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Garcia-Garcia HM, Adamo M, Soud M, Yacob O, Picchi A, Sardella G, Frigoli E, Limbruno U, Rigattieri S, Diletti R, Boccuzzi G, Zimarino M, Contarini M, Russo F, Calabrò P, Andò G, Varbella F, Garducci S, Palmieri C, Briguori C, Karagiannis A, Valgimigli M. Assessment of residual thrombus burden in patients with ST-segment elevation myocardial infarction undergoing bivalirudin versus unfractionated heparin infusion: The MATRIX (minimizing adverse hemorrhagic events by transradial access site and angioX) OCT study. Catheter Cardiovasc Interv 2019; 96:1156-1171. [PMID: 31883294 DOI: 10.1002/ccd.28661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/08/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Residual stent strut thrombosis after primary percutaneous coronary intervention (PCI), negatively affects myocardial perfusion, may increase stent thrombosis risk, and it is associated with neointima hyperplasia at follow-up. OBJECTIVES To study the effectiveness of any bivalirudin infusion versus unfractionated heparin (UFH) infusion in reducing residual stent strut thrombosis in patients with ST-elevation myocardial infarction (STEMI). METHODS Multi-vessel STEMI patients undergoing primary PCI and requiring staged intervention were selected among those randomly allocated to two different bivalirudin infusion regimens in the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) Treatment-Duration study. Those receiving heparin only were enrolled into a registry arm. Optical coherence tomography (OCT) of the infarct-related artery was performed at the end of primary PCI and 3-5 days thereafter during a staged intervention. The primary endpoint was the change in minimum flow area (ΔMinFA) defined as (stent area + incomplete stent apposition [ISA] area) - (intraluminal defect + tissue prolapsed area) between the index and staged PCI. RESULTS 123 patients in bivalirudin arm and 28 patients in the UFH arm were included. Mean stent area, percentage of malapposed struts, and mean percent thrombotic area were comparable after index or staged PCI. The ΔMinFA in the bivalirudin group was 0.25 versus 0.05 mm2 in the UFH group, which resulted in a between-group significant difference of 0.36 [95% CI: (0.05, 0.71); p = .02]. This was mostly related to a decrease in tissue protrusion in the bivalirudin group (p = .03). There was a trend towards more patients in the bivalirudin group who achieved a 5% difference in the percentage of OCT frames with the area >5% (p = .057). CONCLUSIONS The administration of bivalirudin after primary PCI significantly reduces residual stent strut thrombosis when compared to UFH. This observation should be considered hypothesis-generating since the heparin-treated patients were not randomly allocated.
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Affiliation(s)
| | - Marianna Adamo
- Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Cardio-Thoracic Department, Civil Hospitals, Brescia, Italy
| | - Mohamad Soud
- Rutgers New Jersey Medical School, Newark, New Jersey
| | - Omar Yacob
- MedStar Washington Hospital Center, Washington, District of Columbia
| | - Andrea Picchi
- Cardiovascular and Neurologic Department, Misericordia Hospital, Grosseto, Italy
| | - Gennaro Sardella
- Department of Cardiology, Policlinico Umberto I, Sapienza University of Rome, Rome, Italy
| | - Enrico Frigoli
- Clinical Trials Unit, University of Bern, Bern, Switzerland
| | - Ugo Limbruno
- Cardiovascular and Neurologic Department, Misericordia Hospital, Grosseto, Italy
| | | | - Roberto Diletti
- Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Giacomo Boccuzzi
- Department of Cardiology, San Giovanni Bosco Hospital, Turin, Italy
| | - Marco Zimarino
- Institute of Cardiology "G. d'Annunzio" University, Chieti, Italy
| | - Marco Contarini
- Interventional Cardiology Unit Umberto I Hospital, Syracuse, Italy
| | - Filippo Russo
- Interventional Cardiology Unit, Cardio-thoracic-Vascular Department, San Raffaele Scientific Institute, Milan, Italy
| | - Paolo Calabrò
- Division of Cardiology, Department of Cardiothoracic and Respiratory Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Giuseppe Andò
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | | | - Stefano Garducci
- Unita' Operativa Complessa di Cardiologia ASST di Vimercate (MB), Vimercate, Italy
| | - Cataldo Palmieri
- Fondazione Toscana G. Monasterio - Ospedale del Cuore G. Pasquinucci, Pisa/Massa, Massa, Italy
| | - Carlo Briguori
- Department of Cardiology, Interventional Cardiology, Mediterranea Cardiocentro, Naples, Italy
| | | | - Marco Valgimigli
- Swiss Cardiovascular Center Bern, University of Bern, Bern, Switzerland
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Structural and biochemical characterization of the interaction between KPC-2 beta-lactamase and beta-lactamase inhibitor protein. Biochemistry 2009; 48:9185-93. [PMID: 19731932 PMCID: PMC2769493 DOI: 10.1021/bi9007963] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
