Residency · Residency · Interventional Radiology
Preprocedural Assessment: Anticoagulation and Coagulation Management
Introduction
Interventional radiology procedures span a wide range of bleeding and thrombotic risks. Proper preprocedural assessment of the patient's coagulation status and thoughtful management of anticoagulant and antiplatelet therapies are essential to minimize both hemorrhagic and thromboembolic complications. The SIR consensus guidelines provide a framework for stratifying procedures and managing medications.
SIR Procedure Bleeding Risk Classification
| SIR Category | Bleeding Risk | Example Procedures | INR Threshold | Platelet Threshold |
|---|---|---|---|---|
| 1 | Low | PICC, port, tunneled catheter, thoracentesis, paracentesis, IVC filter | <2.0 | >20,000/mcL |
| 2 | Moderate | Angioplasty/stent, chemoembolization, nephrostomy, biliary drainage | <1.5 | >50,000/mcL |
| 3 | High | Renal biopsy, hepatic biopsy, complex ablation | <1.5 | >50,000/mcL (hold all anticoagulants) |
Category 1 (Low Bleeding Risk)
Venous access (PICC, port, tunneled catheter). Drainage catheter exchange, thoracentesis, paracentesis. IVC filter placement or retrieval. Coagulation parameters: INR < 2.0, platelets > 20,000/mcL.
Category 2 (Moderate Bleeding Risk)
Arterial interventions (angioplasty, stent placement). Chemoembolization, bland embolization. Percutaneous nephrostomy, biliary drainage. Tunneled dialysis catheter placement. Coagulation parameters: INR < 1.5, platelets > 50,000/mcL.
Category 3 (High Bleeding Risk)
Renal biopsy, hepatic biopsy (transjugular may reduce risk). Percutaneous nephrolithotomy. Complex ablation procedures. Coagulation parameters: INR < 1.5, platelets > 50,000/mcL; hold all anticoagulants.
Preprocedural Laboratory Assessment
Standard Laboratories
INR/PT: assess warfarin effect and synthetic liver function. aPTT: assess heparin effect and intrinsic pathway. Platelet count: minimum thresholds vary by procedure category. Hemoglobin/Hematocrit: baseline for comparison if post-procedural bleeding. Creatinine/eGFR: assess renal function for contrast planning and medication dosing.
When to Check Labs
INR and platelets for Category 2 and 3 procedures. Within 24-48 hours of the procedure for reliability. Category 1 procedures in patients on stable anticoagulation may not require routine labs if recent values are available. Patients with liver disease, renal disease, or hematologic disorders require more comprehensive assessment.
Anticoagulant Management
Warfarin
Category 1 procedures: may proceed with INR < 2.0-3.0 depending on institutional protocol. Category 2-3 procedures: hold warfarin 5 days before the procedure; check INR day of procedure. Bridging anticoagulation with LMWH or UFH for high thromboembolic risk patients (mechanical heart valve, recent VTE < 3 months, high CHA2DS2-VASc). Reversal: vitamin K (oral or IV for non-emergent correction), 4-factor PCC for emergent reversal.
Direct Oral Anticoagulants (DOACs)
| DOAC | Hold Time (Cat 2-3) | Renal Adjustment | Reversal Agent |
|---|---|---|---|
| Apixaban (Eliquis) | 48 hours | Longer if CrCl <30 | Andexanet alfa (Andexxa) |
| Rivaroxaban (Xarelto) | 48 hours | Longer if CrCl <30 | Andexanet alfa (Andexxa) |
| Dabigatran (Pradaxa) | 48-72 hours | Longer if CrCl <50 | Idarucizumab (Praxbind) |
| Edoxaban (Savaysa) | 48 hours | Longer if CrCl <30 | Andexanet alfa (Andexxa) |
Apixaban, rivarelbaan: hold 48 hours before Category 2-3 procedures (longer if CrCl < 30 mL/min). Dabigatran: hold 48-72 hours (longer with renal impairment); specific reversal agent idarucizumab (Praxbind). Edoxaban: hold 48 hours. DOACs have shorter half-lives than warfarin; bridging is generally not required. Reversal agent for factor Xa inhibitors: andexanet alfa (Andexxa) for life-threatening bleeding.
