Blood Coagulatio

n

ContentsHaemostasis

Vascular Phase

Platelet Phase

Clot formation

Clot retraction

Fibrinolysis

Bleeding Disorders

Diagnosis of bleeding disorders

Clinical implication in periodontology

Haemostasis

Haima + Stasis

Prevent blood loss

Maintains blood flow

Prevents bleeding

• Stages of Hemostasis

Vascular Phase

PLATELET Phase

• 1,50,000 to 400,000 per cu mm Lifespan is 9 – 12 days

• Thrombocyte = “ thrombos” + “ Kytos”

Platelets

• Membrane• Outer glycocalyx layer—

glycoproteins • Inner lipoprotein layer—

phospholipid

Platelet PLUG

Blood coagulation

Role of thrombin

Fibrin formation

SEM of clot

• Release of fibrin stabilizing factor• Contractile protein of platelets• Activated and accelerated by thrombin

and Ca ions.

Clot Retraction

Fibrinolysis

ROLE OF ENDOTHILIUM

Approach to the diagnosis of bleeding disorder

Clinical Evaluation

History

Physical Examination

Family history

Laboratory Evaluation

Screening test

Specific test

Clinical Features of Bleeding Disorders Platelet disorders Coagulation

disorders

Site of bleeding Skin Deep in soft tissues (epistaxis, gum, Mucous vaginal, GI tract) membranes,

joints, muscles) Petechiae Yes No

Ecchymoses (“bruises”) Small, superficial Large, deep

Hemarthrosis / muscle bleeding Extremely rare Common

Bleeding after cuts & scratches Yes No

Bleeding after surgery or trauma Immediate, Delayed (1-2

days), usually mild often severe

Platelet Coagulation

Petechiae, Purpura Hematoma, Joint bl.

Tests for Primary Hemostasis• Bleeding time platelet & vascular phases

• PFA – 100 system Platelet function

• Platelet count Quantification of platelets

• Blood smear Quantitative & morphological abnormalities of platelets , Detection of underlying haemotological disorder

Tests for Secondary hemostasis• Clotting factor Crude test of coagulation

phase

• Prothrombin factor Extrensic & common pathway

• Activated partial

thromboplastin time Intrensic & common pathway

PLATELET COUNT

NORMAL 150,000 - 400,000 CELLS/MM3

< 100,000 Thrombocytopenia

50,000 - 100,000 Mild Thrombocytopenia

< 50,000 Sev Thrombocytopenia

BLEEDING TIME

PROVIDES ASSESSMENT OF PLATELET COUNT AND FUNCTION

NORMAL VALUE

2-8 MINUTES

PROTHROMBIN TIME

Measures Effectiveness of the Extrinsic Pathway Measures the activity of V, VII, X, II , I

NORMAL VALUE 11-16 SECS

Prothrombin time prolongs..

Extrinsic pathway factor deficiencies(FII, V, VII, X)– Inherited or acquired– Consumption (DIC)– oral anticoagulant therapy

INR

INR: International normalized ratio

- was established by the WHO and the International Committee on Thrombosis and Hemostasis for reporting the results of prothrombin tests

- All PT results are standardized by this calculation:

INR= ( Patient PT / Control PT)ISI

ISI= International sensitivity index

- Given by the manufacturer for each particular thromboplastin reagent and instrument combination

ACTIVATED THROMBOPLASTIN TIME

Measures Effectiveness of the Intrinsic

Pathway & common pathway

NORMAL VALUE 25-40 SECS

APTT prolongs..

1. Intrinsic pathway factor deficiencies (FXII, XI,VIII, IX, HMWK, prekallikrein )

- Inherited or acquired- Consumption (DIC)- PIVKA factors in cumarin therapy

2. Specific inhibitors against FXII, XI, VIII, IX, HMWK, prekallikrein

3. Lupus anticoagulant

4. Non-fractionated heparin therapy

THROMBIN TIME

Time for Thrombin To Convert Fibrinogen Fibrin

A Measure of Fibrinolytic Pathway

NORMAL VALUE 9-13 SECS

TT Prolongs..

1. Hypo- afibrinogenaemia2. Dysfibrinogenaemia3. Non fractionated heparin 4. Fibrinogen/ fibrin degradation product s5. Chronic liver disease

SPECIFIC TESTS

Tests for specific Platelet Functions

1. Platelet aggregration test

2. Flow cytometry

3. Test for platelet secretion

4. Clot retraction test

5. Platelet procoagulant activity

Test for Coagulation Phase

6. Quantitative estimation of Fibrinogen

7. Coagulation factor assays

8. F XIII Qualitative assay

Latex agglutination test for Fibrinolysis

Bleeding Disorders

Inherited• Vascular• Platelet• coagulation• Fibrinolytic

Acquired• Vascular• Platelet• coagulation

HEMORRHAGIC DISORDERS

Hemorrhagic syndromes are characterized by a disorder of one or more factors that participate in hemostasis. The majority of hemorrhagic syndromes are blood vessel disorders, platelet number and function disorders, or coagulation factor disorders:

• vasculopathies• thrombocytopenias• thrombocytopathies• coagulopathies.

