Structure-function relationships of variegin: A novel class of thrombin inhibitors

Ph.DDOCTOR OF PHILOSOPH

A systematic review on the role of bivalirudin in patients undergoing percutaneous coronary interventions: primus inter pares or a falling star?

Intracoronary thrombosis triggered by ruptured or eroded atherosclerotic plaques constitutes the predominant underlying cause of acute coronary syndromes (ACS). Thrombin is considered a central enzyme in hemostasis and thrombosis, and a well-established target for anticoagulant therapies. Bivalirudin was introduced in the clinical practice as a promising, reversible, direct thrombin inhibitor with a predictable anticoagulant effect. Initial randomized clinical trials demonstrated that bivalirudin compared with heparin on top of a glycoprotein IIb/IIIa inhibitor was associated with a significant reduction of major bleeding and favorable net clinical outcomes in patients undergoing percutaneous coronary interventions (PCI). The HORIZON-AMI trial even indicated mortality benefit in bivalirudin-treated patients. Thereby, the 2011 and 2012 European Society of Cardiology Guidelines on the management of non-ST-segment elevation ACS and ST-segment elevation myocardial infarction positioned bivalirudin as the anticoagulant of choice in the PCI setting. Further randomized studies, better reflecting routine clinical practice, revealed significantly increased rates of stent thrombosis and myocardial infarction in the bivalirudin arm. Additionally, these findings were corroborated in the subsequent meta-analyses. Speculations that excessive occurrence of stent thrombosis and myocardial infarction may be caused by too short duration of post PCI bivalirudin infusion did not find confirmation in the latest MATRIX trial. In this systematic review, we aim to assess the efficacy and safety of bivalirudin therapy in patients undergoing PCI and to formulate recommendations on the bivalirudin use for clinicians. In our opinion, the research evidence and pharmacoeconomic considerations strongly support the use of bivalirudin in PCI patients at high risk of bleeding complications, while in other situations old and inexpensive UFH or enoxaparin remain the first line antithrombotic drugs

Anticoagulant profile of subcutaneous enoxaparin in healthy dogs

Enoxaparin, a low-molecular-weight heparin, is commonly used as an anticoagulant in dogs, and is currently dosed at 0.8mg/kg every 6 hours. With an increase in individual enoxaparin doses, less frequent dosing may be possible, thereby reducing owner inconvenience and expense. The three phases of this study investigated the appropriate dose (Phase one- 0.8mg/kg, SQ once; Phase two- 2mg/kg, SQ once; Phase three- 1.3 mg/kg, SQ q8h for 7 total doses) and dosing interval needed for maximum effectiveness of enoxaparin. A Sonoclot® analyzer and factor Xa activity were used to assess level of anticoagulation in six healthy dogs. Anticoagulation was inconsistent at the 0.8mg/kg dose, while the 2mg/kg dose showed a high level of anticoagulation, and the 1.3mg/kg dose provided more reliable anticoagulation than the other dosages and dosing intervals. Small sample size and the use of same-breed healthy dogs potentially affected the strength of the results

2022 Update of the consensus on the rational use of antithrombotics and thrombolytics in Veterinary Critical Care (CURATIVE) Domain 6: Defining rational use of thrombolytics

Objectives To systematically review available evidence and establish guidelines related to the use of thrombolytics for the management of small animals with suspected or confirmed thrombosis. Design PICO (Population, Intervention, Control, and Outcome) questions were formulated, and worksheets completed as part of a standardized and systematic literature evaluation. The population of interest included dogs and cats (considered separately) and arterial and venous thrombosis. The interventions assessed were the use of thrombolytics, compared to no thrombolytics, with or without anticoagulants or antiplatelet agents. Specific protocols for recombinant tissue plasminogen activator were also evaluated. Outcomes assessed included efficacy and safety. Relevant articles were categorized according to level of evidence, quality, and as to whether they supported, were neutral to, or opposed the PICO questions. Conclusions from the PICO worksheets were used to draft guidelines, which were subsequently refined via Delphi surveys undertaken by the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) working group. Results Fourteen PICO questions were developed, generating 14 guidelines. The majority of the literature addressing the PICO questions in dogs is experimental studies (level of evidence 3), thus providing insufficient evidence to determine if thrombolysis improves patient-centered outcomes. In cats, literature was more limited and often neutral to the PICO questions, precluding strong evidence-based recommendations for thrombolytic use. Rather, for both species, suggestions are made regarding considerations for when thrombolytic drugs may be considered, the combination of thrombolytics with anticoagulant or antiplatelet drugs, and the choice of thrombolytic agent. Conclusions Substantial additional research is needed to address the role of thrombolytics for the treatment of arterial and venous thrombosis in dogs and cats. Clinical trials with patient-centered outcomes will be most valuable for addressing knowledge gaps in the field

Biochemische und pharmakokinetische Charakterisierung zweier Varianten eines neuen, auf Dipetalogastin II basierenden, chimären Thrombininhibitors

Hirudin und Dipetalogastin II sind hochpotente, natürliche Thrombininhibitoren, die in der Therapie kardiovaskulärer Erkrankungen als auch in der Tumortherapie potentielle Einsatzgebiete aufweisen. In dieser Arbeit wurden zwei Varianten eines neuen, chimären Thrombininhibitors auf der Basis dieser beiden Inhibitoren charakterisiert. Beide Inhibitorvarianten wiesen eine starke Thrombinhemmung auf, wobei Variante 1 eine slow, tight-binding und Variante 2 eine klassisch kompetitive Inhibitionskinetik präsentierte