periprocedural anticoagulation
Contents
Two questions: (1) should the anticoagulant be interrupted? (2) if on warfarin, is bridging needed? For DOACs — the PAUSE (2019) protocol: simple hold-and-resume based on renal function and procedure bleeding risk. For warfarin — BRIDGE (2015) showed bridging increases bleeding without reducing thromboembolism in most AF patients. Thrombosis Canada perioperative tools are an excellent Canadian-specific resource.
- Mechanical valve left unbridged — always bridge with therapeutic LMWH or UFH; never leave unprotected
- Warfarin started during acute heparin-induced thrombocytopaenia — depletes protein C → venous limb gangrene; must wait for platelet recovery
- DOAC not held for neuraxial anaesthesia — epidural haematoma risk; requires 3–5 day hold (not the standard 24–48h)
procedure bleeding risk
Classify first — drives hold duration and bridging decisions.
| risk | examples | management |
|---|---|---|
| minimal/no risk | cataract, minor dental, skin biopsy, pacemaker/ICD | do not interrupt anticoagulation |
| low | endoscopy ± biopsy, minor orthopaedic, hernia repair, laparoscopic cholecystectomy | standard interruption |
| high | major orthopaedic (hip/knee replacement), urological (TURP), cardiac surgery, neuraxial anaesthesia, complex abdominal, renal biopsy | extended interruption; consider delayed restart |
thrombosiscanada.ca/clinical-tools — free decision aids for perioperative DOAC management, bridging decisions, and procedure-specific hold times. Canadian-developed, regularly updated. Includes downloadable quick-reference cards.
DOAC interruption — PAUSE protocol
PAUSE (2019) — prospective cohort, n=3007 AF patients on DOACs. Simple standardised interruption without bridging → arterial thromboembolism rate <1%, major bleeding <2%.
hold times (pre-procedure)
| low bleeding risk | high bleeding risk | |
|---|---|---|
| apixaban / rivaroxaban | skip 1 day (24h) | skip 2 days (48h) |
| dabigatran, CrCl ≥50 | skip 1 day (24h) | skip 2 days (48h) |
| dabigatran, CrCl 30–49 | skip 2 days (48h) | skip 4 days (96h) |
- No preoperative anti-Xa or dTT levels required in routine cases
- No bridging with LMWH — PAUSE showed bridging adds bleeding risk without benefit
restart timing (post-procedure)
- Low bleeding risk: resume full dose 24 hours post-procedure
- High bleeding risk: resume full dose 48–72 hours post-procedure
- No reduced “ramp-up” dose needed (unlike VTE treatment initiation)
warfarin interruption and bridging
the bridging question
BRIDGE (2015) — RCT, n=1884 AF patients on warfarin requiring elective procedures. Bridging with dalteparin vs. placebo:
- Arterial thromboembolism: 0.4% (no bridge) vs. 0.3% (bridge) — no difference
- Major bleeding: 1.3% (no bridge) vs. 3.2% (bridge) — bridging doubled bleeding
- Bottom line: do not bridge most AF patients
who still needs bridging?
| bridge | do not bridge |
|---|---|
| mechanical mitral valve | AF without recent stroke (most patients) |
| mechanical aortic valve with additional risk factors (AF, prior stroke, hypercoagulable state) | bioprosthetic valve |
| VTE within 3 months | VTE >3 months ago |
| severe thrombophilia (e.g. antiphospholipid syndrome, active cancer with recent VTE) | lower-risk thrombophilia |
warfarin perioperative protocol
- Stop warfarin 5 days pre-procedure (target INR <1.5)
- Check INR day before — if >1.5, consider low-dose vitamin K (1–2 mg PO)
- If bridging indicated: start therapeutic LMWH 3 days pre-procedure → last dose 24h pre-procedure (or 12h if prophylactic dose)
- Post-procedure: restart warfarin evening of procedure (if haemostasis adequate); restart LMWH 24–48h post-procedure if bridging
- Continue bridging until INR therapeutic on two consecutive measurements
neuraxial anaesthesia timing
High-stakes — epidural haematoma risk.
| agent | hold before neuraxial | restart after catheter removal |
|---|---|---|
| heparins (LMWH therapeutic) | 24 hours | 24 hours |
| heparins (LMWH prophylactic) | 12 hours | 4 hours |
| heparins (UFH IV therapeutic) | 4–6 hours (check aPTT) | 1 hour |
| DOACs (apixaban / rivaroxaban) | 3–5 days (per CAS/ASRA guidelines) | 24 hours |
| warfarin | 5 days (INR <1.4) | after catheter removal |
special situations
- Emergency/urgent surgery on DOACs: if last dose <24h and high bleeding risk → consider specific reversal (idarucizumab for dabigatran; andexanet alfa for Xa inhibitors) or 4-factor PCC. If last dose >48h, usually safe to proceed.
- Mechanical valves: always bridge with therapeutic UFH or LMWH — never leave unprotected
- Recent VTE (<3 months): bridge; consider IVC filter if surgery cannot be deferred and anticoagulation must be held >48h
- Active cancer: higher thrombotic risk — shorter interruption periods; consider prophylactic LMWH post-operatively until full anticoagulation resumed
traps
- Bridging AF patients on warfarin — BRIDGE showed this increases bleeding without reducing stroke. The reflex to bridge is strong; resist it for most AF patients.
- Bridging DOAC patients — never indicated. DOACs have short half-lives; the PAUSE protocol of simple hold-and-resume is sufficient.
- Forgetting renal function for dabigatran — 80% renally cleared. CrCl 30–49 needs double the hold time vs. other DOACs.
- Restarting too early after high-risk procedures — the post-operative bleeding risk peaks in the first 48h; rushing to restart anticoagulation causes more harm than a brief thrombotic window.
- Not checking INR before warfarin procedures — an INR of 1.8 the day before surgery may need low-dose vitamin K; discovering this in the pre-op bay causes cancellations.
related: deep vein thrombosis · antiphospholipid syndrome · DOACs · warfarin · heparins · heparin-induced thrombocytopaenia