[Utilisation of gastric ring systems for pulmonary artery banding: an animal study]. / Utilisation d'un système de cerclage gastrique comme cerclage réglable de l'artère pulmonaire: une étude chez l'animal.

OBJECTIVES: Pulmonary artery banding is often required as a first palliative procedure in infants with congenital heart disease and high pulmonary blood flow or to retrain the left ventricle. The purpose of the study was to demonstrate the safety of a gastric banding system as an adjustable pulmonary artery banding in chronic implantation. METHODS: Five ewes underwent implantation of the banding system around the main pulmonary artery through a left thoracotomy. All had functional evaluation with progressive occlusion and opening of the device every two weeks for a total period of three months. Invasive pressure measurements in the right ventricle and aorta were carried out each time. RESULTS: Devices could be implanted easily. Progressive occlusion and re-opening were possible in all animals during each time point. All animals survived throughout the protocol. Retrieval of the device was achieved in all animals. In one, it was challenging because of the presence of a fibrotic reaction around the device. It died because of pulmonary artery perforation before the sacrifice. At autopsy, microscopic examination showed no signs of myocardial fibrosis. CONCLUSIONS: In animals, gastric banding system is a safe and effective implantable device to adjust pulmonary artery diameter over a prolonged period of time. This new device may be a valuable alternative to the repeated conventional pulmonary artery banding needed for ventricular retraining in humans.

[Development and evaluation of a prosthetic valved conduit dilated by percutaneous approach: experimental study in the lamb]. / Développement et évaluation d'un conduit prothétique muni d'une valve dilatable par voie percutanée: étude chez l'agneau.

This study was undertaken to develop a dilated valved conduit for reconstruction of the right ventricular outflow tract in the animal. The conduits were made by sewing a valved tube (Medtronic Inc) inside a vascular stent (Numed Inc). After preparation, they were inserted surgically in five lambs. The conduits were then dilated 6 weeks and 3 months after their implantation. Before sacrificing the animals at 3 months, a 22 mm valved stent was implanted percutaneously inside the surgical conduits. One animal died suddenly due to kinking of the conduit. Balloon dilatation was performed in the surviving animals. The first dilatation only had a modest impact on valvular function but it was much aggravated after the second dilatation. A valved stent was successfully inserted percutaneously. At sacrifice, all the conduits were completely engulfed in an intense fibrosis. In conclusion, a valved biological conduit for reconstruction of the right ventricular ejection tract has been developed and can be dilated sequentially to follow growth. The new product could have an important role to play in the management of congenital malformations involving the right ventricular outflow tract.

[Use of Organon, a synthetic heparinoid, in two cardiopulmonary bypass procedures in the same patient sensitive to heparin]. / Utilisation de l'Orgaran, héparinoïde de synthèse, lors de deux circulations extracorporelles, chez un même patient allergique à l'héparine.

We report the case of a patient who underwent two cardiopulmonary bypass (CPB) procedures with Orgaran because of heparin-induced thrombocytopenia. A 38 years-old man with ischemic mitral insufficiency was operated for coronary artery bypass and valvular replacement. The CPB was carried out with heparin. Heparin-induced thrombocytopenia occured and was proven immunologically. Two months later, a new valvular replacement was performed because of paravalvular leak due to endocarditis. The Orgaran-CPB protocol was as follows: 5,000 units before cardiopulmonary bypass, 5,000 units in the priming volume, anti-Xa level between 0.9 and 1.1 units/mL, with injection of 1,500 units if necessary, no administration of protamine. One month later, a new valvular replacement was necessary and performed with the same protocol using Orgaran. No bleeding or thrombotic complication occurred. Orgaran is a safe and reliable anti-thrombotic substitute if anti-Xa activity is closely monitored.

Chloroplast DNA footprints of postglacial recolonization by oaks.

Recolonization of Europe by forest tree species after the last glaciation is well documented in the fossil pollen record. This spread may have been achieved at low densities by rare events of long-distance dispersal, rather than by a compact wave of advance, generating a patchy genetic structure through founder effects. In long-lived oak species, this structure could still be discernible by using maternally transmitted genetic markers. To test this hypothesis, a fine-scale study of chloroplast DNA (cpDNA) variability of two sympatric oak species was carried out in western France. The distributions of six cpDNA length variants were analyzed at 188 localities over a 200 x 300 km area. A cpDNA map was obtained by applying geostatistics methods to the complete data set. Patches of several hundred square kilometers exist which are virtually fixed for a single haplotype for both oak species. This local systematic interspecific sharing of the maternal genome strongly suggests that long-distance seed dispersal events followed by interspecific exchanges were involved at the time of colonization, about 10,000 years ago.