The role of viscoelastic testing in assessing peri-interventional platelet function and coagulation

Figures & data

Table 1 Comparison of platelet count and function measures in currently available viscoelastic haemostatic assay analysers

Assays		TEG®	ROTEM®	Sonoclot®	Quantra®
Standard Haemostatic Assays	Native	✓	✓	✓	✓
	Intrinsic pathway	✓	✓	✓	✓
	Extrinsic pathway	✓	✓	✓	✓
	Heparinase neutralisation	✓	✓	✓	✓
	Fibrin contribution to clot strength	✓	✓	✓	✓
Platelet Function Tests	P2Y12 and Thromboxane pathway inhibition	✓	X	X	X

TEG = thromboelastography, ROTEM = rotational thromboelastometry

Table 2 Characteristics of viscoelastic haemostatic assay analysers

Indices		TEG	ROTEM	SONOCLOT	Therapy
Clot Initiation:Initial clot generation-Time to develop 2 mm clot amplitude	Enzymatic phase; depends on concentration and function of coagulation factors	R- Reaction time (Normal: 4.6-9.1 minutes; Citrate/kaolin)	CL-clotting time Normal INTEM:122-208 secondsNormal EXTEM:43-82 seconds	ACT – activated clotting time Normal SonACT (85-145s)	Prolonged: factor replacement, protamine depending on heparinise r-time Shortened: hypercoagulability, anticoagulant therapy
Clot Kinetics: Time to develop 20 mm from 2 mm amplitude	Depends on coagulation factors, fibrinogen, platelets, FVIII activity	K – clot kinetics Normal: 0.8-2.1 min	CFT- Clot formation time Normal INTEM:45-110 secondsNormal EXTEM: 48-127 seconds	CR- Clot rate Normal SonACT: 15-45 clot signal units/minute	Prolonged: factor replacement/ cryoprecipitate/platelets/ desmopressin
	Fibrinogen concentration/ function	Α – angle, Normal: 63-78 degrees	CFT alpha angle Normal INTEM:70-81 degreesNormal EXTEM: 65-80 degrees	Peak angle	Increased: thrombolytic therapy Decreased: cryoprecipitate/ fibrinogen
CLOT Strength: Maximum clot strength/firmness	Platelet and fibrinogen function	MA- maximum amplitude Normal: 52-69 mm	MCF- Maximum clot firmness Normal INTEM:51-72 mm Normal EXTEM:52-70 mm	PEAK – peak amplitude	Increased: hypercoagulable. Antiplatelet/anticoagulantDecreased: platelet transfusion/ cryoprecipitate/desmopressin
Clot Stability:Lysis (%) at fixed time	Fibrinolytic activity. Depends on plasmin/plasminogen and activators	LY30/LY60 – lysis at 30/60 minutes Normal LY30: 0–2.6%	LI30/45/60- Lysis at 30/45/60 minutes	-	Increased: antifibrinolytic
Fibrinogen Level	Functional fibrinogen	Measured in the presence of glycoprotein inhibitor. MA-CFF: maximum fibrin clot strength Normal: 15-32 mm FLEV: Functional fibrinogen levelNormal: 278-581mg/dL	FIBTEM Normal FIBTEM:7-24 mm	-	-

TEG = thromboelastography, ROTEM = rotational thromboelastometry

Figure 1. Thromboelastography tracings.

Figure 2. Analysis of antiplatelet drug effect using thromboelastography – platelet mapping assay.