Faculty Bibliography

Among the current agents in the class of direct thrombin inhibitors, bivalirudin (Angiomax(®), The Medicines Company, NJ, USA) has seen increased use in cardiovascular medicine over the past decade through its primary indication as an anticoagulant used during percutaneous coronary interventions. Bivalirudin has been further investigated and used as the anticoagulation strategy in the setting of cardiac and endovascular surgical procedures and is frequently utilized in the management of patients with heparin-induced thrombocytopenia. In comparison with heparin, bivalirudin exhibits a low immunogenic profile and provides similar or reduced major bleeding rates as well as a predictable degree of anticoagulation that is dose related. Bivalirudin primarily undergoes dual elimination via proteolytic cleavage and renal elimination, and requires dose adjustment in the setting of severe renal dysfunction. Given the body of supportive data, bivalirudin is likely to continue to figure prominently as a reliable and efficient anticoagulation strategy. Additional agents in the class of direct thrombin inhibitors are under investigation and may find increasing clinical use.

BACKGROUND:There is uncertainty regarding the optimal adjunctive unfractionated heparin (UFH) regimen for percutaneous coronary intervention (PCI) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) treated with fondaparinux. OBJECTIVE:The aim of this study is to evaluate the safety of 2 dose regimens of adjunctive intravenous UFH during PCI in high-risk patients with NSTE-ACS initially treated with fondaparinux and referred for early coronary angiography. DESIGN/METHODS:This is an international prospective cohort study of approximately 4,000 high-risk patients presenting to hospital with unstable angina or non-ST-segment elevation myocardial infarction, treated with fondaparinux as initial medical therapy, and referred for early coronary angiography with a view to revascularization. Within this cohort, 2,000 patients undergoing PCI will be eligible for enrollment into a double-blind international randomized parallel-group trial evaluating standard activated clotting time (ACT)-guided doses of intravenous UFH versus a non-ACT-guided weight-adjusted low dose. The standard regimen uses an 85-U/kg bolus of UFH if there is no platelet glycoprotein IIb/IIIa (GpIIb-IIIa) inhibitor or 60 U/kg if GpIIb-IIIa inhibitor use is planned, with additional bolus guided by blinded ACT measurements. The low-dose regimen uses a 50 U/kg UFH bolus, irrespective of planned GpIIb-IIIa use. The primary outcome is the composite of peri-PCI major bleeding, minor bleeding, or major vascular access site complications. The assessment of net clinical benefit is a key secondary outcome: it addresses the composite of peri-PCI major bleeding with death, myocardial infarction, or target vessel revascularization at day 30. CONCLUSION/CONCLUSIONS:FUTURA/OASIS 8 will help define the optimal UFH regimen as adjunct to PCI in high-risk NSTE-ACS patients treated with fondaparinux.

BACKGROUND:Major bleeding during an acute coronary syndrome (ACS) is associated with increased late ischemic events. Patients with bleeding are often discharged without antiplatelet therapy (AT). The association between discharge AT use and late ischemic outcomes among ACS patients with bleeding is uncertain. METHODS:We examined discharge AT use among 8,582 ACS patients with in-hospital bleeding from a total of 26,451 patients enrolled in 4 randomized trials. After adjusting for the propensity to receive AT, we compared 6-month postdischarge outcomes between patients discharged with and those discharged without AT. RESULTS:Almost 1 in 10 patients with bleeding was discharged without AT (n=826). Compared with those receiving discharge AT, those not receiving discharge AT had a higher risk of 6-month death, myocardial infarction, and stroke (14.3% vs 7.8%, propensity-adjusted hazard ratio [HR]=1.36, 95% confidence interval=1.01-1.85). Nonuse of AT at discharge was associated with worse outcomes among patients treated with percutaneous coronary intervention compared with those treated without it (adjusted HR=4.22 vs 1.13, interaction P=.0003). Discharge monotherapy was associated with worse outcomes than dual AT among patients receiving stents (adjusted HR=1.78, 95% CI=1.04-3.03). CONCLUSIONS:Bleeding occurred commonly among patients with ACS. AT was often not used in these patients at discharge, and lack of discharge AT was associated with an increased risk of 6-month ischemic events. These data raise the possibility that lack of AT use among patients with in-hospital bleeding may contribute to their excess risk of long-term ischemic outcomes.

The use of glycoprotein IIb/IIIa inhibitors (GPI) reduces ischemic events in patients undergoing percutaneous coronary intervention (PCI). However, the same properties that confer this benefit lead to an increased bleeding risk. Recent studies have shown a less robust net clinical benefit of GPI in the current era of routine thienopyridine and direct thrombin inhibitor use. To optimize the net clinical benefit of GPI, these agents need to be selectively used in patients most likely to benefit from their anti-ischemic effect, namely patients undergoing PCI for non-ST-segment elevation myocardial infarction, select patients undergoing primary PCI, and select patients undergoing PCI without appropriate pre-loading with a thienopyridine. Moreover, strategies to minimize bleeding should be applied in these patients and include shorter GPI infusions (in some patients), dose adjustments of heparin and GPI, careful access site management with more frequent use of the transradial approach, use of smaller sheaths, and identification of patients at high bleeding risk. This review provides an update of the current literature that supports these measures, an insight on the tailored use of GPI, and a potential direction for future research addressing combined antithrombotic therapies.

BACKGROUND:Acute myocardial infarction (MI) remains a leading cause of death despite advances in pharmacologic and percutaneous therapies. Animal models of ischemia/reperfusion have demonstrated that single-dose erythropoietin may reduce infarct size, decrease apoptosis, and increase neovascularization, possibly through mobilization of endothelial progenitor cells. STUDY DESIGN/METHODS:REVEAL is a randomized, double-blind, placebo-controlled, multicenter trial evaluating the effects of epoetin α on infarct size and left ventricular remodeling in patients with large MIs. The trial comprises a dose-escalation safety phase and a single-dose efficacy phase using the highest acceptable epoetin α dose up to 60,000 IU. Up to 250 ST-segment elevation myocardial infarction patients undergoing primary or rescue percutaneous coronary intervention will be randomized to intravenous epoetin α or placebo within 4 hours of successful reperfusion. The primary study end point is infarct size expressed as a percentage of left ventricular mass, as measured by cardiac magnetic resonance imaging 2 to 6 days post study medication administration. Secondary end points will assess changes in endothelial progenitor cell numbers and changes in indices of ventricular remodeling. CONCLUSION/CONCLUSIONS:The REVEAL trial will evaluate the safety and efficacy of the highest tolerated single dose of epoetin α in patients who have undergone successful rescue or primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction.