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Heparin-Induced Thrombocytopenia - Adult - Inpatient

Heparin-Induced Thrombocytopenia - Adult - Inpatient - Clinical Hub, UW Health Clinical Tool Search, UW Health Clinical Tool Search, Clinical Practice Guidelines, Hematology and Coagulation


1
Heparin Induced Thrombocytopenia –
Adult – Inpatient
Clinical Practice Guideline
Note: Active Table of Contents – Click to follow link
EXECUTIVE SUMMARY ........................................................................................ 3
SCOPE ................................................................................................................. 4
METHODOLOGY .................................................................................................. 4
DEFINITIONS1 ...................................................................................................... 5
INTRODUCTION .................................................................................................. 5
RECOMMENDATIONS ......................................................................................... 6
UW HEALTH IMPLEMENTATION ........................................................................ 13
APPENDIX A. EVIDENCE GRADING SCHEME(S) ................................................... 14
APPENDIX B. DECISION TO TREAT HIT BASED ON 4T SCORE AND LAB TEST
INTERPRETATION – HEPARIN INDUCED THROMBOCYTOPENIA – ADULT – CPG . 15
APPENDIX C. SELECTION OF NON-HEPARIN ANTICOAGULANT – HEPARIN
INDUCED THROMBOCYTOPENIA – ADULT – CPG ............................................... 16
REFERENCES ...................................................................................................... 17
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Contact for Content:
Name: Anne Rose, PharmD - Pharmacy; Anticoagulation Stewardship
Phone Number: (608) 263-9738
Email Address: arose@uwhealth.org

Contact for Changes:
Name: Philip Trapskin, PharmD, BCPS – Drug Policy Program
Phone Number: (608) 263-1328
Email Address: ptrapskin@uwhealth.org

Guideline Author(s):
Anne Rose, PharmD – Pharmacy: Anticoagulation Stewardship

Coordinating Team Members:
John Sheehan, MD – Hematology
Eliot Williams, MD – Hematology

Review Individuals/Bodies:
David Yang, MD – Clinical Lab

Committee Approvals/Dates:
Inpatient Anticoagulation Committee
Pharmacy & Therapeutics Committee (Last Periodic Review: 05/2017)


Release Date: May 2017 | Next Review Date: May 2019




















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Executive Summary
Guideline Overview
The following guideline is intended to guide the diagnosis and management of heparin induced
thrombocytopenia.

Key Practice Recommendations
1. Diagnosis of HIT is based on both clinical (thrombocytopenia or new thrombosis) and
laboratory findings. (UW Health moderate quality of evidence, strong recommendation)

2. The heparin induced platelet Ab (ELISA) can be performed in the clinical lab and should be
utilized first if laboratory diagnosis is needed. (UW Health low quality of evidence, strong
recommendation)
2.1 A strongly positive ELISA (OD > 1) with a high suspicion for HIT can reliably confirm
the diagnosis of HIT (UW Health moderate quality of evidence, strong recommendation)
2.2 A negative ELISA reliably rules out HIT (UW Health moderate quality of evidence, strong
recommendation)

3. A heparin dependant Ab (SRA) may be considered if uncertainty exists in the diagnosis of
HIT based on the ELISA results and 4T score. (UW Health moderate quality of evidence, strong
recommendation)

4. For all patients with suspected or confirmed HIT: discontinue all heparin (including flushes)
and/or low molecular weight heparin orders by any route (UW Health low quality of evidence,
strong recommendation)

5. Start a non-heparin anticoagulant immediately upon ELISA confirmation or if awaiting results
of the SRA. (UW Health low quality of evidence, strong recommendation)

6. Treatment options
6.1 Nonsurgical: Fondaparinux or direct oral anticoagulants (DOAC)
6.2 Surgical: Argatroban
6.3 Cardiac surgery: Bivalirudin

7. Length of treatment
7.1 Isolated HIT (HIT without thrombosis): anticoagulation should be continued for 4
weeks
7.2 HITT: anticoagulation should be continued for at least 3 months and then assess the
risk versus benefit of discontinuing therapy.


