Anticoagulants and Antiplatelets Flashcards
What is blood clotting and how does a blood clot form?
- Process triggered naturally in response to damage to blood vessels from injury or invasive procedures
- Platelets within blood become activated locally
- Leads to increased tendency to adhere to each other and to damaged blood vessel endothelium (primary haemostasis)
- Inactive coagulation factors converted to active forms
- Leads to production of protein fibrin
- Leads to activated cross-linking form of fibrinogen
- Fibrin stabilises primary platelet plug by cross-linking platelets to each other and to damaged blood vessel wall
- Prevents further blood loss (secondary haemostasis)
What do antiplatelets do?
- Interfere with platelet aggregation by reversibly or irreversibly inhibiting various steps in platelet activation for primary haemostasis
- Reduce ability of blood to form clots
What do anticoagulants do?
- Inhibit production or activity of factors required for coagulation stage
- Impair secondary haemostasis
- Reduce ability to coagulate
Why are anticoagulants or antiplatelet drugs prescribed if they lead to increased bleeding risk?
- Atherosclerosis and cardiac arrhythmias have risk of thrombosis
- Thrombus (blood clot) blocks BV at site of formation or thromboembolism
- Can lead to heart attack, pulmonary embolism or stroke
- AC or AP reduce this risk
What are dental procedures unlikely to cause bleeding?
- LA by infiltration, intraligamentary or mental nerve block
- LA by IANB or other nerve blocks
- BPE
- Supragingival removal of plaque, calculus or stain
- Direct or indirect restorations with supragingival margins
- Endodontics - orthograde
- Impressions and other prosthetic procedures
- Fitting and adjustment of ortho appliances
What are dental procedures with low risk of post-op bleeding complications?
- Simple extractions (1-3 teeth with restricted wound size)
- Incision and drainage of intra-oral swellings
- Detailed 6 point full periodontal exam
- Root surface debridement
- Direct or indirect restorations with subgingival margins
What are the dental procedures with higher risk of post-op bleeding complications?
- Complex extractions
- Adjacent extractions that will cause large wound or more than 3 at once
Flap raising procedure inc;
- Elective surgical extractions
- Periodontal surgery
- Preprosthetic surgery
- Periradicular surgery
- Crown lengthening
- Dental implant surgery
- Gingival recontouring
- Biopsies
What patients do you NOT interrupt anticoagulant or antiplatelet therapy for?
- Patients with prosthetic metal heart valves or coronary stents
- Patients who have had pulmonary embolism or deep vein thrombosis in last 3 months
- Patients on anticoagulant therapy for cardioversion
What is the general advice for all patients taking anticoagulants or antiplatelet drugs that require dental treatment likely to cause bleeding?
- Plan treatment early on in day and week
- Pre-treatment instructions dependent on drug
- Treat atraumatically
- Use local measures and only discharge once patient achieved haemostasis
- Post-treatment advice and emergency contact details
What are the most common direct oral anticoagulant drugs?
- Apixaban
- Dabigatran
- Rivaroxaban
- Edoxaban
For low bleeding risk dental procedures what should you advise patient to do with morning dose of DOAC?
- Treat without interrupting medication
For high bleeding risk dental procedures what should you advise patient to do with drug schedule when taking DOAC?
Apixaban/Dabigatran = Miss morning dose and take usual time in evening
Rivaroxaban = Delay morning dose and take 4 hours after haemostasis has been achieved
Edoxaban = Take usual time in evening
What are the main examples of Vitamin K antagonist?
- Warfarin
- Anenocoumarol
- Phenindione
What to do if patient is taking Vitamin K antagonist?
- Check INR no more than 24hrs before procedure (up to 72hrs if patient is stably anticoagulated)
- If INR below 4 = treat without interrupting medication
- Limit initial treatment area and staging extensive or complex procedures
- Suturing and packing
- If INR above 4 delay invasive treatments or refer if urgent
What are the main injectable anticoagulants?
- Dalteparin
- Enozaparin
- Tinzaparin
