Fibrinolysis Flashcards
What are the mechanisms of platelet adhesion ? (Primary H)
GPIb complex
GPVI receptors
VWF
Fibrinogen
Platelet aggregation process
What is the second hameostasiscomposed of?
Extrinsic and intrinsic pathway
How is fibrin formed and polymerised
Thrombin converts solublefibrinoen to insoluble fibrin, this stabilised platelet plug and forms thrombus
Thrombincleavs fibringen and release fibrinoeptide A and B
Creates fibrin monomers
Ptoyofibrils form through monomers
Held by nonconvalent fore’s between Ddomian ad D-E domin
Factor XIII activated b thrombin promoting covalent cross-linking between molecules
What is fibrinolysis?
Enzymaticbreakdown of fibrin clots
prevents excessive vascular occlusion
Fancies wound healing
Generates firin degration products
Activated by tissue plasminogen (tPa) and urokinase (uPA)
What are fbrinolyis inhibition mechanisms ?
1 plasminogen activator (PAI)
Eg PA-1 and PA-2, neutralise circulating plasmin and activators
2 a2-antiplasmin (A2AP)blocks unregulated plasmin activity
3 thrombin activatable fibrnlysis inhibitor (TAFI) prevents continued plasminogen binding
What tests for fibrinolysis?
Coagulation test APTT, Prothromin tme (PT) fibrinogen level assessment
D-Dimer anaylss- indicates Ative thromblysis, used in DVTand DIC DIAGNOSE
Therapeutic interventions or fibrinolysis
-antifibrinolytics such as Tanexamic acid: synthetic lysinederivative,bocks plasminogen binding sites,for surgical procedures,dental extractions, memorrhagia management, hereditaryangioedema
Fibrinolytics- primary - remove blood clot and restore bood flow
Used oracle myocardial infraction,isechemic stroke,DVT,peripheral arterial occuluson
Fibrinolyticagents:
Streptokinase- protein from streptococci cultures, activates plasminogen, reduce MI mortalities
2) tissue plasminogen activator (tPA) recombination variants
What are the limitations and considerations for interventions
Narrow therapeutic time window
Most effective within 6hrs
Otential bleeding risk
Antibody developed with repeated risk
