Anticoagulation With an Inhibitor of Factors XIa and XIIa During Cardiopulmonary Bypass

peer reviewedBackground: Exposure of blood to polyanionic artificial surfaces, for example, during cardiopulmonary bypass (CPB), induces a highly procoagulant condition requiring strong anticoagulation. Unfractionated heparin (UFH) is currently used during CPB but can lead to serious bleeding complications or development of a hypercoagulable state culminating in life-threatening thrombosis, highlighting the need for safer antithrombotics. Ixodes ricinus contact phase inhibitor (Ir-CPI) is a protein expressed by I. ricinus ticks, which specifically inhibits both factors XIIa and XIa, 2 factors contributing to thrombotic disease while playing a limited role in hemostasis. Objectives: This study assessed the antithrombotic activity of Ir-CPI in animal contact phase-initiated thrombosis models, including CPB. The safety of Ir-CPI also was evaluated. Methods: The authors evaluated the antithrombotic activity of Ir-CPI by using in vitro catheter-induced clotting assays and rabbit experimental models of catheter occlusion and arteriovenous shunt. During CPB with cardiac surgery in sheep, the clinical applicability of Ir-CPI was investigated and its efficacy compared to that of UFH using an uncoated system suitable for adult therapy. Taking advantage of the similar hemostatic properties of pigs and humans, the authors performed pig liver bleeding assays to evaluate the safety of Ir-CPI. Results: Ir-CPI prevented clotting in catheter and arteriovenous shunt rabbit models. During CPB, Ir-CPI was as efficient as UFH in preventing clot formation within the extracorporeal circuit and maintained physiological parameters during and post-surgery. Unlike UFH, Ir-CPI did not promote bleeding. Conclusions: Preclinical animal models used in this study showed that Ir-CPI is an effective and safe antithrombotic agent that provides a clinically relevant approach to thrombosis prevention in bypass systems, including highly thrombogenic CPB. © 2019 The Author

Cardiomyoplastie cellulaire avec une préparation cellulaire sans culture pour le traitement de pathologies cardiaques non ischémiques

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

ETUDE BIOMECANIQUE DE LA MOBILITE DE LA COLONNE VERTEBRALE DU CHIEN, ETUDE RADIOLOGIQUE

Ce travail expérimental est une étude in vitro de la mobilité maximale intervertébrale chez le chien sain, en flexion / extension d'une part, ainsi qu'en latéroflexion droite et gauche d'autre part. Six colonnes vertébrales ont été prélevées, préparées et radiographiées en positions de flexion, extension et latéroflexion maximales. La mesure des angles a été effectuée pour chaque espace intervertébral en comparant la mobilité maximale dans deux directions opposées d'un même plan. Les données ont été présentées pour chaque espace et pour les trois segments rachidiens: cervical, thoracique et lombaire. Ces résultats permettent ainsi d'enrichir les connaissances biomécaniques fondamentales sur le rachis canin. Cette démarche permet tout d'abord de mieux décrire un modèle animal pour la chirurgie humaine et peut servir également de base de données pour l'étude des instabilités et des déformations vertébrales chez le chien.MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Steps Toward the Percutaneous Replacement of Atrioventricular Valves An Experimental Study

ObjectivesThe goal of this study was to develop a device for percutaneous replacement of the tricuspid valve in animals.BackgroundPercutaneous valve replacement has recently been introduced, and early clinical experience has been reported. To date, this technique is limited to the replacement of pulmonary and aortic valves in selected patients.MethodsA newly designed nitinol stent, forming two large disks separated by a cylinder with a diameter of 18 mm, was specially designed for the purpose of this study. An 18-mm bovine valve was mounted in the central part of the stent, and a polytetrafluoroethylene membrane was sutured onto the ventricular disk. Eight ewes were equally divided into two groups (group 1, acute study; group 2, killed at one month).ResultsSeven of eight devices were successfully delivered in the desired position. In one animal, the device was trapped in tricuspid cordae, leading to its incomplete opening. A significant paravalvular leak was noticed in one animal of group 2. Mean right atrial pressure increased from 5 to 7 mm Hg and did not change during the follow-up. At autopsy, examination confirmed the good position of devices in successfully implanted animals.ConclusionsImplantation of a semi-lunar valve in the tricuspid position is possible in ewes through a transcatheter approach. A disk-based nitinol stent is needed to allow valve implantation in the atrioventricular position. These studies open new perspectives into tricuspid as well as mitral valve replacement