Balance Thrombosis Risk | Balance Bleeding Risk | Evidence-Based Protocols
BLEEDING RISK STRATIFICATION
Critical Must-Knows
- Warfarin: stop 5 days preop, bridge if high thrombosis risk (mechanical valve, recent VTE)
- DOACs: stop 24h if CrCl greater than 50, 48h if CrCl less than 50
- Neuraxial anesthesia: 12h after LMWH prophylactic, 24h after therapeutic
- Restart anticoagulation 24-72h postop depending on bleeding risk
- Australian eTG guidelines provide evidence-based protocols
Clinical Pearls
- "Bridging with LMWH/UFH only for HIGH thrombosis risk patients (mechanical valve, recent VTE less than 3mo)
- "Most patients do NOT need bridging - BRIDGE trial showed bridging increases bleeding without preventing thrombosis
- "DOACs easier than warfarin - predictable offset, no bridging needed
- "Neuraxial timing critical - spinal hematoma is catastrophic complication
Critical Exam Concepts
Bridging is NOT Routine
Only bridge HIGH thrombosis risk: mechanical mitral valve, recent VTE (less than 3 months), AF with CHA2DS2-VASc greater than or equal to 5. Bridging increases bleeding risk.
DOAC Timing is Drug-Specific
Apixaban, Rivaroxaban: 24-48h. Dabigatran: 24-96h (renal dependent). Check CrCl and use eTG tables.
Neuraxial Anesthesia Timing
Spinal hematoma is catastrophic. Wait 12h after prophylactic LMWH, 24h after therapeutic LMWH before neuraxial.
Restart Based on Bleeding Risk
Low risk: 6-12h. Moderate: 24-48h. High risk (spine, revision): 48-72h. Balance VTE vs bleeding.
Quick Decision Guide
| Anticoagulant | Stop Before Surgery | Restart After Surgery | Bridge? |
|---|---|---|---|
| Warfarin (low thrombo risk) | 5 days preop | 24-72h postop | NO - do not bridge |
| Warfarin (high thrombo risk) | 5 days preop + LMWH bridge | LMWH 24h postop, warfarin overlap | YES - mechanical valve, recent VTE |
| DOACs (CrCl greater than 50) | 24-48h preop | 24-72h postop | NO - never bridge DOACs |
| DOACs (CrCl less than 50) | 48-96h preop (longer) | 24-72h postop | NO - never bridge DOACs |
| LMWH prophylactic | 12h before neuraxial | Restart 6-12h postop | N/A - this IS prophylaxis |
BRAVEHigh Thrombosis Risk Requiring Bridging
| B | BiMechanical valve Mechanical MITRAL valve (highest risk) |
| R | Recent VTE VTE less than 3 months ago |
| A | AF severe CHA2DS2-VASc greater than or equal to 5 |
| V | Valve in mitral position Mitral worse than aortic |
| E | Event history Prior stroke or VTE on therapeutic AC |
| B | BiMechanical valve Mechanical MITRAL valve (highest risk) | V | Valve in mitral position Mitral worse than aortic |
| R | Recent VTE VTE less than 3 months ago | E | Event history Prior stroke or VTE on therapeutic AC |
| A | AF severe CHA2DS2-VASc greater than or equal to 5 |
Hook:Be BRAVE and bridge only the highest thrombosis risk patients - most do NOT need bridging!
RENALDOAC Cessation Timing Factors
| R | Renal function CrCl less than 50 = longer cessation (48-96h) |
| E | Elimination half-life Dabigatran longest (12-14h), apixaban/rivaroxaban shorter |
| N | Normal CrCl If CrCl greater than 50, stop 24-48h preop |
| A | Age matters Elderly have lower CrCl - calculate eGFR |
| L | Low bleeding risk surgery May stop 24h only; high risk stop 48-96h |
| R | Renal function CrCl less than 50 = longer cessation (48-96h) | A | Age matters Elderly have lower CrCl - calculate eGFR |
| E | Elimination half-life Dabigatran longest (12-14h), apixaban/rivaroxaban shorter | L | Low bleeding risk surgery May stop 24h only; high risk stop 48-96h |
| N | Normal CrCl If CrCl greater than 50, stop 24-48h preop |
Hook:Check RENAL function before deciding DOAC cessation timing - it is the key variable!
