The effects of bivalirudin compared with those of unfractionated heparin plus eptifibatide on inflammation and thrombin generation and activity during coronary intervention

Comparison of net adverse clinical events between bivalirudin and heparin as anticoagulants for percutaneous coronary intervention in Chinese patients

Bivalirudin, as a direct thrombin inhibitor, is considered to be safer compared with other anticoagulants, such as heparin; however, relevant data in China are unclear. The present study aimed to compare the safety of bivalirudin and heparin as anticoagulants in Chinese patients who underwent percutaneous coronary intervention (PCI). In the present study, 2,377 patients with ST-segment elevation myocardial infarction (STEMI), unstable angina, non-STEMI or stable coronary artery disease who underwent primary PCI while receiving bivalirudin or heparin (low molecular weight heparin or unfractionated heparin) were reviewed, and then analyzed as the bivalirudin group (n=944) and heparin group (n=1,433). The net adverse clinical events (NACEs) within 30 days were obtained, which were defined as major adverse cardiac and cerebral events (MACCEs) + Bleeding Academic Research Consortium (BARC) grade 2-5 bleeding events. Compared with the heparin group, the incidence of NACEs was reduced in the bivalirudin group (9.3 vs. 13.4%; P=0.003). However, no discrepancy was found in the incidence of MACCEs between the groups (5.9 vs. 7.6%; P=0.116). Moreover, the incidences of BARC 2-5 (4.8 vs. 8.7%; P<0.001) and BARC 3-5 bleeding events (1.9 vs. 4.4%; P=0.001) were decreased in the bivalirudin group compared with the heparin group. Following adjustment using multivariate logistic regression analysis, bivalirudin treatment (vs. heparin treatment) was independently associated with lower risks of NACEs [odds ratio (OR), 0.587; P<0.001], MACCEs (OR, 0.689; P=0.041) and BARC 2-5 (OR, 0.459; P<0.001) and 3-5 bleeding events (OR, 0.386; P=0.002). Overall, the present study demonstrated that bivalirudin decreased the risks of NACEs and bleeding events compared with heparin in Chinese patients who undergo PCI. However, further validation is required.

Safety and Efficacy of Bivalirudin versus Unfractionated Heparin Monotherapy in Patients with CAD and DM Undergoing PCI: A Retrospective Observational Study

Introduction

Optimal anticoagulants for patients with diabetes mellitus (DM) undergoing percutaneous coronary intervention (PCI) are unclear. This retrospective observational study is aimed at evaluating efficacy and safety of bivalirudin versus unfractionated heparin (UFH) monotherapy in patients with DM undergoing PCI.

Methods

A total of 3890 diabetic patients receiving PCI in the General Hospital of Northern Theater Command were divided into the bivalirudin group (n = 869) and the UFH group (n = 3021) according to different anticoagulant therapy regimens. Indication for PCI was in accordance with current guidelines including national cardiovascular data registry. The primary endpoint was 30-day net adverse clinical events (NACEs). The secondary endpoints included 30-day major adverse cardiac and cerebral events (MACCEs), bleeding events defined according to the Bleeding Academic Research Consortium (BARC) definition, and stent thrombosis (ST). Patients were matched by propensity score at a ratio of 1 : 1.

Results

After propensity score matching, the bivalirudin group was associated with a lower incidence of NACEs (3.0% vs. 6.0%, P = 0.003) than the UFH group. The incidence of MACCE (1.7% vs. 3.3%, P = 0.033) was significantly lower in the bivalirudin group, mainly due to a lower mortality rate (0.6% vs. 2.0%, P = 0.010). In addition, patients in the bivalirudin group had less bleeding (1.4% vs. 3.0%, P = 0.022) than those in the UFH group, although BARC 2, 3, and 5 bleeding (0.1% vs. 0.6%, P = 0.218) was numerically lower.

Conclusion

In diabetic patients undergoing PCI, bivalirudin was significantly associated with reduced risks of 30-day NACE and MACCE, mainly driven by the lower rates of bleeding and mortality, compared with heparin monotherapy.

