ROTEM: An introduction and overview Evelyn Lockhart, MD Medical Director, UNMH Transfusion Service...
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Transcript of ROTEM: An introduction and overview Evelyn Lockhart, MD Medical Director, UNMH Transfusion Service...
ROTEM:An introduction and
overview
Evelyn Lockhart, MDMedical Director, UNMH Transfusion Service
January 14, 2015
Disclosures
• TEM Systems, Inc.: Speakers fees, research support (reagents)
• CSL Behring: consulting (honoraria)
Objectives
• Describe the principles of viscoelastic clot-based testing.
• Understand and interpret ROTEM test results
• Know how to order ROTEM at UNMH
What is thromboelastometry or thromboelastograpy?
• Method of measuring the viscoelastic properties of a blood clot
• Demonstrates:• Clot formation• Clot firmness• Clot breakdown (fibrinolysis)
• Global assessment of hemostasis performed in whole blood.
Why Use ROTEM?
1. To detect reduced clotting factor activity, poor clot firmness and premature lysis in the bleeding patient to guide transfusion and other therapy.
2. To provide an estimate of hemostatic reserve in patients to avoid transfusion.
Why Use ROTEM?
Gives information on four critical areas of hemostasis and need for targeted therapy in bleeding patients.
Potential Hemostatic Lesion
Therapeutic Interventions
Fibrinolysis Antifibrinolytic therapy:• tranexamic acid (TXA)• aminocaproic acid (Amicar)
Fibrinogen levels • Cryoprecipitate• fibrinogen concentrates
Clotting factor activity • Plasma• Prothrombin complex concentrates
Platelet activity Platelet transfusion
Why not use standard coagulation tests?
• Standard coagulation tests (PT/INR, PTT, fibrinogen levels) are measured only in plasma.
• These tests do not have cellular blood elements that contribute to hemostasis.
• Does not measure clot lysis or fibrin polymerization.
• Standard testing complements ROTEM, but measures different elements.
When to use ROTEM
Active Hemorrhage
• Trauma• Massive hemorrhage • Obstetric hemorrhage• Acquired coagulation disorders• Cardiac and vascular surgery
When NOT to use ROTEM
• Monitoring therapeutic effects of anticoagulants.• Antiplatelet agents: clopidogrel, aspirin, prasugrel• New oral anticoagulants:
• Dabigatran, rivaroxiban, apixiban• ROTEM will not reliably detect the anticoagulant
effects of these drugs.
• ROTEM can be used in patients who are actively bleeding and on warfarin or heparin.• HEPTEM can evaluate heparin effect.• ROTEM is NOT for therapeutic monitoring of either
warfarin or heparin.
Platelet-fibrin strands
Viscoelastic clot-based testing
Whole blood sample
Oscillating cup or pin
Two platforms in the U.S.:
1) TEG: thromboelastography
2) ROTEM: rotational thromboelastometry
The ROTEM graphAm
plitu
dein
(mm
)
Time (in sec)
The graph demonstrates the change in amplitude (clot firmness) over a time period
The greater the amplitude the firmer the clot
Colors:0-2mm: green2-20 mm: pink> 20 mm: blue
Hemostasis simplified
Platelet surface
Fibrinogen ThrombinFibrinClot
Intrinsic Pathway Clotting factors
Extrinsic Pathway Clotting factors
PTT PT/INR
ROTEM – Assays
EXTEM – Extrinsic pathway activation
INTEM – Intrinsic pathway activation
FIBTEM – adds platelet inhibitor Measures sole contribution of fibrinogen to clot firmness
APTEM – adds antifibrinolytic to EXTEM; evaluates fibrinolysis
HEPTEM – adds heparinase to INTEM; evaluates heparin effect
APTEM –adds aprotinin (antifibrinolytic)
Hemostasis ROTEM
Extrinsic pathway Intrinsic Pathway
Fibrinogen activity
HEPTEM
Extrinsic pathway Intrinsic Pathway
Fibrinogen activityHEPTEM:Reverses heparin.
