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Anticoagulation In Dental Procedures. Galila Zaher MRCPath KAU Assistant Professor. Function of Normal Homeostasis. Prevention of blood loss from intact vessels Arrest of bleeding from damaged vessels. BLOOD CLOTTING. Plasma protein clotting factors Vascular endoth.
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Anticoagulation In Dental Procedures Galila Zaher MRCPath KAU Assistant Professor
Function of Normal Homeostasis Prevention of blood loss from intact vessels Arrest of bleeding from damaged vessels
BLOOD CLOTTING Plasma protein clotting factors Vascular endoth Platelets Bleeding Thrombosis Clotting factors Natural anticoagulant platelets
Vessel wall Local vasoconstriction Platelet release thromboxane A2 Prostacyclin counters effects of Thro-A2 Normal Hemostasis
Vessel wall Platelet Adhesion Shape change Aggregation Release Reaction Normal Hemostasis
ADP Aggregation GpIIb/IIIa GpIIb/IIIa Adrenaline Adhesion Adhesion vWF Endothelium Collagen Platelet Activation Collagen Thrombin ADP GpIIb/IIIa GpIb Adrenaline Adhesion
The “Cascade”, “Waterfall” model: APC (PC +PS) • AT
The “Cascade”, “Waterfall” model: APC (PC +PS) • AT
TF VIIa Xa Va TF-Bearing Cell Normal Hemostasis II X VIII/vWF IIa VIIIa
TF VIIa Xa Va TF-Bearing Cell Normal Hemostasis II X VIII/vWF IIa VIIIa V Va Platelet
TF VIIa Xa Va TF-Bearing Cell Normal Hemostasis II X VIII/vWF IIa VIIIa V Va Platelet Activated Platelet
TF VIIa Xa Va TF-Bearing Cell Normal Hemostasis II X VIII/vWF IIa VIIIa TF V Va VIIa IX Platelet IXa Activated Platelet
TF VIIa Xa Va TF-Bearing Cell Normal Hemostasis II X VIII/vWF IIa VIIIa TF V Va VIIa IX Platelet II IXa X Xa IIa VIIIa IXa Va Activated Platelet
Normal Hemostasis II X VIII/vWF TF VIIa Xa IIa Va VIIIa TF-Bearing Cell TF V Va VIIa IX Platelet II IXa X Xa IIa VIIIa IXa Va Activated Platelet Hoffman et al. Blood Coagul Fibrinolysis 1998;9(suppl 1):S61.
Alternative (Cell-based) Model TF VIIa IXa Fibroblast initiation phase Xa Prothrombin Thrombin Thrombin Amplification Xa IXa XIa Prothrombin XIa VIIIa Platelet Activated platelets
4. Fibrin threads (scanning electron micrograph) Fibrin forms rapidly in stagnant blood. Thrombin plays a pivotal role in the polymerisation of the fibrin strands. Red blood cells become trapped in the fibrin network as the thrombus grows.
Dental extractions BleedingThrombosis
Bleeding complications • Dental extractions OAC 249 :Group 1 INR(1.5–1.99), Group 5 INR >3.5. • INR among the groups did not influence incidence of postoperative bleeding. D. Blinderb Dec 2001
Postoperative bleeding • 214 patients divided into four groups: • Group 1 :no suturing and discontinued • Group 2 no suturing & continued warfarin • Group 3 suturing and discontinued • Group 4 suturing and continued warfarin • Dental extractions may be safely performed for patients on OAC provided the INR level < 3.0 • Decision to suture should be made on case-by-case basis • W. Becker British Dental Journal (2007)
Thrombosis & Bleeding • Medline ,The Cochrane Collaboration database 31 reports • Major bleeding rare ,Thrombo-embolic events (1.6%)Evid Based Dent. 2005 • Descriptive studies (29)1868 patients • Thromboembolic rates were for OAC, 0.6% for D/COAC • Major bleeding was rare despite OAC
Guidelines on oral anticoagulation (warfarin): third edition – • Anticoagulation does not need to be stopped for dental extraction for patients in therapeutic range, i.e. INR <3. 2005 update • Evid Based Dent. 2005 • DATA SOURCES: Medline & Cochrane database • Thrombo-embolic events (1.6%) Major bleeding rare • A guideline, based on the evidence available :Certain surgical or invasive procedures can be undertaken with no interruption of OAC • Nick Malden Dent Update. 2007 Nov
Fibrin glue • Patients OAC without interruption dental extraction • Postoperatively, local hemostasis : • Group I :166 absorbable gelatin sponge and sutures • Group II :154 + fibrin glue • Fibrin glue can be safely used to reduce postoperative bleeding TAWFIK, Egypt 2003 • Group of 250 outpatient clinic setting OAC (INR 1.8-4) and local haemostatic measures were used. • Difference of bleeding complications P= 0.7 ZANON 2003
Bridging Therapy • Long-term OAC therapy Elective surgical procedure. • Retrospective analysis of either IV UH or LMWH • The rates of adverse events (thromboembolic event, major and minor bleeding) NSS (p = 0.67). • Costs were significantly lower in LMWH ACCP 2004 • Large, prospective cohort studies • Procedures with a high bleeding risk will necessitate temporary discontinuation of OAC. • Bridging therapy with shorter-acting anticoagulants, UFH OR LMWH Curr Hematol Rep. 2005 Alex C
RECOMMENDATIONS • Anticoagulation does not need to be stopped for patients in therapeutic range, i.e. INR <3. • Mechanical pressure • Minimize trauma . • Fibrin , Gelatin sponge • Gauze saturated with tranexamic acid • Tranexamic acid mouthwash • Silk suture made on case-by-case