KPC beta-lactamases hydrolyze the "last resort" beta-lactam antibiotics (carbapenems) used to treat multidrug resistant infections and are compromising efforts to combat life-threatening Gram-negative bacterial infections in hospitals worldwide. Consequently, the development of novel inhibitors is essential for restoring the effectiveness of existing antibiotics. The beta-lactamase inhibitor protein (BLIP) is a competitive inhibitor of a number of class A beta-lactamases. In this study, we characterize the previously unreported interaction between KPC-2 beta-lactamase and BLIP. Biochemical results show that BLIP is an extremely potent inhibitor of KPC enzymes, binding KPC-2 and KPC-3 with subnanomolar affinity. To understand the basis of affinity and specificity in the beta-lactamase-BLIP system, the crystallographic structure of the KPC-2-BLIP complex was determined to 1.9 A resolution. Computational alanine scanning was also conducted to identify putative hot spots in the KPC-2-BLIP interface. Interestingly, the two complexes making up the KPC-2-BLIP asymmetric unit are distinct, and in one structure, the BLIP F142 loop is absent, in contrast to homologous structures in which it occupies the active site. This finding and other sources of structural plasticity appear to contribute to BLIP's promiscuity, enabling it to respond to mutations at the beta-lactamase interface. Given the continuing emergence of antibiotic resistance, the high-resolution KPC-2-BLIP structure will facilitate its use as a template for the rational design of new inhibitors of this problematic enzyme.
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Anesthetic implications of the new anticoagulant and antiplatelet drugs. J Clin Anesth 2008; 20:228-37. [DOI: 10.1016/j.jclinane.2007.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 09/16/2007] [Accepted: 10/26/2007] [Indexed: 01/29/2023]
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Abstract
PURPOSE OF REVIEW In this paper, recent advances in new anticoagulants with the potential to be used for prevention or treatment of venous thrombosis are reviewed. RECENT FINDINGS Numerous novel anticoagulants targeting specific stages of the coagulant pathway are in various stages of development. Fondaparinux, an indirect activated factor VII inhibitor, has been shown to be effective for initial treatment and prevention of venous thromboembolism, but still requires parenteral administration. Ximelagatran, an oral direct thrombin inhibitor, has also been shown to effective for treatment and prevention of venous thrombosis. Both agents are associated with bleeding, however, and ximelagatran is associated with hepatic toxicity with long-term use. Direct activated factor X inhibitors, orally available forms of heparin, and other direct thrombin inhibitors remain in early stages of development. Further data on the clinical utility of these agents are likely to emerge in the next few years, and uptake of their use will be affected by the cost considerations. SUMMARY Numerous alternative anticoagulants are in varying stages of development. Clinical data have yet to show that these agents have a clearly superior risk-benefit ratio compared with currently used antithrombotics. Many drugs remain in initial stages of development. The ideal anticoagulant agent is being sought but has yet to be discovered.
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Affiliation(s)
- Simon J McRae
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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McRae SJ, Ginsberg JS. New anticoagulants for the prevention and treatment of venous thromboembolism. Vasc Health Risk Manag 2007; 1:41-53. [PMID: 17319097 PMCID: PMC1993925 DOI: 10.2147/vhrm.1.1.41.58936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Anticoagulant therapy is effective at preventing the development of venous thromboembolism in high-risk patients, and reduces morbidity and mortality in individuals with established thromboembolic disease. Vitamin K antagonists and heparins are currently the most commonly used anticoagulant drugs, but they have practical limitations. Therefore, new antithrombotic agents with predictable dose-responses (thereby decreasing the need for monitoring without compromising efficacy or safety), ideally available in an oral formulation and with a rapidly reversible anticoagulant effect, are needed. New drugs fulfilling some of the above criteria have been developed and have proven to be effective agents for the treatment and prevention of venous thromboembolism.
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Affiliation(s)
- Simon J McRae
- Department of Medicine, McMaster University, Hamilton, ON, Canada.