CLOTNeuraxial Timing Safety
| C | Catheter removal Wait 12h after prophylactic LMWH, 24h after therapeutic |
| L | LMWH timing 12h before spinal for prophylactic, 24h for therapeutic |
| O | Observe for hematoma Monitor for back pain, weakness, urinary retention |
| T | Timing restart Wait 4h after catheter removal before LMWH dose |
| C | Catheter removal Wait 12h after prophylactic LMWH, 24h after therapeutic | O | Observe for hematoma Monitor for back pain, weakness, urinary retention |
| L | LMWH timing 12h before spinal for prophylactic, 24h for therapeutic | T | Timing restart Wait 4h after catheter removal before LMWH dose |
Hook:Prevent CLOT complications with proper neuraxial timing - spinal hematoma is catastrophic!
Overview and Clinical Significance
The Bridging Paradigm Shift
The BRIDGE trial (2015) changed practice. It showed that bridging with LMWH for AF patients increased bleeding (3.2% vs 1.3%) WITHOUT reducing thrombosis. Most patients do NOT need bridging. Only bridge if HIGH thrombosis risk (mechanical mitral valve, recent VTE less than 3mo).
Common Indications for Anticoagulation
- Atrial fibrillation (most common in ortho)
- Mechanical heart valves
- VTE treatment or prophylaxis
- Coronary stents (antiplatelet)
- Stroke prevention
Why Perioperative Management Matters
- Bleeding risk with ongoing anticoagulation
- Thrombosis risk if stopped too long
- Neuraxial anesthesia contraindicated if coagulopathic
- Major surgery requires INR normalization
- Balance is patient-specific
Pathophysiology and Risk Stratification
Risk Stratification Determines Bridging
Assess THROMBOSIS risk first. Only HIGH-risk patients need bridging. Most orthopaedic patients are LOW-MODERATE thrombosis risk and do NOT need bridging.
| Risk Category | Clinical Features | Annual Risk | Periop Management |
|---|---|---|---|
| HIGH | Mechanical MITRAL valve, VTE less than 3mo, stroke less than 3mo | Greater than 10% | BRIDGE with LMWH or UFH |
| MODERATE | Mechanical AORTIC valve, VTE 3-12mo ago, AF CHA2DS2-VASc 3-4 | 5-10% | Consider bridging, individualize |
| LOW | AF CHA2DS2-VASc 0-2, VTE greater than 12mo, bioprosthetic valve | Less than 5% | NO bridging - stop AC, restart postop |
AF Thrombosis Risk (CHA2DS2-VASc Score)
CHA2DS2-VASc Scoring:
- CHF (1 point)
- Hypertension (1)
- Age greater than or equal to 75 (2)
- Diabetes (1)
- Stroke/TIA/thromboembolism (2)
- Vascular disease (1)
- Age 65-74 (1)
- Sex female (1)
| Score | Risk | Bridging Decision |
|---|---|---|
| 0-2 | Low | NO bridging |
| 3-4 | Moderate | Consider bridging if additional risks |
| 5 or more | High | Bridge with LMWH |
Why Mitral Valves are Higher Risk
Mechanical mitral valves have 2-4x higher thrombosis risk than aortic valves due to larger surface area, lower flow velocities, and left atrial stasis. Always bridge mechanical mitral valves.
