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Seit vielen Jahren werden Glukokortikoide routinemäßig eingesetzt, um Zeichen der inflammatorischen Reaktion nach kardiochirurgischen Eingriffen unter extrakorporaler Zirkulation (EKZ) zu mildern. Glukokortikoide sind jedoch für ihre immunsuppressiven Wirkungen bekannt, und bisher blieben die möglichen Auswirkungen auf immunologische Funktionen weitgehend hypothetisch. Ziel der vorliegenden Studie war es daher, den Einfluss von Methylprednisolon (MP) und Tirilazad Mesylat (TM), einer antiinflammatorischen Substanz aus der Klasse der Aminosteroide auf immunologische Funktionen nach koronarchirurgischen Eingriffen mit EKZ zu untersuchen. 38 Patienten wurden randomisiert den Behandlungsgruppen Placebo (NaCl 0,9 %, n=13), MP (15 mg/ kg KG, n=12) und TM (10 mg/kg KG, n=13) zugeteilt. Die Verläufe der Plasmakonzentrationen von IL-6 und IL-10, der monozytären HLA-DR Expression und der ex vivo LPS-stimulierten TNF-alpha, IL-1RA, IFN-gamma und IL-12 Sekretion wurden bestimmt. Im Vergleich zu Placebo resultierte die Gabe von MP in geringeren postoperativen Plasmakonzentrationen von IL-6, aber einer deutlichen Erhöhung von IL-10. Die monozytäre HLA-DR Expression nahm postoperativ in allen Gruppen ab mit einer deutlichen Verstärkung durch MP. Die ex vivo stimulierte TNF-alpha Sekretion nahm postoperativ in allen Gruppen deutlich ab, ebenfalls mit einer deutlichen Verstärkung durch MP. Die IL-1RA Sekretion hingegen war zu keinem Zeitpunkt eingeschränkt. Die ex vivo stimulierte IFN-gamma und IL-12 war postoperativ in allen Gruppen stark vermindert ohne Einfluss einer medikamentösen Behandlung. Die Gabe von TM zeigte keinerlei Beeinflussung aller gemessenen Parameter im Vergleich zu Placebo. Nach koronarchirurgischen Eingriffen sind insbesondere monozytäre Funktionen stark eingeschränkt. Diese Suppression wird durch die Gabe von MP verstärkt, während die Gabe von TM nicht in einer zusätzlichen Immunsuppression resultiert. IL-10 scheint eine Schlüsselrolle bei der beobachteten monozytären Funktionseinschränkung einzunehmen. / Glucocorticoids have been routinely applied in cardiac surgery involving cardiopulmonary bypass (CPB) for many years in order to diminish inflammatory stress reactions. On the other hand glucocorticoids are well known for their immunosuppressive effects, and data on the consequences on immune function are scarce. Thus it was the aim of this trial to determine the influence of methylprednisolone (MP) and tirilazad mesylate (TM), an antiinflammatory drug of the class of aminosteroids, on immunological parameters after coronary surgery involving CPB. 38 patients were randomised to receive either placebo (NaCl 0.9 %, n=13), MP (15 mg/kg, n=12) or TM (10 mg/kg, n=13) treatment. Plasma concentrations of IL-6 and IL-10, monocyte surface expression of HLA-DR and the ex vivo endotoxin-stimulated secretion of TNF-alpha, IL-1RA, IFN-gamma und IL-12 were measured. Compared to placebo IL-6 concentrations were lower after MP treatment, whereas IL-10 levels were much higher. The rate of HLA-DR+-monocytes decreased in all groups with a significant aggravation by MP treatment. The ex vivo stimulated TNF-alpha secretion was postoperatively diminished in all groups, with again significantly lower values after MP treatment. IL-1RA secretion was not suppressed at any point. The ex vivo stimulated IFN-gamma and IL-12 secretion was strongly suppressed postoperatively regardless of the treatment. TM treatment resulted in no alterations of any parameter measured. It was demonstrated that especially monocyte functions are depressed after coronary surgery, and that MP treatment results in marked aggravation of this immunosuppression, whereas TM treatment shows no additional immunosuppressive effect. IL-10 seems to play a key role in the observed monocyte functional depression.

