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

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 housedin the Blood Bank

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

Normal ROTEM tracings

Note:

Normal HEPTEM = INTEM

Normal APTEM = EXTEM

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!

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

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

How to order and view ROTEM at UNMH

STEP 1: Order the ROTEM

Remember to specify a CV panel if excluding heparin effect.

• 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

4. Select UNMH Citrix Applications

6. Select the ROTEM folder

7. Select the ROTEM Viewer

• Select one of the DELTA LABs• Select GO

Pt Name & MRN

ALWAYS CHECK PT NAME AND MRN!

Questions?

Elockhart@salud.unm.edu