Definition of Anticoagulation Therapeutic interference ("blood-thinning") withthe clotting mechanism of the blood to prevent or treat thrombosis and embolism.
ANTICOAGULATION :are given to prevent and reat thrmbo-embolic disease but thereare many use , ANTICOAGULATION are used to treat severalcardice or vascular disease disordes including1-a trial fibrillation2-cardiac valvular disease3- prosthetic cardiac valves4- isachaemic heart disease and post- myocardial infarction5- (some times), deep venous thrombosis,pulmonary embolism6- cerebrovasucular accident and many other . -the long used anticoagulation are the coumarin warfarin for long termtreatment and heparin for short –term treatment .
because it takes several days for the maximumeffect of warfarin to be realized ,heparin given first.The plasminogine activators such as tpa (altplase)or streptokinase also are useful for controllingcoagulation ,in particular during period aftermyocardial infarction .because tpa is highly selectivefor the degradation of fibrin in clots ,it is extermlyuseful in restoring the latency of coronary arteriesafter thromposis.
Some pt on anticoagulant drugs haveatendency to bleeding after trauma orsurgery .Dental preventive care especially importantto minimize the need for surgicalintervention-may can cause problems –alternatives.Systemic conitions that may aggravate thebleeding tentency.
Drug that might worsen the bleedingtenency (aspirin &other NSAIDS).Intramuscular injections should beavoided& regional block injections mayalso be hazardConscious sedation can be given.
Indications of Anticoagulant Therapy1-Treatment and Prevention of DeepVenous Thrombosis2-Pulmonary Emboli Prevention of stroke inpatients with atrial fibrillation, artificialheart valves, cardiac thrombus.3-Ischaemic heart disease.4-During procedures such as cardiaccatheterisation and apheresis.
The four methods by which the dentist can identify the patient who mayhave a bleeding problem are listed below. Skills acquired through applicationof these methods determine how well dentists can protect certain patientsfrom the dangers of excessive bleeding after dental surgical treatment. Thesefour methods consist of the following: • A good history • Physical examination • Screening clinical laboratory tests • Observation of excessive bleeding after a surgical procedure
ANTICOAGULANTS Three classes:1-Heparin and Low MolecularWeight Heparins (e.g. dalteparin)2-Coumarin Derivatves e.g.Warfarin,3-Indandione Derivatves e.g.Phenindione, Anisindione
WARFARIN (also used as rat poison) andother coumarin drugs (such asphennindione) inhibitcoagulation by antagonizingvitamin K.
INTRODUCTIONWarfarin is the most commonly prescribed oralanti- coagulant. At present over 300,000 people in theUK are taking oral anticoagulants and the treatmentis underused in some conditions. With an ageingpopulation in the UK and a greater proportion of thispopulation retaining their teeth, the number ofpatients taking warfarin who require dentalextractions is likely to increase.
.Therapeutic levels of warfarin are measured by theInternational Normalised Ratio (INR). The British Societyof Haemotology has published guidelines onanticoagulant control which recommend a maximumtarget INR of 3.5, with a range of For dental extractions,patients who have been taking warfarin are at an increasedrisk of perioperative thromboembolism if the drug isstopped but may be at an increased risk of bleeding if it iscontinued.
Managing patients who are taking warfarin andundergoing dental treatment: • If patients on warfarin who require dental surgeryhave an International Normalised Ratio (INR) ofbelow 4.0, they can usually receive their dentaltreatment in primary care without needing to stoptheir warfarin or adjust their dose.. The risk of thromboembolism after temporarywithdrawal of warfarin therapy out weighs the riskof oral bleeding following dental surgery.. Patients on warfarin may bleed more thannormal, but bleeding is usually controlled withlocal .measures
Warfarin does not need to be stopped before primary care dental surgical procedures. Are patients at risk of thromboembolic events if warfarin is stopped?• Stopping warfarin for two days increases the risk of thromboembolic events• This risk is difficult to estimate but is probably between 0.02% and 1% It has been common in primary care dental practice to discontinue warfarin treatment for a few days prior to dental surgery in order to limit bleeding problems. It has been assumed that stopping warfarin for a short period presents a negligible risk to the patient.
