Christian Kowalski

Halothane, Isoflurane, and Sevoflurane Reduce Postischemic Adhesion of Neutrophils in the Coronary System

Background Polymorphonuclear neutrophils (PMNs) contribute to postischemic reperfusion damage in many organs and tissues, a prerequisite being adhesion of PMNs to vascular endothelial cells. Because adhesion processes involve orderly interactions of membrane proteins, it appeared possible that “membrane effects” of volatile anesthetics could interfere. We investigated the effects of halothane, isoflurane, and sevoflurane on postischemic adhesion of human PMNs in the intact coronary system of isolated perfused guinea pig hearts. Methods The hearts (n = 7–10 per group) were perfused in the “Langendorff” mode under conditions of constant flow (5 ml/min) using modified Krebs‐Henseleit buffer equilibrated with 94.4% oxygen and 5.6% carbon dioxide. Global myocardial ischemia was induced by interrupting perfusion for 15 min. In the second minute of reperfusion (5 ml/min), a bolus dose of 6 x 105 PMNs was injected into the coronary system. The number of cells reemerging in the coronary effluent was expressed as a percentage of the total number of applied PMNs. Halothane, isoflurane, and sevoflurane, each at 1 and 2 minimal alveolar concentration (MAC), were vaporized in the gas mixture and applied from 14 min before ischemia until the end of the experiment. Results Under nonischemic conditions, 24.7 +/‐ 1.3% of the injected neutrophils did not reemerge from the perfused coronary system. Subjecting the hearts to global ischemia augmented retention (36.4 +/‐ 2.8%, P <.05). Application of halothane reduced adhesion of neutrophils to 22.6 +/‐ 2.1% and 24.2 +/‐ 1.8% at 1 and 2 MAC, respectively (P <.05). Exposure to 1 and 2 MAC isoflurane was similarly effective, whereas basal adhesion was not significantly influenced. Sevoflurane‐treated hearts (1 and 2 MAC) also showed decreased adhesion of PMNs (23 +/‐ 2.3% and 24.8 +/‐ 1.8%, respectively; P <.05) and an identical reduction resulted when sevoflurane (1 MAC) was applied only with the onset of reperfusion. Conclusions Although the mechanism of action of volatile anesthetics remains unclear in these preliminary studies, their inhibitory effect on ischemia‐induced adhesion of PMNs may be beneficial for the heart during general anesthesia.

Successful ABO-incompatible heart transplantation in two infants

In the pediatric age group shortage of donor hearts leads to mortality rates of 30–50% on the waiting list. Because of the immaturity of the immune system of infants, ABO‐incompatible heart transplantation may be an option to increase donor availability. We transplanted two infants with blood type O at the age of 7 and 5 months, respectively, with complex congenital heart disease. Intraoperative plasma exchange was performed during cardiopulmonary bypass followed by standard immunosuppression. Both recipients received a blood type A donor organ. Plasma was exchanged up to six times until anti‐A antibodies were eliminated. No hyperacute rejection occurred, ventricular function is excellent and there have been no acute rejection episodes up to 4 months after transplantation. Anti‐A antibody titers remained low and eventually disappeared. ABO‐incompatible cardiac transplantation shows good short‐term results in young infants and appears to be a safe procedure to reduce mortality on the waiting list.

Retention of leucocytes in reperfused, isolated hearts does not cause haemodynamically relevant permanent capillary plugging

