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Biomedical subjects

E Kreuzer

Publications and source records attributed to E Kreuzer.

At least 55 records · Page 3Linked to original sources

Reduction of the incidence of rejection by adjunct immunosuppression with photochemotherapy after heart transplantation.

In this study, photochemotherapy (PCT) was used for adjunct immunosuppression in the first six months after heart transplantation (HTx). Fifteen patients after orthotopic HTx were included in the study; all received standard triple-drug immunosuppression including cyclosporine, azathioprine and glucocorticoids, but no adjunct therapy with mono- or polyclonal antibodies. The patients were divided into three groups: group I served as control with no additional treatment; group II received adjunct treatment with 10 courses of PCT (single-day treatments); and group III received 20 PCT courses since it was given each time on two consecutive days. PCT was started in both groups on day one after HTx; it was applied with a higher frequency in the early postoperative period and thereafter continued at four-week intervals for a total of 6 months. The photopheresis method for PCT included extracorporeal UVA irradiation of mononuclear cells that were treated with the photosensitive drug 8-methoxypsoralen (8-MOP) and subsequently retransfused to the patient. A new liquid form of 8-MOP was added directly to the buffy coat, resulting in reliable and sufficient drug levels in the cell suspension during the irradiation period; problems caused by oral application due to unpredictable variations in gastrointestinal absorption were thus prevented. Analysis of the total numbers of acute rejection episodes (AREs) within the first four weeks after HTx revealed a more impressive decrease by double PCT (group III, 3 AREs) than by single PCT (group II, 5 AREs) in comparison with the control (group I, 6 AREs). Over the total observation time (mean: 9.6 months), however, both PCT schedules reduced the total number of AREs observed in the control group (20 AREs) equally by more than 50% (9 AREs each in groups II and III) (P = 0.007). Furthermore, PCT treated patients had significantly fewer infections (6 infections in each group) than control group patients (15 infections) (P = 0.026); this, however, may be accounted for by the higher number of acute rejections in the control group and consequent increase in unspecific immunosuppression treatment. Our results suggest that PCT is a safe and effective method of adjunct immunosuppression that can be applied early in the postoperative period; it reduces the number of rejection episodes and does not increase the risk of infections.

Adult↗

Early sepsis treatment with immunoglobulins after cardiac surgery in score-identified high-risk patients.

In patients at risk for sepsis after cardiac surgery, the efficacy of intravenous immunoglobulin (Ig) treatment was compared with a historical control population, equivalent in patient characteristics and disease severity. Using APACHE II scores, especially in the high-risk group (IgG), we could discriminate between low-risk patients (score < 19; mortality 1 percent) and the small groups at risk (score 19 to 23) and high risk (score > or = 24) with a significantly higher mortality (14 percent and 76 percent, respectively) [corrected]. Subsequently, among 1,341 consecutive patients we prospectively identified and treated (IgG n = 41 IgGMA: n = 25) these at-risk groups. In contrast to controls (risk: n = 21; high-risk; n = 21), we found a marked fall in APACHE II scores, especially in the high-risk group (IgG, n = 26: p < 0.05; IgGMA, n = 13: p = 0.08) [corrected]. In this group, Ig therapy produced higher (p < 0.05) response rates (score decrease 7 within 4 days: IgG: 54 percent, IgGMA: 62 percent; controls: 19 percent) and reduced mortality (IgG: 46 percent, IgGMA: 46 percent; controls: 76 percent), statistically significant (p < 0.05) for Ig treatment overall. Thus, early Ig treatment improves disease severity and may improve prognosis in prospectively score-identified high-risk postcardiac surgical patients.

Aged↗

Homograft aortic root replacement for destructive valve endocarditis. The benefit of an in-house homograft bank.

This report concerns the surgical treatment of a 45-year old patient with active staphylococcus-endocarditis of the aortic valve which resulted in an aortic root abscess and consequently in a ventricular aortic discontinuity. A technique of homograft aortic root replacement after removal of all infected and necrotic areas is described. After a six month follow-up, the patient is asymptomatic (New York Heart Association functional class I) and shows no signs of recurrence of endocarditis. This case report makes the benefit of an in-house homograft-bank system obvious.

Abscess↗

Force-frequency-relation in human atrial and ventricular myocardium.