<p>The present thesis addresses various means of reducing inflammatory responses associated with cardiopulmonary bypass (CPB) and retransfusion of pericardial suction blood (PSB) during cardiac surgery.</p><p>Four (I-IV) prospective randomised controlled clinical trials comprising 475 patients were performed in the following areas: effects of heparin coating on measures of clinical outcome and memory function (I, II), inflammatory reactions in PSB and its systemic effects after retransfusion using cardiotomy suction or cell salvage (III) and effects of retransfusion of PSB on memory function and release patterns of protein S100B (IV).</p><p>The use of heparin coated CPB-circuits was associated with a decrease of postoperative blood loss (I, II), transfusion requirements (II), shorter stay in hospital (I) decreased postoperative ventilator time (I), lower incidences of atrial fibrillation (II) and neurological deviations (I), reduction in releases of protein S100B (I, II) and lower postoperative creatinine elevation (I, II).</p><p>PSB contained high concentrations of cytokines, complements, myeloperoxidase, free plasma haemoglobin and protein S100B (III, IV). Retransfusion using cardiotomy suction increased the systemic concentrations of free plasma haemoglobin and protein S100B, whereas retransfusion using cell salvage caused no detectable systemic effects (III, IV). CPB was associated with a small but significant release of protein S100B, despite elimination of PSB-contained protein S100B using cell salvage (IV).</p><p>Subtle signs of impaired memory function were identified that were not associated with the use of heparin coated CPB-circuits (I, II) or retransfusion of PSB (IV).</p><p>Key words: cardiopulmonary bypass, oxygenators, heparin, S100 proteins, blood loss, haemostasis, memory, outcome and process assessment.</p>

The present thesis addresses various means of reducing inflammatory responses associated with cardiopulmonary bypass (CPB) and retransfusion of pericardial suction blood (PSB) during cardiac surgery. Four (I-IV) prospective randomised controlled clinical trials comprising 475 patients were performed in the following areas: effects of heparin coating on measures of clinical outcome and memory function (I, II), inflammatory reactions in PSB and its systemic effects after retransfusion using cardiotomy suction or cell salvage (III) and effects of retransfusion of PSB on memory function and release patterns of protein S100B (IV). The use of heparin coated CPB-circuits was associated with a decrease of postoperative blood loss (I, II), transfusion requirements (II), shorter stay in hospital (I) decreased postoperative ventilator time (I), lower incidences of atrial fibrillation (II) and neurological deviations (I), reduction in releases of protein S100B (I, II) and lower postoperative creatinine elevation (I, II). PSB contained high concentrations of cytokines, complements, myeloperoxidase, free plasma haemoglobin and protein S100B (III, IV). Retransfusion using cardiotomy suction increased the systemic concentrations of free plasma haemoglobin and protein S100B, whereas retransfusion using cell salvage caused no detectable systemic effects (III, IV). CPB was associated with a small but significant release of protein S100B, despite elimination of PSB-contained protein S100B using cell salvage (IV). Subtle signs of impaired memory function were identified that were not associated with the use of heparin coated CPB-circuits (I, II) or retransfusion of PSB (IV). Key words: cardiopulmonary bypass, oxygenators, heparin, S100 proteins, blood loss, haemostasis, memory, outcome and process assessment.

