Module 2

Question 1

What are the 3 steps of interpretation of a TEG?

Answer 1

MARLy

1. Assess MA in CFF and CRT
   - if low CFF MA (<15) replace fibrinogen with cryo or fibrinogen
   - if normal CFF MA but low CRT MA (<52) give platelets once fibrinogen corrected)
2. Asses R in CK and CKH
   - if both prolonged, heparin effect excluded, coagulation defect present
   - if CKH R normal but CK R prolonged, heparin effect
3. Assess Ly30 on CRT
   - if >2.2%, hyperfibrinolsis present, give TXA

Question 2

Differentiate between types 2A, 2B, 2N and 2M vWD

Answer 2

2A: selective deficiency of HMW multimers

2B: increased affinity of vWF for platelet Gp1b (selective deficiency of HMW multimers)

2N: decreased affinity of vWF for FVIII

2M: dysfunctional vWF not associated with deficiency of HMW multimers

Question 3

What are the initial tests for diagnosis of vWD?

Answer 3

vWF:Ag
- if undetectable type 3

vWF: RCo
>0.6 type 1
<0.6 type 2

vWF: CB
>0.6 type 1
<0.6 type 2

FVIII:C
- if only low FVIII:C, likely 2N or mild haemophilia A

Question 4

Differentiate between TEG/ROTEM

• number of cups
• cup fixed or oscillating?
• electronic or optical detection?

Answer 4

TEG

• 1 cup
• fixed pin (oscillating cups)
• electronic detection

ROTEM

• 4 cups
• fixed cups (less distortion with vibration)
• optical detection

Question 5

What are the indications to monitor DOACs?

Answer 5

• emergent/urgent surgery
• major bleeding
• dosing compliance or oOD
• acute thrombosis
• renal/liver failure
• drug interactions

Question 6

What are the useful laboratory tests to monitor

• Rivaroaxaban
• apixaban
• endoxaban
• dabigatran
• fondaparinux
• argatroban
• bivalirudin

Answer 6

• Riv, apix, endo: direct fXa assay for individual agent
• dabigatran: TCT
• fondaparinux : anti-fXA
• argatroban/bival: APTT

Question 7

What are the clinical and laboratory criteria for antiphospholipid syndrome?

What score do you require?

Answer 7

CLINICAL

• thrombosis
• recurrent pregnancy loss
• thrombocytopenia

LABORATORY

• lupus anticoagulant
• anti-cardiolipin antibody
• anti-B2GP1 antibodies

Need 2 or more lab and 2 or more clinical with repeated labs at 12 weeks

Question 8

What is the confirmatory testing for lupus anticoagulant?

Answer 8

dRVTT

• LA screen: LA- sensitive regents, low quantities of PL, prolonges Ct
• LA confirm: LA- insensitive reagents, high wantities of PL, shortens CT

Screen:confirm ratio >1.2 indicative of LA

PNT
Hexagonal
Kaolin clotting time
Tissue thromboplastin inhibition test

Question 9

Describe the pathophysiology of HITTs

Answer 9

PF4 found on endothelial cells and monocytes detaches in presence of heparin and formsH-PF4 commplexes
Antibodies are formed to these antigen sites

Antibodies bind and activate platelets leading to platelet activation aggregation, thrombosis and a positive feedback loop generating more PF4

Question 10

What are the 4 Ts used to diagnose HITTS and what scores are required?

Answer 10

Thrombocytopenia
Timing: 1 point for days 5-10 fall but unclear, 2 points for clear with recent exposure
Thrombosis: 1 point for progressive/recurrent or non-necrotising skin lesions, 2 for new thrombosis or skin necrosis
Other: 1 for possible, 2 for none

0-3 low
4-5 intermediate
6-8 is high

Question 11

What are the key lab investigations for diagnosis of HITTS?

Answer 11

Screening: Rapid antibody detection or immunoassay
Diagnostic: serotonin release assay gold standard, Heparin induced platelet aggregation, electrode aggregometry, Light transmission aggregometry