Anti platelet drugs and anticoagulants are prescribed more than in the past
· Increased prevalence of ischaemic heart disease, strokes and thrombophilia
· More aging population due to increased life expectancy
Anti Platelet Medication is indicated for
· Ischaemia heart disease
· Peripheral vascular disease
· Strokes due to thromboembolic disease
How do anti platelet drugs affect clotting ?
· Platelets provide the initial haemostatic plug at the site of a vascular injury.
· They are also involved in pathological processes and are an important contributor to arterial thrombosis leading to myocardial infarction and ischaemic stroke.
Antiplatelet medications include
Low dose aspirin (75mg-300mg daily).
· Secondary prevention of thrombotic cardiovascular
· or cerebrovascular disease
· and following coronary artery bypass
· Prevention of atherothrombotic events in patients suffering myocardial infarction
· Ischaemic stroke or peripheral arterial disease
· unstable angina or non-Q-wave myocardial infarction in acute coronary syndrome
Dipyridamole (Persantin, Persantin Retard).
· Used as an adjunct to oral anticoagulation for the prophylaxis of thromboembolism associated with prosthetic heart valves,
· For secondary prevention of ischaemic stroke and transient ischaemic attacks.
· Contains both aspirin and dipyridamole and is used for the secondary prevention of stroke and transient ischaemic attacks.
All antiplatelet medications affect clotting by inhibiting platelet aggregation
Aspirin and clopidogrel irreversibly inhibit platelet aggregation within one hour of ingestion and this lasts for the life of the platelets (7-10 days). The effect is only overcome by the manufacture of new platelets.
The action of dipyridamole is reversible.
Non-steroidal anti-inflammatory drugs (NSAIDs) other than aspirin (e.g. ibuprofen, diclofenac) have a reversible effect on platelet aggregation and platelet function is restored once the drug is cleared from the circulation.
What are the thromboembolic risks associated with stopping antiplatelet medications in the perioperative period?
Stopping aspirin prior to surgical procedures may increase the risk of thromboembolic events by 0.005%.
What are the risks of bleeding associated with continuing antiplatelet
medications in the perioperative period?
medications in the perioperative period?
Patients taking antiplatelet medications will have a prolonged bleeding time but this may not be clinically relevant.
Postoperative bleeding after dental procedures can be controlled using local haemostatic measures.
Clinically significant postoperative bleeding
· Continues beyond 12 hours
· Causes the patient to call or return to the dental practice or accident and emergency department
· Results in the development of a large haematoma or ecchymosis within the oral soft tissues
· Requires a blood transfusion
· Patients with underlying hepatic, renal or bone marrow disorders often have disease related Bleeding disorders.
· Bleeding risk also increases with age and with heavy alcohol consumption.
How do the risks of thromboembolic events and postoperative bleeding balance?
· Bleeding complications, while inconvenient, do not carry the same risks as thromboembolic complications.Patients are more at risk of permanent disability or death if they stop antiplatelet medications prior to a surgical procedure than if they continue it.
· Published reviews of the available literature advise that aspirin should not be stopped prior to dental surgical procedures.
· Thromboembolic events, including fatalities, have been reported after antiplatelet withdrawal.
· Although the risk is low, the outcome is serious. This must be balanced against the fact that there is no single report of uncontrollable bleeding when dental procedures have been carried out without stopping antiplatelet medications
· Antiplatelet medications should only be discontinued in the perioperative period when the haemorrhagic risk of continuing them is definitely greater than the cardiovascular risk associated with their discontinuation.
· Consensus is that for minor surgical procedures, including procedures, antiplatelet medications should not be stopped or doses altered but that local haemostatic measures are used to control bleeding.
Which patients taking antiplatelet medication should not undergo surgical procedures in primary care?
· Liver impairment and/or alcoholism renal failure
· Thrombocytopenia, haemophilia or other disorder of haemostasis
· Those currently receiving a course of cytotoxic medication.
· Patients requiring major surgery are unlikely to be treated in the primary care setting.
For what procedures can antiplatelet medications be safely continued?
· Minor surgical procedures can be safely carried out without altering the antiplatelet medication dose. Those likely to be carried out in primary care will be
· Simple extraction of up to three teeth, gingival surgery, crown and bridge procedures, dental scaling and the surgical removal of teeth.
· When more than 3 teeth need to be extracted then multiple visits will be required. The extractions may be planned to remove 2-3 teeth at a time, by quadrants, or singly at separate visits.
· Scaling and gingival surgery should initially be restricted to a limited area to assess if bleeding is problematic.
Patients on Warfarin
· Prophylaxis of deep vein thrombosis 2-3
· Prophylaxis of pulmonary embolism 2-3
· Atrial fibrillation 2-3
· Recurrence of embolism (not on warfarin) 2-3
· Recurrence of embolism (on warfarin) 3-4
· Mechanical prosthetic heart valves 3-4
· Antiphospholipid antibody syndrome 3-4
*** In theory all patients on Warfarin should have INR <4
Are patients at risk of thromboembolic effects if Warfarin discontineud
Stopping Warfarin for two days increases thrombolic effects
Stopping Warfarin can lead to a rebound hypercoagulable state ?