Background: Despite the recent improvements in surgical techniques and postoperative patient care, atrial fibrillation (AF) remains the most frequent complication after cardiac surgery. Although postoperative AF is often regarded as a benign clinical condition, this arrhythmia has significant adverse effects on patient recovery and postoperative survival. Its exact pathophysiology has not yet been elucidated. The present thesis aims to analyze AF risk factors and their interaction, pre-existing histological explanatory alterations of the atrium, the AF impact on postoperative survival and the compliance of a prophylactic drug regimen. Methods: During a 10-year period, consecutive cardiac surgery cases with complete data on AF occurrence and postoperative survival were extracted. All patients were operated on for coronary or valvular surgery, with cardiopulmonary bypass (CPB). Hospital and long-term survival data were obtained from Swedish population registry. Study I) Isolated coronary artery bypass grafting (CABG, n=7056), aortic valve replacement (n=690) and their combination (n=688) were considered. Independent AF risk factors and AF effects on early and 1 year mortality were investigated. Study II) Patients affected by postoperative AF among isolated CABG patients (n=7621), valvular surgeries (n=995) and their combination (n=879) were studied. Long-term survival was obtained and prognostic factors identified. Study III) Seventy patients were randomized to on-pump (n=35) or off-pump (n=35) CABG. Samples from the right atrial appendage were collected and histology was evaluated by means of light and electronic microscopy with reference to preexistent alterations related to postoperative AF. Study IV) Cardiac surgery patients with complete data on smoking status (n=3245) were reviewed. Effects of smoking on AF development and interaction among variables were explored. Study V) CABG patients without clinical contraindications to receive oral sotalol (80 mg twice daily) and magnesium were prospectively enrolled (n = 49) and compared with a matched contemporary control CABG group (n = 844). The clinical compliance to the AF prophylactic drug regimen was tested. Results: The overall AF incidence was around 26%, subdivided into 23%, 40% and 45% for isolated CABG, valve procedures and their combined surgeries, respectively. Age was the strongest predictor of postoperative AF. Coronary disease superimposed risk factors with reference to myocardial conditions at CPB weaning. Considering the preoperative smoking condition, smokers demonstrated a reduced AF incidence compared to non-smokers (20% versus 27%, p&lt;0.001). An interaction between smoking status and inotropic support was observed: without this interaction smoking conferred a 46% risk reduction of AF (p=0.011). At the histological level, myocyte vacuolization and nuclear derangement represented anatomical independent AF predictors (p=0.002 and p=0.016, respectively). CPB exposure was not associated to postoperative AF nor histological changes. Although, postoperative AF increases the length of hospitalization in all patient groups, it did not affect the hospital survival. However, AF independently impaired the late survival, a phenomenon seen in the CABG group only. With reference to the tested sotalolmagnesium drug regimen, only 55% of CABG patients were compliant to the treatment, with marginal effects on AF occurrence. Conclusions: In addition to age, details at the CPB weaning period, pre-existing histopathological changes, the hyperadrenergic state and catecholamines are key mechanisms in the pathophysiology of postoperative AF. In particular, the CPB period hides valuable information for timely AF prophylactic stratifications. Further, compliance effects due to patient selection should also be considered in a prophylactic therapy model. Postoperative AF increases late mortality after isolated CABG surgery, but not after valvular procedures. Although the mechanisms are unclear, our results draw the attention to possible AF recurrence after hospital discharge, indicating a strict postoperative surveillance.