Companion Documents
1. Appendix B. Decision to treat HIT based on 4T score and lab test interpretation – Heparin
Induced Thrombocytopenia – Adult – CPG
2. Appendix C. Selection of non-heparin anticoagulant – Heparin Induced Thrombocytopenia –
Adult – CPG



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Scope
Disease/Condition(s): Heparin Induced Thrombocytopenia

Intended Users:
ξ Physicians
ξ Advanced Practice Providers
ξ Pharmacists
ξ Registered Nurses

Objective(s): This clinical practice guideline is intended to provide recommendations for the
diagnosis and treatment of HIT.

Target Population: Adult inpatients with suspicion or diagnosis of HIT

Interventions and Practices Considered:
ξ Assistance with diagnosis of HIT based on clinical presentation and laboratory
confirmation
ξ Assistance with treatment of HIT including parenteral and oral options and patients with
a history of HIT requiring cardiac surgery

Major Outcomes Considered:
ξ Frequency of HIT laboratory testing
ξ Time to platelet count recovery
ξ Thrombotic event rate
ξ Drug costs
Methodology
Methods Used to Collect/Select the Evidence:
Electronic database searches (e.g., PUBMED) were conducted by the guideline author(s) and
workgroup members to collect evidence for review. Expert opinion and clinical experience were
also considered during discussions of the evidence.

Methods Used to Formulate the Recommendations:
The workgroup members agreed to adopt recommendations developed by external
organizations and/or arrived at a consensus through discussion of the literature and expert
experience. All recommendations endorsed or developed by the guideline workgroup were
reviewed and approved by other stakeholders or committees (as appropriate).

Methods Used to Assess the Quality of the Evidence/Strength of the Recommendations:
Recommendations developed by external organizations maintained the evidence grade
assigned within the original source document and were adopted for use at UW Health.

Internally developed recommendations, or those adopted from external sources without an
assigned evidence grade, were evaluated by the guideline workgroup using an algorithm
adapted from the Grading of Recommendations Assessment, Development and Evaluation
(GRADE) methodology (see Figure 1 in Appendix A).

Rating Scheme for the Strength of the Evidence/Recommendations:
See Appendix A for the rating scheme(s) used within this document.
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Cost Analysis:
Medication Price per dose/vial ($) Price per day ($)
Argatroban 50 mL vial 149.48 per vial Varies based on bags
per day
Apixaban 5 mg 9.14 per dose 18.28
Bivalirudin 250 mg/5 mL 380.98 per vial Varies based on bags
per day
Dabigatran 150 mg 5.23 per dose 10.46
Fondaparinux (5 mg, 7.5 mg or 10 mg) 33.43 per dose 33.43
Rivaroxaban 15 mg 8.46 per dose 16.92

Recognition of Potential Health Care Disparities: Patients with HIT or HITT requiring at least
30 days of anticoagulant therapy it is important to consider both drug and monitoring costs to
the patient. While warfarin is the least expensive medication, the cost for monitoring the INR
should be considered. Additionally, the availability of INR monitoring and access, including
transportation, to clinic facilities should be considered. Direct oral anticoagulants and
fondaparinux may have medication assistance programs for patients who qualify and require
minimal monitoring.
Definitions1
1. Heparin induced thrombocytopenia (HIT): immune mediated drug reaction resulting in
platelet activation, increased thrombin production and increased risk for venous and
arterial thrombosis.
2. Isolated HIT: HIT without thrombosis
3. HITT: HIT with thrombosis
4. Acute HIT: thrombocytopenia with a positive HIT antibody
5. Sub-acute HIT: recovered platelets with a positive HIT antibody
Introduction
HIT is an immune associated thrombocytopenia occurring in 1 to 3% of patients receiving
unfractionated heparin (UFH) and 0.8% of patients receiving low molecular weight heparin (LMWH).2
See Table 2. HIT is an immunologic reaction to heparin with a typical onset of five to fourteen days
after the initiation of heparin. HIT can also present within minutes to hours in patients who have been
previously exposed to heparin within the past 100 days.1-3 An estimated 17-55% of patients with HIT
develop venous thrombosis complications. If left untreated the event can be life or limb-threatening.1

Due to HIT being an immune reaction, it can develop from any source of heparin: intravenous,
subcutaneous, heparin flushes, or heparin-coated vascular catheters.1-3 HIT is more common
with intravenous administration, larger doses, and longer duration of treatment. 1-3 Risk for
developing HIT is influenced by the duration and type of exposure, the dose and specific patient
populations.1