Classification
Classification of Anticoagulant Agents
| Class | Examples | Mechanism | Half-life |
|---|---|---|---|
| Vitamin K antagonists | Warfarin | Inhibits factors II, VII, IX, X | 36-42 hours |
| Direct thrombin inhibitors | Dabigatran | Direct factor IIa inhibition | 12-17 hours |
| Factor Xa inhibitors | Rivaroxaban, Apixaban | Direct factor Xa inhibition | 8-15 hours |
| Heparins | Enoxaparin, UFH | AT-III mediated | 4-7 hours (LMWH) |
| Antiplatelet agents | Aspirin, Clopidogrel | Platelet inhibition | Variable |
DOAC Considerations:
- Renal clearance varies (dabigatran 80%, apixaban 25%)
- No reliable reversal agents for all DOACs
- Shorter half-life allows faster cessation
Clinical Assessment and Bleeding Risk
| Risk Category | Orthopaedic Procedures | Management |
|---|---|---|
| LOW | Arthroscopy, carpal tunnel, trigger finger, K-wire removal | Minimal interruption, restart 6-12h |
| MODERATE | THA, TKA, ORIF, shoulder arthroplasty, fracture fixation | Stop AC preop, restart 24-48h postop |
| HIGH | Spine surgery, revision THA/TKA, pelvic ORIF, tumor resection | Extended cessation, restart 48-72h postop |
Neuraxial Anesthesia = High Bleeding Risk
Spinal or epidural anesthesia is considered HIGH bleeding risk due to catastrophic consequences of spinal hematoma (paralysis). This determines timing of anticoagulation cessation and restart.
Investigations and Monitoring
Laboratory Monitoring Preoperatively
- INR testing if on warfarin - check day before and day of surgery
- Creatinine/eGFR for DOAC patients - determines cessation timing
- Platelet count if on heparin - HIT screening if indicated
- Coagulation studies (PT, APTT) if bleeding concern
- Blood group and crossmatch for major procedures
eTG Anticoagulation Guidelines (Australian)
- Evidence-based cessation/restart protocols
- DOAC timing tables based on renal function
- Bridging decision algorithms
- Neuraxial anesthesia safety guidelines
- Updated regularly with new evidence
Australian-Specific Considerations
Use eTG (Therapeutic Guidelines) as authoritative source for Australian practice. PBS coverage influences DOAC choice. Rural/remote patients may have delayed access to reversal agents.
Differential of Unexpected Perioperative Bleeding / Coagulopathy
When a patient bleeds more than expected or has an abnormal coagulation screen, distinguish residual anticoagulant from other causes before attributing it to the agent alone.
Causes of Abnormal Perioperative Coagulation
| Cause | Discriminating Feature | Typical Screen | Action |
|---|---|---|---|
| Residual warfarin effect | Recent VKA, INR raised | INR/PT prolonged, APTT normal-to-raised | Vitamin K +/- PCC; recheck INR |
| Residual DOAC | Recent dose, reduced CrCl, dabigatran | Variable; raised APTT (dabigatran) or anti-Xa | Time/renal clearance; specific reversal if life-threatening |
| Residual heparin/LMWH | Recent dose, raised anti-Xa | APTT prolonged (UFH); anti-Xa raised | Protamine (full for UFH, partial for LMWH) |
| Liver disease | Stigmata of chronic liver disease, low albumin | INR raised, low platelets | Vitamin K, FFP/PCC, treat cause |
| DIC / dilutional coagulopathy | Massive transfusion, sepsis, trauma | Low fibrinogen, low platelets, raised D-dimer | Treat cause; targeted blood products, fibrinogen |
| Inherited bleeding disorder (e.g. von Willebrand, haemophilia) | Lifelong/familial bleeding history | Prolonged APTT, abnormal factor/vWF assays | Haematology; factor concentrate/desmopressin |
Management Algorithm
Warfarin Perioperative Management
Warfarin Perioperative Protocol
Stop warfarin 5 days before surgery. INR will normalize to less than 1.5 by day of surgery in most patients. Check INR on day before surgery to confirm.
If HIGH thrombosis risk, start LMWH (enoxaparin 1mg/kg BD) or UFH infusion when INR less than 2. Give last LMWH dose 24h before surgery.
Confirm INR less than 1.5 (ideally less than 1.2 for neuraxial). If INR greater than 1.5, delay or give vitamin K 1-2mg PO.
Restart warfarin when hemostasis secure (24h for low bleeding risk, 48-72h for high). If bridging, give LMWH until INR greater than 2 for 2 consecutive days.
This protocol follows eTG recommendations and BRIDGE trial evidence.
Direct Oral Anticoagulant (DOAC) Management
DOACs are Simpler Than Warfarin
Advantages of DOACs: Predictable pharmacokinetics, no INR monitoring needed, no bridging required, rapid offset. Key variable: RENAL FUNCTION determines cessation timing.
