Bivalirudin: an anticoagulant for acute coronary syndromes and coronary interventions

Hirudin in the Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) is a common public health concern. The global burden of CKD is increasing due to the high morbidity and mortality associated with it, indicating the shortcomings of therapeutic drugs at present. Renal fibrosis is the common pathology of CKD, which is characterized by glomerulosclerosis, renal tubular atrophy, and renal interstitial fibrosis. Natural hirudin is an active ingredient extracted from Hirudo medicinalis, which has been found to be the strongest natural specific inhibitor of thrombin. Evidence based on pharmacological data has shown that hirudin has important protective effects in CKD against diabetic nephrology, nephrotic syndrome, and renal interstitial fibrosis. The mechanisms of hirudin in treating CKD are mainly related to inhibiting the inflammatory response, preventing apoptosis of intrinsic renal cells, and inhibiting the interactions between thrombin and protease-activated receptors. In this review, we summarize the function and beneficial properties of hirudin for the treatment of CKD, and its underlying mechanisms.

Efficacy and safety of bivalirudin in coronary artery disease patients with mild to moderate chronic kidney disease: Meta-analysis

BACKGROUND

Patients with chronic kidney disease (CKD) have elevated bleeding and ischemic outcomes. We aim to assess the short- and long-term efficacy and safety of bivalirudin compared to heparin plus glycoprotein IIb/IIIa inhibitors (GPIs) in coronary artery disease (CAD) patients with CKD.

METHODS

Randomized trials were searched in PubMed, Cochrane, and Embase databases up to January 2017. Among the trials retrieved, efficacy endpoints were defined as mortality, myocardial infarction (MI), repeat revascularization, stent thrombosis, and major adverse cardiac events (MACEs). Safety endpoints were reported as non-coronary artery bypass grafting (CABG) related major bleeding and thrombolysis in myocardial infarction (TIMI) major bleeding. Risk ratio (RR) and 95% confidence interval (CI) were calculated for each outcome using a fixed effect model.

RESULTS

Five studies with a total of 3796 patients were included. In short-term follow up (30 days), bivalirudin significantly reduced non-CABG related major bleeding (p=0.0004) and TIMI major bleeding (p=0.007) compared to heparin plus GPIs. No significant differences were observed in rates of mortality, MI, repeat revascularization, stent thrombosis, and MACEs between the two groups in short- and long-term follow up (6 months to 3 years). In patients with ST elevated myocardial infarction (STEMI) with concurrent CKD, the decreased non-CABG related major bleeding (p=0.04) without increasing ischemic events was also observed after short-term follow up.

CONCLUSIONS

(1) Bivalirudin is safer than and as effective as heparin plus GPIs in CAD patients with CKD. (2) Impaired renal function does not affect the safety benefits of bivalirudin. (3) Similar efficacy profiles were identified between the two groups after both short- and long-term follow up in the CAD patients with CKD.

Platelet function and coagulation in patients with STEMI and peri-interventional clopidogrel plus heparin vs. prasugrel plus bivalirudin therapy (BRAVE 4 substudy)

INTRODUCTION

In this prespecified BRAVE 4 substudy we examined the antiplatelet and anticoagulant efficacy of clopidogrel plus heparin vs. prasugrel plus bivalirudin in patients with ST-segment elevation myocardial infarction.

METHODS

26 patients received clopidogrel/heparin, 25 patients received prasugrel/bivalirudin and 20 additional untreated patients served as controls. Platelet aggregation was tested using whole blood impedance aggregometry. Dynamic platelet adhesion and aggregate formation to collagen were quantified under flow conditions. Coagulation tests included activated partial thromboplastin time (aPTT), international normalized ratio (INR) as well as rotational thrombelastography (ROTEM®). Analyses were performed 3 and 72h after drug administration.

RESULTS

At 3, but not at 72h we observed a significant increase in the inhibition of platelet aggregation in response to adenosine diphosphate (P<0.01), but not to arachidonic acid, collagen or thrombin receptor agonist in the prasugrel/bivalirudin group compared to the clopidogrel/heparin group. Inhibition of platelet adhesion to collagen under flow was significantly stronger in the prasugrel/bivalirudin group at 3 and 72h after drug administration (P<0.01). APTT was significantly higher in the clopidogrel/heparin group (P<0.05) and INR was significantly higher in the prasugrel/bivalirudin group (P<0.01) 3h after drug administration. Concerning ROTEM® analysis the drug combinations did not differ in reducing clot formation time (CFT) and both combinations did not influence maximum clot firmness (MCF) compared to the controls.

CONCLUSIONS

We could demonstrate a more pronounced inhibition of platelet aggregation as well as platelet adhesion and aggregate formation to collagen under flow in prasugrel plus bivalirudin treated patients.

Incidence and impact on prognosis of bleeding during percutaneous coronary interventions in patients with chronic kidney disease

BACKGROUND

Limited information exists on the prognostic impact of bleeding after percutaneous coronary intervention (PCI) in patients with chronic kidney disease (CKD). We investigated the impact of bleeding after PCI on the outcome of these patients.

METHODS

The study included 2,934 patients with estimated creatinine clearance <60 ml/min. Bleeding events within 30 days after PCI were assessed using the Bleeding Academic Research Consortium (BARC) criteria. The primary outcome was 1-year mortality.