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Table 2: Incidence of HIT1
Patient Population (after 4 days exposure) Incidence of HIT
Surgical (post-operative)
Heparin – Prophylactic or Therapeutic
Heparin – Flush
LMWH – Prophylactic or Therapeutic
Cardiac surgery
Orthopedic surgery
1-5%
0.1-1%
0.1-1%
1-3%
1-5%
Medical
Heparin – Prophylactic or Therapeutic
LMWH – Prophylactic or Therapeutic
ICU
Cancer
0.1-1%
0.6%
0.4%
1%

Recommendations

Screening for HIT
1. Clinical assessment can assist in the diagnosis of HIT and clinical prediction tools have
been developed to determine the probability of HIT1-3 (UW Health moderate quality of
evidence, strong recommendation)
1.1 The most validated has been the 4T score (Table 3)4-6 (UW Health moderate quality of
evidence, strong recommendation)
1.1.2 The 4T score has less specificity in critically ill patients but can still be utilized
to assist with diagnosis. Other causes of thrombocytopenia should be
investigated in this patient population7,8 (UW Health low quality of evidence,
weak/conditional recommendation)
1.2 Low 4T scores have a low probability of HIT: 0-3%1,4-8
1.2.1 If a low 4T score is calculated then no further diagnostic testing is
recommended. Other causes of thrombocytopenia should be investigated. (UW
Health moderate quality of evidence, strong recommendation)
1.2.2 Table 4 lists medications that may cause thrombocytopenia
1.3 An intermediate or high 4T score requires laboratory confirmation for diagnosis1,4-8 (UW
Health moderate quality of evidence, strong recommendation)



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Table 3. 4T Score – Scoring is based on the summation of all categories1
4T 2 Points 1 Point 0 Points
Thrombocytopenia ξ PLT fall > 50% AND nadir > 20
AND no surgery within previous
3 days
ξ PLT fall > 50% but surgery within
previous 3 days
ξ PLT fall 30-50% or nadir 10-19K
ξ PLT fall < 30%
ξ Any PLT fall with nadir <10K
Timing of PLT count
fall
ξ Fall 5-10 days after heparin
ξ Fall within 1 day after heparin
and exposed to heparin within
past 5-30 days
ξ Fall 5-10 days after heparin but
unclear (e.g. missing PLT)
ξ Fall in 1 day after heparin with
exposure in past 31-100 days
ξ Fall after 10 days
ξ Fall < 4 days without recent
heparin exposure
Thrombosis or other
sequelae
ξ Confirmed new thrombosis
ξ Skin necrosis at injection site
ξ Anaphylactoid reaction to IV
heparin bolus
ξ Adrenal hemorrhage
ξ Recurrent VTE while on
therapeutic anticoagulants
ξ Suspected thrombosis
ξ Erythematous skin lesions at
heparin injection sites
ξ Thrombosis suspected
Other causes of
Thrombocytopenia
ξ No alternative explanation for
platelet fall
ξ Sepsis without proven source
ξ Thrombocytopenia associated
with initiation of ventilator
ξ Other
ξ Within 72 hrs of surgery
ξ Confirmed bacteremia or
fungemia
ξ Chemo/radiation within 20 days
ξ DIC due to non-HIT cause
ξ Post-transfusion purpura
ξ Drug induced thrombocytopenia
ξ Other
Clinical Suspicion Scoring: 0-3 = Low, 4-5 = Intermediate, 6-8 = High


Table 4. Drugs associated with thrombocytopenia1
Causative Drug
Relatively common
Glycoprotein IIb/IIIa antagonists (abciximab, eptifibatide, tirofiban)
Quinine
Quinidine
Sulfa Antibiotics
Carbamazepine
Vancomycin
Less Common
Amitriptyline
Amoxicillin
Piperacillin
Nafcillin
Cephalosporins
Celecoxib
Ciprofloxacin
Fentanyl
Furosemide
Metronidazole
Naproxen
Phenytoin
Propranolol
Ranitidine
Rifampin


Confirming Diagnosis of HIT

2. Diagnosis of HIT is based on both clinical (thrombocytopenia or new thrombosis) and
laboratory findings.1-3 (UW Health moderate quality of evidence, strong recommendation)
2.1 Routine laboratory screening without signs or symptoms of HIT is not recommended
(UW Health moderate quality of evidence, strong recommendation)
2.2 The heparin induced platelet Ab (ELISA) can be performed in the clinical lab and
should be utilized first if laboratory diagnosis is needed. (UW Health low quality of
evidence, strong recommendation)
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2.3 After reviewing clinical and laboratory data if diagnosis remains uncertain consider a
hematology or vascular surgery consult (UW Health low quality of evidence,
weak/conditional recommendation)