Introduction: During cardiac surgery aided by cardiopulmonary bypass (CPB) the autotransfusion of pericardial suction blood (PSB) is regarded mandatory to limit allogeneic blood exposure. PSB is however proposed as a source of lipid microemboli and to contribute to brain damage. This thesis addresses the logistics of allogeneic blood transfusion during coronary artery bypass grafting (CABG), the embolic potential of reinfused PSB, and means to reduce PSB fat contamination, investigated both clinically and experimentally. Methods: Study I) Patients undergoing CABG surgery (n=2469) were included in a database study. The magnitude of surgical bleeding versus blood transfusion was analyzed to extract a subgroup of patients (n=982) in whom transfusions were independent from bleeding. Study II) PSB and venous-blood samples were collected from patients undergoing routine CABG (n=20). The in vitro capillary-flow properties of blood subcomponents and the effects of routine screen filtration were tested. PSB fat contamination was evaluated by imprint microscopy. Study III) Heat extracted liquid human fat or soya oil were mixed with mediastinal drain blood (n=20) and incubated in a temperature controlled column, to evaluate spontaneous density separation of fat. Study IV) The findings from study-III were applied to develop a fat-reducing system (FRS) using two stacked compartments. The FRS was experimentally tested (n=12), with similar methods as in study-III, and clinically evaluated (n=10). A single-chamber blood bag (n=10) served as reference. Results: Study I) A surgical bleeding of less than 400 mL showed no correlation to blood transfusion, although 64 of 982 patients still received allogeneic blood. The strongest predictors for this kind of transfusion were; female gender, weight ≤70 kg, CPB time ≥90 minutes, CPB temperature ≤32 ºC, and advanced age (P&lt;.001 - .038). Study II) The capillary-flow profile of PSB plasma was highly impaired compared to venous plasma (P&lt;.001). Conversely, blood-cell components showed no difference between PSB and venous blood. Routine screen filtration showed no ameliorating effect on capillary-flow resistance. Fat debris was detected on imprints in all PSB samples in contrast to venous plasma (P&lt;.05). Study III) After 10-min of incubation had 77% of added soya oil separated and found contained in the top 20% fraction of blood (P&lt;.001), aimed to be discarded. The density separation of human fat was less efficient compared to soya oil (P=.011). Fat also adsorbed to surface which was more pronounced at low temperature (P&lt;.001). The overall reduction of human fat was 70%. Study IV) PSB contained 1.5 mL fat suspended in 418 mL PSB. Of this fat was 24% surface-bound. Experimental analysis of the proposed FRS revealed an 83% fat-reduction which was clinically confirmed, suggesting 80% reduction (P=.001). The FRS also gave a small but significant erythrocyte-concentrating effect. Conclusions: Transfusion of allogeneic blood during CABG surgery appeared associated with an institutional, individual, and technical bias of an anticipated need and not only used to compensation for surgical bleeding. In part may this reflect a non-compliant CPB methodology and hemodilution. It was confirmed that PSB plasma contained fat, with a suggested embolic potential. Human fat was significantly reduced from mediastinal drain blood by spontaneous density separation and surface adsorption. The prototype FRS used for PSB incubation during CPB allowed an efficient fat reduction.

Abdominelle Komplikationen, zu denen auch das akute Leberversagen nach Einsatz der Herz-Lungen-Maschine und systemischer Hypothermie nach herzchirurgischen Korrekturoperationen neugeborener Patienten zählt, sind seltene, aber dennoch erst zu nehmende unerwünschte Folgen. Die Untersuchungen erfolgten an neugeborenen Schweinen, die in 4 Gruppen eingeteilt wurden: Eine Gruppe wurde mit extrakorporaler Zirkulation in moderater Hypothermie (32°C) operiert (CPB), die zweite Gruppe wurde in tiefer Hypothermie (18°C) und totalem Kreislaufstillstand operiert (DHCA). In der dritten Gruppe (Sham) erfolgte die Instrumentation nach Sternotomie und ohne Einsatz der Herz-Lungen-Maschine. Die Tiere der vierten Gruppe waren unbehandelte Kontrolltiere. Es zeigte sich, dass das Entstehen der Inflammation wesentlich abhängig von der Anwendungsdauer der Herz-Lungen-Maschine ist. Tiefe systemische Hypothermie scheint einen protektiven Effekt auf die Inflammation und Apoptose zu haben. Im Gegensatz dazu verursacht tief-hypothermer Kreislaufstillstand vermehrt die Bildung eines hepatozellulären Ödems. Bei allen untersuchten Aspekten (Inflammation, hepatozelluläres Ödem, Apoptose) zeigt sich deutlich, dass der operative EIngriff selbst Veränderungen an der Leber hervorruft. Insbesondere für das Auftreten von Apoptose ist das chirurgsiche Trauma von größter Bedeutung.