RESULTS

Bleeding events occurred in 485 patients (16.5 %). BARC classes were: class 1 (n = 155), class 2 (n = 73), class 3a (n = 182), class 3b (n = 68), class 3c (n = 6) and class 4 (n = 1). There were 212 deaths over the first year after PCI: 60 deaths in patients who bled and 152 deaths in patients who did not bleed (Kaplan-Meier [KM] estimates, 12.5 and 6.3 %; odds ratio [OR] = 2.11, 95 % confidence interval [CI] 1.57-2.83, P < 0.001). Nonfatal myocardial infarction occurred in 71 patients who bled and in 141 patients who did not bleed (KM estimates, 14.8 and 5.8 %; OR = 2.70 [2.05-3.55], P < 0.001). After adjustment, bleeding was independently associated with increased risk of 1-year mortality (adjusted hazard ratio [HR] = 1.90 [1.33-2.72], P < 0.001) and myocardial infarction (adjusted HR = 2.74 [1.99-3.78], P < 0.001). Bleeding improved the discriminatory power of the multivariable model for prediction of mortality (absolute and relative integrated discrimination improvement [IDI], 0.011 and 15.4 %; P = 0.004) or myocardial infarction (absolute and relative IDI, 0.017 and 70.8 %; P < 0.001).

CONCLUSIONS

Peri-PCI bleeding in patients with CKD is independently associated with the increased risk of 1-year mortality and nonfatal myocardial infarction.

The pharmacological landscape and therapeutic potential of serine hydrolases

Serine hydrolases perform crucial roles in many biological processes, and several of these enzymes are targets of approved drugs for indications such as type 2 diabetes, Alzheimer's disease and infectious diseases. Despite this, most of the human serine hydrolases (of which there are more than 200) remain poorly characterized with respect to their physiological substrates and functions, and the vast majority lack selective, in vivo-active inhibitors. Here, we review the current state of pharmacology for mammalian serine hydrolases, including marketed drugs, compounds that are under clinical investigation and selective inhibitors emerging from academic probe development efforts. We also highlight recent methodological advances that have accelerated the rate of inhibitor discovery and optimization for serine hydrolases, which we anticipate will aid in their biological characterization and, in some cases, therapeutic validation.

New antithrombotic agents in acute coronary syndromes

PURPOSE OF REVIEW

Acute coronary syndromes still account for high mortality in many countries. Antithrombotic therapy represents a cornerstone in the therapy of acute coronary syndromes. Recent research has focussed on improving anti-ischemic potency and reducing bleeding complications as well as improving predictability of antithrombotic efficacy.

RECENT FINDINGS

New antithrombotic drugs such as the factor Xa antagonists and the direct thrombin inhibitors have been developed and evaluated in clinical trials. Fondaparinux and bivalirudin are approved for clinical use in acute coronary syndromes. They improve the risk/benefit ratio and make routine control of their antithrombotic effect unnecessary. Other agents are being developed to further improve and facilitate antithrombotic therapy in acute coronary syndromes.

SUMMARY

Antithrombotic therapy is essential in acute coronary syndrome. New drugs are being developed to enter clinical practice and improve efficacy and safety of this therapeutic strategy.

By what mechanism do leeches help to salvage ischaemic tissues? A review

The therapeutic use of leeches in medicine dates back to 50 b.c. and was cited by ancient authors. The medicinal leech, Hirudo medicinalis, has been used with increasing frequency during the past few years by reconstructive surgeons to help salvage ischaemic tissues. We aim to summarise the anatomy, physiology, and pharmacological mechanisms of action of leeches to provide reconstructive surgeons with a theoretical basis for their use.

Bivalirudin provides increasing benefit with decreasing renal function: a meta-analysis of randomized trials

Chronic kidney disease is associated with an increased risk of ischemic and bleeding events after percutaneous coronary intervention (PCI). The direct thrombin inhibitor bivalirudin reduces these combined events. We sought to assess whether this benefit was influenced by renal function. A meta-analysis of 3 randomized trials (n = 5,035) comparing bivalirudin with heparin during PCI, stratified by estimated creatinine clearance using the Cockcroft-Gault equation (>90 [n = 1,578], 90 to 60 [n = 2,163], 59 to 30 [n = 1,255], and <30 ml/min [n = 39]), was conducted. The composite end points of death, myocardial infarction or revascularization, hemorrhage, and combined ischemic or bleeding events were assessed. A common odds ratio for each creatinine clearance strata was estimated with a random-effects model. The interaction between renal impairment and benefit from bivalirudin was assessed. Adverse ischemic and bleeding events increased with decreasing renal function. The relative benefit of bivalirudin with respect to ischemic and bleeding events was maintained within each stratum. The absolute benefit in terms of ischemic and bleeding complications increased with decreasing creatinine clearance (normal 2.2%, mild 5.8%, moderate 7.7%, severe 14.4%; p trend <0.001, interaction p = 0.044). Renal dysfunction remains a prevalent risk factor for ischemic and bleeding events in patients who undergo PCI. Bivalirudin provides greater absolute benefit in patients with impaired renal function.

An assessment of different filter systems for extracorporeal elimination of bivalirudin: an in vitro study

IMPLICATIONS

Bivalirudin is a new, direct thrombin inhibitor. We investigated the extracorporeal elimination rate of different hemofilters and one plasmapheresis filter for bivalirudin. Our data show that bivalirudin can be effectively eliminated via hemofiltration and plasmapheresis, although there were significant differences in the elimination rates among the filter systems investigated.