Table 5. Laboratory Tests for Diagnosing HIT1,9,10
Test Lab Test Name Performed
at UW Lab
Turn Around
Time
Sensitivity Specificity
ELISA
Enzyme Linked
Immunosorbent Assay
Heparin Induced
Platelet Ab
YES 3 hours (STAT)
*if after 4pm call
lab to arrange for
STAT testing
> 95% 50-89%
SRA
Serotonin Release
Assay
Heparin Dependant
Ab – Serotonin
Release Assay
NO 48 hours > 90% > 90%

3. A heparin induced platelet Ab (ELISA) should be ordered for intermediate or high
suspicion of HIT (as scored by 4T)1. (UW Health low quality of evidence, strong
recommendation)
3.1 The optical density (OD) of the ELISA can identify the probability of HIT1 (UW Health
low quality of evidence, strong recommendation)
3.1.1 An OD < 1: weak positive; more likely to be HIT negative
3.1.2 An OD > 1: strong positive; more likely to be HIT positive
3.2 A strongly positive ELISA (OD > 1) with a high suspicion for HIT can reliably confirm
the diagnosis of HIT1,9,10 (UW Health moderate quality of evidence, strong
recommendation)
3.3 The ELISA method can be associated with false positive results.1 An SRA may be
needed to confirm diagnosis – see Section 4.
3.4 A negative ELISA reliably rules out HIT9,10 (UW Health moderate quality of evidence,
strong recommendation)

4. A heparin dependant Ab (SRA) may be considered if uncertainty exists in the diagnosis of
HIT based on the ELISA results and 4T score.1,9,10 (UW Health moderate quality of evidence,
strong recommendation)
4.1 In a weakly positive ELISA with an intermediate/high suspicion for HIT (based on 4T
score) consider sending a SRA for confirmation. (UW Health low quality of evidence,
strong recommendation)
4.2 A positive SRA reliably confirms the diagnosis of HIT, 1,9,10 (UW Health moderate
quality of evidence, strong recommendation)
4.3 A negative SRA reliably rules out HIT9,10 (UW Health moderate quality of evidence,
strong recommendation)

5. The following steps should be done for all patients with suspected or confirmed HIT
5.1 Discontinue all heparin (including flushes) and/or low molecular weight heparin
orders by any route (UW Health low quality of evidence, strong recommendation)
5.2 Discontinue and reverse warfarin with phytonadione1 (UW Health low quality of
evidence, strong recommendation)
5.2.1 If started less than 7 days when HIT diagnosed
5.2.2 Resume warfarin when platelet count has recovered to 100-150 x109/L
5.3 Obtain bilateral lower extremity ultrasonography to evaluate for deep vein
thrombosis, even if clinical findings are absent (UW Health low quality of evidence,
weak/conditional recommendation)
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5.3.1 Consider bilateral upper extremity ultrasonography if central infusion lines are
present (UW Health low quality of evidence, weak/conditional recommendation)
5.4 Start a non-heparin anticoagulant immediately upon ELISA confirmation or if awaiting
results of the SRA.1 (UW Health low quality of evidence, strong recommendation)


Anticoagulant Treatment Options for HIT

6. Fondaparinux

Fondaparinux is a synthetic pentasaccaride that selectively binds to antithrombin III which
results in an indirect inhibition of factor Xa. When given subcutaneously, fondaparinux has
a half-life of 17-21 hours. It is eliminated by renal excretion with 80% excreted
unchanged11. While fondaparinux has demonstrated similar efficacy and safety outcomes
compared to traditional treatment in small studies and case reports, its use has not been
completely established for treatment of HIT.11-14

6.1 Therapeutic dosing should be based on renal function and total body weight
(TBW)11– In patients with CrCl > 80 mL/min see Table 6 (UW Health low quality of
evidence, weak/conditional recommendation)
6.1.1 For CrCl < 80 mL/min refer to UW Health Renal Dosing Guidelines

Table 6. Therapeutic Fondaparinux Dosing11-14
CrCl > 80 mL/min
Total Body Weight (kg) Dose
< 50 5 mg subcutaneous daily
50 - 100 7.5 mg subcutaneous daily
> 100 10 mg subcutaneous daily

