ROTEM:
An introduction and overview
Evelyn Lockhart, MD
Medical 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
Why very few people like coagulation talks
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.
Basics of Thromboelastometry
The ROTEM Instrument
Two instruments housed
in the Blood Bank
Viscoelastic clot-based testing
Whole blood
sample
Two platforms in the U.S.:
1) TEG: thromboelastography
Platelet-fibrin
strands
Oscillating
cup or pin
1) ROTEM: rotational
thromboelastometry
The ROTEM graph
Amplitude
in (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: green
2-20 mm: pink
> 20 mm: blue
Hemostasis simplified
Intrinsic Pathway
Clotting factors
Extrinsic Pathway
Clotting factors
PTT
PT/INR
Fibrinogen
Thrombin
Platelet surface
Fibrin
Clot
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
Extrinsic pathway
Fibrinogen activity
Intrinsic Pathway
APTEM –adds aprotinin
(antifibrinolytic)
Hemostasis ROTEM
Extrinsic pathway
Intrinsic Pathway
Fibrinogen activity
HEPTEM:
Reverses heparin.
HEPTEM
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)
ROTEM Parameters
A10: Clot amplitude 10
minutes after CT.
Predicts MCF
Clotting Time
Represents:
PT (Extem)
PTT (Intem)
If prolonged:
Low clotting factor activity
Maximum Clot Firmness
Represents:
Greatest amplitude
If decreased:
Low fibrinogen or
platelets
Maximum Lysis:
Represents fibrinolysis
ROTEM® Thromboelastometry - Parameters
A10 – 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)
MCF Ref Value: 51 - 72 mm
MCF Ref Value: 50 - 70 mm
Easy to remember: “A10 plus 10 mm”
ROTEM – graph information
The 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
Normal ROTEM tracings
Note:
Normal HEPTEM = INTEM
Normal APTEM = EXTEM
In your bleeding patient, ROTEM demonstrates:
CTINTEM Prolonged
Suggests 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 Reduced
Suggests inadequate clot firmness due
to either decreased platelets and/or
fibrinogen
A10 = 27 mm
A10FIBTEM Reduced
A10 = 4 mm
Suggests inadequate
fibrin contribution to clot
firmness: low fibrinogen
In your bleeding patient, ROTEM demonstrates:
A10EX
Reduced
Suggests inadequate clot firmness as a
result of decreased platelets and/or
fibrinogen
A10 = 27
A10FIB
Normal
A10 = 9mm
Suggests adequate fibrinogen
Platelets are the cause for low
A10 on EXTEM
In your bleeding patient, ROTEM demonstrates:
MLEX = 30% @ 23MIN
4% @ 20min
30% @ 23min
> 15% @ 23min
Suggests hyperfibrinolysis
The APTEM is then run
& lysis is corrected
in APTEM vs EXTEM
Confirms hyperfibrinolysis
and shows efficacy of
antifibrinolytic therapy
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!
Case examples
52 year old man with chronic liver disease,
hematemesis for last 5 hours
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
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
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
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
10 year old with gunshot
wound to the head
10 year old with gunshot wound to the head
Elevated MCF on the
FIBTEM suggestive of
hyperfibrinogenemia.
No intervention
necessary.
Secondary to
acute phase response
How to order and view ROTEM
at UNMH
STEP 1: Order the ROTEM
Remember to specify a CV panel if excluding heparin effect.
STEP 2: Collect sample and route to the blood
bank
•
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 3: Viewing ROTEM tracing real time
1. Go to the UNM
Hospital Intranet
2. Select Web
Based Systems
3. Click on Citrix
Web Interface
4. Select UNMH Citrix Applications
6. Select the ROTEM folder
7. Select the ROTEM Viewer
• Select one of the DELTA LABs
• Select GO
ALWAYS
CHECK PT
NAME
AND
MRN!
Pt Name & MRN
Questions?
Elockhart@salud.unm.edu