only: anticoagulation preferred; intervention if massive, phlegmasia, or symptomatic failure
- Iliofemoral DVT (involving external iliac, common iliac): stronger indication for CDT/PMT
- IVC thrombosis: CDT via bilateral iliofemoral approach + inferior approach if suprarenal
Contraindications to Lysis (CDT/PMT with rtPA)
- Active internal bleeding or recent major surgery (<10 days) or GI bleed (<3 months)
- Intracranial pathology — recent CVA (<2 months), intracranial neoplasm, AVM, aneurysm
- Severe hypertension (>185/110 not controlled)
- Recent obstetric delivery (<10 days), recent organ biopsy (<10 days)
- Severe thrombocytopenia (platelets <50K)
- Allergy to thrombolytics
Note: Relative CI for catheter-directed lysis is less strict than for systemic lysis. Discuss each patient with attending.
📋 AHA 2024 DVT Guideline Highlights
- Iliofemoral CDT (Class IIa): pharmacomechanical CDT reasonable for acute iliofemoral DVT (<14 days) in patients with good functional status, low bleeding risk, and high clot burden (iliofemoral > femoral-popliteal only).
- Mechanical-only (Class IIb): Large-bore aspiration thrombectomy (ClotTriever/AngioJet) without thrombolytics is a reasonable alternative when lysis is contraindicated or undesired — insufficient RCT data but growing evidence.
- Femoral-popliteal DVT (Class III): CDT NOT routinely recommended for isolated femoral-popliteal DVT — anticoagulation alone preferred. Reserve for phlegmasia.
- Anticoagulation duration: minimum 3 months for provoked DVT; extended (indefinite) anticoagulation preferred for unprovoked DVT, recurrent VTE, or active malignancy.
- Compression stockings: 30–40 mmHg for 2 years — Class I for prevention of post-thrombotic syndrome.
- IVC filter: NOT routinely recommended as adjunct to CDT. Reserve for patients with absolute anticoagulation contraindication at very high PE risk.
2
Pre-Procedure
Duplex US + CT venography (bilateral LE/pelvic): define thrombus extent, age (acute vs chronic), underlying anatomy (May-Thurner), IVC involvement.
Screen for hypercoagulable state: Factor V Leiden, prothrombin mutation, antiphospholipid Ab, AT-III, Protein C/S — draw before anticoagulation if possible.
Hemodynamics: if phlegmasia — emergent resuscitation, Foley, ICU, emergent IR.
Labs: CBC, INR, fibrinogen (target >100 mg/dL to continue lysis), creatinine.
IVC filter (optional, controversial): consider retrievable IVC filter placement at start of procedure if large free-floating thrombus or bilateral iliofemoral DVT with high PE risk during lysis. Most guidelines do not mandate routine filter placement.
Bilateral femoral/popliteal US to plan access site.
Consent obtained: PE during procedure, ICH during lysis (~0.2–0.4%), access site bleeding, complete failure to lyse (chronic thrombus), post-thrombotic syndrome despite treatment.
3
Relevant Anatomy
Venous Anatomy
- Popliteal vein → femoral vein (formerly superficial femoral vein) → common femoral vein → external iliac vein → common iliac vein → IVC
- May-Thurner syndrome (iliac vein compression syndrome): right common iliac artery crosses and chronically compresses left common iliac vein against L5 vertebral body → left-sided DVT predominance (80% of bilateral DVTs involve left side). Treat residual stenosis with venous stent (Veniti Vici or Zilver Vena) after thrombus clearance.
Access Anatomy
- Popliteal vein access: ipsilateral prone or lateral position; mid-popliteal fossa; US-guided. Preferred for CDT to allow catheter spanning from popliteal to IVC.
- Femoral vein access: femoral triangle; medial to femoral artery; US-guided. Alternative when popliteal access not feasible or for isolated iliac thrombus.
- Contralateral femoral approach: used for suprarenal IVC thrombus or when ipsilateral access inadequate.