6.2 Prophylactic dosing of fondaparinux for suspected or confirmed HIT may also be
considered at a dose of 2.5 mg daily if there is not an indication for therapeutic
anticoagulation15 (UW Health low quality of evidence, weak/conditional recommendation)
6.3 Should not be used in patients with bacterial endocarditis or scheduled neuraxial
anesthesia or spinal puncture11 (UW Health low quality of evidence, strong
recommendation)

7. Argatroban

Argatroban directly inhibits thrombin. When given intravenously the half-life is dependent
on hepatic function. In patients with normal hepatic function the expected half-life is 40
minutes. In patients with impaired hepatic function the half-life is prolonged to 180
minutes.16

7.1 Dosing is based on TBW16 (UW Health low quality of evidence, strong recommendation)
7.2 No initial bolus is needed. Infusion rates should be initiated and adjusted based on
recommendations in table 8 and 9. (UW Health low quality of evidence, strong
recommendation)
7.3 The maximum infusion rate is 10 mcg/kg/min (UW Health low quality of evidence, strong
recommendation)

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Table 8. Argatroban Initial Infusion Rate16,17
Indication for dose adjustment Initial Infusion rate Based on total body weight
Normal hepatic function 2 mcg/kg/min
Moderate hepatic function 0.5 mcg/kg/min
Heart Failure, Multiple organ system failure,
severe anascara, cardiac surgery
0.5-1.2 mcg/kg/min

Table 9. Argatroban Dose Adjustments16,17
Hepatic function PTT Adjustment
Normal hepatic
function
< 1.5 x baseline PTT Increase by 0.5 mcg/kg/min
Goal 1.5 - 3.0 x baseline PTT
(*Maximum 100 seconds) Continue same rate
> 3 x baseline PTT Decrease by 0.5 mcg/kg/min
Moderate hepatic
function
< 1.5 x baseline PTT Increase by 0.25 mcg/kg/min
Goal 1.5 - 3.0 x baseline PTT
(*Maximum 100 seconds) Continue same rate
> 3 x baseline PTT Decrease by 0.25 mcg/kg/min
7.4 PTT should be measured every 2 hours after initiation or any rate adjustment (UW
Health low quality of evidence, strong recommendation)
7.5 Once 2 consecutive PTTs are in target range then PTT may be checked daily (UW
Health low quality of evidence, strong recommendation)


8. Direct Oral Anticoagulants (DOACs)
The use of DOACs (i.e. dabigatran, rivaroxaban, apixaban) has recently been reported as
possible alternative treatment options for HIT. Case reports and small case series are the
only data currently available as large randomized, controlled trials are unlikely to occur
due to the low prevalence of HIT. To date each of these agents have shown promising
outcomes regarding platelet recovery and preventing thrombotic events with no major
bleeding events.18-25 They offer an easier alternative for treatment as they have
standardized dosing, minimal monitoring and oral administration.18 Between the 3 DOAC
options rivaroxaban has the most case reports and case series data.21-25

8.1 When selecting a DOAC for treatment of HIT it is important to consider patient risk
factors. DOAC should be avoided in patients with: (UW Health low quality of evidence,
weak/conditional recommendation)
8.1.1 Creatinine clearance < 30 mL/min or hemodialysis26,27
8.1.2 Weight: < 50 kg, > 120 kg or BMI > 35 kg/m2 28,29
8.1.3 The potential for procedure or surgery in 24 hours26,27
8.1.4 Critical illness
8.2 Rivaroxaban 15 mg by mouth twice daily until platelet count recovers then decrease
dose to 20 mg daily21-25 (UW Health low quality of evidence, weak/conditional
recommendation)
8.2.1 Platelet count recovery defined as > 150 x 109/L or to previous baseline
8.2.2 If thrombosis confirmed continue 15 mg twice daily for 21 days then decrease
to 20 mg daily27
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8.3 Dabigatran 150 mg by mouth twice daily19,20 (UW Health low quality of evidence,
weak/conditional recommendation)
8.4 Apixaban 5 mg by mouth twice daily30 (UW Health low quality of evidence,
weak/conditional recommendation)
8.5 For duration of therapy see Section 10.


