Elective Surgery Guideline : Low Molecular Weight Heparin, Warfarin, Direct Oral Anticoagulant and Anti-Platelet Management

What's new / Latest updates

This guideline is an update to the previous Endoscopy Anticoagulation Guidance (v4) and was adapted for use from NHS Lothian.

Scope

This document provides guidance for the management of warfarin, LMWH, DOACs and APT in elective surgery for adult patients. The decision to stop these high-risk medications before surgery and the timing of restarting afterwards reflects a balance between risk of surgical bleeding and the risk of a repeat event. Different surgical procedures hold varying bleeding risk, so an individualised approach is necessary.

Patients who require bridging are those who are at high-risk of thrombosis- see section 6.1 for risk stratification: thrombosis risk. Those who are not high-risk thrombosis are unlikely to need bridging.

This guidance does not cover emergency surgery, and any anticoagulation therapy in emergency surgery should be addressed according to individual risk factors, with consideration using existing emergency reversal protocols, and at the discretion of the surgeon. This guidance is not to be used for pregnant patients.

Audience

Operating surgeon – to define the bleeding risk posed to the patient for the operation and how quickly anticoagulation is to be introduced post-operatively. To ensure thrombotic risks associated with perioperative cessation of anticoagulation are discussed with the patient and understood.

The responsibility for advising when to stop anticoagulation and prescription of peri- procedural medicines, falls to the peri-operative team.

Introduction

This guideline provides generalised guidance for the management of warfarin, therapeutic low molecular weight heparin (LMWH), direct oral anticoagulant (DOACs), and anti-platelet (APT) in elective surgery.

The decision to stop these high-risk medications before surgery and the timing of restarting afterwards reflects a balance between risk of surgical bleeding and the risk of a repeat event.

Different surgical procedures hold varying bleeding risks, so an individualised approach is necessary with reference to local unit guidance. For example, operations and procedures involving bleeding into a confined space, such as neurosurgery, or procedures with high bleeding risk, require a more cautious re-introduction of anticoagulation.

Form to Download - Pre- and Post-Procedure Plan for Anticoagulation Patients with High Risk Thrombotic Indications

Pre And Post Procedure Bridging Form With Elective Surgery Guideline

Dosing Tables

The tables below go through the prophylactic and therapeutic dosing of enoxaparin as set out in the NHS Borders Antithrombotic Guide. Where the guideline mentions prophylactic enoxaparin, please refer to Table 1; where the guideline mentions therapeutic enoxaparin, please refer to Table 2. This document also refers to intermediate dosing, which is elaborated in Table 3.

This guidance does not cover patients who have Creatinine Clearance (CrCl) <30/min and those who weigh over 200kg. These patients should be discussed with Haematology.

Table 1: Prophylaxis doses of enoxaparin

Weight (kg)	Dosage in eGFR ≥ 30ml/min/1.73m²
<50kg	20mg ONCE daily
50-100kg	40mg ONCE daily
101-150kg	40mg TWICE daily
>150kg	60mg TWICE daily*

Table 2: Therapeutic doses of enoxaparin for high-risk thrombosis

Weight (kg)	Dosage in eGFR ≥ 30ml/min/1.73m²
35-49kg	40mg TWICE daily
50-69kg	60mg TWICE daily
70-89kg	80mg TWICE daily
90-129kg	100mg TWICE daily
130-159kg	120mg TWICE daily
160-200kg	150mg TWICE daily

Table 3: Intermediate dosing for enoxaparin

Weight (kg)	Dosage in eGFR ≥ 30ml/min/1.73m²
35-49kg	20mg TWICE daily
50-69kg	20mg in the MORNING and 40mg in the EVENING
70-100kg	40mg TWICE daily
101-150kg	60mg TWICE daily
151-200kg	80mg TWICE daily

Main Content - Key Messages

KEY MESSAGES:

A written pre-operative management plan, based on this guidance, should be available. The anaesthetist in pre op clinic will contact haematology/cardiology and make a plan. This will be via email or over the phone. Emails will be printed and placed in patient notes. The advice will be recorded in the anaesthetic chart or more formally in a letter.

