Topic Highlight
Copyright ©2014 Baishideng Publishing Group Inc.
World J Gastroenterol. May 28, 2014; 20(20): 6146-6158
Published online May 28, 2014. doi: 10.3748/wjg.v20.i20.6146
Table 1 Risks of transfusion
General risks
Transfusion related immunomodulationAccumulation of immune mediators in stored blood
Transfusion associated circulatory overloadAcute left ventricular failure or congestive cardiac failure
Transfusion related acute lung injuryCapillary leak and neutrophil extravasation and activation caused by: Immune mediated: Donor antibodies react with recipient white blood cells, forming leukoagglutinate that become trapped in the lung Non-immune mediated: Endothelium suffers initial insult (e.g., sepsis, surgery or trauma), attracting neutrophils that are activated by biologically active compounds in stored blood
Haemolytic transfusion reactionsImmediate: Donor membrane antigens react with antibodies against these present in recipient plasma
Delayed: Alloimmunised recipient with specific antibodies respond to re-exposure to antigen positive red blood cells
Acute non haemolytic transfusion reactionsFebrile: Donor leucocyte antigens react with recipient white cell antibodies
Allergic: Soluble donor antigens react in an already sensitised recipient
Post-transfusion purpuraPrevious sensitisation produces antibodies which attach donor platelet antigens and additionally destroy their own platelets
Transfusion associated graft vs host diseaseDonor lymphocytes proliferate within immunocompromised recipient, attacking host cells as ‘‘foreign’’
InfectionBacterial 1:2000-1:500000
Viral: hepatitis B 1:450000; hepatitis C 1:32000000; HIV 1:5000000; human T-cell leukaemia virus 1:12500000
Table 2 Alterations in both anti- and pro- haemostatic dynamics in liver disease
Primary haemostasis (platelet-vessel wall interaction)ThrombocytopaeniaElevated levels of Von Willebrand factor
Platelet function defectsDecreased levels of ADAMTS-13
Increased nitric oxide and prostacyclinPlatelet hyper reactivity
Secondary haemostasis (thrombin generation and inhibition)Low levels of factors II, V, VII, IX, X, XIIncreased factor VIII
Vitamin K deficiencyDecreased protein C, S, AT-III, alpha 2 macroglobulin, heparin co-factor II
FibrinolysisLow levels of alpha 2 anti-plasmin, factor XIII, thrombin activatable fibrinolysis inhibitorLow levels of plasminogen
Elevated tissue plasminogen activatorHigh levels of plasminogen activator inhibitor
Table 3 Coagulopathy during transplantation
StageCoagulation abnormalities increasing bleedingOther risk factors for bleedingTEG
DissectionThrombocytopaenia Platelet function defects Increased nitric oxide and prostacyclin Low levels of factors II, V, VII, IX, X, XI Vitamin K deficiency Low levels of alpha 2 anti-plasmin, factor XIII, thrombin activatable fibrinolysis inhibitor Elevated t-PA DysfibrinogenaemiaSurgical technical difficulty Portal hypertension Oesophago-gastric venous distension secondary to compression and vascular clampingProlonged R time Decreased alpha-angle Reduced MA
AnhepaticReduced coagulation factor synthesis Reduced clearance of t-PADuration greater than 45 minIncreased lysis
Reperfusion‘‘Heparin like effect’’ Platelet entrapment in sinusoids of donor liver Reduction of all coagulation factors Decreased PAI-1 Decreased antifibrinolytic factors Hyper-fibrinolysisAcidosis HypothermiaVirtually ‘‘flat’’ native trace with prolonged R time and significantly reduced MA Heparinase trace required Lysis
Post reperfusionAccelerated t-PA release Thrombocytopaenia (balanced by increased activation)Delayed graft functionMA reduced
Table 4 Parameters of viscoelastic tests - thromboelastography/rotational thromboelastometry
Clotting timeRCTRelates to concentration of soluble clotting factors in the plasma, the period of initial fibrin formation (time to reach 2 mm amplitude on the tracing)
Clot kineticsK (K value) (min)CFTMeasure the kinetics of clot formation
Measures the speed to reach a specific level of clot strength (period for amplitude to increase from 2 to 20 mm)
Alpha angle (angle in degrees) (°)AlphaMeasures the rate of clot formation, reflects rate of fibrin build up and cross-linking (angle between a tangent to the tracing at 2 mm amplitude and the horizontal midline)
Clot strengthMA (mm)MCFRepresents the ultimate strength of the clot (platelets and fibrin), maximum dynamic properties of fibrin and platelet bonding via GPIIb/IIIa receptors (greatest vertical width of tracing)
Clot stabilityLY30CLIRelates to clot stability and lysis, measures the rate of amplitude reduction from MA at 30 min (in per cent)