Surgical myocardial revascularization remains the standard of care for patients with multi-vessel coronary artery disease. A growing body of evidence indicates that systemic inflammation and myocardial oxidative stress are associated with the development of postoperative atrial fibrillation (POAF) and low cardiac output syndrome in patients undergoing cardiac surgery. Statins have been shown to exert rapid anti-inflammatory and antioxidant effects by inhibiting myocardial NOX2 oxidases and by increasing the bioavailability of nitric oxide (NO). However, whether these so-called pleiotropic effects of statins result in improved patient outcomes remains to be established. To provide further insights into the mechanisms of action and impact on clinical outcomes of peri-operative statin treatment in patients undergoing cardiac surgery, I studied the molecular mechanisms underlying the myocardial nitroso-redox balance in samples of the right atrial appendages (RAA) obtained before (PRE) and after cardiopulmonary bypass (CPB) and reperfusion (POST) and setup two double-blind randomised placebo-controlled trials: 1) STARR (Statin Treatment on Atrial Refractoriness and Reperfusion injury), which tested the effect of Atorvastatin (80 mg once daily for up to 6 days before surgery and 5 days after) on the atrial effective refractory period (AERP, over 4 post-operative days) and superoxide production in paired PRE- and POST- RAA samples from 60 patients 2) STICS (Statin Treatment In Cardiac Surgery), which assessed the effects of peri-operative treatment with Rosuvastatin (20mg od) on POAF (assessed by continuous holter ECG monitoring for 5 days postoperatively) and myocardial injury (assessed by serial troponin I measurements) in 1922 patients undergoing elective cardiac surgery. I observed that atrial superoxide production increased significantly after reperfusion due to increased mitochondrial and NOX2 oxidase activity and to uncoupling of NOS activity. NOS activity in RAA samples decreased significantly after reperfusion (by 60&percnt;), but this reduction was not prevented by BH4 supplementation (10 &mu;M) or NOX2 inhibition. Instead, I identified increased endothelial NOS S-glutathionylation as the main mechanism responsible for NOS uncoupling after reperfusion. In STARR, atorvastatin prevented increase in RAA superoxide production, maintained the functionally coupled status of NOS and NO bioavailability after reperfusion but had no measurable effect on postoperative AERP. In STICS, treatment with rosuvastatin significantly reduced LDL-C concentration by 48 hours after surgery but had no effect on the incidence of POAF (203 (21&percnt;) of the Rosuvastatinallocated patients vs. 197 (20&percnt;) of the placebo-allocated patients) or on perioperative myocardial damage (P = 0.80). Pre-defined subgroup analyses (age, sex, prior statin use, baseline troponin concentration, duration of randomized treatment before surgery, type of cardiac surgery, and postoperative use of anti-inflammatory drugs) did not identify any category of patient who benefited from perioperative rosuvastatin treatment. Nor were there beneficial effects on any of the other in-hospital clinical outcomes that were assessed. In conclusion, cardiac surgery on CPB is associated with myocardial nitroso redox imbalance that is reversed by perioperative intensive therapy with statins. However, these effects have no beneficial effects on common in-hospital complications after elective cardiac surgery. Although the benefits of long-term statin therapy in patients requiring myocardial revascularization are well established, the work presented in this thesis does not support routine use of perioperative intensive therapy with statins for the prevention of postoperative complications in patients undergoing elective cardiac surgery.