9. Special Populations

9.1 Urgent cardiac surgery with acute or sub-acute HIT or cardiac catheterization or
percutaneous coronary intervention1
9.1.1 Bivalirudin is recommended (UW Health low quality of evidence, weak/conditional
recommendation)
9.1.2 Dosing is based on TBW to a max of 150 kg (UW Health low quality of evidence,
strong recommendation)
9.1.3 No initial bolus is needed. Infusion rates should be initiated and adjusted
based on recommendations in tables 10 and 11. (UW Health low quality of
evidence, strong recommendation)

Table 10. Initial Bivalirudin Infusion Rate31-35
Estimated Creatinine Clearance
(mL/min)
Initial Bivalirudin Infusion
Rate (mg/kg/hr)
> 60 0.15
30 – 60 0.08
< 30 / Renal Replacement Therapy 0.05

Table 11. Bivalirudin Dose Adjustments36-40
PTT
(seconds)
Dose Adjustment

Monitoring Recommendation
< 1.5 x baseline Increase infusion by 20% Recheck PTT 2 hrs after rate change
1.5 to 2.5 x baseline Continue current rate
Recheck PTT in 2 hrs; if within
therapeutic range 2 consecutive times,
check PTT every 12 hours.
>2.5 - 3 x baseline Decrease infusion by 20% Recheck PTT 2 hrs after rate change
>3 x baseline Hold for 1 hour, then restart
at 50% lower rate Recheck PTT 2 hrs after rate change

9.2 Urgent cardiac surgery with a history of HIT and a negative HIT antibody1
9.2.1 Recommend unfractionated heparin during the procedure (UW Health low
quality of evidence, weak/conditional recommendation)
9.2.2 Recommend a non-heparin anticoagulant post operatively (UW Health low
quality of evidence, weak/conditional recommendation)


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10. Transitioning Therapies

Transitioning from a parenteral anticoagulant to oral anticoagulant should occur only in a
stable patient and after platelet recovery to at least 150 K/uL or upon return to usual
baseline1. (UW Health low quality of evidence, strong recommendation)

10.1 Fondaparinux to warfarin1,11
10.1.1 Once platelet count normalizes start warfarin 5 mg daily (UW Health low quality
of evidence, strong recommendation)
10.1.2 Dose adjust warfarin until the INR is > 2. When INR is within a therapeutic
range for two consecutive results and after a minimum of 5 days, discontinue
fondaparinux. (UW Health low quality of evidence, strong recommendation)
10.2 Argatroban to warfarin1,16,36
10.2.1 Adjust infusion rate to achieve a PTT level just above 1.5x normal before
starting warfarin at 5 mg daily. (UW Health low quality of evidence, strong
recommendation)
10.2.2 The combination of argatroban and warfarin creates a laboratory discrepancy
which falsely elevates INR values. During the combination target an INR of >
4.
10.2.3 Once the INR is > 4 and after a minimum of 5 days on dual anticoagulant
therapy, argatroban can be held and the INR repeated in 4-6 hours. (UW
Health low quality of evidence, strong recommendation)
10.2.4 If the repeat INR off of argatroban is sub-therapeutic the infusion should be
resumed at the previous rate and the procedure repeated daily until the INR
on warfarin alone is therapeutic. When this occurs argatroban can be
discontinued. (UW Health low quality of evidence, strong recommendation)

10.3 Parenteral to DOAC11,16,20,26,27,41
10.3.1 Stop fondaparinux and start DOAC at the time of next scheduled
fondaparinux dose. (UW Health low quality of evidence, strong recommendation)
10.3.2 Stop argatroban infusion and start DOAC at the same time. (UW
Health low quality of evidence, strong recommendation)
11. Duration of Anticoagulation
11.1 Isolated HIT (HIT without thrombosis): anticoagulation should be continued for 4
weeks1
11.2 HITT: anticoagulation should be continued for at least 3 months and then assess the
risk versus benefit of discontinuing therapy.2

12. Laboratory Monitoring1,11,16,26,27 (UW Health low quality of evidence, strong recommendation)
12.1 Platelets should be monitored daily for recovery. Once they have normalized (100-
150 x 109/L) they may be monitored less often.
12.2 CBC should be monitored every 48 hours while hospitalized and on an
anticoagulant.
12.3 Creatinine should be monitored as clinically indicated.