DOAC Cessation Timing (eTG Guidelines)
| DOAC | CrCl greater than 50 | CrCl 30-50 | CrCl less than 30 |
|---|---|---|---|
| Apixaban | 24-48h preop | 48h preop | 48-72h preop |
| Rivaroxaban | 24-48h preop | 48h preop | 48-72h preop |
| Dabigatran | 24-48h preop | 72h preop | 96h preop (4 days) |
| Edoxaban | 24-48h preop | 48h preop | 48-72h preop |
Preoperative DOAC Management
- Calculate CrCl (Cockcroft-Gault)
- Stop 24h if CrCl greater than 50 and LOW bleeding risk surgery
- Stop 48h if CrCl greater than 50 and HIGH bleeding risk surgery
- Stop 48-96h if CrCl less than 50 (dabigatran longest)
- NO bridging - DOACs have rapid offset
Postoperative DOAC Restart
- Low bleeding risk: Restart 6-12h postop (full dose)
- Moderate risk: Restart 24-48h postop
- High risk: Restart 48-72h postop
- Start at full therapeutic dose (no loading)
- Ensure hemostasis before restarting
Dabigatran is Renally Cleared
Dabigatran is 80% renally excreted. If CrCl less than 50, stop 72-96h preop (3-4 days). Check renal function in all patients on dabigatran. Apixaban and rivaroxaban are less renal-dependent.
Neuraxial Anesthesia and Anticoagulation
Spinal Hematoma is Catastrophic
Spinal epidural hematoma causes irreversible paralysis if not decompressed within 8 hours. Prevention requires strict adherence to anticoagulation timing guidelines.
Neuraxial Timing (ASRA 4th Edition, 2018)
| Anticoagulant | BEFORE Neuraxial (Wait Time) | AFTER Neuraxial / Catheter (Restart) |
|---|---|---|
| LMWH prophylactic | 12 hours | 4h after needle/catheter (catheter OK) |
| LMWH therapeutic | 24 hours | 24h after block; no indwelling catheter |
| Unfractionated heparin SC (prophylactic) | 4-6 hours (or normal APTT) | 1 hour |
| Warfarin | INR less than or equal to 1.4 | Restart once catheter removed |
| Apixaban / Rivaroxaban | 72 hours | 6 hours after catheter removal |
| Dabigatran | 72-120 hours (renal dependent) | 6 hours after catheter removal |
Surgical vs Neuraxial Intervals Differ
The DOAC interval that makes surgery safe (PAUSE: 1-2 days) is shorter than the interval ASRA requires for a neuraxial block (72h for factor Xa inhibitors). When a spinal/epidural is planned, the ASRA neuraxial interval governs - this is a classic exam discriminator.
Catheter Removal Timing
If epidural catheter in situ, anticoagulation must be held until AFTER catheter removal. Wait 12h after LMWH prophylactic dose, 24h after therapeutic dose, before removing catheter. Then wait 4h after removal before next LMWH dose.
Surgical Technique
Pre-operative Assessment
Confirm Anticoagulation Status:
- Document last dose date/time
- Check INR (warfarin) or drug levels if available (DOACs)
- Review renal function for DOAC clearance
- Confirm bridging plan if applicable
Pre-operative Checklist:
- Anticoagulation held per protocol
- Bridging LMWH stopped appropriately (24h for prophylactic, 24-48h therapeutic)
- Platelet function normal if on aspirin/clopidogrel
- Group and screen current
- Discuss plan with anaesthesia for neuraxial
Day of Surgery:
- Confirm patient fasted and anticoagulation held
- Recheck INR for warfarin patients (target less than 1.5)
- Document consent includes bleeding risks
Complications and Special Situations
Emergency Surgery on Anticoagulation
Patient needs urgent surgery but is anticoagulated:
Emergency Reversal Protocol
Give Vitamin K 5-10mg IV (onset 6-12h) PLUS Prothrombin Complex Concentrate (PCC) 25-50 units/kg (immediate reversal). Check INR 30 min after PCC.