Abstract Effects of microspheres (5 μm or 10 μm diameter) and polymorphonuclear leucocytes (PMN) on coronary resistance were compared in beating, non-working isolated guinea-pig hearts (Langendorff preparation). The hearts were buffer perfused (5 ml/min, constant flow) and particles or cells were infused into the coronary system as a bolus (1 ml, 1 min). Coronary perfusion pressure, coronary flow and formation of epicardial transudate were measured before and after bolus administration. Coronary resistance was estimated from these parameters. Retention of particles or cells was monitored by quantifying the numbers emerging in the coronary effluent in relation to the number administered. The effects of PMN were also studied after 15 min of global ischaemia. Coronary resistance correlated with the number of 10-μm particles infused, which were almost quantitatively retained. In contrast, 5-μm beads had no such effect and were not retained in the coronary system. Though considerable numbers of PMN were retained in the hearts (about 21% under control conditions and 35% after ischaemia), coronary resistance was not increased in either case. Blockage of the CD18 adhesion complex by monoclonal antibodies lowered basal retention to 11% and completely prevented the elevation of retention by ischaemia. We conclude that, in this experimental model, PMN, permanently retained in the hearts under normal flow conditions and especially after brief ischaemia, do not cause acute, haemodynamically relevant capillary plugging, but adhere to postcapillary venules via CD18.

Hybrid occlusion of a paravalvular leak with an Amplatzer Septal Occluder after mechanical aortic and mitral valve replacement

FIGURE 1. Preoperative echocardiography showing paravalvular leak of mechanical prosthesis in mitral position. Development of a paravalvular leak after prosthetic valve replacement is a rare but hard to treat complication. In many cases, it requires reoperation. Reoperation is associated with higher mortality and excess risk of recurrent paravalvular insufficiency. During the last couple of years, several hybrid procedures have been developed to decrease operative risk and trauma.

Successful ABO-incompatible heart transplantation in a child despite blood-group sensitization after ventricular assist device support.

Abstract:  In the first two yr of life blood‐group incompatible (ABO‐incompatible) heart transplantation can be performed leading to immune tolerance to donor blood group. Antibody titers should be below 1:4. VAD use is correlated with sensitization toward blood‐group antigens. A boy was diagnosed with dilated cardiomyopathy at nine months of age and listed for 0‐compatible transplantation. Progressive heart failure required implantation of a left VAD. His listing was extended for ABO‐incompatible transplantation despite antibody titers of 1:32 anti‐A and 1:8 anti‐B. After 26 days on VAD, he was transplanted with a B donor heart. No hyperacute or acute rejection occurred in 12 months post‐transplant. Anti‐B antibodies rose to a maximum of 1:2. No use of rituximab or plasmapheresis was required. There are no signs of graft vasculopathy. This indicates that inclusion criteria for ABO‐incompatible transplantation may be extended to immediate cases. This is the first case with a healthy immune system to show signs of tolerance development after ABO‐incompatible heart transplantation with increased prior antibody titers and without specific treatment.

Successful management of late right ventricular perforation after pacemaker implantation

Complications of pacemaker implantation include myocardial perforation, venous thrombosis, vegetations of the tricuspid valve or pacing lead, and tricuspid regurgitation. We report a patient presenting with a case of delayed ventricular lead perforation through the right ventricle. The lead was uneventfully extracted under transesophageal echocardiographic observation in the operating room with cardiac surgery backup.

Cardiovascular Actions ofAdenosine

Adenosine is a pluripotent bioactive metabolite, long known to be formed and released from ischemic and reperfused myocardium owing to enhanced catabolism of adenine nucleotides under these conditions.2,6,16 However, beyond its familiar dilatory actions on coronary and peripheral vessels and its bradyarrhythmic potential in the heart, adenosine also exerts potent effects on the intracoronary adhesion of leukocytes and blood platelets and may be involved in the phenomenon of ischemic preconditioning.3–810,23,33 Table 1 summarizes these actions according to the type of membrane receptor presumably involved, 4 kinds—designated Al, A2a, A2b and A3—having been pharmacologically characterized and cloned to date.23

Successful implantation of a Berlin Heart ventricular assist device in ventricular heart failure 23 years after Senning operation.

Right (systemic) ventricular (RV) failure in patients with transposition of the great arteries (TGA) after the Senning operation is a well-known late complication. Although double switch operations have been advocated by some groups, orthotopic heart transplantation (HTx) remains the only definitive option to treat these patients. However, there is a high mortality rate for patients on transplant waiting lists, and the use of ventricular assist devices (VADs) is often required as a bridge to HTx.