Heparin
Unfractionated heparin (UFH) infusion: hold 4-6 hours before procedure; check aPTT. Low-molecular-weight heparin (LMWH): hold 24 hours before procedure (therapeutic dose); 12 hours for prophylactic dose. Reversal: protamine sulfate (partially effective for LMWH).
Antiplatelet Management
Aspirin
Category 1-2 procedures: generally continue aspirin. Category 3 procedures: consider holding 5-7 days before procedure. Aspirin for secondary cardiovascular prevention should ideally be continued to reduce cardiac events.
P2Y12 Inhibitors (Clopidogrel, Prasugrel, Ticagrelor)
Clopidogrel: hold 5 days before Category 2-3 procedures. Prasugrel: hold 7 days. Ticagrelor: hold 5 days. Critical consideration: patients with recent coronary stent placement (< 6 months for drug-eluting stents) should not have P2Y12 inhibitors interrupted without cardiology consultation due to risk of stent thrombosis. Dual antiplatelet therapy (DAPT) interruption decisions require multidisciplinary discussion.
Dual Antiplatelet Therapy After Stent Placement
Bare metal stent: minimum 4 weeks of DAPT before elective interruption. Drug-eluting stent: minimum 6 months (ideally 12 months) of DAPT. If the procedure cannot wait, consider performing under DAPT with awareness of increased bleeding risk. Never stop both antiplatelet agents simultaneously in stented patients.
Special Populations
Liver Disease
INR elevation in cirrhosis reflects decreased synthesis but does not accurately predict bleeding risk. Cirrhotic patients have a rebalanced hemostasis; both bleeding and thrombotic risk are elevated. Standard INR targets may not apply; thromboelastography (TEG/ROTEM) may better guide management. Transjugular approach for liver biopsy reduces bleeding risk compared to percutaneous.
Renal Disease
Uremic platelet dysfunction impairs hemostasis; platelet count may be normal. Desmopressin (DDAVP): 0.3 mcg/kg IV before the procedure to improve platelet function. Consider dialysis before the procedure to reduce uremic toxins.
Thrombocytopenia
Platelet transfusion to achieve appropriate threshold before the procedure. Platelets > 20,000 for Category 1; > 50,000 for Category 2-3. In ITP, transfused platelets are rapidly consumed; consider TPO receptor agonists preprocedurally.
Post-Procedural Anticoagulation Resumption
Category 1: resume anticoagulation same day or next morning. Category 2: resume 24-48 hours after the procedure if no bleeding complications. Category 3: resume 48-72 hours after the procedure. DOACs reach therapeutic levels within 2-4 hours of dosing; delay resumption accordingly. Warfarin may be restarted the evening of the procedure as it takes 3-5 days to reach therapeutic effect.
Key Clinical Pearls
Stratify every IR procedure by SIR bleeding risk category before making anticoagulation decisions. Bridging anticoagulation is reserved for high thromboembolic risk patients on warfarin; DOACs generally do not require bridging. Never interrupt DAPT in patients with recent coronary stents without cardiology consultation. INR in cirrhosis does not reliably predict bleeding risk; consider viscoelastic testing. Communicate the medication management plan clearly with the patient, referring physician, and anesthesia team.
References
- Defined the Core Practice Standards. Patel IJ, Rahim S, Davidson JC, et al. SIR Consensus Guidelines for Periprocedural Management of Coagulation Status. Journal of Vascular and Interventional Radiology. 2019;30(7):1003-1023.
- Defined the Core Practice Guidelines. Defined Core Clinical Practice. Defined Core Practice Standards. Defined Core Competencies. ACC/AHA Guidelines on DAPT Management. Circulation. 2016.
- Defined the Core Practice Guidelines. Defined Core Clinical Practice. Defined Core Practice Standards. Defined Core Competencies. Defined Core Practice Guidelines. Defined Core Updates. ASH Guidelines on VTE and Anticoagulation. 2020.
- Defined the Core Practice Standards. Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies. Defined Core Practice Guidelines. Tripodi A, Mannucci PM. The Coagulopathy of Chronic Liver Disease. NEJM. 2011;365(2):147-156.