Consider Idarucizumab (dabigatran reversal) or Andexanet alfa (Xa inhibitor reversal). Expensive and limited availability. May delay surgery 12-24h if possible.
Protamine sulfate reverses heparin (1mg per 100 units UFH). Partial reversal of LMWH. Wait 4-6h if possible.
Balance: Bleeding risk of surgery vs thrombosis risk of reversal. Discuss with hematology.
Postoperative Care
Anticoagulation Restart Timing
| Procedure Risk | DOAC Restart | Warfarin Restart |
|---|---|---|
| Low bleeding risk | 24-48 hours | Day 1 (takes days to effect) |
| Moderate risk | 48-72 hours | Day 1-2 |
| High risk | 72-96 hours | Day 2-3, check hemostasis |
| Very high risk (spine, intracranial) | 5-7 days | Delayed, individualized |
Decision Factors:
- Hemostasis adequacy (drain output, wound)
- Thrombotic risk vs bleeding risk
- Neuraxial anaesthesia removal timing
- Hematology input for complex cases
Bridging Phase-out:
- For high-risk patients who were bridged, continue LMWH until INR therapeutic (warfarin) or 24-48 hours (DOACs)
Outcomes
Bleeding Outcomes
| Scenario | Major Bleeding Risk |
|---|---|
| Bridging (therapeutic LMWH) | 3-5% |
| No bridging | 1-2% |
| DOACs held appropriately | 1-2% |
| Continued anticoagulation | 5-10% |
Major Bleeding Definitions:
- Hb drop ≥20 g/L
- Transfusion ≥2 units
- Bleeding at critical site
- Reoperation for bleeding
- Fatal bleeding
Risk Factors for Bleeding:
- Inadequate drug cessation
- Renal impairment (DOAC accumulation)
- Concurrent antiplatelet therapy
- Complex/revision surgery
Evidence Base and Key Trials
BRIDGE Trial - Bridging Anticoagulation in AF
- Double-blind RCT of 1884 AF patients on warfarin interrupted for elective procedure; randomised to dalteparin bridging or placebo
- Arterial thromboembolism 0.4% (no-bridge) vs 0.3% (bridge) - no-bridging non-inferior (P=0.01 for non-inferiority)
- Major bleeding 1.3% (no-bridge) vs 3.2% (bridge); RR 0.41 (95% CI 0.20-0.78), P=0.005 for superiority
- Most procedures were low bleeding risk; minor bleeding also reduced by forgoing bridging
PAUSE Cohort - Standardised DOAC Interruption
- Prospective cohort of 3007 AF patients on apixaban, dabigatran or rivaroxaban undergoing elective surgery/procedure
- Standardised, pharmacokinetics-based interruption: omit 1 day pre-op (low bleeding risk) or 2 days (high bleeding risk); no heparin bridging or coagulation testing
- 30-day major bleeding 0.9-1.85% across DOAC cohorts; ~3% for high-bleeding-risk procedures
- 30-day arterial thromboembolism 0.16-0.6%; most patients had minimal residual DOAC level (less than 50 ng/mL) at surgery
ARISTOTLE - Apixaban vs Warfarin in AF
- Double-blind RCT of 18,201 AF patients with at least one stroke risk factor; apixaban 5mg BD vs dose-adjusted warfarin
- Stroke or systemic embolism 1.27% vs 1.60% per year (HR 0.79, 95% CI 0.66-0.95; superior)
- Major bleeding 2.13% vs 3.09% per year (HR 0.69, 95% CI 0.60-0.80)
- All-cause mortality 3.52% vs 3.94% per year (HR 0.89, 95% CI 0.80-0.99)
RE-LY - Dabigatran vs Warfarin in AF
- RCT of 18,113 AF patients; dabigatran 110mg and 150mg BD vs adjusted-dose warfarin
- Dabigatran 150mg reduced stroke/systemic embolism (1.11% vs 1.69% per year; RR 0.66)
- Dabigatran 110mg non-inferior for stroke with lower major bleeding (2.71% vs 3.36% per year)
- Both doses reduced haemorrhagic stroke; GI bleeding higher with 150mg
PERIOP-2 - Postoperative LMWH Bridging RCT
