Safety and efficacy of combined use of low molecular weight heparin (enoxaparin, lovenox) and glycoprotein IIb/IIIa receptor antagonist (eptifibatide, integrelin) during nonemergent coronary and peripheral vascular intervention

Adjunctive anticoagulation during peripheral vascular intervention

Endovascular techniques for the treatment of peripheral arterial disease are becoming an increasingly common alternative to open surgery, yet the degree of anticoagulation and choice of anticoagulant to optimize outcomes in these procedures remain uncertain. To date, few randomized trials have directly compared different anticoagulants for use during peripheral vascular interventions. It is also unclear if the approach to anticoagulation should be individualized to each vascular bed or if common principles are shared among them. This has led practitioners across different specialties to use a variety of different methods for anticoagulation, with most extrapolated from techniques used in percutaneous coronary interventions. In this review, we analyze the current literature for anticoagulation used during peripheral vascular intervention of the lower extremity, renal, carotid, and aortic arteries, with special consideration to the choice of anticoagulant used to maximize safe and effective procedural outcomes.

Macroscopic thrombus formation on angioplasty equipment following antithrombin therapy with enoxaparin

Increasing evidence suggests that treatment with the low molecular weight heparin enoxaparin during percutaneous coronary intervention (PCI) is safe and effective. We evaluated the incidence and consequences of periprocedural macroscopic thrombus formation on PCI equipment following antithrombin therapy with enoxaparin. Between April 2003 and December 2004, all patients undergoing cardiac catheterization following antithrombin therapy with enoxaparin were evaluated. All patients had blood sampled at the onset of procedure for subsequent measurement of anti-factor-Xa levels. Of the 4,504 patients who underwent PCI during this period, in 122 (3%) the procedure was performed within 8 hr of treatment with subcutaneous enoxaparin and no additional unfractionated heparin (UFH) was used periprocedurally. Of these, macroscopic thrombus was observed on PCI equipment in 6 patients (5%) necessitating withdrawal of all catheters and wires. All patients had therapeutic anti-factor-Xa levels at the time of PCI, and had been treated with double antiplatelet therapy with aspirin and clopidogrel. No periprocedural thrombus was observed in 356 patients who were >12 hr of the last dose of enoxaparin and received UFH at the time of PCI. Following observation of thrombus, additional anticoagulation with UFH resulted in significant epistaxis in one patient. In another patient, the procedure was complicated by distal coronary embolization. Percutaneous coronary intervention following antithrombin therapy with enoxaparin is associated with a 5% incidence of macroscopic thrombus formation on PCI equipment. The necessity for subsequent exchange of all equipment and/or the need for additional anticoagulation may have disastrous consequences for the patient. Our findings suggest that the safety of antithrombin therapy with low molecular weight heparin during PCI requires further evaluation.

Glycoprotein IIb-IIIa receptor inhibition with eptifibatide in percutaneous intervention for symptomatic peripheral vascular disease: the circulate pilot trial

The benefits of glycoprotein (GP) IIb-IIIa inhibitors in percutaneous coronary intervention are well established, but the experience with these agents in the setting of peripheral interventions is limited. In this single-center pilot trial, the safety and feasibility of adjunctive treatment with the GP IIb-IIIa inhibitor eptifibatide (INTEGRILIN, Millennium Pharmaceuticals, Inc., Cambridge, Massachusetts, and Schering-Plough Corporation, Kenilworth, New Jersey) was evaluated in 85 patients undergoing percutaneous transluminal angioplasty or stenting for severe claudication or critical limb ischemia. Eptifibatide treatment was safe, with low rates of major bleeding (3.5%) and thrombocytopenia (1.2%); one patient developed a post-procedure compartment syndrome requiring fasciotomy. The procedure was technically successful (defined as <30% residual stenosis or >50% increase in vessel diameter) in 84 of 85 (98.8%) patients. None of the patients required target vessel revascularization (TVR) during hospitalization, and only 1 patient (1.2%) required TVR within 30 days. These results demonstrate that adjunctive use of eptifibatide during percutaneous peripheral intervention is safe and supports further studies to establish the potential efficacy of GP IIb-IIIa inhibitors in this setting.

Heparin in interventional radiology: a therapy in evolution

Interventional radiology techniques made possible by the antithrombotic properties of heparin have revolutionized treatment for a myriad of disorders. Newer low-molecular-weight heparins (LMWHs) offer several advantages over unfractionated heparin (UFH), especially in chronic settings. They are increasing in popularity for use during vascular procedures. However, LMWH shares limitations with UFH such as heterogeneity, nonspecificity, and induction of thrombocytopenia. These drawbacks have led to a search for the next generation of antithrombotic agents. Homogeneous drugs targeting specific coagulation cascade molecules are now available. The number of alternative anticoagulant drug combinations presents clinicians with a confusing array of choices. The strengths and weaknesses of UFH, LMWH, and direct antithrombin agents are presented. The promising future of LMWH and hirudins is discussed.

