Bicarbon valve -- European multicenter clinical evaluation.

Objective: Fifteen collaborating centers in eight countries present their pooled experience with the new Bicarbon bileaflet valve.

Methods: Between 4/90 and 4/96, 1351 patients, 806 males and 545 females, aged 10 to 83, mean 58.4 +/- 12.

Patterns of changes in neutrophil adhesion molecules during normothermic cardiopulmonary bypass. A clinical study.

The adhesion of activated neutrophils to endothelial cells is a key feature of the inflammatory response to cardiopulmonary bypass (CPB) because it "unlocks" a cascade of cytotoxic events. This adhesion is made possibly by the sequential involvement of two sets of neutrophil cell surface receptors: L-selection and beta 2 integrins (CD 11 a/CD 18; CD 11 b/CD 18; CD 11 c/CD 18). We have assessed the changes in the expression of these adhesion molecules in ten patients who underwent various open-heart procedures with the use of "warm" (33.

Preconditioning with potassium channel openers. A new concept for enhancing cardioplegic protection?

Ischemic preconditioning defines an adaptive endogenous mechanism in which a brief episode of reversible ischemia renders the heart more resistant to a subsequent period of sustained ischemia. Because the cardioprotective effects of ischemic preconditioning might be mediated by an activation of adenosine triphosphate-sensitive potassium channels, this study was designed to assess whether these effects could be duplicated by the preischemic administration of a potassium channel opener. Fifty isolated isovolumic buffer-perfused rat hearts underwent 45 minutes of normothermic potassium arrest followed by 1 hour of reperfusion.

Hypothermia during cardiopulmonary bypass delays but does not prevent neutrophil-endothelial cell adhesion. A clinical study.

Background: An accurate evaluation of warm heart surgery cannot be limited to the assessment of the myocardial effects of warm blood cardioplegia but should also address the effects of systemic normothermia on the inflammatory response to cardiopulmonary bypass. A major component of this response is the endothelial adhesion of neutrophils, because it is linked to the release of cytotoxic compounds. This study was designed (1) to characterize the bypass-induced changes in the expression of neutrophil adhesion molecules (L-selectin and beta 2-integrins) and (2) to assess the influence of bypass temperature on these changes.

Influence of temperature on neutrophil trafficking during clinical cardiopulmonary bypass.

Background: The adhesion of neutrophils to endothelial cells and their subsequent transendothelial migration play a major role in inflammatory damage elicited by cardiopulmonary bypass (CPB) because these events are linked to the release of cytotoxic proteases and oxidants. However, the patterns of neutrophil trafficking in relation to systemic temperature during clinical CPB have not yet been characterized.

Methods And Results: Twenty case-matched patients undergoing warm (31.

[Does temperature in extracorporeal circulation affect neutrophil-endothelium interactions?].

The increasing interest in "warm" aerobic cardioplegia requires a critical reevaluation of the systemic effects of the associated normothermic cardiopulmonary bypass (CPB). As activated neutrophils seem to be essential mediators of the inflammatory response to CPB via the cytotoxicity of the products that are released during their adhesion to endothelial cells, the authors undertook a study of the influence of temperature on the interaction between the neutrophils and the endothelium in 95 patients undergoing warm (31-33.5 degrees C, n = 49) and cold (26-27 degrees C, n = 46) CPB surgery.

Metabolic and functional evidence that retrograde warm blood cardioplegia does not injure the right ventricle in human beings.

Background: Retrograde warm blood cardioplegia is now recognized as an effective method of myocardial protection, but concerns persist about its ability to adequately preserve the right ventricle.

Methods And Results: A total of 75 patients in whom warm blood cardioplegia was continuously given through the coronary sinus were included in this three-part study. Part 1, which involved 30 patients undergoing coronary artery bypass grafting operations, was designed to assess whether the right ventricle incurred a greater degree of anaerobic metabolism than the left ventricle during warm arrest.

Does normothermia during cardiopulmonary bypass increase neutrophil-endothelium interactions?

Background: The use of warm blood cardioplegia is usually associated with that of warm cardiopulmonary bypass (CPB). Little is known, however, about the effect of temperature during bypass on neutrophil-endothelium interactions, which are currently considered a key component of the inflammatory response to CPB.

Methods And Results: Twenty-five patients operated on under CPB were studied.

Retrograde warm blood cardioplegia preserves hypertrophied myocardium: a clinical study.

The ability of retrograde warm blood cardioplegia to preserve hypertrophied myocardium remains controversial. This two-part study was undertaken to address this question in patients subjected to aortic valve replacement for calcified aortic valve stenosis complicated with echocardiographically defined left ventricular hypertrophy. Part 1 was designed to assess the intraoperative patterns of myocardial oxidative metabolism in 20 patients in whom the severity of left ventricular hypertrophy was reflected by a mean (+/- standard error of the mean) myocardial mass index of 213 +/- 15 g/m2.

[Use of myoplasty after acute mediastinitis occurring after heart surgery. Apropos of 167 cases].

Infected median sternotomy often requires open wound management. A large thoracic defect usually results in subsequent exposure of heart, great vessels, aorto-coronary bypass grafting or vascular prosthesis. After thorough wound debridement, coverage with muscle transposition was carried out in a series of 167 cases observed over a period of 10 years.

A potential mechanism of vasodilation after warm heart surgery. The temperature-dependent release of cytokines.

Peripheral vasodilation is a common feature of warm heart surgery and creates clinical concerns when pressor agents become necessary because of the potential for some of these drugs to adversely affect flow through newly engrafted arterial and venous bypass conduits. The possible role of a temperature-dependent production of cytokines in the pathogenesis of this vasodilation was investigated in a two-part study. In part I, lipopolysaccharide-activated peritoneal rabbit macrophages (5 x 10(6)/ml) were incubated at 30 degrees or 37 degrees C up to 9 hours and the concentration of tumor necrosis factor released in the supernatant was serially measured by a bioassay.

Experimental evaluation of Celsior, a new heart preservation solution.

An original heart preservation solution (Celsior) has been developed, the formulation of which has been designed to fulfil two major objectives: (1) to combine the general principles of hypothermic organ preservation with those specific for the myocardium, and (2) to offer the possibility of being used not only as a storage medium but also as a perfusion fluid during initial donor heart arrest, poststorage graft reimplantation and early reperfusion. The major principles addressed by the Celsior formulation include (1) prevention of cell swelling (by mannitol and lactobionate), (2) prevention of by the Celsior formulation include (1) prevention of cell swelling (by mannitol and lactobionate), (2) prevention of oxygen-derived free radical injury (by reduced glutathione, histidine and mannitol), and (3) prevention of contracture by enhancement of energy production (glutamate) and limitation of calcium overload (high magnesium content, slight degree of acidosis). Two experimental preparations were used: The isolated isovolumic buffer-perfused rat heart model and the heterotopic rabbit heart transplantation model.

Efficacy of lactobionate-enriched cardioplegic solution in preserving compliance of cold-stored heart transplants.

Cardioplegic solutions of the extracellular type are commonly used as storage media for heart transplants. Because this type of formulation was not originally designed for preventing hypothermically induced edema, we assessed the effects of supplementing a standard, extracellular-like cardioplegic solution with the high molecular weight impermeant lactobionate on water content and postischemic compliance of isolated rat hearts. In one series of experiments, hearts were immersed in either a standard cardioplegic solution of the extracellular type or in the same solution supplemented with lactobionate (80 mmol/L).

Limitation of vasodilation associated with warm heart operation by a "mini-cardioplegia" delivery technique.

Peripheral vasodilation is commonly seen during and after warm heart operations and can become of clinical concern when it requires vasopressors because some of these drugs adversely affect coronary artery bypass graft flows. As hemodilution lowers systemic vascular resistance, we assessed whether peripheral vasodilation could be limited by a drastic reduction of the volume of infused cardioplegia. Fifty patients underwent isolated coronary artery bypass grafting procedures using normothermic (35 degrees to 37 degrees C) bypass and normothermic continuous retrograde blood cardioplegia.

Triiodothyronine therapy in open-heart surgery: from hope to disappointment.

A controversy persists as to whether cardiopulmonary bypass (CPB) decreases plasma levels of triiodothyronine (T3), thereby justifying peri-operative administration of T3 to improve haemodynamic recovery. To examine the effects of T3 therapy on post-CPB haemodynamics and to determine whether the potential inotropic effects of T3 are mediated by an increase in beta-adrenergic responsiveness, a prospective, randomized, double-blind, placebo-controlled study was performed in 20 patients undergoing cardiac surgery with CPB. T3 or placebo solution (10 patients in each group) was given intravenously at the time of aortic unclamping and 4, 8, 12 and 20 h thereafter.

Improved recovery of heart transplants with a specific kit of preservation solutions.

In the course of cardiac transplantation, donor hearts undergo a four-step sequence of events (arrest, cold storage, global ischemia during implantation, and reperfusion) during which myocardial damage can occur. We tested the hypothesis that the functional recovery of these hearts could be improved by exposure to two interdependently formulated preservation solutions throughout this four-step sequence. Solution I was used as a perfusion and storage medium during the first three steps, and solution II served as a modified reperfusate.

Simplified method for delivering normothermic blood cardioplegia.

We describe a simple technique for optimizing oxygen delivery during normothermic continuous blood cardioplegia. It involves the use of a minimal volume of cardioplegic agents, the infusion rate of which is adjusted so as to keep the heart arrested. The resulting enhancement of oxygen supply is marshalled from the maintenance of hematocrit values in the range of 0.

[Towards an integrated protection of heart grafts].

In an attempt to provide a consistent protection of cardiac allografts during the sequence of events inherent in transplantation procedures, we developed two preservation solutions of which one is used for initial arrest, storage and cardioplegia during graft implantation, whereas the other serves as initial reperfusate. The formulations of these solutions are closely interrelated and their design has integrated the basic principles of organ preservation with those of myocardium-specific metabolism. Based upon experimental studies in the isolated rat heart model, this integrated approach has yielded better functional recoveries than conventional preservation protocols.

Normothermic cardioplegia: is aortic cross-clamping still synonymous with myocardial ischemia?

The enthusiastic clinical reports on normothermic blood cardioplegia contrast with the paucity of data on the myocardial metabolic effects of this technique. The present study was therefore designed to assess whether normothermic blood cardioplegia really provides an aerobic environment during aortic cross-clamping. Thirty-one patients undergoing coronary (16 patients), valve (13 patients), and transplantation (2 patients) procedures were given continuous normothermic blood cardioplegia through the coronary sinus.

Pivot design in bileaflet valves.

The design criteria leading to the development of a new bileaflet valve (Sorin Bicarbon) were derived from the analysis of functional requirements, the performance of existing prostheses, and the availability of an advanced carbon coating technology (Carbofilm). The hinge is the critical element affecting fluid dynamics, durability, and thrombus formation in bileaflet valves. A comparative study of three existing models led to a new hinge design that was based on coupling two spheric surfaces with different radii of curvature (leaflet pivot and hinge recess) and obtained by electroerosion into a Carbofilm-coated metallic housing.