4
Technique
Supplies
Ultrasound machine
6 Fr vascular sheath
5 Fr multipurpose catheter
Hydrophilic guidewire (Glidewire 0.035")
Multi-sidehole infusion catheter (UniFuse / Cragg-McNamara)
rtPA (alteplase) 1 mg/h infusion
Unfractionated heparin (300–500 units/h)
PMT device (AngioJet / Penumbra Indigo / INARI ClotTriever)
Venoplasty balloon (8–14 mm)
Venous-specific nitinol stent (Veniti Vici 14–18 mm / Zilver Vena)
Fibrinogen monitoring / lab samples
1
US-guided ipsilateral popliteal or femoral vein access
Popliteal preferred for iliofemoral DVT (allows infusion catheter to span full thrombus length). Position patient prone or lateral for popliteal access. Place 6 Fr sheath.
2
Venogram
Inject contrast through sheath to delineate thrombus extent, identify upper limit of clot, assess IVC involvement.
3
Traverse thrombus with wire
Advance Glidewire through thrombus into patent iliac vein or IVC. Confirm with gentle injection.
4
Place infusion catheter
Advance multi-sidehole infusion catheter to span full thrombus (from most distal margin to proximal end). Catheter tip in patent IVC or external iliac above thrombus.
5
PMT (pharmacomechanical, same session — if selected)
AngioJet or Penumbra Indigo — spray rtPA into thrombus, wait 20 min, then aspirate macerated clot. Multiple passes. Completion venogram. Proceed to anticoagulation + stenting if residual stenosis.
6
CDT (overnight infusion — if selected)
Infuse rtPA at 1 mg/h through infusion catheter. Systemic heparin at 300–500 units/h via peripheral IV. Check fibrinogen q6h — hold lysis if fibrinogen <100 mg/dL or INR >3.0.
7
Check-angiogram at 12–24h (CDT)
Bring patient back, inject through catheter. If >50% lysis: continue. If <50% after 24h total: consider adjunctive PMT or accept partial result.
8
Treat underlying stenosis
If May-Thurner identified: balloon angioplasty 8–12 mm × 4–8 cm, then venous stent deployment. Stent must extend from IVC confluence to common femoral vein to fully cover compressed segment.
9
Completion venogram
Confirm patency, document residual thrombus burden, confirm stent position if placed.
10
Remove catheter
Apply compression dressing at access site (popliteal). Confirm hemostasis.
PMT Devices — Know These
- AngioJet: high-pressure saline jets create Venturi effect to macerate/aspirate thrombus; can deliver rtPA via power pulse; risk of hemolysis, bradycardia
- Penumbra Indigo CAT8/CAT12: pure aspiration; large bore, suitable for large veins
- INARI ClotTriever: large-bore mechanical clot extraction without thrombolytics; increasingly used for acute DVT as monotherapy (no lysis needed); good for older thrombus
Sign in to view and create community cards
5
Troubleshooting
Cannot Cross Thrombus
Unable to Traverse with Wire
Cause: Organized/chronic thrombus, complete lumen occlusion, vessel wall adhesion. Next step: Multiple wire angles (angled tip, stiff wire). Consider retrograde access from contralateral femoral. If truly cannot cross: thrombus is chronic — CDT will not work; anticoagulation only.
Fibrinogen Drops <100 mg/dL
Systemic Fibrinogenolysis from rtPA
Hold lysis infusion immediately. Give cryoprecipitate 10 units IV (raises fibrinogen ~50 mg/dL). Do not restart lysis until fibrinogen >150 mg/dL.
Residual Iliac Vein Stenosis
Persistent Stenosis After Thrombus Clearance
Cause: Underlying May-Thurner, prior DVT wall changes, external compression. Next step: Angioplasty to 8–12 mm. If residual stenosis >50% or elastic recoil: stent with venous-specific nitinol stent. Do NOT use arterial stents in veins (too rigid, risk of stent fracture in mobile vein).
PE During CDT Infusion
Thrombus Fragmentation and Embolization
If hemodynamically stable: monitor, continue anticoagulation, obtain CTA chest. If unstable: emergent PE intervention (catheter-directed lysis or thrombectomy at pulmonary level). Anticoagulate. Consider IVC filter if not already placed.