Re-escalation of anticoagulation is dependent on the bleeding risk of surgery. For very high bleeding risk situations seek advice from Haematology or follow unit-specific protocol.

Within 3 months of an episode of VTE, TIA or stroke consider postponement of elective surgery.
Do not withhold dual antiplatelet therapy in patients with recent acute coronary syndrome (ACS) or recent percutaneous coronary intervention (PCI). Elective surgery should usually be postponed for at least 6 months after these events. Cases must be discussed with cardiology.

The table below outlines bleeding risks of common procedures including those where anticoagulation therapy may not need to be interrupted. This is intended as a guide rather than a comprehensive list of the bleeding risks for all operations. The operating surgeon best defines the exact bleeding risk of the procedure, and impact of bleeding (i.e. bleeding in neurosurgery is of high impact); the operating surgeon should be consulted to confirm the need for anticoagulation interruption.

Minor Bleeding Risk*

Dental surgery (simple 1-3 extractions, abscess incision)

Cataract of glaucoma intervention

Endoscopy without resection or biopsy

Superficial surgery (e.g. Abscess excision, simple skin biopsy)

Low Bleeding Risk (Bleeding infrequent or of low clinical impact)

Endoscopy with biopsy

Prostate or bladder biopsy

Pacemaker or ICD implantation

Biliary or pancreatic stenting

Device-assisted enteroscopy without polypectomy

High Bleeding Risk (Bleeding frequent and/or of high impact)

Complex endoscopy (e.g. polypectomy, ERCP with sphincterotomy etc.)

Spinal or epidural anaesthesia: lumbar diagnostic puncture

Thoracic surgery

Abdominal surgery

Major Orthopaedic surgery

Liver biopsy

Transurethral prostate resection

Kidney biopsy

*It is often possible to perform minor bleeding risk procedures without interrupting anticoagulation therapy – this will be dependent on the INR for warfarin and ensuring prudent timing of the procedure in relation to DOAC administration time.

Warfarin

Patients are prescribed long term warfarin to reduce the lifetime risk of stroke, transient ischaemic attack (TIA) or venous thrombo-embolism (VTE).

For a patient prescribed warfarin after a recent (defined as within 3 months) stroke, TIA or VTE, consider postponing elective surgery for three to six months. **PLEASE NOTE THIS IS A HIGH-RISK SITUATION - SEEK ADVICE FROM THE DUTY HAEMATOLOGIST **

Risk stratification: thrombosis risk

If none of the indications in the “increased risk / consider bridging” column apply. The patient has a low risk of thrombosis and bridging is not necessary.

Indication for warfarin	The patient is at INCREASED risk of thrombosis and bridging should be CONSIDERED if any of the following apply:
Venous thrombo- embolism (VTE)	Patient has had VTE in the last three months ¹ Patient has previously had VTE whilst on therapeutic anticoagulation Patient has a target INR > 5 Patient with VTE event with underlying high risk medical condition e.g. myeloproliferative disorder
Atrial Fibrillation (AF)	Patient has had stroke or TIA in the last three months¹. Patient has had a previous stroke or TIA (at any time) and three or more of the following risk factors: Hypertension (>140/90 mmHg or on antihypertensives) Age >75 years Diabetes mellitus Severe LV impairment²
Mechanical Heart Valve (MHV)	All patients with mechanical mitral or aortic valve All patients with mechanical valves require a discussion with a cardiology consultant.
Cerebral Vascular Accident or Transient Ischaemic Attack (CVA/TIA)	Patient with CVA/TIA in last 3 months Patients with previous CVA/TIA and 3 or more of the following Congestive cardiac failure Hypertension (BP>140/90mmHg or on antihypertensive treatment) Age >75 years Diabetes mellitus

¹ VERY HIGH RISK: if possible postpone elective surgery until at least 3 months after event.

² If cardiac function has not been documented there is no need to perform echocardiography to access need for bridging unless there is a clinical concern about congestive cardiac failure.

