Bivalirudin Versus Heparin During PCI in NSTEMI: Individual Patient Data Meta-Analysis of Large Randomized Trials

Translating proof-of-concept for platelet slip into improved antithrombotic therapeutic regimens

Platelets are central to thrombosis. Research at the intersection of biological and physical sciences provides proof-of-concept for shear rate-dependent platelet slip at vascular stenosis and near device surfaces. Platelet slip extends the observed biological "slip-bonds" to the boundary of functional gliding without contact. As a result, there is diminished engagement of the coagulation cascade by platelets at these surfaces. Comprehending platelet slip would more precisely direct antithrombotic regimens for different shear environments, including for percutaneous coronary intervention (PCI). In this brief report we promote translation of the proof-of-concept for platelet slip into improved antithrombotic regimens by: (1) reviewing new supporting basic biological science and clinical research for platelet slip; (2) hypothesizing the principal variables that affect platelet slip; (3) applying the consequent construct model in support of-and in some cases to challenge-relevant contemporary guidelines and their foundations (including for urgent, higher-risk PCI); and (4) suggesting future research pathways (both basic and clinical). Should future research demonstrate, explain and control platelet slip, then a paradigm shift for choosing and recommending antithrombotic regimens based on predicted shear rate should follow. Improved clinical outcomes with decreased complications accompanying this paradigm shift for higher-risk PCI would also result in substantive cost savings.

Antithrombotic Therapy in Patients with Complex Percutaneous Coronary Intervention and Cardiogenic Shock

Managing antithrombotic therapy in patients undergoing complex and high-risk in indicated patients, including those treated with complex percutaneous coronary intervention (PCI) or presenting with cardiogenic shock (CS), is challenging. This review highlights the critical role of antithrombotic therapy, during and after PCI, to optimize the efficacy while minimizing risks. Unfractionated heparin remains the mainstay anticoagulant for complex PCI and CS, with bivalirudin as a potential safer alternative. Cangrelor offers consistent antiplatelet effects, especially when timely absorption of oral agents is uncertain.

Bivalirudin versus heparin in patients with or without bail-out GPI use: a pre-specified subgroup analysis from the BRIGHT-4 trial

BACKGROUND

Conflicting results comparing bivalirudin versus heparin anticoagulation in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI), in part due to the confounding effect of glycoprotein IIb/IIIa inhibitors (GPI). The aim of the study was to compare the safety and effectiveness of bivalirudin plus a post-PCI high-dose infusion vs heparin with or without bail-out GPI use.

METHODS

We conducted a pre-specified subgroup analysis from the BRIGHT-4 trial that randomized 6016 STEMI patients who underwent primary PCI to receive either bivalirudin plus a post-PCI high-dose infusion for 2-4 h or heparin monotherapy. GPI use was only reserved as bail-out therapy for procedural thrombotic complications. The primary outcome was a composite of all-cause death or Bleeding Academic Research Consortium (BARC) types 3-5 bleeding at 30 days.

RESULTS

A total of 5250 (87.4%) patients received treatment without GPI while 758 (12.6%) received bail-out GPI. Bail-out GPI use was associated with an increased risk of the primary outcome compared to non-GPI use (5.28% vs. 3.41%; adjusted hazard ratio (aHR), 1.62; 95% confidence interval (CI), 1.13-2.33; P = 0.009) and all-cause death (5.01% vs. 3.12%; aHR, 1.74; 95% CI, 1.20-2.52; P = 0.004) but not in the risk of BARC types 3-5 bleeding (0.53% vs. 0.48%; aHR, 0.90; 95% CI, 0.31-2.66; P = 0.85). Among patients without GPI use, bivalirudin was associated with lower rates of the primary outcome (2.63% vs. 4.21%; aHR, 0.55; 95% CI, 0.39-0.77; P = 0.0005), all-cause death (2.52% vs. 3.74%; aHR, 0.58; 95% CI, 0.41-0.83; P = 0.003), and BARC types 3-5 bleeding (0.15% vs. 0.81%; aHR, 0.19; 95% CI, 0.06-0.57; P = 0.003) compared with heparin. However, among patients requiring bail-out GPI, there were no significant differences observed in the rates of the primary outcome (5.76% vs. 4.87%; aHR, 0.77; 95% CI, 0.36-1.66; P = 0.50; Pinteraction = 0.07) or its individual components between bivalirudin and heparin groups.

CONCLUSIONS

Bivalirudin plus a post-PCI high-dose infusion was associated with significantly reduced 30-day composite rate of all-cause death or BARC types 3-5 bleeding compared with heparin monotherapy in STEMI patients undergoing primary PCI without GPI use. However, these benefits might be less pronounced in patients requiring bail-out GPI due to thrombotic complications during primary PCI.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03822975.

Unified Methodology for the Primary Preclinical In Vivo Screening of New Anticoagulant Pharmaceutical Agents from Hematophagous Organisms

The development of novel anticoagulants requires a comprehensive investigational approach that is capable of characterizing different aspects of antithrombotic activity. The necessary experiments include both in vitro assays and studies on animal models. The required in vivo approaches include the assessment of pharmacokinetic and pharmacodynamic profiles and studies of hemorrhagic and antithrombotic effects. Comparison of anticoagulants with different mechanisms of action and administration types requires unification of the experiment scheme and its adaptation to existing laboratory conditions. The rodent thrombosis models in combination with the assessment of hemostasis parameters and hematological analysis are the classic methods for conducting preclinical studies. We report an approach for the comparative study of the activity of different anticoagulants in vivo, including the investigation of pharmacodynamics and the assessment of hemorrhagic effects (tail-cut bleeding model) and pathological thrombus formation (inferior vena cava stenosis model of venous thrombosis). The reproducibility and uniformity of our set of experiments were illustrated on unfractionated heparin and dabigatran etexilate (the most common pharmaceuticals in antithrombic therapy) as comparator drugs and an experimental drug variegin from the tick Amblyomma variegatum. Variegin is notorious since it is a potential analogue of bivalirudin (Angiomax, Novartis AG, Basel, Switzerland), which is now being actively introduced into antithrombotic therapy.

Bivalirudin in acute coronary syndromes

INTRODUCTION

Bivalirudin, a bivalent direct thrombin inhibitor, has been developed to reduce bleeding without any trade-off in thrombotic events in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI).

AREAS COVERED

Despite showing a superior safety profile compared with unfractionated heparin (UFH), bivalirudin is not considered the anticoagulant of choice in ACS patients undergoing PCI, mainly because of an increased rate of acute stent thrombosis (ST) shown by several randomized controlled trials (RCTs), in addition to limited availability in certain countries and increased costs. However, RCTs on bivalirudin have been characterized by several confounding factors hindering the interpretation of its safety and efficacy compared with UFH among the spectrum of ACS patients. Furthermore, a significant body of evidence has demonstrated that the risk of acute ST can be mitigated by a full-dose infusion regimen following PCI, without compromising the favorable safety profile compared to UFH.

EXPERT OPINION

In light of the increased understanding of the prognostic relevance of bleeding events and the excellent safety profile of bivalirudin, recent trial evidence may allow for this anticoagulant agent to reemerge and have a more prominent role in the management of ACS patients undergoing PCI.