A novel enoxaparin regime for ST elevation myocardial infarction patients undergoing primary percutaneous coronary intervention: a WEST sub-study.
ABSTRACT To evaluate the anticoagulation effect of subcutaneous (SQ) and intravenous (IV) enoxaparin through systematic anti-Xa sampling during primary PCI for acute STEMI.
Although appropriate anticoagulation is essential to maximize the efficacy and safety of primary PCI, the optimal dosing of enoxaparin in this setting is unclear.
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.
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.
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.
- SourceAvailable from: Keith A A Fox[show abstract] [hide abstract]
ABSTRACT: Unfractionated heparin is often used as adjunctive therapy with fibrinolysis in patients with ST-elevation myocardial infarction. We compared a low-molecular-weight heparin, enoxaparin, with unfractionated heparin for this purpose. We randomly assigned 20,506 patients with ST-elevation myocardial infarction who were scheduled to undergo fibrinolysis to receive enoxaparin throughout the index hospitalization or weight-based unfractionated heparin for at least 48 hours. The primary efficacy end point was death or nonfatal recurrent myocardial infarction through 30 days. The primary end point occurred in 12.0 percent of patients in the unfractionated heparin group and 9.9 percent of those in the enoxaparin group (17 percent reduction in relative risk, P<0.001). Nonfatal reinfarction occurred in 4.5 percent of the patients receiving unfractionated heparin and 3.0 percent of those receiving enoxaparin (33 percent reduction in relative risk, P<0.001); 7.5 percent of patients given unfractionated heparin died, as did 6.9 percent of those given enoxaparin (P=0.11). The composite of death, nonfatal reinfarction, or urgent revascularization occurred in 14.5 percent of patients given unfractionated heparin and 11.7 percent of those given enoxaparin (P<0.001); major bleeding occurred in 1.4 percent and 2.1 percent, respectively (P<0.001). The composite of death, nonfatal reinfarction, or nonfatal intracranial hemorrhage (a measure of net clinical benefit) occurred in 12.2 percent of patients given unfractionated heparin and 10.1 percent of those given enoxaparin (P<0.001). In patients receiving fibrinolysis for ST-elevation myocardial infarction, treatment with enoxaparin throughout the index hospitalization is superior to treatment with unfractionated heparin for 48 hours but is associated with an increase in major bleeding episodes. These findings should be interpreted in the context of net clinical benefit. (ClinicalTrials.gov number, NCT00077792.).New England Journal of Medicine 04/2006; 354(14):1477-88. · 51.66 Impact Factor
Article: Randomized evaluation of the efficacy of enoxaparin versus unfractionated heparin in high-risk patients with non-ST-segment elevation acute coronary syndromes receiving the glycoprotein IIb/IIIa inhibitor eptifibatide. Long-term results of the Integrilin and Enoxaparin Randomized Assessment of Acute Coronary Syndrome Treatment (INTERACT) trial.[show abstract] [hide abstract]
ABSTRACT: Patients with high-risk non-ST-segment elevation acute coronary syndromes (NSTE ACS) benefit from the early administration of aspirin, a small molecule glycoprotein IIb/IIIa inhibitor such as eptifibatide, and heparin. The INTERACT trial demonstrated that in high-risk patients with ACS receiving aspirin and eptifibatide, the use of enoxaparin compared with unfractionated heparin (UFH) was associated with less bleeding, less early myocardial ischemia, and improved 30-day outcomes. The aim of our study was to determine whether the short-term benefits of enoxaparin compared with UFH observed in high-risk patients with NSTE ACS are maintained over a prolonged period of follow-up. Six hundred thirty-nine patients that were representative of the total population of subjects in the INTERACT trial were followed up for a median period of 2.5 years. In this group, the early benefit of enoxaparin was maintained. The incidence of death or myocardial infarction at the time of long-term follow-up was 39% lower in patients receiving enoxaparin compared with those who received UFH (8.9% vs 14.7%, P = .024). There was no difference in the frequency of cardiac catheterization in the groups receiving either enoxaparin or UFH. The early treatment of high-risk patients with NSTE ACS receiving aspirin and eptifibatide with enoxaparin is associated with early outcome benefits that are sustained over a prolonged follow-up period. This trial supports the concept that early treatment directed against platelet and thrombin formation is associated with better short- and long-term outcomes.American heart journal 03/2006; 151(2):373-9. · 4.65 Impact Factor
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ABSTRACT: The objective of this study was to evaluate the pharmacokinetic response to intravenous (IV) enoxaparin given 8-12 hr after subcutaneous (SC) dosing in patients undergoing percutaneous coronary intervention (PCI). Fifty-five patients received SC enoxaparin (1 mg/kg every 12 hr) followed by an IV bolus (0.3 mg/kg) 8-12 hr after the last SC dose, at the start of PCI or during catheterization. Anti-Xa levels were within the target range in 98% of patients 2-8 hr after the last SC dose, in 96% of patients following the IV bolus, and in 91% of patients for a further 2 hr. Subcutaneous enoxaparin (1 mg/kg every 12 hr) provides sufficient anti-Xa levels for PCI 2-8 hr after the last dose. An additional 0.3 mg/kg enoxaparin dose given IV 8-12 hr after the last SC dose reliably maintains anti-Xa levels within the target for at least 2 additional hr.Catheterization and Cardiovascular Interventions 03/2004; 61(2):163-70. · 2.51 Impact Factor