1 New patients should be assessed carefully
Confirm the following:
- The indication for anticoagulation, including documented ECG for atrial fibrillation (AF).
- For AF, clearly document objective rate of embolic stroke (CHA2DS2VASc), and objective rate of major bleeding risk (HAS-BLED).1,2
- Good blood pressure control (systolic <160 before starting; and <140 ideally for ongoing management).
- Patient understanding of the above and the need for compliance and monitoring/follow up.
- Ensure GP documented patient specific directive, if advice is being provided by a non-prescriber.
2 Prospective planning is key to a smooth, efficient and safe anticoagulation review
Make sure you have logged into the INR software with the correct patient details, and that the testing equipment is ready. Be prepared for a contingency situation, eg the INR machine does not work. Have internal protocols within the practice how you would overcome these obstacles.
3 Treat INRs out of target range with an agreed protocol
High INR is associated with increased risk of bleeding and must be treated as per an agreed protocol, with oversight from a clinician. It is essential to understand when interventions are required, eg hold warfarin for a few days, vitamin K administration and consideration of hospital assessment.
Low INR is associated with increased risk of stroke or systemic embolism. Categorisation of risk status is essential to clarify when heparin cover is required in patients at high risk of embolism, eg metallic heart valves or a recent embolic event. In most situations, a transient increase in warfarin dose with a repeat INR in a few days is likely to suffice.
4 Understand time in therapeutic range (TTR)
All staff managing anticoagulation should understand the concept of TTR and be aware that NICE guidelines recommend that the TTR should be >65% for warfarin to be effective.3 Suboptimal TTR (<65%) should prompt a clinical review, including:
- Review of contributory factors such as poor compliance and concomitant medications.
- Review of anticoagulant choice, and consideration of newer agents (DOAC) assuming a licensed indication (non-valvular AF or VTE).
5 Simplify warfarin use
Use 1mg tablets as standard to avoid confusion with dosing. Over the longer term, higher dose tablets (eg 5mg) may allow reduction in pill burden and should be considered in full discussion with the patient. Encourage patients to take the dose at 6pm as standard.
6 Inform patients on warfarin about alternative anticoagulants
All staff managing anticoagulation need to be aware of DOACs, standard doses and dose adjustment requirements and be able to address basic questions around comparisons between warfarin and DOACs to enable patient choice in line with NICE recommendations.3 Patients on warfarin should be informed of alternative anticoagulants if they have a licensed indication.
7 Have access to local policy on anticoagulation
Staff need to be aware of and have access to local policy surrounding anticoagulation and risk management and have pathways to access prompt advice for patients on anticoagulation. Drug usage should be in line with product license and supported by a patient specific directive.
8 Always work within your limitations and competencies
Software to support anticoagulation monitoring can advise on dosage, but this needs to be tempered by clinical judgement, and can be overridden by clinical judgement. Managing INR results when it is within a patient’s target range is relatively easy. However, when INR is out of target range, inexperienced clinicians may lack confidence in dosing and need support.
9 Know the software, support helplines, guidelines and equipment
Various toolkits and software exist to support warfarin dosing, eg INRstar. Ensure appropriate level of access to the software, active login status, and familiarity with local guidelines, equipment
10 Standardise documentation
Use of standardised documentation enables a structured record of information given and rationale for clinical decisions, eg anticoagulation choice, risk-benefit discussion, anticoagulation booklet and alert card. Consider providing a printout summary from the system to minimise human error.
- Lip GYH, Nieuwlaat R, Pisters R, et al. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach CHEST 2010;137:263-272
- Pisters R, Lane DA, Nieuwlaat R, et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation CHEST 2010;138:1093-1100.
- NICE. CG180: Atrial fibrillation. London;NICE:2014
- Kaur D, Langford N, Mistri AK. Local audit data on DOAC dose choice. Leicester;2018