ASH 2018: HIT

Question 1

If risk of HIT is low for patient receiving heparin, don’t do

Answer 1

Platelet count monitoring to screen for HIT

Question 2

If risk of HIT is 0.1% - 100%, do

Answer 2

Platelet count monitoring to screen for HIT

Question 3

For platelet count monitoring, when to start
A. If patient has had heparin in the 30 days prior
B. If patient is heparin naive
C. If patient is high risk (frequency)
D. If patient is intermediate risk (frequency)

Answer 3

A. Day 0
B. Day 4 - 14 or until heparin is stopped
C. Every other day
D. Every 2 - 3 days

Question 4

If suspected HIT and 4T score shows intermediate or high probability, strong recommendation for

Answer 4

Immunoassay

If immunoassay is positive, conditional recommendation to follow up with a functional assay

Question 5

If suspected HIT and low 4T score, don’t do (2 things)

Answer 5

1. HIT laboratory testing
2. Empiric HIT therapy

Strong recommendations

Question 6

If suspected HIT and intermediate 4T score, regardless of whether or not they have an indication for therapeutic anticoagulation, strong recommendation to

Answer 6

Discontinue heparin

Question 7

If suspected HIT, intermediate 4T score, no Other indication for therapeutic anticoagulation, conditional recommendation for (incl if high bleeding risk or no high bleeding risk)

Answer 7

Non-heparin anticoagulation at therapeutic dosing if not at high risk for bleeding
Non-heparin anticoagulation at prophylactic dosing if at high risk for bleeding

Question 8

If suspected HIT, intermediate 4T score, and Another indication for therapeutic anticoagulation, conditional recommendation for

Answer 8

Therapeutic dosing of non-heparin anticoagulant

Question 9

If suspected HIT, high 4T score, strong recommendation for

Answer 9

Discontinuation of heparin and initiation of non-heparin anticoagulant

Question 10

If suspected HIT, high 4T score and negative immunoassay, strong recommendation to

Answer 10

Stop non-heparin anticoagulant and restart heparin

Question 11

If suspected HIT, intermediate 4T score and positive immunoassay, strong recommendation to

Answer 11

Continue avoiding heparin

Administer therapeutic doses of non-heparin anticoagulant

Question 12

In acute HITT (HIT + Thrombosis) or HIT patients, strong recommendation to

Answer 12

Discontinue heparin and start non-heparin anticoagulant

Question 13

Preferred drugs for acute HIT if critical illness, increased bleed risk, life or limb threatening thromboembolism, or increased need for urgent procedures

Vs.

Reasonable options in clinically stable patients at average bleeding risks

Answer 13

Argatroban or Bivalirudin

Vs.

Fondaparinux or DOACs

Question 14

If DOAC for acute HITT, most published option (with dose)

If acute, isolated HIT (with dose)

Answer 14

Rivaroxaban 15 mg BID x 3 weeks, then 20 mg daily

Rivaroxaban 15 mg BID until platelet count recovery, then 20 mg daily

Question 15

Routine insertion of IVC filter in acute HIT or HITT?

Answer 15

No

Question 16

When to start warfarin in acute HITT or HIT

Answer 16

After platelet count recovery (150 x 10^9)

Question 17

If on warfarin and diagnosed with HIT or HITT

Answer 17

Stop warfarin, give vitamin K and start non-heparin anticoagulant

Question 18

Routine platelet transfusion for acute HIT or HITT?

Answer 18

No

Question 19

If acute isolated HIT, to screen for asymptomatic proximal DVT, conditional recommendation to do

Answer 19

Bilateral lower extremity compression ultrasonography

Question 20

If acute isolated HIT and upper extremity central venous catheter, conditional recommendation to do… And to not do…

Answer 20

(Do) upper extremity ultrasonography in the limb with the catheter to screen for asymptomatic DVT

(Don’t) upper extremity ultrasonography in limbs without the catheter

Question 21

How long to anticoagulate in acute isolated HIT with no DVT found?

Answer 21

Until platelet count recovery

Question 22

If subacute HIT A, which is preferred between DOACs or warfarin

Answer 22

DOACs

Question 23

What is Suspected vs. 
Acute vs. 
subacute HIT A vs. 
subacute HIT B vs. 
Remote

Answer 23

Suspected: low platelets
Acute: positive immunoassay and if possible functional assay
Subacute A: platelet count recovery
Subacute B: functional assay recovery
Remote: immunoassay recovery

Question 24

If acute HIT or subacute HIT A and requiring cardiovascular surgery

Answer 24

Delay surgery until functional assay recovery (subacute B) or immunoassay recovery (remote HIT)

Question 25

If cannot delay surgery while acute HIT or subacute HIT A

Answer 25

Intraoperative Bivalirudin or plasma exchange and then intraoperative heparin or intraoperative heparin with a potent antiplatelet like tirofiban

Question 26

If cardiovascular surgery needed in a patient with subacute HIT B or remote HIT

Answer 26

Intraoperative heparin

Question 27

If subacute HIT A or acute HIT and need PCI

Answer 27

Bivalirudin

If Bivalirudin is not available, can use Argatroban

Question 28

If subacute HIT B or remote HIT and need PCI

Answer 28

Bivalirudin

Heparin is an acceptable alternative if no other anticoag can be used

Question 29

If acute HIT on dialysis

Answer 29

Argatroban, Danaparoid, or Bivalirudin

Question 30

In subacute HIT A, subacute HIT B, or remote HIT and on dialysis and not otherwise receiving anticoagulation

Answer 30

Regional Citrate

Question 31

If remote HIT and require VTE tx/prophylaxis

Answer 31

DOAC, warfarin, fondaparinux, or Danaparoid > UFH/LMWH

Question 32

How long to wear an emergency identifier post HIT

Answer 32

3 months