About HIT/HITTS
Heparin-induced thrombocytopenia (HITTS) is an immune-mediated clinicopathological
syndrome initiated by heparin therapy and associated with thrombocytopenia and the
presence of antiplatelet factor 4/heparin antibodies.1
Diagnosis and impact: Under-recognized risk4
Heparin-induced thrombocytopenia and thrombosis syndrome (HITTS) is an immune-mediated
clinicopathological syndrome initiated by heparin therapy and associated with thrombocytopenia
plus venous or arterial thrombosis.1
Impact of HITTS1
- Associated with morbidity and mortality
- The risk of thrombosis in HIT patients is 35-75%
- Most common of thrombotic events are venous thromboembolism (DVT and PE).
- Arterial thrombosis most often manifests as an acutely ischemic lower limb due to
occlusion of large limb arteries or the distal aorta.
- Thrombosis can lead to amputation and death
- 20% limb amputation
- 20-30% death
Patients with or at risk for HIT/HITTS undergoing PCI pose a challenge since use
of heparin should be avoided. In
in vitro studies, Angiomax® (bivalirudin)
exhibited no cross-reactivity with heparin-induced antibodies in patients with a
history of HIT/HITTS.2
ATBAT: The Anticoagulant Therapy With Bivalirudin to Assist
in the Performance of Percutaneous Coronary Intervention in Patients With Heparin-Induced
Thrombocytopenia (ATBAT) Study3
ANGIOMAX in HIT/HITTS patients
- Ninety-eight percent (n=51) (n/N=52) of the heparin-induced thrombocytopenia
and thrombosis syndrome (HIT/HITTS) patients undergoing percutaneous coronary intervention
(PCI) with ANGIOMAX had a successful procedure
- The patient population had a number of risk factors for increased risk of
ischemic and bleeding complications, including a higher proportion of women than
expected (50%), a majority of patients with prior myocardial infarction (MI) (70%),
and 21% reported a history of HIT/HITTS
- Major bleeding occurred in 1 patient (1.9%; 95% CI, 0.04% to 10.65%) in the
high-dose group, who underwent elective bypass surgery. Only 1 unit of packed red
blood cells was given
- This study provides further evidence that ANGIOMAX overcomes the limitations
of heparin in PCI, and demonstrates safe and effective management of high-risk patients—those
with HIT/HITTS undergoing PCI
ANGIOMAX does not generate heparin antibodies, posing no risk of heparin-induced
thrombocytopenia or thrombosis syndrome (HIT/HITTS).

- ATBAT was conducted prospectively from July 1999 to February 2003; a total of 52
patients were recruited
- The protocol defined HIT as:
- A positive heparin-induced platelet aggregation or other functional assay for HIT
or immunoassay for HIT antibodies. Or,
- As thrombocytopenia associated with heparin therapy in which the platelet count
had decreased to <100x109/L (decrease of ≥30% from the pretreatment
platelet count) or to <150x109/L (decrease of ≥40% from the pretreatment
platelet count)
- ATBAT Dosing:3
- Open-label use of IV ANGIOMAX (bolus followed by infusion – duration of procedure
and/or up to 4 hours)
- ANGIOMAX was to be given > 5 minutes before the PCI as a 1 mg/kg intravenous bolus
and continued as a 2.5 mg/kg/hour infusion for 4 hours (BAT dose group).
- In January 2002, the ANGIOMAX dosing was changed to a 0.75 mg/kg bolus and 1.75
mg/kg/hour infusion during PCI and for up to 4 hours after PCI.
- If the attending physician determined that the patient required anticoagulant therapy
for > 4 hours, then the ANGIOMAX dose was reduced to 0.2 mg/kg/hour for up to 20
hours after PCI.
- The use of concomitant medications was allowed and included clopidogrel, aspirin,
ticlopidine, and glycoprotein (GP) IIb/IIIa inhibitors.
- Ten patients had concomitant GP IIb/IIIa therapy. Aspirin and clopidogrel were given
to 98% and 86% of patients, respectively.
- Primary end point was the incidence of major bleeding within 48 hours of study-drug
administration or until hospital discharge, whichever occurred first
- Secondary end points included event rates for components of the primary end
point and the activated clotting time (ACT), activated partial thromboplastin time
(aPTT), and platelet counts at baseline, pre-PCI, post-PCI, and pre-discharge
Baseline Characteristics3
Baseline Characteristic |
BAT Dose
1.0 mg/kg
2.5 mg/kg/h
|
|
PCI Dose
0.75 mg/kg
1.75 mg/kg/h
|
|
Patients undergoing PCI
|
25
|
|
25
|
|
Age (median years)
|
71
|
|
68
|
|
Female
|
48%
|
|
52%
|
|
Prior MI
|
74%
|
|
67%
|
|
Peripheral arterial disease |
28%
|
|
29%
|
|
Diabetes
|
32%
|
|
48%
|
|
CHF |
36%
|
|
26%
|
Clinical Outcomes3
- No major bleeding was observed in any patients undergoing PCI. Major bleeding occurred
in 1 patient (1.9%; 95% CI, 0.04% to 10.65%) in the high-dose group, who underwent
elective bypass surgery. Only 1 unit of packed red blood cells was given. No bleeding
source was identified, and the bleeding was defined by a drop in hemoglobin/hematocrit
without hemodynamic compromise.* There were no reports of intracranial bleeding,
retroperitoneal bleeding or transfusions
*Major bleeding was defined as intracranial or retroperitoneal bleeding,
bleeding resulting in hemodynamic compromise; bleeding with transfusion of ≥3
units of blood; or a decrease in hemoglobin of ≥3 g/dL or in hematocrit of ≥
9%.