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Motlekar NA, Youan BBC. The quest for non-invasive delivery of bioactive macromolecules: a focus on heparins. J Control Release 2006; 113:91-101. [PMID: 16777255 PMCID: PMC1539865 DOI: 10.1016/j.jconrel.2006.04.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 04/06/2006] [Indexed: 11/24/2022]
Abstract
The development of a non-invasive drug delivery system for unfractionated heparin (UFH) and low molecular weight heparins (LMWHs) has been the elusive goal of several research groups since the initial discovery of this glycosaminogylcan by McLean in 1916. After a brief update on current parenteral formulations of UFH and LMWHs, this review revisits past and current strategies intended to identify alternative routes of administration (e.g. oral, sublingual, rectal, nasal, pulmonary and transdermal). The following strategies have been used to improve the bioavailability of this bioactive macromolecule by various routes: (i) enhancement in cell-membrane permeabilization, (ii) modification of the tight-junctions, (iii) increase in lipophilicity and (iv) protection against acidic pH of the stomach. Regardless of the route of administration, a simplified unifying principle for successful non-invasive macromolecular drug delivery may be: "to reversibly overcome the biological, biophysical and biochemical barriers and to safely and efficiently improve the in vivo spatial and temporal control of the drug in order to achieve a clinically acceptable therapeutic advantage". Future macromolecular drug delivery research should embrace a more systemic approach taking into account recent advances in genomics/proteomics and nanotechnology.
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Affiliation(s)
- Nusrat A. Motlekar
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter Drive, Amarillo, TX 79106, USA
| | - Bi-Botti C. Youan
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter Drive, Amarillo, TX 79106, USA
- * Corresponding author. Tel.: +1 806 356 4015x236; fax: +1 806 354 4034. E-mail address: (B.-B.C. Youan)
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Abstract
Classic anticoagulant drugs are very effective, save lives and have been used for more than 50 years. Nevertheless, some drawbacks are encountered in their routine clinical use. Recently, pharmaceutical research has developed new drugs, some of which are already on the market. This is the case of fondaparinux, a pentasaccharide which can interact with antithrombin, thus inhibiting factor Xa. Modification of its structure (idraparinux) has led to more stable binding with antithrombin and to an increase in its half-life allowing for once-a-week administration. Another important oral compound is ximelagatran which directly binds thrombin and blocks its catalytic site. There is no need for laboratory control, and phase II and phase III studies are encouraging. Thus, in the next few years, we may witness great changes in the treatment of patients with thromboembolic disorders.
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Affiliation(s)
- V Pengo
- Clinical Cardiology, Thrombosis Centre, University of Padua School of Medicine, Padua, Italy.
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Johansson S, Ohlsson L, Stenhoff H, Wåhlander K, Cullberg M. No effect of encapsulation on the pharmacokinetics of warfarin. Biopharm Drug Dispos 2005; 26:121-7. [PMID: 15751004 DOI: 10.1002/bdd.441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND In double-blind comparator studies with the oral direct thrombin inhibitor (oral DTI) ximelagatran, warfarin (Coumadin) was administered in encapsulated form in order to maintain patient and investigator blinding. This open, randomized, two-way crossover study was conducted to determine whether the encapsulated warfarin tablets (Coumadin) used in the ximelagatran studies are bioequivalent to nonencapsulated, commercially available warfarin (Coumadin) tablets. METHODS AND RESULTS Eighteen healthy men received two 2.5 mg tablets of encapsulated warfarin and two 2.5 mg tablets of nonencapsulated warfarin as single oral doses, 14 days apart. The 90% confidence intervals for the mean treatment ratio (encapsulated tablet/nonencapsulated tablet) fell within the limits considered to reflect bioequivalence (0.80, 1.25) for total area under the plasma concentration-versus-time curve (AUC(infinity)), AUC to the last evaluable concentration (AUC(t)), and maximum plasma concentration (C(max)) for both R-warfarin (AUC(infinity) [0.93, 1.03], AUC(t) [0.95, 1.03], C(max) [0.90, 1.04]) and S-warfarin (AUC(infinity) [0.93, 1.03], AUC(t) [0.94, 1.03], C(max) [0.90, 1.06]). CONCLUSIONS The encapsulated form of warfarin (Coumadin) used in comparator studies with the oral DTI ximelagatran is bioequivalent to the nonencapsulated, commercially available form of warfarin (Coumadin). Thus, the results of ximelagatran clinical trials with encapsulated warfarin can be generalized to the commercially available form.
