A novel enoxaparin regime for ST elevation myocardial infarction patients undergoing primary percutaneous coronary intervention: a WEST sub-study.

Abstract

OBJECTIVE:

To evaluate the anticoagulation effect of subcutaneous (SQ) and intravenous (IV) enoxaparin through systematic anti-Xa sampling during primary PCI for acute STEMI.

BACKGROUND:

Although appropriate anticoagulation is essential to maximize the efficacy and safety of primary PCI, the optimal dosing of enoxaparin in this setting is unclear.

METHODS:

STEMI patients randomized to primary PCI received ASA, clopidogrel 300 mg and enoxaparin 1 mg/kg SQ at earliest point of care, including prehospital. Plasma anti-Xa determination occurred just prior to and after primary PCI. Supplemental IV enoxaparin (0.3-0.5 mg/kg) and abciximab was encouraged prior to PCI.

RESULTS:

The 1st anti-Xa level 56 min (median, IQR 47-77) post SQ enoxaparin was 0.28 U/ml (0.23-0.41); 85% of patients (28/33) were <0.5 U/ml (the recommended therapeutic level). Following PCI, 126 min (118-185) after SQ enoxaparin in those without IV dosing (8/33) the 2nd anti-Xa level was 0.44 U/ml (0.29-0.53); 6 of 8 patients remained <0.5 U/ml. With IV enoxaparin (25/33) the 2nd anti-Xa was 0.96 U/ml (0.82-1.16) 97 min (82-109) after SQ enoxaparin: all were >or=0.5 U/ml and 2 had levels 1.5 U/ml.

CONCLUSION:

A single SQ enoxaparin dose fails to achieve anti-Xa levels >or=0.5 U/ml in the majority of STEMI patients. When combined with a strategy of supplemental IV enoxaparin, adequate anti-Xa levels were achieved in all patients with few having levels >1.5 U/ml. This regime of SQ injection with additional IV enoxaparin provides an attractive strategy enhancing effective early anti-thrombotic therapy at first medical contact prior to primary PCI.

• Authors: Robert C Welsh, Phillip Gordon, Cynthia M Westerhout, Christopher E Buller, Blair O'Neill, Paul W Armstrong
• Journal: Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions (Catheter Cardiovasc Interv) Vol. 70 Issue 3 Pg. 341-8 (Sep 2007) ISSN: 1522-1946 [Print] United States
• PMID: 17295333 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: (c) 2007 Wiley-Liss, Inc.

Chemical References

• Antibodies, Monoclonal
• Enoxaparin
• Fibrinolytic Agents
• Immunoglobulin Fab Fragments
• Platelet Aggregation Inhibitors
• Platelet Glycoprotein GPIIb-IIIa Complex
• Clopidogrel
• Ticlopidine
• Abciximab

Topics

• Abciximab
• Aged
• Angioplasty, Balloon, Coronary (methods)
• Antibodies, Monoclonal (administration & dosage)
• Canada
• Clopidogrel
• Coronary Angiography
• Dose-Response Relationship, Drug
• Drug Therapy, Combination
• Electrocardiography
• Enoxaparin (administration & dosage)
• Female
• Fibrinolytic Agents (administration & dosage)
• Follow-Up Studies
• Humans
• Immunoglobulin Fab Fragments (administration & dosage)
• Injections, Intravenous
• Male
• Middle Aged
• Myocardial Infarction (diagnostic imaging, physiopathology, therapy)
• Platelet Aggregation Inhibitors (administration & dosage)
• Platelet Glycoprotein GPIIb-IIIa Complex (antagonists & inhibitors)
• Ticlopidine (administration & dosage, analogs & derivatives)
• Treatment Outcome
• Urban Population