Review of haemostasis
Dr J Jordaan
Dept Cardiothoracic surgery and Critical care
University of the Free State
Bloemfontein
EACTS/ Hannes Meyer symposium 2012
Blood• Jean-Baptiste Denis first blood transfusion-3U Sheep blood in
1667.• Dr P Physick, Philadelphia first successful blood transfusion in
1795.• Dr Karl Landsteiner discovered A B and O blood types in 1900.• First blood bank USA, 1937.• 14 MU packed cells given in 2001 in USA.
• Theories on the coagulation of blood have existed since antiquity. Physiologist Johannes Peter Müller in 1858 described fibrin, and isolated chemically by Prosper Sylvain Denis in 1863
• Alexander Schmidt suggested that the conversion from fibrinogen to fibrin is the result of an enzyme process, and labeled the hypothetical enzyme "thrombin" and its precursor "prothrombin".
• Nicolas Maurice Arthus discovered in 1890 that calcium was essential in coagulation.
• Platelets were identified in 1865, and their function was elucidated by Giulio Bizzozero in 1882.
• The theory that thrombin is generated by the presence of tissue factor was consolidated by Paul Morawitz in 1905. At this stage, it was known that thrombokinase/thromboplastin (factor III) is released by damaged tissues, reacting with prothrombin (II), which, together with Calcium, forms thrombin, which converts fibrinogen into fibrin (I).
FIRST RESPONSE:
• Initial Vasoconstriction• Release of TA2 and
Endothelin• Reduction in Prostacyclin
and Nitric oxide• Immediately limits blood
loss
Endothelium:• Endothelium
damage • Exposure of
Collagen• Collagen and vWF
interaction• Platelet activation
Traditional pathway:• Intrinsic and extrinsic
pathways• Activation of F X• Activation of F II• Fibrin formation with Fibrin
clot• In Vitro and In Vivo results
findings not supportive
FXII FXIIa
F XI F XIa
FIX FIXa
FX FXa
Pro thrombin Thrombin
Fibrinogen
Fibrin
Firm clot
Intrinsic pathway
Ca CaF VIIIPhospholipid
F VCa
F XIII
Extrinsic Pathway
TF- FVIIa
Hageman factor
Cell based coagulation
• Initiation• Priming• Propagation
Monroe DM, Arterioscler Thromb Vasc Biology 22:1381-1389, 2006
Cell based coagulation
• Vascular injury• Tissue factor exposed by TF
bearing cell• Endothelium• Myoepithelium• Adventitia• Monocytes• Macrophages
1. Initiation:
Tissue factor bearing cell
EndotheliumAdventitial cellsMyoepitheliumSquamous cellsMonocytesMacrophages
TF
FVIIa
FVII FX
FXa F X-F Va
Pro thrombin
Thrombin
F IX
FIXa
TF
FVIIa
Enhance platelet activationAccelerate coagulation response
Priming:
Tissue factor bearing cell
TF
VIIa Xa
Va
Platelet
Thrombin
Platelet primed due to collagen exposure through GP 1b reseptor
Shape conformation and release of granules
F V
F Va
F XI
F XIa
vWF/F VIII
vWF
F VIIIa
Top Related