Are patients at increased risk of bleeding if warfarincontinues?Yes. Treatment with warfarin impairs clotting and consequently patients have anincreased risk of bleeding during surgical procedures and post-operatively. Bleeding in themouth can be excessive, even in non-anticoagulated patients. This is because the toothsupport structures are highly vascular .If warfarin is continued what is the incidence of postoperativebleeding and is it clinically significant?•Continuing warfarin during dental surgical procedures will increase the risk of postoperativebleeding requiring intervention.•Stopping warfarin is no guarantee that the risk of postoperative bleeding requiringintervention will be eliminated as serious bleeding can occur in non-anticoagulated patients.•Most cases of postoperative bleeding can be managed by pressure or repacking andresuturing the socket.•The incidence of postoperative bleeding not controlled by local measures varies from 0% to3.5%.
Clinically significant postoperative bleeding has been defined12 h as that which; • Continues beyond 12 hours, Causes the patient to call or return to the dental practice or accident and emergency department, or Results in the development of a large haematoma or ecchymosis within the oral soft tissues, or Requires a blood transfusionThe following medical problems may affect coagulation and clotting:•liver impairment and/or alcoholism•renal failure•thrombocytopenia, haemophilia or other disorder of haemostasis•those currently receiving a course of cytotoxic medication.
When should the INR be measured before a dentalprocedure?The INR must be measured prior to dental procedures, ideally this should bedone within 24 hours before the treatment However, this is difficult toachieve in primary care dental practice. For patients who have a stable INR,an INR measured within 72 hours before the procedure is acceptable.Patients will need either to co-ordinate their dental treatment with their nextplanned INR measurement or have an extra INR measurement within 72hours of their planned dental treatment..The INR is valid only for patients who have stable anticoagulant therapy.Patients presenting with an INR much higher than their normal value, even ifit is less than 4.0, should have their procedure postponed and should bereferred back to the clinician maintaining their anticoagulant therapy.
Advice to be given to patients: Advice for patients is available in the patient leaflet, Oral Anticoagulant Therapy: Important information for dental patients*Dental surgery covered by this advice includes:Treatment where the INR does not need to be checked:• Prosthodontics• Conservation• EndodonticsTreatment where the INR does need to be checked :• Extractions• Minor oral surgery• Periodontal surgery• Biopsies
What is the normal INR range?The activity of warfarin is expressed using the international normalised ratio (INR).For an individual not taking warfarin a normal coagulation profile is an INR of 1.0.Pulmonary embolus (PE) 2.5 2.0-3.0Deep vein thrombosis (DVT) 2.5 2.0-3.0Atrial fibrillation 2.5 2.0-3.0Recurrence of embolism - no longer on warfarin 2.5 2.0-3.0Recurrence of embolism on warfarin 3.5 3.0-4.0Mechanical prosthetic heart valves 3.5 3.0-4.0Antiphospholipid syndrome 3.5 3.0-4.0
Which patients taking warfarin shouldnot undergo surgical procedures inprimary care?Patients who have an INR greater than 4.0 should not undergo anyform of surgical procedure without consultation with the clinician who isresponsible for maintaining their anticoagulation (this may be the GP orthe hospital anticoagulant clinic haematologist). The warfarin dose willneed to be adjusted prior to the procedure. Patients who aremaintained with an INR >4.0 or who have very erratic control may needto be referred to a dental hospital or hospital based oral/maxillofacialsurgeon.
Should the primary care dentist ever advise an alteration to the warfarinregimen? No. The GP or the anticoagulant clinic must do this.For what procedures can warfarin be continuedsafely?Minor surgical procedures can be safely carried out without altering the warfarin dose.Those likely to be carried out in primary care will be classified as minor e.g. simpleextraction of up to 3 teeth, gingival surgery, crown and bridge procedures, dentalscaling and the surgical removal of teeth .
-When more than 3 teeth need to be extracted thenmultiple visits will be required.-The extractions may be planned to remove 2-3teeth at a time, by quadrants, or singly at separatevists.- Scaling and root planning should initially berestricted to a limited area to assess if the bleedingis Problematic.
>If acute infection is present, surgery should be avoided untilthe infection has been treated. When the patient is free ofacute infection and the INR is 3.5 or less, minor surgery canbe performed. The procedure should be done with as littletrauma as possible. The American College of Chest Physicians and the American Heart Association/American College of Cardiology also recommend that warfarin therapy should not be interrupted for invasive dental procedures, and that a tranexamic acid(Cyklokapron) or EACA (Amicar) mouthwash should be applieduring the first 2 postoperative days to help control excessive bleeding.