- Double-blind RCT of 1471 patients with AF or mechanical heart valves whose warfarin was interrupted for a procedure
- Randomised after the procedure to postoperative dalteparin bridging vs placebo
- Major thromboembolism 1.0% (dalteparin) vs 1.2% (placebo) - no significant difference (risk difference -0.3%)
- Major bleeding 1.3% (dalteparin) vs 2.0% (placebo) - no significant difference; results consistent for AF and mechanical-valve subgroups
ASRA Evidence-Based Guidelines (4th Edition) - Neuraxial Anaesthesia and Antithrombotics
- Defines safe intervals between antithrombotic dosing and neuraxial puncture/catheter removal to prevent spinal-epidural haematoma
- Prophylactic LMWH: 12h before neuraxial; therapeutic LMWH: 24h before; resume 4h after needle/catheter (prophylactic) or 24h (therapeutic)
- Apixaban/rivaroxaban: hold 72h before neuraxial; dabigatran: 72-120h depending on CrCl
- Warfarin should be stopped and INR normalised (=1.4-1.5) before neuraxial block
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Elective THA on Warfarin (~2-3 min)
"A 72-year-old woman is scheduled for elective total hip arthroplasty in 10 days. She takes warfarin for atrial fibrillation (CHA2DS2-VASc score 3). Her INR today is 2.5. How would you manage her anticoagulation perioperatively?"
Scenario 2: TKA on Apixaban with Spinal (~3-4 min)
"A 68-year-old man on apixaban 5mg BD for AF is scheduled for TKA with spinal anesthesia. His CrCl is 55 ml/min. When would you stop the apixaban, when is it safe to perform the spinal, and when would you restart?"
MCQ Practice Points
Warfarin Cessation Timing
Q: How many days before elective surgery should warfarin be stopped? A: 5 days. Warfarin half-life is 36-42 hours. Stopping 5 days preop allows INR to normalize to less than 1.5 in most patients.
Bridging Indication
Q: Which patients require bridging anticoagulation with LMWH when stopping warfarin? A: HIGH thrombosis risk only: Mechanical MITRAL valve, recent VTE (less than 3 months), or AF with CHA2DS2-VASc greater than or equal to 5. BRIDGE trial showed bridging increases bleeding without preventing thrombosis in most patients.
DOAC Advantage
Q: What is the main advantage of DOACs over warfarin for perioperative management? A: Predictable offset and NO bridging needed. DOACs can be stopped 24-48h preop and restarted postop without bridging, unlike warfarin which may need LMWH bridging in high-risk patients.
Neuraxial Timing
Q: How long after prophylactic LMWH is it safe to perform spinal anesthesia? A: 12 hours. Therapeutic LMWH requires 24 hours. This prevents spinal epidural hematoma, which causes irreversible paralysis.
Dabigatran Cessation
Q: Why does dabigatran require longer preoperative cessation than other DOACs? A: 80% renal excretion. If CrCl less than 50, dabigatran must be stopped 72-96h preop (3-4 days) vs 48h for apixaban/rivaroxaban.
Guidelines, Registries & Global Practice
Global Burden Driving This Topic
Atrial fibrillation affects an estimated 50+ million people worldwide and prevalence rises sharply with age; roughly 1 in 6 patients presenting for elective surgery is on long-term anticoagulant or antiplatelet therapy. With ageing arthroplasty and fragility-fracture populations, the orthopaedic surgeon manages perioperative anticoagulation almost daily, and DOACs have now overtaken warfarin as the most prescribed oral anticoagulant in most high-income health systems.