Vasculopathies

• Vasculopathies may be inherited or acquired. Inherited forms result from blood vessel structure disorders (inherited telangiectasia,Rendu-Osler-Weber’s disease) while acquired disorders can be a consequence of inflammatory or immune processes that damage blood vessel walls.

• In clinical practice, acquired disorders are found more frequently (secondary purpuras, infections,

effects of some drugs, allergic purpura, effect of aspirin, vitamin C deficiency, etc.).

Thrombocytopenias

• Thrombocytopenia, or reduced circulating platelet count, can be inherited or acquired; the acquired form being more frequent.

• Thrombocytopenia occurs as a result of:

– decreased platelet formation with normal platelet survival time (effects of irradiation, drugs, malignant tissue pressure on bone marrow, leukemias, aplastic anemias) or

− increased platelet degradation or platelet deposit in spleen with decreased platelet survival (DIC, effects of drugs, bacterial or viral infections, inherited idiopathic thrombocytopenic purpura, chronic leukemias, lupus erythematosus,Hodgkin’s disease, massive transfusions and liver cirrhosis).

Thrombocytopathies• Inherited Qualitative Platelet Disorders may be due

to abnormalities of

1. platelet membrane glycoproteins,

- Glanzmann Thrombastenia, abnormal GPIIb/IIIa

– Bernard-Soulier Syndrome, abnormal GPIb, GPIX and GPV

– platelet-type of vWD, abnormal GPIb

2. platelet granules,• These may occur due to absence of granules in

platelets, storage pool disorder (characterized by disturbed platelet aggregation to collagen, adrenaline and thrombin), or disturbed release (absence of T A2).

3. platelet coagulant activity, or

4. signal transduction and secretion.• defects in arachidonic acid metabolism,• cyclooxigenase deficiency, platelets unable to produce

thromboxane; endothelium may not produce prostacyclin,

• thromboxane synthesis deficiency, and• defects in platelet secretion and the second wave of

platelet aggregation, found in response to epinephrine or ATP.

Coagulopathies

ACQUIRED BLOOD CLOTTING DISORDERS

They occur in:

– vitamin K deficiency,

– liver diseases,

– liver transplantation,

– disseminated intravascular coagulation,

– renal diseases,

– primary pathological fibrinolysis

– during the course of anticoagulant therapy.

• The extent and severity of periodontal disease determines the necessity for a surgical or nonsurgical treatment approach in its management.

• The nature and severity of an acquired bleeding disorder, and the degree of invasive dental procedures, determines the need to modify the treatment to be provided.

• Various Illnesses, along with pharmacotherapy,may contribute to the tendency for excessive bleeding.

Clinical Implications In Periodontics

Pre-operative management of patients starts with a medical history focusing on the previous bleeding history of the patient and medical conditions associated with bleeding.

Presence of following illness may need a modification in treatment protocol to minimize the risk of intra-operative and postoperative bleeding.

• Chronic renal failure• Lack of vitamin K• Liver failure• Aspirin• Antiplatelet medication• Anticoagulant therpay

•Platelet count should be assessed Surgeries

• Iv infusion 1 hr before• Level should be 50% higher in plasma for

Regional anesthesia

• Antifibrinolytic mouthwash (Lee , Boyle)Scaling and root

planing

• regional anesthesia should be avoidedLA

• Conservative design• Mandibular molarFlap

• Curettage of extraction socket• Granulation tissue

Prevention of infection

Intra-operative measures include a number of systemic and local measures administered prior to, or during, the procedure to prevent unlikely bleeding diathesis.

Hemostatic agent

•Absorbable gelatin•Absorbable collagen•Microfibrillar collagen•Oxidised cellulose•Thrombin•Tranexamic acid•Fibrin glue•PRP

Other means

•Sponge•Surgical splint•Electrocautery•Laser•Moistened or hemostatic soaked gauze

Hard tissue

•Bone burnishing•Bone wax

General recommendations is crucial for preventing bleeding, postoperatively.

Prohibition of Rinsing

Liquid , high protein diet

Antifibrinolytic mouthwash

Antibiotics

Pain medication

References :-

• Textbook of Medical Physiology ,10th edition,Hall & Guyton

• Essentials of hematology , Shirish M Kawthalkar• Periodontal Medicine, Rose• Bleeding disorders and periodontology, Philip

Vassilopoulos & Kent Palcanis , Periodontology 2000, Vol. 44, 2007, 211–223.

• Coagulation Pathway and Physiology, Jerry B. Lefkowitz• Hemostasis And Hemorrhagic Disorders, R. Baklaja, M.

C. Pešic´, J. Czarnecki• Platelet function analysis,Paul Harisson, Blood Reviews

(2005) 19, 111–123

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