Cardiovascular ROTEM
ROTEM® Measured Parameters
CT – onset of clot formation (sec)
CFT – clot propagation rate (sec)
-a angle – tangent to the clotting curve from 2mm (degrees o)
A10– amplitude 10 minutes after CT (mm)
MCF – Maximum Clot Firmness (mm)
LI30– Lysis Index (% of clot remaining 30 minutes after CT)
ML – Maximum Lysis (% of lysis at any time)
ROTEM Thromboelastometry - Parameters
CT (clotting time) – Measured in seconds- Reflects the clotting factor activity (similar to PT/INR and PTT)
MCF (maximum clot firmness) – Measured in amplitude (mm)-Reflects the firmness and stability of a clot-Due to interaction of platelets, fibrin and factor 13
ML (maximum lysis) – Measured in (%)- Reflects the presence of premature clot lysis (hyperfibrinolysis)
Clotting TimeRepresents:PT (Extem)PTT (Intem)If prolonged:Low clotting factor activity
Maximum Clot FirmnessRepresents:Greatest amplitudeIf decreased:Low fibrinogen or platelets
Maximum Lysis: Represents fibrinolysis
ROTEM Parameters
A10: Clot amplitude 10 minutes after CT.Predicts MCF
ROTEM® Thromboelastometry - ParametersA10 – Amplitude(mm) 10 minutes after CT
Provides an early and highly predictive assessment of clot firmness (MCF).
IMPORTANT FOR RAPID ASSESSMENT AND THERAPEUTIC DECISIONS
ROTEM Parameters
MCF – Maximum Clot Firmness (mm)
Easy to remember: “A10 plus 10 mm”
MCF Ref Value: 51 - 72 mm MCF Ref Value: 50 - 70 mm
ROTEM – graph informationThe shape of the graph indicates whether a clot is:
• firm and stable•has premature lysis• weak or fragile.
Firm & Stable Unstable (early Lysis) Relatively Weak
In your bleeding patient, ROTEM demonstrates:
CTINTEM ProlongedSuggests Heparin influence or
enzymatic factor deficiency
A corrected CTHEPTEM provides clarity in this case:
210 vs 350 sec
Suggests Heparin effect
In your bleeding patient, ROTEM demonstrates:
A10EXTEM ReducedSuggests inadequate clot firmness due
to either decreased platelets and/or fibrinogen
A10 = 27 mm
A10FIBTEM ReducedA10 = 4 mm
Suggests inadequate fibrin contribution to clot firmness: low fibrinogen
In your bleeding patient, ROTEM demonstrates:
A10EX ReducedSuggests inadequate clot firmness as a
result of decreased platelets and/or fibrinogen
A10 = 27
A10FIB NormalA10 = 9mm
Suggests adequate fibrinogen
Platelets are the cause for low A10 on EXTEM
In your bleeding patient, ROTEM demonstrates:
MLEX = 30% @ 23MIN
Suggests hyperfibrinolysis
The APTEM is then run& lysis is corrected
in APTEM vs EXTEM
Confirms hyperfibrinolysis and shows efficacy of
antifibrinolytic therapy
> 15% @ 23min
4% @ 20min
30% @ 23min
ROTEM Interpretation takeaways
1. Learn what normal tracings look like.
2. Keep it simple:a. CT: clotting factor activity plasma or (rarely)PCCs
b. MCF: Clot firmness cryo/fibrinogen, platelets
c. A10: clot firmness at 10 minutes, predicts MCF
d. ML: Clot lysis antifibrinolytics
3. Call for a pathology consult if you need help!
52 year old man with chronic liver disease, hematemesis for last 5 hours
Normal ROTEM
FIBTEM MCF borderline low; needs repeat testing if ongoing hemorrhage.
No current recommendations for plasma, platelets, or cryoprecipitate
62 year old woman presenting with subdural hematoma
Low A10 and MCF on EXTEM and INTEM
Normal FIBTEM
Suggests low platelet activity; recommend platelet transfusion.
35 year old woman on labor and delivery with postpartum hemorrhage
Fulminant hyperfibrinolysis
Recommend immediate antifibrinolytics
Poor CT, clot formation kinetics, and clot firmness in APTEM
Recommend plasma, cryoprecipitate, and platelets (MTP activation)
60 year old man bleeding s/p CABG x 3
Prolonged CTINTEM
which corrects on CTHEPTEM
Suggests heparin effect; protamine recommended
FIBTEM MCF slightly below normal, suggests below normal fibrinogen
May require cryoprecipitate if bleeding not corrected with protamine
Elevated MCF on the FIBTEM suggestive of hyperfibrinogenemia.
No intervention necessary.
Secondary to acute phase response
10 year old with gunshot wound to the head
• Light blue top tube (either 2.7 or 4.0 mL size)• Sodium citrate tube
• CANNOT go through tube system• Hand deliver to blood bank
STEP 2: Collect sample and route to the blood bank
1. Go to the UNM Hospital Intranet
2. Select Web Based Systems
3. Click on Citrix Web Interface
STEP 3: Viewing ROTEM tracing real time