Are patients at risk of bleeding if Warfarin continues? Yes
Treatment with Warfarin impairs clotting and the patients have increased risk of bleeding during surgical procedures and post operatively.
Bleeding in mouth can be excessive even in non anticoagulated patients as the tooth support structures are highly vascular and due to the fibrinolytic effect of saliva.
Most cases of bleeding can be managed by pressure or repacking and resuturing the socket
The incidence of post operative bleeding not controlled by local measures varies from 0-3.5%
How do the thromboembolic effects and bleeding risk balance?
Bleeding complications, while inconvenient, do not carry the same risk as thrombo-embolic complications.
Patients whose INR are within the therapeutic range are more at risk of permanent disability or death if they have Warfarin stopped prior to surgical procedure than continuing it.
Which patients taking Warfarin should not undergo surgery in primary care
Patients who have INR over 4 should not undergo surgery without consulting the haematologist. Their Warfarin dose needs to be adjusted before surgery.
Patients who are maintained with an INR over 4 needs to be referred to a dental hospital for surgery.
When should the INR be measured before a dental procedure?
INR must be measured prior to dental procedures, ideally this should be done 24 hours before the procedure.
For patients who have stable INR values, the INR should be measured at least 72 hours before the procedure.
Up to what INR value can dental procedures be carried out?
Minor surgical procedures can be safely carried out in patients with INR <4
Minor procedures can be carried out without altering the Warfarin therapy if the INR is within therapeutic range.
How should the risk of bleeding due to either antiplatelet or anticoagulants be managed?
Think about the timing of the surgery. Planned surgery should ideally be:
At the beginning of the day - this allows more time to deal with immediate re-bleeding problems.
Early in the week - this allows for delayed re-bleeding episodes occurring after 24–48 hours to be dealt with during the working week.
A local anaesthetic containing a vasoconstrictor should be administered by infiltration or by intraligamentary injection wherever practical.
Regional nerve blocks should be avoided when possible. However, if there is no alternative, local anaesthetic should be administered cautiously using an aspirating syringe.
Local vasoconstriction may be encouraged by infiltrating a small amount of local anaesthetic containing adrenaline (epinephrine) close to the site of surgery.
Sockets should be gently packed with an absorbable haemostatic dressing e.g.
oxidised cellulose, collagen sponge, resorbable gelatin, sponge
Then carefully sutured. Resorbable sutures.
If non-resorbable sutures are used, remove after 4-7 days.
Following closure, pressure should be applied to the socket(s) by using a gauze pad that the patient bites down on for 15 to 30 minutes.
Efforts should be made to make the procedure as atraumatic as possible and any bleeding should be managed using local measures.
Tranexemic mouth washes are useful.
Patients should be given clear instructions on the management of the clot in the postoperative period and advised
To look after the initial clot by resting while the local anaesthetic wears off and the clot fully forms (2-3 hours)
To avoid rinsing the mouth for 24 hours
Not to suck hard or disturb the socket with the tongue or any foreign object
To avoid hot liquids and hard foods for the rest of the day
To avoid chewing on the affected side until it is clear that a stable clot has formed.
Care should then be taken to avoid dislodging the clot if bleeding continues or restarts, to apply pressure over the socket using a folded clean handkerchief or gauze pad. Place the pad over the socket and bite down firmly for 20 minutes. If bleeding does not stop, the dentist should be contacted; repacking and re suturing of the socket may be required
whom to contact if they have excessive or prolonged postoperative bleeding.
How should postoperative pain control be managed?
Generally paracetamol is considered a safe over the counter analgesic for patients taking antiplatelet medications and it may be taken in normal doses if pain control is needed and no contraindication exists.
Patients should be advised to not to take Aspirin at analgesic doses and non-steroidal anti-inflammatory drugs (NSAIDs) e.g. ibuprofen are considered less safe and should be avoided if possible
Are there any drug interactions that are relevant to patients on antiplatelet drugs undergoing dental surgical procedures
NSAIDs in combination with aspirin or clopidogrel should be used with caution. NSAIDs can damage the lining of the gastro-intestinal tract leading to bleeding that may be worsened by aspirin or clopidogrel.
There is no evidence of an interaction between dipyridamole and NSAIDs.
The concomitant use of dipyridamole plus aspirin does not increase the risk of bleeding.
Drug interactions with Warfarin
Amoxycillin: Increases INR and may cause bleeding
Metranidazole: Caution! Interacts with Warfarin and should be avoided. If unavoidable, use 1/3-1/2 dose of Warfarin.
Erythromycin: unpredictable interaction
Aspirin & NSAID: Avoid! There is increased risk of gastro intestinal haemorrhage
Antiplatelet and anticoagulant therapy does not need to be stopped before minor dental surgical procedures
Discontinuing antiplatelet /anticoagulation therapy for surgery was associated with an increased risk of thromboembolism
Good local haemostasis & better planning will decrease the excessive bleeding and minimize complications