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Perioperative Management of NOACs (Direct Oral Anticoagulants)

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Introduction

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Pharmacokinetics Relevant to Perioperative Management

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Preoperative Assessment

Step 1: Risk Stratification

• Indication for NOAC: AF (CHA₂DS₂-VASc score), VTE, mechanical heart valve
• Recent VTE (<3 months) = very high risk
• Active cancer with VTE = high risk

Step 2: Patient Factors

• Renal function (CrCl) - especially critical for dabigatran (80% renal clearance)
• Hepatic function
• Prior bleeding history
• Concomitant antiplatelet use

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Preoperative Interruption Protocol

For Elective Procedures (Standard Protocol - PAUSE Study):

For Minimal-Risk Procedures:

• Omit a single dose on the day of (or evening prior to) the procedure only; no prolonged interruption needed.

For Continuous/Uninterrupted DOAC Therapy:

• For catheter ablation of AF and cardiac device implantation - uninterrupted DOAC is preferred (lower major bleeding and thromboembolism vs. interruption).

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Neuraxial Anaesthesia - Special Considerations

• Neuraxial catheter removal: treat same as needle placement - same interruption window applies.
• NOAC can be restarted no sooner than 6 hours after catheter removal.
• Measuring anti-Xa levels or dTT before neuraxial block is advisable in patients with CKD (CrCl <45 ml/min for dabigatran; CrCl 15-29 for FXa inhibitors).

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Routine Preoperative DOAC Level Testing

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Postoperative Resumption of NOACs

• Prophylactic-dose anticoagulation (LMWH) can be started earlier (12-24h post-op) if there is concern about thromboembolism, transitioning to therapeutic NOAC after 48-72 h.
• Do NOT restart NOAC until surgical haemostasis is secured.

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Emergency / Urgent Surgery

• Risk is higher: major bleeding 17-23%, arterial thromboembolism 7-16%.
• Delay surgery where possible to allow NOAC clearance (time-dependent on last dose and CrCl).
• If surgery cannot be delayed: use reversal agents.

Reversal Agents:

• Stop NOAC
• Mechanical compression/haemostasis
• Tranexamic acid (TXA) 1g IV
• Specific reversal agent OR 4F-PCC
• FFP and cryoprecipitate as needed

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Laboratory Monitoring

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Bridging Therapy - NOT Recommended

• NOACs have short half-lives and rapid onset.
• Bridging increases bleeding without reducing thromboembolism.
• This is supported by BRIDGE trial and confirmed in all major 2024-2025 guidelines.

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Special Situations in Anaesthesia

Regional Anaesthesia (Peripheral Nerve Blocks):

• Deep/non-compressible blocks (paravertebral, lumbar plexus): treat as neuraxial - hold 3-4 days.
• Superficial/compressible blocks: hold 1-2 days (similar to low-moderate risk surgery).

Patients on NOACs for Mechanical Prosthetic Valves:

• NOACs (except dabigatran in RE-ALIGN study - higher stroke rate) are generally not indicated for mechanical valves - continue VKA (warfarin) management.

Renal Impairment:

• CrCl <15 mL/min: most NOACs contraindicated.
• Dabigatran particularly sensitive to renal function - consider anti-Xa or dTT preoperatively.

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Summary Algorithm

Patient on NOAC for surgery
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Assess: Procedure bleeding risk + Patient thrombotic risk
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Minimal risk procedure → Omit 1 dose only
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Low-moderate risk → Hold 1 day (FXa-i) or 1-2 days (Dabigatran)
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High risk → Hold 2 days (FXa-i) or 2-4 days (Dabigatran per CrCl)
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Neuraxial → Hold 3 days (FXa-i) or 4 days (Dabigatran)
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NO BRIDGING
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Resume: 24h (low risk) or 48-72h (high risk) postoperatively
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Emergency surgery → Reversal agent (Idarucizumab/Andexanet/4F-PCC)

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Key Examination Points to Remember

1. No bridging - the hallmark difference from warfarin management.
2. Dabigatran requires longer interruption due to renal dependence and longer half-life at lower CrCl.
3. PAUSE study - landmark evidence validating standard interruption intervals.
4. ASRA requires 3-4 day hold for neuraxial procedures.
5. Specific reversal agents: idarucizumab (dabigatran) vs. andexanet alfa (FXa inhibitors); 4F-PCC for both when unavailable.
6. Routine DOAC levels NOT needed preoperatively (except CKD/neuraxial).
7. Resume no earlier than 24 hours postoperatively; hemostasis must be confirmed first.

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• Miller's Anesthesia, 10th edition - Anticoagulation chapter
• ACC/JAMA 2024 Review: Perioperative Management of DOACs (Douketis & Spyropoulos)
• 2025 DOAC Guidelines, Internal Medicine Journal (PMID: 40448969)
• PAUSE Study - Douketis et al., JAMA Intern Med 2019