Hemostasis and Coagulation Flashcards
aPTT
activated partial thromboblastin time
aPTT ingredients
1 part citrated plasma 1 part
silica contact activator plus phospholipid- incubate at 37 degrees for 5 minutes and then 1 part add calcium ions
PT
prothrombin time
PT ingredients
- citrated plasma to 2 parts calcium, phospholipid and tissue factor
what does aPTT test for?
2, 8, 9, 10, 11. Heparin therapy, lupus anticoagulant, hereditary or acquired deficiency, severe liver disease.
what does PT test for
2, 5, 7, 10. Warfarin therapy, vitamin K deficiency, liver disease, factors or assay inhibitors
Vitamin K dependent factors
2-7-9-10
Cortifact
drug for factor XIII deficiency
Factor VIII deficiency treatment
recombinant factor VIII or virus inactivated monoclonal antibody purified plasma derived factor VIII products.
GP1b
binds to vWF on exposed collagen - primary hemostasis
GPIIb/IIIa
binds to fibrinogen to form bridge between other platelets (complex: Gp2b/3a-fibrinogen-Gp2b/3a)
vwbF- what it is and what it does, where is is
von willebrand factor mediates platelet adherence to injured vessel wall by binging collagen and platelet receptor complex (Gp1b/V/IX) binding causes platelets to degranulate and attract more platelets. Von Willebrand factor is synthesized in the walls of the blood vessels and circulates freely in the blood in a folded form. When it encounters damage to the wall of a blood vessel, particularly in situations of high velocity blood flow, it binds to the collagen beneath the damaged endothelium and uncoils into its active form.
ADAMTS13
cleaves ULvwF multimers- if not cleaved, promotes platelet aggregation-microthrombi
List the Intrinsic pathway for coagulation
12 activates 11-(with ca)11a, which activates 9-(with ca)9a, 8+9= activation of 10a(with PS and Ca), 10+5=2-2a(with PS and Ca)- activates fibrinogen to soluble fibrin. 13 crosslinks fibrin
List extrinsic (trauma) coagulation cascade
Vascular injury- exposed Tissue Factor- activates VII-VIIa, this complex TF-VIIa activates 10- 10 and 5 make 2(with PS and Ca), activates prothrombin-thrombin and fibrinogen to fibrin, XIII- crosslinks fibrin
Heyde’s syndrome
aortic stenosis, the stenotic aortic valve becomes narrowed. Blood flow rate is increased to make up for the narrowing, the combination of narrowing and increased flow rate causes sheer stress which causes vWF to unravel like it does when it senses capillary vessel trauma, cleaved by ADAMTS13, the amount of (inactivated) vWF in the blood decreases and therefore bleeding increases. due to angiodysplasia- causes GI bleeds
angiodysplasia
small vascular malformation in the gut
Primary hemostasis
formation of the platelet plug due to platelet binding and aggregation
Secondary hemostasis
coagulation cascade- ending in crosslinking and stabilization of fibrin. Triggered by Tissue Factor released from epithelial cells with vascular trauma.
Tertiary hemostais
Fibrinolysis
Which part of primary hemostasis effects secondary hemostasis
Primary hemostasis creates Phospholipid which is used in some of the steps within the coagulation cascade.
gla
Gamma carboxyl glutamate residues on 2,7,9,10, these residues are formed by vitamin K dependent enzymes and facilitate calcium dependent complex binding to phospholipid membranes
which coagulation factor has the shortest half-life
VII, 5-8 hours, this is why FFP needs to be frozen in 8 hours. more than 8 hours, half the VII is left.
PCC
prothrombin complex concentration, factor 9 complex, medication 2,9, 10. some version contain factor 7 as well.
Hemophilia B
factor 9 deficiency”christmas disease”- joint bleeding,
Treatment for hemophilia B
PCC, recombinant factor IX- recombinant- animal derived.
Choice for material replacement: Fibrinogen
Cryo, FFP, fibrinogen concentrate
Choice for meterial replacement : Prothrombin
PCC, FFp
Factor 5 choice for material replacement
FFP
Factor7 choice for material replacement
FVIIa, FFP PCC (if it contains factor VII)
Factor 8 choice for material replacement (secondary name for Factor 8)
antihemolytic factor=factor 8, choice for material replacement= Factor VIII concentrate, rFVIII (recombinant factor VIII= drug of choice)
Factor 9 alternate name and choice for material replacement
Christmas factor and Factor 9 concentrate, rFIX, PCC
Factor 10 alternate name and choice for material replacement
Stuart factor, PCC, FFP
XII alternate name and choice for material replacement
Hageman factor and not necessary for replacement, no history of bleeding with this factor deficiency, will show a prolonged aPTT but invivo functionality is normal without this factor.
Non correction with plasma mixing studies
denotes an inhibitor, factor deficiency corrects, and stays corrected
Immediate correction with plasma mixing studies
Due to factor deficiency
Slow correction
Could be due to time sensitive inhibition.
Factor XIII alternate name and choice for material replacement
fibrin stabilizing factor, cryoprecipiate and FFP
vWF choice of replacement
Cryo, humate-P
humate P
used in treatment of vWF deficiency, combination of antihemolytic factor(VIII) and vWF complex, purified from pooled human plasma
HMWK
high molecular weight kininogen
Tissue Factor deficiency
Factor III, this is a trick question there is no such thing as TF deficiency- no known examples causing the industry to imagine that if this were a possible deficiency it is probably incompatible with life and this is why we don’t see it.
Plasmin
the active form (plasminogen is the inactive form) o
INR
international normalized ratio. used to standardize PT between different labs. INR= (PTpatient/PTcontrol)^ISI
ISI
international sensitivity index- varies between different PT reagents
Thrombin Time what does it measure
Time to fibrin clot formation, this bypasses clotting cascade
Thrombin Time what is involved in the testing
Bovine thrombin added to patient plasma
Elevated TT: what does it tell you
Heparin, Low or dysfunctional fibrinogen, DIC due to high D Dimer consumption