Immediate effects of individualized heparin and protamine management on hemostatic activation and platelet function in adult patients undergoing cardiac surgery with tranexamic acid antifibrinolytic therapy

Objective:

This randomized prospective study was initiated to clarify whether individualized heparin and protamine dosing has immediate effects on hemostatic activation and platelet function in adult cardiac surgery.

Methods:

Sixty adults undergoing elective coronary artery bypass grafting (CABG) were assigned to receive individualized heparin and protamine (HMS group, n= 29) or a standard dose (ACT group, n=24). Measures of thrombin generation and Multiplate® (Verum Diagnostica, Munich, Germany) platelet function tests were performed before and after cardiopulmonary bypass (CPB).

Results:

HMS patients received higher heparin (p = 0.006) and lower protamine (p<0.001) doses. Post-CPB, HMS managed patients showed significantly lower thrombin generation (thrombin-antithrombin (TAT) p<0.02) than the ACT group. Moreover, HMS managed patients had a better preservation of platelet function (COL p = 0.013; ADP p = 0.04; TRAP p = 0.04).

Conclusion:

An individualized and stable heparin concentration and appropriate dosing of protamine can reduce thrombin generation and preserve platelet function, even in short-time CPB.

Advanced glycation endproducts: a biomarker for age as an outcome predictor after cardiac surgery?

OBJECTIVE

A decline in the function of all organs can be detected during ageing. Although the trend appears to be stable, deviation within the elderly population is much greater in comparison to young controls. The aim of the study was to identify a marker of senescence which correlates to heart function. Advanced glycation endproducts (AGEs) accumulate with age and are associated with degenerative diseases.

METHODS

Carboxymethyllysine (CML) concentrations in the pericardial fluid (as a measure of AGEs) were analysed with ELISA technique in 75 patients undergoing cardiac surgery and correlated with clinical parameters and outcome of these patients.

RESULTS

CML content of pericardial fluid increases significantly with age. AGEs show an inverse correlation to left ventricular ejection fraction. High CML levels correlate with poor outcome of patients as shown by adverse cardiac events, prolonged ventilation time and prolonged stay within the Intensive Care Unit. Within all parameters, AGE concentration of the pericardial fluid fits better with the outcome of the patients in comparison to age alone. Interestingly, medical treatment with nitrates correlates with increased CML content.

CONCLUSION

AGEs, in addition to being a marker of senescence, appear to represent a prognostic factor in cardiac surgery, which can be used as a predictor of patient outcome.

Existence of functional M3-muscarinic receptors in the human heart

It has been recently shown that, in adult rat ventricular cardiomyocytes, functional muscarinic receptors (M-receptors) of the M(3)-subtype exist that mediate inositol phosphate (IP) formation. The aim of this study was to characterize the M-receptor subtype mediating IP formation in the human heart. For this purpose in [3H]-myo-inositol labeled slices of human right atria, carbachol-induced [3H]-IP formation and its inhibition by several M-receptor antagonists was assessed. Carbachol (0.1 microM-100 microM) increased [3H]-IP formation; maximal increase at 100 microM was 93+/-16% above basal ( n=20); the pEC(50)-value for carbachol was 5.56. Atropine (1 microM) completely suppressed 100 microM carbachol-induced [3H]-IP formation. Among the M-receptor subtype "selective" antagonists himbacine (1 microM) and pirenzepine (1 microM) only marginally affected carbachol-induced [3H]-IP formation whereas the M(3)-receptor antagonist darifenacin (1 nM-1 microM) concentration-dependently inhibited carbachol-induced [3H]-IP formation with a pK(i)-value of 8.49. We conclude that in human right atrium there exist functional M(3)-receptors that couple to IP formation.

Different expression of cytokines in survivors and non-survivors from MODS following cardiovascular surgery

OBJECTIVE

Cardiopulmonary bypass is often associated with pathophysiological changes in form of systemic inflammatory response syndrome (SIRS) or multiple organ dysfunction syndrome (MODS). In the present study, we investigated plasma levels of pro- and anti-inflammatory cytokines in survivors and non-survivors from MODS in the early postoperative course following open heart surgery.