³ This type of valve was not implanted after 1993.

Management of warfarin before and after surgery

Before surgery Can surgery proceed without stopping warfarin? i.e. some patients undergoing dental extraction, cataract surgery, simple biopsy procedures or where the operation site is easily compressed. If not known, check with patient’s surgeon. If warfarin is to be stopped before surgery, the last dose should be taken on Day minus 6 (where “Day 0” is date of surgery). Further management is guided by risk stratification Patients at increased risk of thrombosis may require peri-operative therapeutic anticoagulation (“BRIDGING”) with LMWH i.e. enoxaparin. Patients at low risk of thrombosis may simply stop warfarin. The need for peri-operative prophylactic enoxaparin is determined by the usual VTE risk assessment criteria.
	Increased Risk of Thrombosis	Low Risk of Thrombosis
Day minus 6	Take last dose of warfarin	Take last dose of warfarin
Day minus 5	No warfarin	No warfarin
Day minus 4	No warfarin	No warfarin
Day minus 3	Check INR; if INR <2 commence *therapeutic* dose Enoxaparin at 8pm. (No warfarin)	No warfarin
Day minus 2	Continue *therapeutic* dose Enoxaparin at 8am and 8pm (No warfarin)	No warfarin
Day minus 1	Last *therapeutic* dose Enoxaparin at 8am only (not for evening dose). If very high bleeding risk, then for prophylactic dose at 8am, max 60mg ONCE daily. (No warfarin)	No warfarin
Day 0 = day of procedure	Check INR pre-operatively	Check INR pre-operatively.
Day 0 = day of procedure	No enoxaparin/ warfarin before surgery. Prophylactic enoxaparin 8-12 hours after end surgery (if no issues with haemostasis, directed by surgeon).

After surgery (“standard bleeding risk”)

Definition: “Day 1” = the first day after surgery, if haemostasis has been secured (as directed by the operating surgeon)

Restart warfarin at the patient’s usual maintenance dose as soon as the risk of post-op bleeding is acceptable. INR should be checked daily after warfarin has been restarted if an in-patient.

For operations and procedures involving bleeding into a confined space, such as neurosurgery, or

procedures with high bleeding risk, a more cautious re-introduction of anticoagulation is necessary.

Increased Risk of Thrombosis

Low Risk of Thrombosis

Days 1 & 2

Warfarin: at patient’s usual dose Enoxaparin: prophylactic dose (not for therapeutic dosing until at least 48-72 hours post-op due to increased bleeding risk).

Warfarin at patient’s usual dose Enoxaparin: prophylactic dose

Days 3 & 4

Warfarin at patient’s usual dose. Enoxaparin, either:

Intermediate dose or if bleeding risk is low, start therapeutic dose

Continue warfarin at patient’s usual dose

Continue prophylactic Enoxaparin until INR is patient’s usual therapeutic range i.e. >2 (if INR range is 2-3) (or 2.5 if target range is 2.5-3.5)

If the oral route is not available by day 3 consider following the Increased Risk pathway

Day 5

Warfarin at patient’s usual dose.

If not already done or INR subtherapeutic: start therapeutic enoxaparin

Day 6 onwards

Warfarin at patient’s usual dose.

Continue therapeutic Enoxaparin until INR is >2 (if INR range is 2-3)

INR should be checked daily in all in-patients taking warfarin until it is in the patient’s therapeutic range.

For patients being discharged home, the INR should be checked on the third day after restarting the patient’s usual maintenance dose of warfarin.

Arrangements for INR post-discharge must be organised with the GP surgery (or to return to the ward if this falls on a weekend or if GP cannot accommodate) by the surgical team, prior to patient going home.

Prophylactic enoxaparin should be continued until INR is >2 or within the patient’s therapeutic range i.e. 2.5 if target range is 2.5-3.5. If this falls over a weekend the patient will need to attend the parent ward for INR check.