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UW Health Implementation
Potential Benefits:
ξ Standardized approach to diagnosis of HIT
ξ Selection of optimal treatment based on patient specific factors

Potential Harms:
ξ Hemorrhagic complications
ξ Thrombotic complications

Qualifying Statements:
Neither fondaparinux nor the DOACs are FDA approved for the treatment of HIT. Current
existing data is from case reports and/or case series. There are no randomized, controlled trials
using these medications for the treatment of HIT. The workgroup agreed that case reports and
case series will likely be the only available data as HIT is a rare occurrence which makes large
randomized trials a challenge for this disease state. The workgroup reviewed the available data
and felt the benefit to using these agents (as described in the guideline) outweighed the lack of
strong clinical data. Recommendations were graded to reflect the lack of controlled clinical
data.

Pertinent UW Health Policies & Procedures
1. None identified

Guideline Metrics
1. VTE Performance Measure – VTE 4 – UFH with dosage and platelet monitored by protocol
2. Frequency for HIT laboratory testing and false positive ELISA HIT results
3. Time to platelet count recovery
4. Thrombotic event rate

Implementation Plan/Clinical Tools
1. Guideline will be posted on uConnect in a dedicated location for Clinical Practice Guidelines.
2. Guideline will be posted on the uwhealth.org/anticoagulation webpage.
3. Release of the guideline will be advertised in the Physician/APP Briefing newsletter.
4. Content and hyperlinks within clinical tools, documents, or Health Link related to the
guideline recommendations (such as the following) will be reviewed for consistency and
modified as appropriate.

Order Sets & Smart Sets
IP – HIT (Heparin Induced Thrombocytopenia) Adult – Supplemental – Order Set [3596]


Disclaimer
Clinical practice guidelines assist clinicians by providing a framework for the evaluation and
treatment of patients. This guideline outlines the preferred approach for most patients. It is not
intended to replace a clinician’s judgment or to establish a protocol for all patients. It is
understood that some patients will not fit the clinical condition contemplated by a guideline and
that a guideline will rarely establish the only appropriate approach to a problem.

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14


Appendix A. Evidence Grading Scheme(s)

Figure 1. GRADE Methodology adapted by UW Health


GRADE Ranking of Evidence
High We are confident that the effect in the study reflects the actual effect.
Moderate We are quite confident that the effect in the study is close to the true effect, but it
is also possible it is substantially different.
Low The true effect may differ significantly from the estimate.
Very Low The true effect is likely to be substantially different from the estimated effect.

GRADE Ratings for Recommendations For or Against Practice
Strong The net benefit of the treatment is clear, patient values and circumstances
are unlikely to affect the decision.
Weak/conditional
Recommendation may be conditional upon patient values and
preferences, the resources available, or the setting in which the
intervention will be implemented.


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Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised:
 
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15


Appendix B. Decision to treat HIT based on 4T score and lab test
interpretation – Heparin Induced Thrombocytopenia – Adult – CPG







HIT Suspicion
4T Score
Low Intermediate / High
Continue Heparin Product
& Consider Other Causes
Stop All Heparin Products &
Obtain STAT ELISA
Negative
ELISA
Positive ELISA (OD >1)
AND
High 4T Score

Obtain a SRA AND
Start non-heparin anticoagulant
while waiting for SRA to result
and HIT to be diagnosed
Positive ELISA (OD < 1) AND
Intermediate 4T Score OR
Diagnostic uncertainty OR
HIT diagnosis would impact future
therapy (CAD patient who may
need a CABG)
HIT Diagnosed
Start non-heparin
anticoagulant
Negative
SRA
Positive SRA
HIT Diagnosed
Continue non-heparin anticoagulant
CPG Contact for Changes:
Name: Philip J Trapskin, PharmD, BCPS
Phone Number: 263-1328
Email Address: ptrapskin@uwhealth.org
Revised: 2/2017
Copyright © 2017 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised:
 
05/2017CCKM@uwhealth.org

16


Appendix C. Selection of non-heparin anticoagulant – Heparin Induced
Thrombocytopenia – Adult – CPG






CPG Contact for Changes:
Name: Philip J Trapskin, PharmD, BCPS
Phone Number: 263-1328
Email Address: ptrapskin@uwhealth.org
Revised: 2/2017
Copyright © 2017 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised:
 
05/2017CCKM@uwhealth.org

17


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Copyright © 2017 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised:
 
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