Anticoagulation and Dentistry Flashcards
Why are anticoagulants/antiplatelets prescribed?
Prescribed to reduce the risk of thrombosis, with potential for heart attack, pulmonary embolism or stroke in patients with:
- vascular or thromboembolic conditions
- cardiac conditions
- history of stroke
- following heart valve replacement surgery
- cardiac stents
- joint replacements
What are the dental aspects of anticoagulants?
The reduction in thromboembolic events comes at a cost of an increased risk of bleeding either spontaneously of associated with invasive procedures.
The balance of these risks for an individual patient requiring dental treatment os the primary consideration in their management
What are the most commonly used anticoagulants?
- vitamin K antagonists (warfarin)
- antiplatelet drugs
- novel oral anticoagulants (NOACs)
How does warfarin work?
What are its limitations:
Warfarin inhibits coagulation by antagonising vitamin K
- takes at least 48-72 hours for the anticoagulant effect to develop fully
- warfarin action is reversible by vitamin K
- around for over 50 years
- treatment of thromboembolism
- narrow therapeutic range, sensitivity to diet and drug interactions
- requirement for frequent monitoring and dose adjustment
How is warfarin patients monitored?
General management required prior to examination?
- measured by the international normalised ratio (INR) test which is the prothrombin time ratio
- Prothrombin time within normal range - INR of approx 1
- INR above 1 indicates clotting will take longer than normal
Information required prior to examination:
- INR assessed within 72 hours of dental procedure
- INR stable - does not require weekly monitoring, and INR below 4 for past 2 months
- INR should be below 4
How should Warfarin patients be managed before treatment?
What other considerations should be taken?
- ensure pt INR has been checked ideally no more than 24 hours before procedure
- if pt has a stable INR, 72 hours before treatment is acceptable
- pts with unstable INR or who require weekly monitoring or who have had INR > 4 in the last 2 months, must have INR checked within 24 hours of dental treatment
- if INR is 4 or above, inform pts GMP or anticoagulation service and delay treatment, for urgent treatment refer pt to secondary dental care
Consider limiting the initial treatment area:
- single extraction first if possible
- scaling and RSD should be restricted to a limited area to assess for potential bleeding
- suturing over socket with an absorbable haemostatic dressing is essential
Is LA likely to cause bleeding on an anticoagulated patient?
When should a patient book an appointment?
Post op adivce?
LA is unlikely to cause bleeding - should try infiltration prior to a block, but no evidence to suggest a block poses significant risk of bleeding
Timing - at the beginning of the day - increases time to deal with bleeding episodes
- early in the week such as tuesday, check INR on Monday, then deal with any issues for the rest of the working week
Post-op management - as normal
- NHS 111
- local A&E for trauma, pain not relieved, or haemorrhage
- pain relief - follow advice of anticoagulant clinic, do not advice aspirin or any other NSAIDs
When should advice be sought from GMP or anticoagulant clinic on a warfarin patient?
- unstable INR
- INR > 4 in last two months
- other disorders of haemostasis
- renal failure, liver disease or alcoholism
- pt receiving cytotoxic drugs or radiotherapy
What drugs increase warfarin activity?
Decreases warfarin activity?
Increases warfarin activity:
- amoxicillin, metronidazole
- antiepileptics
- antifungals
- hormones
- cardiac drugs
- analgesics
Decreases warfarin activity:
- antiepileptics
- antifungals
- cardiac drugs
- analgesics
- oral contraceptives
Other things that can influence warfarin activity?
Important points to note regarding Warfarin:
- irregular tablet taking
- diets high in vitamin K - green tea, avocado
- alcohol ingestion
- cranberry juice - enhance effects
Warfarin and other vitamin K antagonists should never be stopped by dentist!
Increase risk of thrombosis outweighs the risk of oral bleeding.
Only GMP or anticoagulant clinic can alter or stop patients warfarin treatment
Give some examples of antiplatelet drugs and why they are taken:
Advice for treating patients on these drugs?
Aspirin:
- propylaxis of cerebrovascular disease or MI
- may be self prescribed
Clopidogrel:
- used in conjunction with low dose long term aspirin
Treat without interrupting medication, again, consider limiting initial treatment
Give examples of novel oral anticoagulants (NOACs)
What are they used for?
Rivaroxaban, apixaban, dabigatran
Prophylaxis of venous thromboembolism in adults after hip/knee replacement surgery
Does not require anticoagulant monitoring
Which procedures are unlikely to cause bleeding:
Low risk of post-op bleeding complications?
Unlikely to cuase bleeding:
- LA, BPE, supragingival calculus removal, direct or indirect restorations with supragingival margins, endodontics, impressions/othrodontic treatment
Low risk of bleeding:
- simple extractions, incision and drainage of intra-oral swellings, 6-point perio exam, RSD and subgingival scaling, restorations with subgingival margins
Patients receiving high risk bleeding complications should adjust their schedule as follows:
What is the general advice for all patients taking anticoagulants and antiplatelet drugs:
- plan treatment for early in day and week
- use appropriate local measures and only discharge patient once haemostasis has been achieved
- if travel time to emergency care is a concern, place particular emphasis on use of measures to avoid complications
- provide patient with written post-op advice and emergency contact details