Direct Oral Anticoagulants (DOACs)

Examples of direct oral anticoagulants are apixaban, dabigatran, rivaroxaban and edoxaban. Advantages of DOACs compared with warfarin and heparin are a predictable dose response, fewer drug-drug interactions and oral administration. On the other hand, they accumulate in patients with renal impairment and monitoring tests for measuring their anticoagulant activity are not widely available. Bridging with therapeutic LMWH is not required for patients on a DOAC due to the predictable pharmacokinetics allowing for properly timed short-term cessation prior to surgery, except if acute thrombosis within 3 months and /or patient has eGFR less than 45ml/min when a switch to pre-operative LMWH may be indicated.

Guidance on the management of DOACs at the time of elective surgery is based on an estimation of the drug’s half-life and thus its persistence in the circulation (taking into account renal function), combined with the bleeding risk of the proposed procedure.

Most operations should be classified as “high bleeding risk”.
For operations and procedures for which warfarin would be continued consider classifying
as “low bleeding risk”.
“Day 0” is the day of surgery; assume the patient is on the morning list.

Management of DOACs before surgery

Direct Oral Anticoagulants (DOACs)			When to stop before surgery
Direct Oral Anticoagulants (DOACs)	CrCl (ml/min)	Estd half-life (hours)	Low bleeding risk *	High bleeding risk or Spinal or epidural anaesthesia is likely
Apixaban	≥30	8	24h, last dose on evening of day minus 2	48h, last dose on evening of day minus 3
Apixaban	<30		48h, last dose on evening of day minus 3	72 h, last dose on evening of day minus 4
Dabigatran	>50	15	24h, last dose on evening of day minus 2	48h, last dose on evening of day minus 3
Dabigatran	30 to 49	18	72h, last dose on evening of day minus 4	96h, last dose on evening of day minus 5
Rivaroxaban^¥	≥30	9	24h, last dose day minus 2	48 h, last dose day minus 3
Rivaroxaban^¥	<30		48h, last dose day -3	72h, last dose day minus 4
Edoxaban	≥30	10-14	24h, last dose day -2	48h, last dose day minus 3
Edoxaban	<30		48h, last dose day -3	72h, last dose day minus 4
*e.g: superficial operations, procedures for which warfarin would be continued.

Note: ¥peri-operative cessation of low-dose rivaroxaban (2.5mg twice daily) has not been studied and patients should be managed on a case-by-case basis by discussing arterial thrombotic risk with a cardiologist or vascular surgeon.

Restarting DOAC after surgery

DOACs are well absorbed orally and reach peak anticoagulant levels a few hours after ingestion. With the exception of elective hip and knee arthroplasty*, use of prophylactic doses of LMWH may be considered post-operatively if the patient is unable to recommence the DOAC within 24 hours of surgery due to potential bleeding risks associated with surgery/procedure or inability to take oral therapy. Commencement of LMWH should be based on thrombosis risks vs associated bleeding risks as highlighted earlier.

Procedure Risk	Post-operative advice
Minor/low risk procedures	Once haemostasis has been fully secured, DOAC can be recommenced within 8-12 hours post-operatively
High risk procedure / increased bleeding risk	Do not recommence at full-dose until at least 48-72 hours post-op Can consider prophylactic LMWH 8-12 hours post-op based on thromboembolic and bleeding risks
Very high bleeding risk/potential to bleed into confined space	Consider no earlier than 5-7 days post-operatively
*Prophylactic LMWH should be discontinued immediately on recommencing the DOAC*

* Rivaroxaban 10mg once daily, and Apixaban 2.5mg twice daily are licensed for use in thromboprophylaxis in elective hip and knee arthroplasty, and the instructions for use should be followed as set out by the manufacturer in terms of timing of initiation.

Therapeutic low-molecular-weight heparin (LMWH) before & after scheduled surgery (normal renal function)

Note: if any other LMWH brand is in use, this guidance is not relevant. Seek advice from haematology.

Essential information: body weight (kg), FBC and creatinine clearance. If CrCl less than 30 ml/min then seek advice from haematology.