International Guidance Compared (Perioperative Anticoagulation & Neuraxial)
| Body / Document | Region | Key Position | Evidence Level |
|---|---|---|---|
| ACCP / CHEST (Douketis 2022) | North America / Global | No bridging for most AF; selective bridging only for highest thrombotic risk; standardised DOAC interruption | Guideline (GRADE) |
| ASRA 4th ed (2018) | North America / Global | Defines neuraxial intervals: 72h for factor Xa inhibitors, 12h/24h for prophylactic/therapeutic LMWH | Guideline |
| ESC AF Guidelines (2020/2024) + EHRA DOAC guide | Europe | DOAC interruption by bleeding risk and renal function; bridging discouraged in AF | Guideline |
| NICE NG197 / NG89 | UK | DOAC-led stroke prevention in AF; perioperative VTE prophylaxis for major orthopaedic surgery | Guideline |
| Therapeutic Guidelines (eTG) + ANZCA | Australia / NZ | PK-based DOAC interruption tables; ANZCA neuraxial timing aligned with ASRA | Guideline |
Registry & Trial Evidence Underpinning Practice
| Source | Type | Practice Point |
|---|---|---|
| BRIDGE (NEJM 2015) | RCT, n=1884 | Forgoing bridging non-inferior for ATE, halves major bleeding in AF |
| PAUSE (JAMA IM 2019) | Prospective cohort, n=3007 | Standardised 1-2 day DOAC interruption without bridging is safe |
| PERIOP-2 (BMJ 2021) | RCT, n=1471 | No benefit of postoperative LMWH bridging, including mechanical valves |
| AOANJRR / national joint registries | Registry | Track VTE, reoperation for haematoma and bleeding-related revision after TJA |
Practice Variation
Despite concordant guidelines, real-world bridging rates vary widely between centres and countries (historically 10-40% of warfarin patients), reflecting clinician risk perception rather than evidence. The consistent message across AAOS-aligned practice, NICE, ESC/EHRA, ACCP and eTG is: bridge rarely, interrupt DOACs by a simple PK rule, and let renal function and the neuraxial plan drive timing.
Australian Guidelines
ANZCA Guidelines (Neuraxial Anaesthesia):
- Warfarin: INR less than 1.4 before neuraxial
- LMWH prophylactic: 12 hours before insertion
- LMWH therapeutic: 24 hours before insertion
- DOACs: variable based on renal function and drug
Therapeutic Guidelines (eTG):
- Bridging rarely needed for AF (BRIDGE trial evidence)
- High-risk patients (mechanical valves, recent VTE) may require bridging
- Multidisciplinary consultation for complex cases
NHMRC VTE Prevention Guidelines:
- Mechanical prophylaxis for all major orthopaedic surgery
- Pharmacological prophylaxis: LMWH or DOACs
- Extended prophylaxis for THA (28-35 days)
AOA Position Statement:
- Risk stratification before surgery
- Standardized cessation protocols
- Early mobilization as primary prevention
PERIOPERATIVE ANTICOAGULATION MANAGEMENT
Clinical summary
Warfarin Protocol
- •Stop 5 days preop, check INR day before surgery (target less than 1.5)
- •Bridge only if HIGH risk: mechanical mitral, VTE less than 3mo, AF CHA2DS2-VASc greater than or equal to 5
- •Last LMWH bridge dose 24h before surgery
- •Restart 24-72h postop (bleeding risk dependent)
DOAC Protocol
- •Calculate CrCl first - determines cessation timing
- •Stop 24-48h if CrCl greater than 50, 48-96h if CrCl less than 50
- •Dabigatran longest (96h if CrCl less than 50)
- •NO bridging ever - DOACs have rapid offset
Neuraxial Timing (ASRA 2018 - Spinal Haematoma Prevention)
- •LMWH prophylactic: Wait 12h before neuraxial, restart 4h after
- •LMWH therapeutic: Wait 24h before neuraxial; avoid indwelling catheter
- •Factor Xa inhibitors (apixaban/rivaroxaban): Wait 72h before neuraxial
- •Dabigatran: 72-120h before neuraxial (renal dependent); restart 6h after catheter out
Bridging Indications (HIGH Risk Only)
- •Mechanical MITRAL valve (always bridge)
- •Recent VTE less than 3 months
- •AF with CHA2DS2-VASc greater than or equal to 5
- •Prior stroke/VTE while on therapeutic anticoagulation
Bleeding Risk Stratification
- •LOW: Minor procedures - restart 6-12h postop
- •MODERATE: THA/TKA/fracture ORIF - restart 24-48h
- •HIGH: Spine, revision THA/TKA - restart 48-72h
- •Neuraxial anesthesia = HIGH bleeding risk