Anti-Inflammatory Effects of Heparin and Its Derivatives: A Systematic Review

Background. Heparin, used clinically as an anticoagulant, also has anti-inflammatory properties. The purpose of this systematic review was to provide a comprehensive review regarding the efficacy and safety of heparin and its derivatives as anti-inflammatory agents. Methods. We searched the following databases up to March 2012: Pub Med, Scopus, Web of Science, Ovid, Elsevier, and Google Scholar using combination of Mesh terms. Randomized Clinical Trials (RCTs) and trials with quasi-experimental design in clinical setting published in English were included. Quality assessments of RCTs were performed using Jadad score and Consolidated Standards of Reporting Trials (CONSORT) checklist. Results. A total of 280 relevant studies were reviewed and 57 studies met the inclusion criteria. Among them 48 studies were RCTs. About 65% of articles had score of 3 and higher according to Jadad score. Twelve studies had a quality score > 40% according to CONSORT items. Asthma (n = 7), inflammatory bowel disease (n = 5), cardiopulmonary bypass (n = 8), and cataract surgery (n = 6) were the most studied disease condition. Forty studies use unfractionated heparin (UFH) for intervention; the remaining studies use low molecular weight heparin (LMWH). Conclusion. Despite the conflicting results, heparin seems to be a safe and effective anti-inflammatory agent; although it is shown that heparin can decrease the level of inflammatory biomarkers and improves patient conditions, still more data from larger rigorously designed studies are needed to support use of heparin as an anti-inflammatory agent in clinical setting. However, because of the association between inflammation, atherogenesis, thrombogenesis, and cell proliferation, heparin and related compounds with pleiotropic effects may have greater therapeutic efficacy than compounds acting against a single target.

Safety and efficacy of bivalirudin monotherapy in patients with diabetes mellitus and acute coronary syndromes: a report from the ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy) trial

OBJECTIVES

We sought to evaluate clinical outcomes of patients with diabetes mellitus in the ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy) trial, overall and by treatment arm.

BACKGROUND

In the ACUITY trial, 13,819 patients with moderate- or high-risk acute coronary syndromes (ACS) were randomized to heparin (unfractionated or enoxaparin) plus glycoprotein IIb/IIIa inhibition (GPI), bivalirudin plus GPI, or bivalirudin monotherapy. Compared with heparin plus GPI, bivalirudin monotherapy resulted in similar protection from ischemic events with less major bleeding. Whether these results apply to patients with diabetes is unknown.

METHODS

We evaluated the impact of diabetes on 30-day net adverse clinical outcomes (composite ischemia [death, myocardial infarction, or unplanned ischemic revascularization] or major bleeding), overall and by antithrombotic strategy.

RESULTS

Diabetes was present in 3,852 randomized patients (27.9%). Compared with nondiabetic patients, diabetic patients had higher 30-day rates of net adverse clinical outcomes (12.9% vs. 10.6%; p < 0.001), composite ischemia (8.7% vs. 7.2%; p = 0.003), and major bleeding (5.7% vs. 4.2%; p < 0.001). Among diabetic patients, compared with heparin plus GPI, bivalirudin plus GPI resulted in similar rates of net adverse clinical outcomes (14.0% vs. 13.8%; p = 0.89), while bivalirudin monotherapy resulted in a similar rate of composite ischemia (7.9% vs. 8.9%; p = 0.39) and less major bleeding (3.7% vs. 7.1%; p < 0.001), yielding fewer net adverse clinical outcomes (10.9% vs. 13.8%; p = 0.02).

CONCLUSIONS

Diabetic patients with ACS managed invasively have higher rates of composite ischemia and major bleeding. Compared with treatment with heparin plus GPI, bivalirudin monotherapy provides similar protection from ischemic events with less major bleeding, resulting in a significant reduction in net adverse clinical outcomes.