Check indication for anticoagulation: was VTE over 3 months ago? **If less than 3 months ago seek advice from haematology as this is a high-risk situation**

Check patient on correct dose of therapeutic enoxaparin and the time of administration.

Note: the re-escalation regimen is at the discretion of the attending surgical team

	High risk of thrombosis “standard risk of bleeding”	Any thrombotic risk, but increased risk of bleeding/ consequences of bleeding (e.g. neurosurgery)
Before surgery
Day minus 3	Take therapeutic Enoxaparin twice daily as usual	Take last dose of therapeutic Enoxaparin
Day minus 2	Take therapeutic Enoxaparin twice daily as usual	No Enoxaparin
Day minus 1	Last therapeutic dose Enoxaparin at 8am only (not for evening dose). If very high bleeding risk, then for prophylactic dose at 8am, max 60mg ONCE daily.	No Enoxaparin
*If therapeutic Enoxaparin is usually taken at 1800hrs or later, then there is no need for a prophylactic dose on day minus 1 (i.e. no anticoagulation is required on day minus 1).
Day 0 = day of procedure	No Enoxaparin before operation; Prophylactic Enoxaparin 8-12 hours after surgery if no issues with haemostasis	No Enoxaparin before operation; Mechanical measures (TEDs and flowtron boots) after surgery
After surgery
If an epidural catheter is in situ post-operatively, then only standard weight-based prophylaxis can be given until the catheter is removed (usually post-op day 2), and prescribing is at the discretion of the Pain Team and anaesthetist.
Day 1 + 2	Prophylactic Enoxaparin	Mechanical measures (TEDs and flowtron boots) Prophylactic Enoxaparin at discretion of surgeon
Day 3	Intermediate dose Enoxaparin or therapeutic Enoxaparin, at discretion of surgeon	Prophylactic Enoxaparin at discretion of surgeon
Day 4	Intermediate dose Enoxaparin or therapeutic Enoxaparin, at discretion of surgeon	Prophylactic Enoxaparin
Day 5	Therapeutic Enoxaparin	Prophylactic Enoxaparin
Day 6	Therapeutic Enoxaparin	Prophylactic Enoxaparin
Day 7	Therapeutic Enoxaparin	Depending on surgery, consider Intermediate dose¥ Enoxaparin (i.e. prophylactic dose 12 hourly) continuing days 7-14 or longer, prior to re-introducing therapeutic anticoagulation

Anti-platelet medication

Anti-platelet drugs are used in the secondary prevention of cardiovascular disease. Examples include clopidogrel after stroke or TIA and dual antiplatelet therapy with aspirin plus (most commonly) clopidogrel after acute coronary syndromes (ACS) and particularly after coronary stenting.

If a patient is on dual anti-platelet therapy, please discuss with the consultant anaesthetist.

**Dual anti-platelet therapy after ACS or coronary stenting should not be stopped without discussion with the patient’s cardiologist** THIS IS DEEMED A HIGH-RISK SITUATION

Anti-platelet drug	Time to peak effect on coagulation	Elimination half life	When to stop before surgery
Non-steroidal anti-inflammatory drugs (NSAIDs)	1 – 12 hours	1 – 12 hours	Continue¹ (*see note below*) For high-bleeding risk surgery, long-acting NSAIDs should be stopped²
Dipyridamole	75 min	10 hours	Continue¹ (*see note below*), unless also taking another anti-platelet drug
Aspirin (low-dose ≤150mg)	12 – 24 hours	Irreversible effect	Continue¹ (*see note below*)
Clopidogrel	12- 24 hours	Irreversible effect	7 days (last dose day minus 8)
Prasugrel	15 – 30 min	Irreversible effect	7 days (last dose day minus 8)
Ticagrelor	2 hours	8 – 12 hours	5 days (last dose day minus 6)
Dual antiplatelets: aspirin + P2Y12inhibitor i.e. clopidogrel, prasugrel, ticagrelor)	As above	As above	Low bleeding risk: continue both Moderate bleeding risk: continue aspirin and withhold P2Y12inhibitor as above

1 In the following circumstances (see bullet points below), as these antiplatelet drugs remain in the circulation and affect transfused platelets, aspirin, dipyridamole and non-steroidal anti-inflammatory drugs (NSAIDs) (short-acting) should be withheld as per the table below:

If a platelet transfusion is required and/or major blood loss is a possibility
For those procedures associated with high risk of bleeding or bleeding complications (e.g. spinal surgery, certain ophthalmological and neurosurgical procedures)
For individuals who refuse blood transfusion for religious reasons g. Jehovah’s Witness.

