Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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COMPLETED
PHASE1
504 participants
INTERVENTIONAL
2012-06-30
2014-12-31
Brief Summary
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Detailed Description
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We will first identify enrolled patients with altered heparin responsiveness (AHR) as defined by an ACT \< 450 seconds (the MGH standard target ACT after the initial dose of heparin for CPB). Patients who achieve an ACT \> 450 sec will not enter the randomization phase of the study, their participation in the study will be complete and their routine clinical care will continue unaltered. Those with AHR (post-heparin ACT \< 450 sec) will be randomized to receive either supplemental heparin or supplemental AT. Those that fail to achieve an adequate ACT after the first supplementation will cross-over to receive the alternate supplement. Blood samples (totaling at most 20 ml) will be taken at each step to measure heparin level, AT level, AT activity. Once a patient is placed onto cardiopulmonary bypass their participation in the study will be complete.
By design, this study replicates routine clinical management of heparin anticoagulation for cardiopulmonary bypass at the MGH. Most patients (80%) coming to cardiac surgery who will undergo CPB respond adequately to a routine initial bolus dose of heparin (ACT \> 450 after 350 U/kg); as noted, subjects in this study that achieve the target ACT will be managed according to routine clinical practice without further testing or intervention.
Under routine care, patients with an inadequate initial response to heparin receive either supplemental heparin (150 U/kg) or pooled human antithrombin (1000 Units), or both. In this study, subjects with inadequate heparin response (ACT \< 450) after the initial heparin bolus, will be randomly assigned to two comparison groups; half will receive supplemental heparin (150 U/kg) and half will receive AT (1000 IU). Subjects who fail to respond to their assigned first intervention will cross-over to receive the alternate intervention.
Some subjects may not achieve the target ACT despite receiving both supplemental heparin and AT comprising a group of patients with "true heparin resistance" whose coagulation profiles can be further characterized to better understand the mechanisms of the resistance. These subjects will be considered to have completed the study even though they are not yet on cardiopulmonary bypass and will be managed according to the best clinical judgment of their physicians. They may receive additional heparin, additional AT, fresh-frozen plasma, or any combination of these. These patients may be at risk for thrombotic complications during the post-operative period. Accordingly, when clinically appropriate, these individuals may be referred for further evaluation of their coagulation status, but these evaluations will not be done as part of this study.
This is a pathophysiological risk-factor association study that seeks to better understand the phenomenon of altered heparin responsiveness. Accordingly, there is no specific study endpoint apart from achieving an ACT of \> 450 sec. In all enrolled subjects we will measure the levels of three acute phase reactants, Factor VIII, fibrinogen and CRP, heparin levels (anti Xa), AT level (immunofixation) and AT activity after the initial heparin dose. For all subjects who do not achieve and ACT of \> 450 we will also measure additional heparin levels (anti Xa), AT level (immunofixation), and AT activity after each intervention in the randomization/crossover phase. The total amount of blood taken for the research-specific laboratory test is less than 20 ml.
Conditions
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Study Design
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RANDOMIZED
CROSSOVER
BASIC_SCIENCE
NONE
Study Groups
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ACT after initial heparin bolus less than 450
If a patients activated clotting time (ACT) is less than 450 after the bolus dose of heparin (350U/kg) they will be randomized to one of two interventions.
Heparin
150 U/kg
ATryn
1000 IU
ACT after first intervention less than 450
Heparin
150 U/kg
ATryn
1000 IU
Interventions
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Heparin
150 U/kg
ATryn
1000 IU
Other Intervention Names
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Eligibility Criteria
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Inclusion Criteria
* Patients scheduled for urgent surgery who are hemodynamically stable and capable of giving voluntary consent
* Patients with platelet factor 4 antibody positivity (antiPF4+) for whom heparin anticoagulation will be used
Exclusion Criteria
* Patients with known congenital AT-deficiency
* Patients with known goat milk allergy
18 Years
ALL
Yes
Sponsors
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rEVO Biologics
INDUSTRY
Massachusetts General Hospital
OTHER
Responsible Party
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Greg Koski
Greg Koski, PhD, MD, CPI (Honorary)
Principal Investigators
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Greg Koski, MD, PhD
Role: PRINCIPAL_INVESTIGATOR
Massachusetts General Hospital
Locations
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Massachusetts General Hospital
Boston, Massachusetts, United States
Countries
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Other Identifiers
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Altered Heparin Responsiveness
Identifier Type: -
Identifier Source: org_study_id