Diese Arbeit beschäftigt sich mit den Auswirkungen der Herz-Lungen-Maschine auf das Gewebe des Hippocampus in einem Ferkelmodell. Die Tiere untereilte man in 5 Gruppen: „Kontrolle“, „Kontrolle mit Minozyklin“, „HLM pulsatil“, „HLM nicht-pulsatil“, sowie „HLM nicht-pulsatil mit Minozyklin“. Es wurde untersucht, ob eine pulsatile Perfusion Schäden in den Zellen des Hippocampus gegenüber eines nicht-pulsatilen Blutflusses während der extrakorporalen Zirkulation abmildern kann. Des Weiteren überprüfte man neuroprotektive Effekte des Tetrazyklin-Derivates Minozyklin während eines kardiochirurgischen Eingriffes mit Herz-Lungen-Maschine. Während der Operation wurde bei allen Ferkeln eine Hypothermie von 28 °C durchgeführt und die HLM-Zeit betrug 90 Minuten. Die Rekonvaleszenzzeit umfasste 120 Minuten. Minozyklin verabreichte man in den entsprechenden Gruppen sowohl zu Beginn des Versuches (4 mg/kg KM) und nach Abkopplung von der Herz-Lungen-Maschine (2 mg/kg KM) intravenös. Hauptbestandteil der Arbeit waren histologische und immunhistochemische Färbemethoden zur Untersuchung des Hippocampus. Mithilfe eines Mikroskops wurden Veränderungen auf zellulärer Ebene im CA1- und CA3-Areal des Cornu ammonis im Hippocampus ausgewertet. Für die Ergebnisse betrachtet man die Pyramidenzellen des Stratum pyramidale. In der Hämatoxylin-Eosin-Färbung wurden Zellen mit den Eigenschaften „Ödem“, „Eosinophilie“ und „Pyknose“ für jedes Versuchstier gezählt. Mit den immunhistochemischen Färbungen sollten Faktoren für den programmierten Zelltod, für Hypoxie (HIF 1-alpha) und für oxidativen Stress (3-Nitrotyrosin) detektiert werden. Als Marker für Apoptose wählte man den Apoptose-induzierenden Faktor (AIF), cleaved Caspase 3 und Poly(ADP)Ribose (PAR).:Inhaltsverzeichnis 1 Einführung 1.1 Kinderherzchirurgie 1.2 Herz-Lungen-Maschine 1.3 Pathophysiologie der HLM 1.3.1 Inflammationsreaktion 1.3.2 Ischämie 1.3.3 Reperfusion 1.4 HLM und Folgen für das Gehirn 1.5 Neuroprotektive Strategien 1.5.1 Pulsatile Perfusion 1.5.2 Minozyklin 1.6 Hippocampus 2 Aufgabenstellung 3 Tiere, Material und Methoden 3.1 Versuchstiere 3.2 Versuch Teil 1: Operation 3.2.1 Gruppeneinteilung und Versuchsaufbau 3.2.2 Anästhesie 3.2.3 Operation 3.2.3.1 Vorbereitungszeit 3.2.3.2 Kardioplegie 3.2.3.3 Herz-Lungen-Maschine mit nicht-pulsatilen Blutfluss/ pulsatilen Blutfluss 3.2.3.4 Medikation mit Minozyklin 3.2.4 Intraoperatives Monitoring 3.2.4.1 Vitalparameter 3.2.4.2 Arterielle Blut-Gas-Analyse 3.2.4.3 Elektrolyt-Haushalt 3.2.4.4 Laktat- und Glukose-Haushalt 3.3. Versuch Teil 2: Laboruntersuchungen 3.3.1 Einbetten der Proben und Herstellung der Schnittpräparate 3.3.2 Histologie 3.3.2.1 Hämatoxylin-Eosin-Färbung 3.3.3 Immunhistochemie 3.3.3.1 Allgemeines Prinzip 3.3.3.2 Nachweis: Apoptose-induzierender Faktor 3.3.3.3 Nachweis: Hypoxie-induzierter Faktor 1- alpha 3.3.3.4 Nachweis: cleaved Caspase 3 3.3.3.5 Nachweis: 3-Nitrotyrosin 3.3.3.6 Nachweis: Poly(ADP)Ribose 3.3.4 RP-HPLC – Reversed Phase High Performance Liquid Chromatography 3.4 Blutgasanalyse 3.5 Auswertung am Mikroskop 3.6 Statistik 4 Ergebnisse 4.1 Intraoperatives Monitoring 4.2 Arterielle Blutproben 4.3 Arterielles Blut: Laktat-Haushalt 4.4 Ergebnisse der RP-HPLC 4.5 Ergebnisse der Hämatoxylin-Eosin-Färbung 4.6 Ergebnisse der immunhistochemischen Färbungen 4.6.1 Apoptose-induzierender Faktor 4.6.2 Hypoxie-induzierter Faktor 1-alpha 4.6.3 3-Nitrotyrosin 4.6.4 Cleaved Caspase 3 4.6.5 Poly-(ADP)-Ribose 5 Diskussion 5.1 Tiermodell und Versuchsaufbau 5.2 Blutproben 5.3 Herz-Lungen-Maschine und nicht-pulsatiler Blutfluss versus pulsatiler Blutfluss 5.4 Extrakorporale Zirkulation und die Gabe von Minozyklin 5.5 Beantwortung der Fragestellungen 6 Zusammenfassung 7 Literaturverzeichnis 8 Anhang 8.1 Einführung 8.1.1 Kinderherzchirurgie 8.1.2 Pathophysiologie der HLM 8.2 Tiere, Material und Methoden 8.2.1 Operation 8.2.2 Intraoperatives Monitoring 8.2.3 Laboruntersuchungen 8.3 Ergebnisse 8.3.1 Intraoperatives Monitoring 8.3.2 Arterielles Blut 8.3.3 Arterielles Blut – Laktat-Haushalt 8.3.4 RP-HPLC 8.3.5 Hämatoxylin-Eosin-Färbung 8.3.6 Immunhistochemie 9 Selbständigkeitserklärung 10 Lebenslauf 11 Koautorenschaft 12 Danksagung