NHS Forth Valley guideline on perioperative management of patients taking warfarin, having elective surgery

Preoperative assessment guidelines
NHS Forth Valley
  • This guidance is to assist in the perioperative management of elective surgical patients who are taking warfarin. A balance has to be made between the risk of bleeding if the patient is anticoagulated and the thrombotic risk if the patient has anticoagulation stopped.
  • These guidelines are not meant to be a substitute for clinical assessment and decision making but are intended to inform and support the process.
  • Target INR for surgical procedures is given as below 1.5. Individual surgeons may have lower levels and should communicate these clearly in advance in these cases.
  • Use the Thromboembolism risk assessment Q & A pathway to support decision making.
  • Record the management plan in the notes
  • Give the patient verbal and written instructions
  • Liaise with primary care in circumstances where LWWH (Clexane) could be given in the community.
  • If guidance given does not cover a specific clinical setting contact anaesthetist, surgeon or on-call consultant haematologist to discuss. 

Clexane bridging therapy

Clexane Bridging therapy

  • Cautions:
    • Weight >150kg (relative contra indication: use estimated lean body weight to calculate dose)
    • Renal impairment (must be adjusted in renal impairment)
  • Exclusion criteria:
    • History of heparin induced thrombocytopenia
    • End stage renal disease
    • Allergy to LMWH or unfractionated heparin
    • Gastrointestinal bleeding in last 10 days

Addendum: Valves

ALL mechanical valve prostheses should be in the higher risk group EXCEPT those patients with a newer generation mechanical valve in the aortic position without any additional risk factors (e.g. structural heart disease, AF, heart failure).


Antithrombotic therapy in patients with replaced heart valves is guided by the type of prosthesis implanted (mechanical or biological), position of the implant, associated risk factors (such as atrial fibrillation), previous thromboembolism, bleeding risk, and the patient's age.

Replacement valves are at highest risk of thromboembolic events in the first 3 months after implantation; so elective non cardiac surgery should be avoided where possible soon after a new valve is implanted.

Patients with mechanical heart valves require lifelong anticoagulant treatment, and patients with first generation valves (with the highest thromboembolic risk) need a higher target INR than patients with single tilting disc prostheses (intermediate thromboembolic risk) or the newer bileaflet prosthesis (lower thromboembolic risk).

First generation valves : older generation aortic valve replacements with high thrombogenicity (1960 to 1985 approx)

  • Starr-Edwards
  • Bjork-Shiley
  • Omniscience

Second generation valves:

  • St Jude Medical (1978 onwards)
  • Medtronic Hall (with intermediate thrombogenicity - used 1978 to 2000)

Third generation valves:

  • Sorin Bicarbon bileaflet valve (1980 onwards) 
  • ATS valve (1992 onwards)

Thromboembolic events are commoner with prosthetic mitral valves than aortic valves and in patients with double replacement valves compared with those with single replaced valves.

Types of thrombotic valves and thrombogenicity

 

Editorial Information

Author(s): R Neilson, C Labinjoh, J Wilson, S Tracey, A Longmate.