The following medications should be withheld:

NSAIDs (short-acting)	Withhold on day of surgery
Dipyridamole	Stop day before surgery
Aspirin	Stop 7 days pre-operatively

Longer acting NSAIDs

2 Longer acting NSAIDs are listed below. Their anti-platelet effect does not warrant withholding routinely before surgery, but they may need to be withheld in patients at increased risk of post-operative renal dysfunction and/or any additional raised bleeding risk:

Long-acting NSAIDs
Name of Drug	Half-life (hours)	Time to stop pre-operatively (days)
Etodolac MR	Approx. 7	2
Indomethacin	2 – 11	3*
Ketoprofen MR	8	2
Nabumetone	Approx. 24	5
Naproxen	12 – 15	4
Piroxicam	50	11
Sulindac	16 – 18 **	4
Tenoxicam	72	15

Restarting anti-platelet medication after surgery

Anti-platelet medication may be restarted after surgery as soon as the bleeding risk is considered acceptable and the oral route is available and should be given alongside enoxaparin thromboprophylaxis for venous thrombosis.

Last reviewed: 30/01/2026

Next review date: 31/01/2029

Author(s): Harvey, K.

Version: 4.0

Co-Author(s): McKaig, R, Berlanski, M, Siddiqi, R, Pal, K.

Approved By: NHS Borders Area Drug & Therapeutics Committee

Reviewer name(s): Harvey, K, NHS Borders Anticoagulation Committee.

Related guidelines

Antithrombotic Guideline - NHS Borders

Related resources

Elective Surgery: Timing of Cessation of Antithrombotic Agents for Spinal or Epidural Anaesthesia – to be Borderised (Kyna Harvey)

References

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van Veen JJ, Makris M. Management of peri-operative antithrombotic therapy. Anaesthesia 2015, 70 (Suppl. 1), 58–67 http://onlinelibrary.wiley.com/doi/10.1111/anae.12900/pdf

Association of Anaesthetists of Great Britain and Ireland, Obstetric Anaesthetists’ Association and Regional Anaesthesia UK. Regional anaesthesia and patients with abnormalities of coagulation. Anaesthesia 2013; 68: 966-72 http://onlinelibrary.wiley.com/doi/10.1111/anae.12359/abstract

Douketis J D, Spyropoulos A, Duncan J, Carrier M et al. Perioperative management of patients with atrial fibrillation receiving a direct oral anticoagulant. JAMA Intern Med. 2019 179 (11): 1469-1478 (PAUSE) cohort study.

The Handbook of Perioperative Medicines, UK Clinical Pharmacy Association (UKCPA) https://www.ukcpa-periophandbook.co.uk/

Doherty J, Gluckman T, Hucker W et al. 2017 ACC Expert Consensus Decision Pathway for Periprocedural Management of Anticoagulation in Patients with Nonvalvular Atrial Fibrillation – A Report of the American College of Cardiology Clinical Expert Consensus Document Task Force. Journal of the American College of Cardiology. 2017; 69(7):871-898

Scottish Dental Clinical Effectiveness Programme (SDCEP). Management of Dental Patients Taking Anticoagulants or Antiplatelet Drugs: Dental Clinical Guidance Date prepared August 2015. Available

at http://www.sdcep.org.uk/published-guidance/anticoagulants-and-antiplatelets [Accessed on 5th June 2023]

Steffel J, Verhamme P, Potpara TS et al. European Society of Cardiology. The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation. European Heart Journal. 2018; 39:1330-1393