In human heart failure, an increase in frequency of stimulation is followed by a reduced force of contraction in vivo and in vitro. The present study aimed to investigate whether a different origin of the myocardial sample or pretreatment with the cardioprotective agent 2,3-butanedione-monoxime (BDM) influences the force-frequency-relationship in electrically driven muscle strips taken from failing and nonfailing human myocardium. With as well as without pretreatment with BDM, the altered force-frequency-relationship in failing compared to nonfailing human ventricular myocardium can be observed. The effectiveness and the potency to increase force of contraction following an increase in frequency of stimulation was significantly higher in atrial than in ventricular myocardium in nonfailing and failing tissue. The different observations in atrial and ventricular myocardium provide evidence for functionally relevant differences in the electromechanical coupling between the human atrial and ventricular myocardium.

Adult↗

Evidence for an interaction of halothane with the L-type Ca2+ channel in human myocardium.

BACKGROUND: The present study was aimed at investigating the underlying mechanisms for the cardiac depressant effect of halothane. To test the hypothesis, whether there is an interaction of halothane with the L-type Ca2+ channels in human myocardium and whether this interaction has functional consequences for force generation in the human myocardium, effects of halothane were studied in human myocardial membranes and isolated cardiac preparations. METHODS: The experiments were performed on isolated, electrically driven ventricular preparations (1 Hz, 37 degrees C) and cardiac membranes with radioligand binding experiments using 3H-PN 200-110. Myocardium from human failing and non-failing hearts was obtained at cardiac surgery. RESULTS: Halothane produced a negative inotropic effect, which was similar in nonfailing and failing myocardium. Halothane shifted the concentration-response curve for the positive inotropic effect of the L-type Ca2+ channel agonist BayK 8644 to the right. The density of dihydropyridine receptors as judged from 3H-PN 200-110 radioligand binding experiments was similar in nonfailing and failing myocardium, whereas the density of beta-adrenoceptors was reduced. Halothane concentration dependently reduced the binding of 3H-PN 200-110, an antagonist at the 1,4 dihydropyridine receptor site of the Ca2+ channel, to myocardial membranes. Furthermore, halothane produced a rightward shift of the competition curve of BayK 8644 for binding of 3H-PN 200-110 to cardiac membranes. CONCLUSIONS: In human ventricular myocardium, halothane exhibits an interaction with the L-type Ca2+ channel by interfering with its dihydropyridine binding sites. This may explain, at least in part, the observed negative inotropic effect of this agent and could hypothetically play a general role in its anesthetic effects.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

Effect of inotropic stimulation on the negative force-frequency relationship in the failing human heart.

BACKGROUND: In severe human heart failure, an increase in frequency of stimulation is accompanied by a reduced force of contraction in vivo and in vitro. The present study was aimed to investigate whether inotropic stimulation influences the inverse force-frequency relationship in failing human myocardium. METHODS AND RESULTS: The effects of the cAMP-independent positive inotropic agents ouabain (0.01 mumol/L) and BDF 9148 (0.1 mumol/L) as well as the beta-adrenoceptor agonist isoprenaline (0.01 mumol/L and 0.1 mumol/L) on the force-frequency relationship in electrically driven papillary muscle strips from nonfailing (brain death, n = 5) and terminally failing (NYHA class IV, heart transplants, dilated cardiomyopathy, n = 22) human myocardium were studied. For comparison, we examined the effect of elevation of the extracellular Ca2+ concentration (3.2 mmol/L and 6.2 mmol/L). In nonfailing myocardium, force of contraction, peak rate of tension rise, and peak rate of tension decay increased, whereas time to peak tension and time to half relaxation decreased following an increase of stimulation frequency. In NYHA class IV, force of contraction gradually declined followed by changes of other parameters of isometric contraction. Moderate stimulation of contractility by isoprenaline (0.01 mumol/L) partly reversed the negative force-frequency relationship in NYHA class IV and preserved the positive force-frequency relationship in nonfailing myocardium. The addition of ouabain and BDF 9148 together restored completely the force-frequency relationship in NYHA class IV. In contrast, high concentrations of isoprenaline (0.1 mumol/L) and an elevation of the extracellular Ca2+ concentration enhanced the decline in force of contraction in the presence of higher stimulation frequencies. CONCLUSIONS: It is concluded that functionally important changes occur in the intracellular Ca2+ handling, leading to the negative force-frequency relationship in terminally failing human myocardium. Interestingly, the negative force-frequency relationship can be restored by agents producing positive inotropic effects by elevation of the intracellular Na+ concentration. These findings suggest that hitherto unknown changes in the intracellular ionic homeostasis occur in the failing human heart. Even though increasing [Ca2+]i in failing heart cells may be detrimental, increasing [Na+bdi may be beneficial through a mechanism independent of an increase in [Ca2+]i.