Comparison of platelet function and morphology in patients undergoing percutaneous coronary intervention receiving bivalirudin versus unfractionated heparin versus clopidogrel pretreatment and bivalirudin

We hypothesized that direct thrombin inhibition could attenuate platelet activation and release of soluble CD40 ligand (sCD40L), a marker of inflammation, during percutaneous coronary intervention (PCI). To assess platelet function under flow conditions with bivalirudin versus unfractionated heparin (UFH), we employed the cone and plate(let) analyzer (CPA) assay in drug-spiked blood samples from volunteers (n = 3) in vitro, and then in PCI patients who received bivalirudin alone (n = 20), UFH alone (n = 15), and clopidogrel pretreatment plus bivalirudin (n = 15). Scanning electron microscopy was employed to image bivalirudin or UFH-treated platelets to determine whether platelet function observations had a morphologic explanation. Enzyme immunoassay was used to measure sCD40L levels in PCI patients. In vitro, bivalirudin decreased platelet surface coverage; UFH increased platelet surface coverage. In PCI patients, bivalirudin alone decreased platelet surface coverage, UFH alone increased platelet surface coverage, and clopidogrel pretreatment plus bivalirudin additively reduced platelet surface coverage. Unlike UFH, bivalirudin did not activate platelets in SEM studies. Bivalirudin alone or coupled with clopidogrel significantly reduced plasma sCD40L in PCI patients. In conclusion, our findings suggest that under flow conditions, bivalirudin alone or coupled with clopidogrel may have an antiplatelet effect versus UFH alone during PCI. These data suggest that bivalirudin and UFH may confer an anti-inflammatory effect by reducing sCD40L during PCI.

Greater inhibitory effects of bivalirudin compared with unfractionated heparin plus eptifibitide on thrombin-induced platelet activation

OBJECTIVES

The effects of antithrombotic agents on the activation of platelets by thrombin were determined in blood from patients (n=12) with symptomatic coronary artery disease.

METHODS

Blood obtained immediately before cardiac catheterization was incubated in vitro with therapeutic concentrations of unfractionated heparin (1.2 and 2.0 U/ml) alone and in combination with eptifibatide (unfractionated heparin 1.2 U/ml+eptifibatide, 1.7 microg/ml) or bivalirudin (8 and 14 microg/ml). An activated clotting time was determined. Platelet activation was induced with thrombin (0, 5, 15, and 40 U/ml) and assessed with the use of flow cytometry. Fibrin polymerization was prevented by the peptide Gly-Pro-Arg-Pro. The activation of glycoprotein IIb-IIIa and surface expression of P-selectin were identified with antibodies (PAC-1 and anti-CD62).

RESULTS

The activated clotting time was 258+/-13 s with 1.2 U/ml unfractionated heparin alone, 396+/-8 s with unfractionated heparin+eptifibatide, and 348+/-9 s with 8 microg/ml bivalirudin. The binding of PAC-1 (reflecting the potential to aggregate) was decreased most effectively by bivalirudin (percentage of platelets binding PAC-1 in response to 15 U/ml thrombin-unfractionated heparin=54+/-7%, unfractionated heparin+eptifibatide=12+/-4%, bivalirudin=1+/-0.3% of platelets, P<0.05 for bivalirudin compared with unfractionated heparin or unfractionated heparin+eptifibatide and unfractionated heparin+eptifibatide compared with unfractionated heparin). Bivalirudin prevented thrombin-induced surface expression of P-selectin more effectively than unfractionated heparin alone or unfractionated heparin+eptifibatide (percentage of platelets expressing P-selectin in response to 15 U/ml thrombin-unfractionated heparin alone=74+/-5%, unfractionated heparin+eptifibatide=53+/-7%, bivalirudin=1+/-0.3%, P<0.05 for bivalirudin compared with unfractionated heparin or unfractionated heparin+eptifibatide).

CONCLUSION

Comparison between pharmacologic concentrations shown to be therapeutic demonstrated that bivalirudin inhibited thrombin-induced activation of platelets to a greater extent than unfractionated heparin alone or in combination with eptifibatide.