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Affiliation(s)
- Susanne Johansson
- Experimental Medicine, AstraZeneca R&D Mölndal, S-431 83 Mölndal, Sweden.
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Abstract
Although heparin has been a cornerstone of treatment for the prevention of thrombosis, it is limited by its adverse effects and unpredictable bioavailability. Direct thrombin inhibitors are a novel class of drugs that have been developed as an effective alternative mode of anticoagulation in patients who suffer from heparin-induced thrombocytopaenia, and for the management of thromboembolic disorders and acute coronary syndromes. The main disadvantages of the direct thrombin inhibitors are the lack of an antidote or readily available clinical monitoring. The mechanism of action, the properties of direct thrombin inhibitors and their potential to replace currently available anticoagulants are reviewed.
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Affiliation(s)
- P C A Kam
- Department of Anaesthesia, University of New South Wales, St George Hospital, Kogarah, NSW 2217, Australia.
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Abstract
Adequate initial anticoagulant therapy of deep venous thrombosis (DVT) is required to prevent thrombus growth and pulmonary embolism (PE). Intravenous unfractionated heparin (UFH) is being replaced by low-molecular-weight heparin (LMWH) as the anticoagulant of choice for initial treatment of venous thromboembolism (VTE). Both agents are relatively safe and effective when used to treat VTE, with LMWH suitable for outpatient therapy because of improved bioavailability and more predictable anticoagulant response. Serious potential complications of heparin therapy, such as heparin-induced thrombocytopenia (HIT) and osteoporosis, seem less common with LMWH. The potential for fetal harm and changes in maternal physiology complicate the treatment of VTE during pregnancy. Although systemic thrombolysis is used in patients with massive PE and in some patients with proximal DVT, controversy persists with respect to appropriate patient selection for this intervention.
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Affiliation(s)
- Simon J McRae
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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Affiliation(s)
- Mitchell S V Elkind
- Department of Neurology, College of Physicians and Surgeons, Columbia University, and the Columbia University Medical Center of New York-Presbyterian Hospital, New York, USA.
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Hankey GJ, Klijn CJM, Eikelboom JW. Ximelagatran or Warfarin for Stroke Prevention in Patients With Atrial Fibrillation? Stroke 2004; 35:389-91. [PMID: 14757889 DOI: 10.1161/01.str.0000115528.53718.1b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Graeme J Hankey
- Stroke Unit, Royal Perth Hospital, 197 Wellington Street Perth, Australia 6001.
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Abstract
Abstract
Venous thromboembolism, which includes deep vein thrombosis and pulmonary embolism, is the result of an imbalance among procoagulant, anticoagulant and profibrinolytic processes. This imbalance reflects a complex interplay between genetic and environmental or acquired risk factors. Genetic thrombophilic defects influence the risk of a first episode of thrombosis. How these defects influence the risk of recurrence in patients whose first episode of venous thromboembolism was unprovoked is less certain. Thus, when anticoagulants are stopped, patients with unprovoked venous thromboembolism have a risk of recurrence of at least 7% to 10% per year, even in the absence of an underlying thrombophilic defect. Consequently, there is a trend toward longer durations of anticoagulation therapy for these patients, which is problematic given the limitation of existing anticoagulants. This chapter provides an overview of the thrombophilic defects and how they influence the risk of venous thromboembolism. The chapter also details advances in anticoagulant therapy, focusing on new inhibitors of factor Xa and thrombin.
In Section I, Dr. Saskia Middeldorp describes the various thrombophilic defects and reviews their relative importance in the pathogenesis of a first episode of venous thromboembolism. She then discusses the influence of these defects on the risk of recurrent thrombotic events in patients with unprovoked venous thromboembolism and in those whose thrombosis occurred in association with a known risk factor, such as surgery.
In Section II, Dr. William Geerts reviews the pharmacology of new parenteral and oral factor Xa inhibitors and describes the results of the Phase II and III clinical trials with these agents. He then provides perspective on the potential advantages and drawbacks of these drugs for the prevention and treatment of venous thromboembolism.
In Section III, Dr. John Heit focuses on direct thrombin inhibitors. He discusses their mechanism of action and compares and contrasts their pharmacological profiles prior to describing the results of Phase II and III clinical trials. Dr. Heit then provides perspective on the potential advantages and limitations of these drugs relative to existing anticoagulants.
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