DESIGN

Prospective clinical study.

SETTING

A University Cardiothoracic Intensive Care Unit.

METHODS

Levels of cytokines (IL-6, IL-8, IL-10, IL-18, and TGF- ) and procalcitonin (PCT) were measured at the first four postoperative days in 16 adult male patients with an Apache II-score >24 and two or more organ dysfunctions after myocardial revascularization.

MAIN RESULTS

All pro-inflammatory cytokines, except for IL-6, were significantly elevated in non-survivors from MODS, with peak values at the first two postoperative days. The plasma levels of immunoinhibitory cytokines showed no differences between the groups.

CONCLUSIONS

The results of our study show a different expression of pro-inflammatory cytokines in survivors and non-survivors from MODS following operations with extracorporeal circulation. In addition to Apache-II score, especially IL-8, IL-18, and PCT may be used as parameters for the prognosis of patients with organ dysfunctions after cardiac surgery.

IgM-enriched immunoglobulin preparation for immunoprophylaxis in cardiac surgery

OBJECTIVE

Evaluating the effects of prophylactic administration of IgM-enriched immunoglobulins (IVIG) on immunological- and clinical parameters in cardiac surgical patients.

PATIENTS AND METHODS

41 patients were randomized to receive either an IgM-enriched immunoglobulin (Pentaglobin(R)) preparation (1,300 ml immunoglobulin, equivalent to 65 g protein) combined with routine antibiotic prophylaxis (Group A; n = 20, 1 drop-out), or routine antibiotic prophylaxis plus placebo (Group B; n = 20). Patients were comparable with respect to their APACHE II score, comorbidity, coronary risk, operating time, clamp, and ischemic time. Endotoxin and endotoxin neutralizing capacity (ENC) were determined by a kinetic turbidimetric Limulus amebocyte lysate (LAL) assay with internal standardization. Serum levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF)-alpha, soluble TNF-Receptor I (sTNF-R1), and interleukin-10 (IL-10) were determined by ELISA. Data analysis was performed by area under the curve (AUC) calculation and ANOVA for endotoxin neutralizing capacity and by ANOVA for all other cases.

RESULTS

All patients survived. Endotoxin plasma levels were generally but not significantly higher in group A than in controls, while the difference in endotoxin neutralizing capacity (ENC) reached significance. IL-6, TNF-alpha, IL-10 and TNF-R1 were not different between both groups, however. There were significantly less patients with signs of inflammation (fever, leukocytosis, hypotension) in group A (group A n = 2; group B n = 9; p<0.05). This was paralleled by a slightly reduced hospitalization period in group A patients compared to group B patients (A:12.05 +/- 3.66 vs. B:13.45 +/- 3.72 days; n.s.). All data are given as mean +/- standard deviation (SD).

CONCLUSION

The results of this study support that IgM-enriched IVIG preparation are effective when used prophylactically in patients undergoing procedures with cardiopulmonary bypass. The mechanisms of endotoxin neutralization and the effect of the host immune status on the efficacy of IVIG treatment remain to be elucidated.

Iatrogenic ruptures of the tracheobronchial tree

OBJECTIVE

Iatrogenic tracheobronchial ruptures are seldom but severe complications after intubation or bronchoscopy. Therefore, we evaluated the reasons, the subsequent therapy and the outcome of patients with tracheal rupture, who were admitted to our hospital.

METHODS

In a retrospective study we examined 19 patients (15 women, four men; 43-87 years) treated for acute tracheobronchial lesions. Eleven (58%) patients had a tracheobronchial rupture by single-lumen tube, four (21%) by double-lumen tube and two patients (10%) by tracheal cannula. A total of 47% of whom were carried out under emergency conditions. Two patients had a rupture due to a stiff bronchoscopy. Mean symptoms were mediastinal and subcutaneous emphysema. Two emergency collar incisions had been done.