6
Complications
Immediate
- PE during lysis
- Access site bleeding (popliteal hematoma)
- Catheter-related thrombosis
- Contrast nephropathy
Delayed
- ICH during lysis (0.2–0.4%)
- Major hemorrhage (GI, retroperitoneal, 2–5%)
- Deep wound infection at access site
- Stent thrombosis (1–2 year)
- Rethrombosis (10–30% at 2 years without anticoagulation)
- Hemolysis (AngioJet-specific)
7
Post-Procedure
Monitoring During CDT
- ICU or telemetry during CDT infusion — bleeding monitoring, fibrinogen checks q6h
- Check fibrinogen before and after each assessment: hold lysis if <100 mg/dL
- Monitor access site q4h for hematoma
- Ambulate early after catheter removal and adequate hemostasis
- Elastic compression stockings: 30–40 mmHg knee-high — start immediately after procedure; continue 2 years (prevents PTS)
Anticoagulation Post-Intervention
- Start therapeutic anticoagulation immediately after catheter/sheath removal (LMWH or UFH bridge → DOAC)
- DOACs preferred: rivaroxaban 15 mg BID × 21 days, then 20 mg daily; OR apixaban 10 mg BID × 7 days then 5 mg BID
- Duration: minimum 3 months; consider extended (indefinite) for unprovoked DVT, recurrent DVT, active malignancy, or hypercoagulable state
- Anticoagulation for stented veins: minimum 3 months therapeutic regardless of DVT duration guidelines
- Duplex US at 3 months to confirm patency
8
Critical Pearls
✦
Iliofemoral = intervention territory. Isolated popliteal/femoral DVT rarely benefits from intervention. Iliofemoral DVT (involving iliac veins) is the primary indication — 5× higher post-thrombotic syndrome rate without clot removal.
✦
Always assess for May-Thurner. Any left-sided DVT in a young woman without obvious provoking factor should prompt CT venography to evaluate left iliac vein compression. If present: stent after thrombus removal — untreated compression leads to rapid re-thrombosis.
✦
Popliteal access is usually best for CDT. Allows catheter to span the entire thrombus from popliteal to IVC. Retrograde access from contralateral femoral can be used for IVC/iliac thrombus unreachable from below.
✦
Phlegmasia cerulea dolens = emergency. Massive iliofemoral DVT causing limb-threatening venous ischemia. Requires emergent CDT/PMT + fasciotomy if compartment syndrome develops. Call vascular surgery immediately.
✦
Compression stockings for 2 years. The only intervention proven to reduce post-thrombotic syndrome incidence. Start immediately post-procedure and do not skip. Use 30–40 mmHg graduated compression.
✦
Fibrinogen monitoring is mandatory during CDT. <100 mg/dL = stop lysis immediately. Fibrinogen depletion predicts major bleeding. Do not rely on PT/INR alone during rtPA infusion.
9
References
Key Guidelines
- AHA/ACC/HFSA/HPNA/SCAI/STS VTE Guidelines 2024 — Updated recommendations covering DVT diagnosis, risk stratification, and endovascular management. Key updates: ClotTriever/aspiration thrombectomy now recognized as alternative to pharmacomechanical CDT; DOAC-preferred for anticoagulation; compression stockings for PTS prevention remain Class I; routine CDT for femoral-popliteal DVT NOT recommended (Class III: no benefit).
- ACCP Antithrombotic Therapy Guidelines (2016) — LMWH/DOAC dosing, duration thresholds
- SIR Standards of Practice: Venous Thromboembolic Disease (2018) — CDT technique and lysis dose
Primary References
- Vedantham S, et al. Pharmacomechanical catheter-directed thrombolysis for deep-vein thrombosis. N Engl J Med. 2017;377:2240–2252. (ATTRACT trial)
- Kearon C, et al. Antithrombotic therapy for VTE disease: CHEST Guideline. Chest. 2016.
- Neglén P, et al. Venous stenting across the inguinal ligament. J Vasc Surg. 2008.
- Mewissen MW, et al. Catheter-directed thrombolysis for lower extremity deep venous thrombosis. Radiology. 1999.