The STREAM Percutaneous Coronary Intervention Anticoagulant Sub-study
Acute Myocardial Infarction
Drug: Unfractionated heparin
|Study Design:||Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||The STrategic Reperfusion Early After Myocardial Infarction (STREAM) Anticoagulation With Enoxaparin vs. Unfractionated Heparin in Primary PCI Sub-study.|
- Adequacy of anticoagulation with enoxaparin (anti-Xa levels ≥ 0.5 U/ml to 1.5 U/ml) vs. unfractionated heparin (ACT - ≥200 - 250 seconds with concomitant GP IIb/IIIa antagonist and ACT - ≥250 - 350 seconds without concomitant GP IIb/IIIa antagonist). [ Time Frame: During Primary PCI ] [ Designated as safety issue: Yes ]
- Composite of major bleeding (non-CABG), death, cardiogenic shock, and congestive heart failure [ Time Frame: 30 days ] [ Designated as safety issue: Yes ]
- ECG & angiographic measures before and after primary PCI [ Time Frame: 24 hours ] [ Designated as safety issue: Yes ]
|Study Start Date:||October 2008|
|Study Completion Date:||June 2012|
|Primary Completion Date:||June 2012 (Final data collection date for primary outcome measure)|
Enoxaparin 0.5 mg/kg IV bolus (Regardless of whether the investigator has chosen to initiate concomitant GP IIb/IIIa antagonist; provision for additional IV enoxaparin to be administered if elapsed time to PCI exceeds 2 hours (from original IV dose) - enoxaparin 0.25 mg/kg IV will be administered At the discretion of the treating physician, if sustained anticoagulation is required then enoxaparin subcutaneously will be administered - enoxaparin 1.0 mg/kg SQ q 12 hours.
Maintenance dose adjustment for renal insufficiency - creatinine clearance < 30 ml/min, sc enoxaparin should be administered at 1.0 mg / kg / q24 hours. No adjustment of IV dose is required in case of renal insufficiency
|Active Comparator: Unfractionated heparin||
Drug: Unfractionated heparin
Unfractionated heparin 70 u/kg IV bolus (consistent with ASSENT 4 PCI) Baseline ACT will be draw at time of sheath insertion - With use of GP IIb/IIIa antagonist additional UFH will be administered to achieve an ACT of ≥200 - 250 seconds If IIb/IIIa is not utilized - additional UFH will be administered to achieve an ACT of ≥250-350 seconds At the discretion of the treating physician if sustained anticoagulation is required:UFH infusion 12/u/kg/hr IV infusion to commence
Past research in stable patients with coronary artery disease and those with non-ST elevation acute coronary syndromes (NSTEMI) has demonstrated the safety and efficacy of enoxaparin as an anticoagulant strategy in patients undergoing percutaneous coronary intervention 1-3.
In patients with ST-elevations myocardial infarction (STEMI) receiving pharmacological reperfusion (fibrinolysis), enoxaparin has been shown to be an attractive alternative to unfractionated heparin based upon past modest scale trials (HART-2, ENTIRE TIMI 23, ASSENT-3, ASSENT-3+)4-6. These results were definitively extended by the ExTRACT-TIMI 25 trial which compared fibrinolysis with unfractionated heparin versus enoxaparin in 20,506 patients with STEMI 7. The primary endpoint of death and re-MI occurred in 9.9% of patients with enoxaparin and 12.0% of patients in the unfractionated heparin group (17% RR, p<0.001); major bleeding occurred in 2.1% and 1.4% respectively (p<0.001). This was achieved using a dose reduction strategy in the elderly (>75yrs) that omitted the intravenous enoxaparin bolus and decreased the subcutaneous injection to 0.75 mg/kg. After initial fibrinolysis, fewer patients underwent PCI through 30 days in the enoxaparin group versus the unfractionated heparin group (22.8% vs 24.2%, p=0.027). Among those who underwent PCI (n=4674) by 30 days the primary endpoint occurred in 10.7% with enoxaparin versus 13.8% unfractionated heparin randomization (0.77 RR, p<0.001); major bleeding was not different (1.4% vs. 1.6%, p=NS) 8.
Despite existing data in stable coronary artery disease, NSTEMI, and STEMI patients treated with fibrinolysis there is limited data regarding the approach to anticoagulation therapy with enoxaparin in those STEMI patients undergoing primary PCI. Within a sub-study of the Which Early ST Elevation Myocardial Infarction Therapy study (WEST) we undertook systematic anti-Xa sampling to address the adequacy of anticoagulation with an enoxaparin based regime9, 10. WEST patients undergoing primary PCI received aspirin, clopidogrel, and subcutaneous enoxaparin (1mg/kg) at the time of randomization. Subsequent administration of intravenous enoxaparin and abciximab at the time of PCI was encouraged. Those receiving supplemental intravenous enoxaparin (0.3 - 0.5 mg/kg) in addition to subcutaneous enoxaparin achieved anti-Xa levels > 0.5 units/ml (the proposed therapeutic concentration). Amongst those receiving 1 mg/kg of enoxaparin subcutaneous at randomization and 0.3 mg/kg intravenous enoxaparin at time of PCI, none had excessive anticoagulation (anti-Xa > 1.5 units/ml) suggesting that this may be an attractive dosing strategy.
Recently a non-randomized comparison of unfractionated heparin and enoxaparin within the FINNESSE study was presented in STEMI patients undergoing primary PCI. Preliminary reports indicate superior outcomes amongst those receiving enoxaparin 0.5mg/kg intravenous as compared to unfractionated heparin intravenously.
The STREAM study provides a unique and important opportunity to acquire randomized safety and efficacy data on anticoagulation with enoxaparin vs. unfractionated heparin in STEMI patients undergoing primary PCI.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00882635
|University of Alberta Hospital|
|Edmonton, Alberta, Canada, T6G 2B7|
|NewMarket, Ontario, Canada, l3y 2P9|
|Principal Investigator:||Robert C Welsh, MD||University of Alberta|