RESULTS

The localization of ruptures was in all cases in the paries membranaceus, length: 1-7 cm (mean: 4.8 cm). The interval between the onset of symptoms and the diagnose differed widely (up to 72 h), nine (47%) diagnoses were made during intubation/bronchoscopy. One patient, with a small tear (1 cm) was treated conservatively with fibrin-glue. The other 18 patients had surgical repair through a thoracotomy. The postoperative mortality was determined with 42%, which was not dependent on the rupture but basically by the underlying diseases requiring intubation.

CONCLUSIONS

Iatrogenic tracheal rupture is a dangerous complication with potentially high postoperative mortality, mostly influenced by the underlying disease. Early surgical repair must be the preferred treatment.

Microscopic (R1) and macroscopic (R2) residual disease in patients with resected non-small cell lung cancer

OBJECTIVES

This retrospective study evaluates the probability of survival in patients who had undergone resection for non-small cell lung cancer (NSCLC) and in whom residual disease at the resection margins was found.

METHODS

During a period of 6 years, 596 patients with NSCLC were operated upon with curative intention. Residual disease at the resection margin was divided into microscopic (R1) and macroscopic (R2).

RESULTS

Twenty-six patients (4.4%) showed R1 and 12 (2%) R2 residual disease. An extrabronchial (thoracic wall, vessels) R1 situation was found in five patients and a bronchial R1 infiltration in 21 cases. The bronchial resection margin was subject to peribronchial infiltration in most cases (16/21). A total of 17/21 (65%) patients with bronchial infiltration had N2 disease. Thirty day lethality was 3.8% in the R1 group. Fifteen patients had postoperative irradiation. The 5-year survival rate for patients with R1 resection was 14%. The differences in survival between patients with extrabronchial vs. bronchial infiltration and N0/N1 vs. N2 were significant using univariate analysis. Adjuvant radiation did not result (especially in N2 disease) in a survival benefit. Among 12 patients with macroscopic residual disease (R2), 3/12 (25%) died within the first 30 days after the operation, and none of the R2 patients survived the first year after the operation.

CONCLUSIONS

Patients with an R1 situation have a survival rate of 14% comparable to curative resected patients (RO) in stage III. Adjuvant radiation had no clear effect on survival. Patients with macroscopic tumor (R2) should receive palliative treatment after the operation depending on their condition.

Age-dependent myocardial reinduction of apoptosis inhibitors under VAD in heart failure

Hemodynamic unloading using the ventricular assist device [VAD] results in partial functional recovery of failing hearts that show increased susceptibility to cardiomyocyte apoptosis. The caspase cascade is the central element of the apoptotic process in cells. We therefore tested expression shifts of left ventricular mRNA of caspases and their endogenous inhibitors from 15 patients with VAD support and successful bridging to transplantation using semiquantitative RT-PCR. Cardiac unloading was shown by the reduction in ventricular Pro-ANP mRNA under VAD. No alteration of mRNA expression under VAD could be observed for initiator caspases, for their selective inhibitors or for apoptotic signal molecules from the mitochondrial intermembrane space. Only two unselective cardiac IAPs (inhibitor of apoptosis protein) were increased under VAD with better recovery in younger patients. In conclusion, our findings indicate that successful hemodynamic unloading by VAD support causes only minor, age-dependent recovery in the expression of IAPs, while presumed alterations in antiapoptotic modulator systems upstream of the caspase cascade still remain to be identified.

Lipopolysaccharide-binding protein (LBP) and markers of acute-phase response in patients with multiple organ dysfunction syndrome (MODS) following open heart surgery

