Tanaka: ROTEM-guided Coagulation Management

Clinical Pearls (assisted by Dr. Mustafa Abdulmahdi)

• Traditional approach:
  • Coagulopathy = low platelet count & prolonged PT/aPTT after cardiopulmonary bypass ⇒ platelet & FFP transfusion
• Whole Blood Viscoelastic Tests
  • Clot onset in whole blood (CT) ⇒ clot strength (maximum amplitude [MA]) ⇒ clot stability (i.e., degree of systemic fibrinolysis; maximum lysis time)

• Clot stability example:
  • Control (Stable clot)

Bolliger D, Tanaka KA, et al. Br J Anaesth 2009; 102:793-9

• • Hemodilution

Bolliger D, Tanaka KA, et al. Br J Anaesth 2009; 102:793-9

• • • • Antifibrinolysis can be used here
• Key differences between ROTEM & TEG systems:
  • ROTEM
    1. Uses EXTEM (Platelet-specific) & FIBTEM (fibrinogen-specific) assays that are activated by extrinsic pathway tissue factor
       • EXTEM-CT (clotting time): similar to TEG in that it’s the duration for onset of clot formation
    2. Heparin neutralized by polybrene so, unlike TEG, NO NEED to specify need to neutralize heparin
    3. Shorter turnaround time (important in targeted transfusion)
  •  TEG
    1. Always has intrinsic activation (Kaolin), even in rapid TEG, which is partially dependent on TF extrinsic pathway; also has intrinsic activation, unlike ROTEM that only has TF
    2. TEG assays don’t contain heparinase type reagent so MUST specify need to neutralize heparin
• ROTEM & TEG can complement one another, when in doubt.
  • Conventional TEG teaching ⇒ if there’s a low α angle, give fibrinogen or platelets
  • ROTEM FIBTEM system can differentiate between the two conditions to guide transfusion
• 10-40-80 rule ⇒ you don’t have to remember PT & PTT or platelet thresholds at 2 in the morning!
  • If FIBTEM A10 <10 mm ⇒ think cryo
  • If EXTEM A10 <40mm & FIBTEM normal ⇒ think platelets
  • If EXTEM-CT >80s ⇒ think FFP or PCC
• ROTEM-based approach during cardiac surgery
  • Baseline FIBTEM is reference point
    • Hemodilution assessed by changes in FIBTEM A10 and/or EXTEM-CT
  • Coagulation trajectory corrected by concentrated plasma on CPB (hemoconcentration) ⇒ this can maintain antithrombin in plasma & avoid DIC
• Warfarin and TEG/ROTEM
  • INR vs. EXTEM or Kao TEG ⇒ compared to TEG, EXTEM (ROTEM) system correlated better with INR values & provides faster results
• TF (extrinsic ROTEM activation pathway) vs. contact trigger (TEG-activation system)
  • Contact-activated tests are less sensitive to low vitamin K factors & hemodilution
    • During stress states, we release Factor VIII (+vWF), which is a contact system factor and makes the contact tests less sensitive
• ROTEM weaknesses:
  1. Does not reflect platelet function (vWF, P2Y12, TXA2)
  2. Data not robust for DOACs (↑EXTEM-CT)
  3. Not sensitive to thombophilia: FV Leiden, Deficient protein C/S, ATIII
  4. Impact of hct changes; low hct ⇒ larger amplitude