- No significant thrombocytopenia was observed and no patient had a platelet count
<50 x 109/L after treatment with study drug. However, after receiving ANGIOMAX and
GP IIb/IIIa inhibitor, 2 patients with a diagnosis of HIT/HITTS developed moderate
thrombocytopenia
- Procedural success was achieved in 98% of patients† and clinical success
in 96% of patients
† Procedural success was defined as Thrombolysis In Myocardial
Infarction (TIMI) grade 3 flow after PCI and a final lesion stenosis <50%. Clinical
success was defined as procedural success without death, emergency bypass surgery,
or Q-wave MI as reported by investigators.
- * Major cardiac events were rare. One patient in the low-dose ANGIOMAX group
died ~46 hours after a clinically uncomplicated PCI from asystolic cardiac arrest
without evidence of recurrent ischemia, infarction, or congestive heart failure.
No patient suffered acute MI, transient ischemic attack, or stroke
ATBAT Bleeding Events
|
Events* |
Low-Dose Group
(n=25)
|
High-Dose Group
(n=27)
|
All Patients
(n=52)
|
|
Intracranial bleeding
|
0
|
0
|
0
|
|
Retroperitoneal bleeding
|
0
|
0
|
0
|
|
Hemodynamic compromise
|
0
|
1/25 (4.0%)
|
1/50 (2.0%)
|
|
Transfusion needed ≥3 U †
|
0
|
0
|
0
|
|
Drop in Hgb ≥3 g/dL, Hct ≥9% |
0
|
1/25 (4.0%)
|
1/50 (2.0%)
|
|
Composite |
0
|
1/27 (3.7%)
|
1/52 (1.9%)
|
|
Minus 2 duplicate patients ‡
|
0
|
1/25 (4.0%)
|
1/50 (2.0%)
|
|
Data are presented as n/n (%) unless otherwise noted
* Not mutually exclusive
† Sum of packed red cells and whole blood units
‡ Two patients were enrolled a second time (as per original protocol)
For this analysis only their first enrollment information was used.
|
Procedural Details and Results
|
|
Low-Dose Group
(n=25)
|
High-Dose Group
(n=27)
|
All Patients
(n=52)
|
|
PCI performed
|
25 (100%)
|
25 (93%)
|
50 (96%)
|
|
>1 lesion treated
|
7 (28%)
|
9 (33%)
|
16 (31%)
|
|
Vessel treated*
|
|
|
|
|
Left main
|
0
|
0
|
0
|
|
LAD
|
9/34 (26%)
|
12/34 (35%)
|
21/68 (31%)
|
|
Circumflex
|
9/34 (26%
|
9/34 (26%)
|
18/68 (26%)
|
|
RCA
|
7/34 (21%)
|
9/34 (26%)
|
16/68 (24%)
|
|
Bypass graft
|
9/34 (26%)
|
4/24 (12%)
|
13/68 (19%)
|
|
Post-PCI TIMI grade 3 flow |
34/34 (100%)
|
33/34 (97%)
|
67/68 (99%)
|
|
Thrombus |
|
|
|
|
Pre-PCI
|
1/34 (3%)
|
1/31 (3%)
|
2/65 (3%)
|
|
During PCI
|
0
|
0
|
0
|
|
Post-PCI
|
0
|
0
|
0
|
|
Abrupt closure
|
0
|
0
|
3/50 (6%)
|
|
Major dissection |
3/25 (12%)
|
0
|
3/50 (6%)
|
|
Procedural success
|
25/25 (100%)
|
24/25 (96%)
|
49/50 (98%)
|
|
Clinical success
|
24/25 (96%)
|
24/25 (96%)
|
48/50 (96%)
|
|
* Not mutually exclusive.
Data are presented as number (%) or n/n (%).
PCI = percutaneous coronary intervention.
LAD = left anterior descending artery.
RCA = right coronary artery.
TIMI = Thrombolysis in Myocardial Infarction.
|
Safety Considerations
ANGIOMAX with provisional use of glycoprotein IIb/IIIa inhibitor is indicated for
use as an anticoagulant in patients undergoing percutaneous coronary intervention
(PCI), and in patients with or at risk for heparin-induced thrombocytopenia and
thrombosis syndrome (HIT/HITTS) undergoing PCI. ANGIOMAX is intended for use with
aspirin and has been studied only in patients receiving concomitant aspirin. ANGIOMAX
is contraindicated in patients with active major bleeding or hypersensitivity to
ANGIOMAX or its components. The most common (≥10%) adverse events for ANGIOMAX were back pain, pain, nausea, headache,
and hypotension. An unexplained fall in blood pressure or hematocrit, or any unexplained
symptom, should lead to serious consideration of a hemorrhagic event and cessation
of ANGIOMAX administration. Please see complete prescribing information.
1Warkentin TE. New approaches to the diagnosis of heparin-induced thrombocytopenia.
Chest. 2005;127:35S-45S.
2Angiomax Prescribing Information, The Medicines Company, Parsippany;
NJ, December 6, 2005.
3Mahaffey KW, Lewis BE, Wildermann NM, et al, for the ATBAT Investigators.
The Anticoagulant Therapy with Bivalirudin to Assist in the performance of percutaneous
coronary intervention in patients with heparin-induced Thrombocytopenia (ATBAT)
study: main results. J Invas Cardiol. 2003;15:611-616.
4Warkentin TE, Greinacher A. Heparin-Induced Thrombocytopenia.
3rd ed. New York, NY: Marcel Dekker, Inc; 2004:223.