Cardiopulmonary bypass (CPB) is associated with an immunological injury that may cause pathophysiological alterations in the form of a systemic inflammatory response syndrome (SIRS) or a multiple organ dysfunction syndrome (MODS). Previous studies on this issue have reported different changes of immunological parameters during and after CPB, but there are no reports about the lipopolysaccharide-binding protein (LBP) in relationship to other markers of inflammation in patients with MODS following cardiovascular surgery. In the present study, we investigated the acute-phase response of patients with MODS of infectious and non-infectious origin following open-heart-surgery. Plasma levels of procalcitonin (PCT), c-reactive protein (CRP), interleukin-6 (IL-6), and LBP were measured in the first four postoperative days in 12 adult male patients with the signs of SIRS and two or more organ dysfunctions after myocardial revascularization (MODS-group), and 12 patients without organ insufficiencies (SIRS-group). There were no significant differences regarding age, weight, height, preoperative NYHA-classification, preoperative LVEDP, or the number of anastomosis. Patients with MODS had a significantly longer operation time, duration of ischemia, and duration of extracorporeal circulation. None of the patients in the SIRS group died, whereas in the MODS group, 4 patients died due to septic multiorgan failure. Plasma PCT and IL-6 concentrations were significantly elevated in all MODS patients. CRP and LBP showed no differences between the MODS and the SIRS group. Comparing the MODS patients with and without positive microbial findings, we found significantly elevated levels of PCT and LBP in those patients with documented infections. Our results indicate that LBP may be a new marker for the differentiation between a severe non-infectious SIRS and an ongoing bacterial sepsis in the early postoperative course following CPB, while a microbiological result is still missing.

Ischemic pre-conditioning of 5 minutes but not of 10 minutes improves lung function after warm ischemia in a canine model

BACKGROUND

Protection from reperfusion injury by ischemic pre-conditioning (IPC) before prolonged ischemia has been proven for the heart and the liver. We now assess the efficacy of IPC to protect lungs from reperfusion injury.

METHODS

Eighteen foxhounds (25 to 30 kg) were anesthetized, intubated, and ventilated with a fraction of inspired oxygen of 0.3 at a volume-controlled mode to maintain arterial pCO2 of 30 to 40 mm Hg. After left thoracotomy, we performed warm ischemia for 3 hours by clamping the left hilus, and followed with 8 hours of reperfusion (control, n = 6). In the treated groups, IPC was performed either for 5 minutes followed by 15-minute reperfusion (n = 6, IPC-5), or by 2 successive cycles of 10-minute ischemia, followed by 10-minute reperfusion (n = 6, IPC-10) before prior to the 3-hours warm-ischemia period. Pulmonary compliance and gas exchange were determined separately for each lung, and we recorded pulmonary and systemic hemodynamics. We performed bronchoalveolar lavage (BAL) at the end of the experiment and determined total protein concentration as well as tumor necrosis factor alpha (TNF-alpha) mRNA expression in cell-free supernatant and in BAL cells, respectively. We also assessed the wet/dry ratio of the lung.

RESULTS

In the controls, on reperfusion, we encountered a progressive deterioration of gas exchange, especially of the reperfused left lung, which we could largely avoid using the IPC-5 protocol. Similarly, pulmonary compliance steadily declined but was much better in the ICP-5 group. Parallel to the improvement of gas exchange and lung mechanics, we found less total alveolar protein content and TNF-alpha mRNA expression in BAL cells in the IPC-5 than in the controls. However, we did not find IPC-10 to be paralleled by a significant improvement of lung function. Neither IPC-5 nor IPC-10 influenced the pulmonary vascular resistance index or the fluid accumulation in the lung.

CONCLUSION

The major finding of the present study was that 5 minutes of IPC improved lung function after 3 hours of warm ischemia of the lung.

Treatment of sepsis in cardiac surgery: role of immunoglobulins

Cardiopulmonary bypass (CPB) is associated with an injury that may cause pathophysiological changes such as systemic inflammatory response syndrome, multiple organ dysfunction syndrome, and mediator-induced multiorgan failure. Systemic endotoxinaemia, release of proinflammatory cytokines, and interactions between neutrophils and endothelium have been reported to correlate with a high incidence of organ dysfunction, infection and sepsis following cardiac surgery. This review discusses the dysregulation of the immune response as a major reason for the higher susceptibility to infections following cardiac surgery, various treatment strategies to reduce CPB-induced inflammation, and especially the prophylactic use of immunoglobulins in cardiac surgery.