Role of low-molecular-weight heparin in invasive management of non-ST-elevation acute coronary syndromes

OBJECTIVE

To review the available literature addressing the role of low-molecular-weight heparin (LMWH) as an alternative to unfractionated heparin (UFH) in percutaneous coronary intervention (PCI) for treatment of non-ST-elevation acute coronary syndromes (NSTEACS).

DATA SOURCES

A MEDLINE search (1966-March 2004) identified pertinent articles using the key words acute coronary syndromes, unstable angina, non-ST-elevation myocardial infarction, low-molecular-weight heparin, enoxaparin, dalteparin, glycoprotein IIb/IIIa receptor antagonists, abciximab, tirofiban, eptifibatide, percutaneous transluminal coronary angioplasty, and percutaneous coronary intervention. The references of these articles were reviewed for additional pertinent references.

STUDY SELECTION AND DATA EXTRACTION

All human trials of LMWH in PCI for treatment of NSTEACS were evaluated. All pertinent studies were included in the review.

DATA SYNTHESIS

Administration of LMWH with or without a glycoprotein IIb/IIIa inhibitor during PCI appears to be similar to UFH in terms of efficacy. LMWH, especially in combination with a glycoprotein IIb/IIIa inhibitor, may increase risk of bleeding compared with UFH.

CONCLUSIONS

Available clinical trials do not provide definitive evidence to suggest superiority of LMWH over UFH when managing NSTEACS during PCI; however, dosing strategies are available if an LMWH is to be used in this setting.

Administration of eptifibatide to acute coronary syndrome patients receiving enoxaparin or unfractionated heparin: effect on platelet function and thrombus formation

OBJECTIVES

The goal of this study was to compare the antithrombotic effects of enoxaparin versus unfractionated heparin (UFH) when combined with eptifibatide in acute coronary syndrome (ACS) patients.

BACKGROUND

An increasing number of high-risk ACS patients are treated with low-molecular-weight heparin and a glycoprotein (GP) IIb/IIIa inhibitor. There is a paucity of data regarding the antithrombotic properties of such a combination as compared with UFH and GP IIb/IIIa inhibitors.

METHODS

Twenty-six ACS patients scheduled to undergo coronary angiography were treated with subcutaneous enoxaparin (n = 13) or intravenous UFH (n = 13). All patients received eptifibatide just before coronary angiography. Antithrombotic effects were assessed as changes in platelet-thrombus formation using the Badimon ex vivo perfusion chamber. Perfusions were carried out at a high shear rate (HSR) and a low shear rate (LSR). Patients underwent two perfusion studies: at baseline (under enoxaparin or UFH) and 10 min after the eptifibatide bolus. Platelet function was evaluated by ADP-induced platelet aggregation and the rapid platelet function analyzer.

RESULTS

Both therapeutic combinations achieved a marked reduction in platelet aggregation after eptifibatide (83% to 89.7% reduction in the enoxaparin-eptifibatide group and 77.8% to 85.5% reduction in the UFH-eptifibatide group, inter-group differences not significant). Both groups also demonstrated marked reductions in thrombus formation, but the reductions achieved in the enoxaparin-eptifibatide group were significantly higher than those achieved in the UFH-eptifibatide group (HSR: 75.6% reduction vs. 63.9%, respectively, p = 0.01; LSR: 79.7% reduction vs. 66.1%, respectively, p = 0.0001).

CONCLUSIONS

The combination of eptifibatide with enoxaparin appears to have a more potent antithrombotic effect than that of eptifibatide and UFH in the doses tested.

Effects of heparin on liver fibrosis in patients with chronic hepatitis B

AIM: To evaluate the effects of heparin on liver fibrosis in patients with chronic hepatitis B.

METHODS: Fifty-two cases under study were divided into two groups, group A and group B. The two groups were given regular treatment and heparin/low molecular weight heparin (LMWH) treatment respectively. Hepatic functions, serum hyaluronic acid (HA) and type IV collagen levels were measured before and after the treatment, and six cases were taken liver biopsy twice.

RESULTS: After treatment, hepatic functions became significantly better in both groups. Serum HA and type IV collagen levels in group B compared with group A, decreased significantly after treatment. Collagen proliferation also decreased in group B after treatment.

CONCLUSION: Heparin/LMWH can inhibit collagen proliferation in liver tissues with hepatitis B.