Adult↗

[Early immunoglobulin therapy in high risk patients for infection after heart surgery].

The efficacy of early supplemental intravenous immunoglobulin G (ivIgG) treatment was investigated in 41 patients at risk for sepsis following cardiac surgery (APACHE II score > or = 19 on the 1st postoperative day). The ivIgG preparation (Psomaglobin N) was chosen because of its reported high antibody titers and effectiveness in animal models against gram-positive microorganisms, preponderant as infective agents after heart surgery. The control group consisted of a historical cohort of 42 cardiac surgical patients of comparable pretreatment disease and sepsis severity. Following ivIgG therapy on the 1st and 2nd days after surgery, we found a marked improvement in disease severity (fall in APACHE II scores) in contrast to the control patients, especially evident in the high-risk group of patients with an APACHE II score > or = 24 on the 1st postoperative day (n = 26). In this group, ivIgG therapy led to higher (p < 0.05) response rates defined as a score decrease > or = 7 within 4 days (ivIgG-treated patients 54%, controls 19%), and a reduction in mortality (ivIgG-treated patients 46%, controls 76%; p = 0.08). Given the good comparability of the study groups, the results of this trial indicate, despite its nonrandomized design, that early supplemental ivIgG treatment seems to decrease disease severity and probably also improve the prognosis in APACHE II score identified high-risk patients after cardiac surgery.

Aged↗

[Early detection of patients at risk for infection after heart surgery].

Since sepsis is a major cause of mortality after cardiac surgery, early identification of the patients at risk of developing septic complications is of considerable importance. In the present study on 110 patients after elective heart surgery, we, therefore, examined scoring systems as well as various single parameters with regard to an early prediction of septic complications. In a first step, the Elebute score definition for postoperative sepsis in general surgery patients (score > or = 12) could be confirmed for cardiac surgery patients as well. Septic complications, defined as an Elebute score > or = 12 on > or = 2 days, occurred in 16 patients and were associated with a significantly worse prognosis than in non-septic patients (mortality 69 vs. 1%). Consequently, other more practicable parameters were investigated: five additional scores (APACHE II, Goris, HIS, SAPS, SSS) were comparable and superior to plasma levels of elastase and neopterin, haemodynamic data, and clinical parameters in predicting septic complications as early as by the 1st postoperative day. For reasons of practicability and availability, the APACHE II score (predictive values: positive 86%, negative 96%, Youden index 0.73; diagnostic cut off point: > or = 19 on the 1st postoperative day) seemed to be best suited. Therefore, this was further investigated within a consecutive prospective study (independent group of 106 patients) which confirmed an APACHE II score > or = 19 as discriminating criterion (mortality 36 vs 0%). Thus, the APACHE II score may be useful for prospective screening, with the intention to treat, of patients after cardiac surgery who are at risk of postoperative septic complications.

Coronary Artery Bypass↗

Early prediction of septic complications after cardiac surgery by APACHE II score.

In 110 patients admitted to the intensive care unit after cardiac surgery, daily monitoring [clinical parameters, cardiac index (CI), left ventricular stroke work index (LVSWI) and APACHE II score] was performed in regard to its usefulness in the early prediction of septic complications, a major cause of postoperative mortality. Septic complications (defined as Elebute sepsis score of > or = 12 on > or = 2 days) occurred in 16 patients and were associated with a significantly worse prognosis (mortality 69% vs 1%, P < 0.0001) than was seen in patients without sepsis. While preoperative APACHE II score values did not differentiate between the patients with an uneventful postoperative course and those with septic complications, patients who ultimately developed septic complications had significantly (P < 0.001) higher scores as early as on the evening of the operation day ("day 0"). In addition, in contrast to patients without sepsis, whose scores dropped markedly (P < 0.001) between day 0 and day 1, patients with septic complications invariably had high scores. Compared to single parameters (fever, leucocyte count, CI, LVSWI), the APACHE II score proved to be superior in differentiating between patients who developed sepsis and those who did not. A score of 19 or more on the 1st postoperative day had a sensitivity of 75%, a specificity of 98%, a Youden index of 0.73, a positive predictive value of 86%, and a negative predictive value of 96% in regard to prediction of septic complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Surgical Procedures↗