Are there any drug interactions that are relevant to this patient group undergoing dentalsurgical procedures? Amoxicillin - There are anecdotal reports that amoxicillin interacts with warfarin causing increased prothrombin time and/or bleeding but documented cases of an interaction are relatively rare. Clindamycin - Clindamycin does not interact with warfarin when given as a single dose for endocarditis prophylaxis. Metronidazole - CAUTION metronidazole interacts with warfarin and should be avoided wherever possible. If it cannot be avoided the warfarin dose may need to be reduced by a third to a half by the GP or anticoagulant clinic. Erythromycin - Erythromycin interacts with warfarin unpredictably by only affecting certain individuals. Most are unlikely to develop a clinically important interaction. Patients should be advised to be vigilant for any signs of increased bleeding.
Paracetamol – The anticoagulant effect of warfarin is normally not affected, or only increased by asmall amount, by occasional doses of paracetamol. Paracetamol is considered to be safer than aspirinas an analgesic in patients taking warfarin and is the analgesic advised by anticoagulant clinics and thepatient held ‘Anticoagulant therapy booklet’. The anticoagulant effect of warfarin may be enhanced byprolonged regular use of paracetamol.Aspirin – AVOID use as an analgesic and anti-inflammatory agent. Concurrent aspirin increasesthe likelihood of bleeding by 3-5 times, increases the bleeding time and may damage the stomachlining.42 The interaction is well documented and clinically important.Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) - AVOID NSAIDs e.g. ibuprofen, diclofenac.Care should be taken when using NSAIDs in patients on anticoagulant therapy due to the increased riskof bleeding from the gastro-intestinal tract.Rofecoxib (COX-2 inhibitor) – Patients should be closely monitored if rofecoxib is used. Inpatients on chronic warfarin therapy treatment with rofecoxib has been associated with an increase inINR values. Although rofecoxib can increase the risk of gastro-intestinal bleeding, this risk is less thanwith standard NSAIDs and rofecoxib may be considered a safer option. Close monitoring is important inthe first few days of rofecoxib therapy and patients should be advised to be vigilant for signs ofincreased bleeding.
Local anaesthetic:A local anaesthetic containing a vasoconstrictor should beadministered by infiltration or by intraligamentary injection.Regional nerve blocks should be avoided when possible.However, if there is no alternative, local anaesthetic should beadministered cautiously using an aspirating syringe .Localvasoconstriction may be encouraged by infiltrating asmallamount of local anaesthetic containing adrenaline(epinephrine) close to the site of surgery .
HeparinHeparin is a parenteral anticoagulant, which is oftenused for acute thromboembolic episodes orforhospitalizatio protocols that include significantsurgical procedures. Heparin is administeredsubcutaneously or intravenously to prevent deepvenous thrombosis and pulmonary emboli.
Most patients treated with standard heparin arehospitalized and will be prescribed warfarin oncedischarged. Dental emergencies in these patientsduring hospitalization should be treated asconservatively as possible, with avoidance of invasiveprocedures, if possible. Patients treated withhemodialysis are given heparin. The half-life ofheparin is only 1 to 2 hours; thus, if they wait untilthe day after dialysis, these patients can receiveinvasive dental treatment.
Antiplatelet DrugsPlatelets are an important contributor to arterial thrombi.Antiplatelet treatment has been reported to reduce overallmortality from vascular disease by 15% and to reduce nonfatalvascular complications by 30%. Aspirin, the prototypicalantiplatelet drug, exerts its antithrombotic action by irreversiblyinhibiting platelet cyclooxygenase, preventing synthesis ofthromboxane A2, and impairing platelet secretion andaggregation. Aspirin is the least expensive, most widely used, andmost widely studied antiplatelet drug. NSAIDs such as ibuprofenand indobufen act as reversible inhibitors of cyclooxygenase.
Salicylic acid (SA) irreversibly decreases plateletaggregation and is used chronically in the preventionof cardiovascular events and stroke in patients atrisk. In large doses, SA may caus hypoprothrombinemia.Even small doses of SA increase the bleeding.time and decrease platelet adhesiveness
VITAMIN K DEFICIENCY.Deficiency of factors II, VII, IX, X, protein C, protein S •Causes: • 1.Decreased vitamin K intake. 2.Decreased production of vitamin by gut flora (antibiotics) 3. Poor absorption - sprue, biliary obstruction, etc 4.Inhibition of vitamn K action (warfarin, certain antibiotics) Treatment: vitamin K (oral or parenteral) •