UK Clinical Pharmacy Association

Anticoagulants (oral) Overview

Risk of thromboembolism

Perioperative anticoagulation decision-making should take into account the patient’s underlying thrombotic risk (see below). Risk of thrombosis should be balanced against urgency of surgery; non-urgent surgery should be delayed where possible in acute situations where thrombosis risk will improve (e.g. patients with recent CVA or VTE). A Haematologist should be consulted for complex VTE patients.

Thromboembolic risk stratification

High Thromboembolism RiskModerate Thromboembolism RiskLow Thromboembolism Risk

Stroke or TIA within 3 months

7 or more

Rheumatic valvular disease

5 - 6

Stroke or TIA more than 3 months prior

0 - 4
(and no history of stroke / TIA)

Metallic heart valve*
Mitral valve prosthesis

Cage-ball or tilting disc (aortic or mitral)

Stroke or TIA within 3 months

Bileaflet aortic valve with major risk factors for strokea

Bileaflet aortic valve with no other risk factors for stroke

Venous Thromboembolism (VTE)
VTE within
3 months

Severe thrombophiliab

VTE with INR target of 3.5

Active cancer associated with high VTE riskc
Recurrent VTE

VTE 3 - 12 months prior

Non-severe thrombophiliad

Active cancer or recent history of cancer
(i.e. 6 months prior)

VTE more than 12 months prior

* All DOACs are currently contraindicated for patients with a metallic heart valve

aMultiple prior strokes, prior perioperative stroke, prior valve thrombosis

bAntiphospholipid syndrome, deficiency of protein C, protein S, or Antithrombin, multiple thrombophilia

cPacreatic cancer, myeloproliferative disorders, primary brain cancer, gastric cancer, oesophageal cancer

dHeterozygous for Factor V Leiden or prothrombin gene mutation

Risk of bleeding

The information below outlines the bleeding risk of common procedures including those where anticoagulation therapy may not have to be interrupted. This is intended as a guide rather than a comprehensive list of the bleeding risk for all operations. The operating surgeon best defines the exact bleeding risk of the procedure and, if necessary, should be consulted to confirm the need for anticoagulant interruption.

Minor bleeding risk

Minor risk interventions (bleeding infrequent and low clinical impact)*
Dental surgery (e.g. simple 1 - 3 extraction, abscess incision)
Cataract or glaucoma intervention
Minor dermatologic procedures (e.g. excision of basal or squamous cell cancers)
Superficial surgery (e.g. abscess excision, simple skin biopsy)
Pacemaker or cardioverter defibrillator (ICD) implantation

*It is often possible to perform low 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 (see individual drug records for further advice)

Low / moderate bleeding risk

Low / moderate risk interventions (bleeding infrequent or non-severe clinical impact)
Complex dental procedures
Prostate or bladder biopsy
Small orthopaedic surgery (foot, hand, arthroscopy)
Abdominal hernia repair
Haemorrhoid surgery
Abdominal hysterectomy

High bleeding risk

High risk interventions (bleeding frequent and / or of important clinical impact)
Cardiac surgery
Cancer surgery (especially solid tumour resection)
Spinal or epidural anaesthesia; lumbar diagnostic puncture
Thoracic surgery
Abdominal surgery (including liver biopsy)
Major orthopaedic surgery
Major urologic surgery / biopsy (including kidney)
Extracorporeal shockwave therapy
Peripheral arterial revascularisation surgery (e.g., aortic aneurysm repair, vascular bypass)
Reconstructive plastic surgery

Bridging therapy with low molecular weight heparin (LMWH)


Bridging with therapeutic LMWH is not required for patients on a DOAC. The predictable pharmacokinetics of DOACs allows for properly timed short-term cessation of DOAC therapy prior to surgery. In addition, bridging with heparin/LMWH is associated with an increased bleeding risk without reducing cardiovascular events.

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 the potential risk of bleeding associated with the surgery/procedure or inability to take oral therapy. Commencement of prophylactic doses of LMWH should be based on the patient’s thromboembolic risk versus the associated bleeding risk (as detailed above). LMWH should never be administered in conjunction with DOAC therapy.


Bridging with therapeutic LMWH may be required for patients on warfarin. The decision to use bridging therapy should be based on the patient’s thromboembolic risk and the associated bleeding risk (as detailed above) – see warfarin drug record for details of the British Committee for Standards in Haematology’s recommendations.

Use of prophylactic doses of LWMH should be considered if the patient is unable to recommence warfarin in the immediate post-operative period (e.g. due to concerns around post-operative bleeding or oral absorption).

In some cases, patients may require post-operative bridging therapy with therapeutic LMWH until they are able to safely recommence their warfarin.


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