Production of proinflammatory cytokines and myocardial dysfunction after arterial switch operation in neonates with transposition of the great arteries

Effect of Perioperative Nicorandil on Myocardial Protection in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass, a Retrospective Study

Background

The potential myocardial protective effect of nicorandil (NICD) in patients undergoing percutaneous coronary intervention has been established. However, its efficacy in the context of cardiac surgery remains controversial. The present study aimed to evaluate the myocardial protective effect of perioperative NICD use in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).

Methods

We retrospectively gathered data from patients undergoing cardiac bypass surgery between 12/2018 and 04/2021 in Fuwai Hospital. Subsequently, the patients were divided into two groups, NICD group and non-nicorandil (non-NICD) group. A 1, 3 propensity score matching (PSM) was conducted. The primary outcome was the incidence of myocardial injury. The secondary outcomes included the mechanical ventilation (MV) duration, intensive care unit (ICU) length of stay (LOS), hospital LOS, duration of chest drainage, the drainage volume, the total cost, the incidence of acute kidney injury (AKI), and the incidence of acute liver injury (ALI). Subsequently, we divided the entire population into two distinct subgroups based on their administration of NICD, and performed a comprehensive subgroup analysis.

Results

A total of 2406 patients were ultimately included in the study. After PSM, 250 patients in NICD group and 750 patients in non-NICD group were included in the analysis. Perioperative NICD reduced the incidence of myocardial injury (47.2% versus 38.8%, P=0.025). Our subgroup analysis revealed that preoperative NICD administration not only provided myocardial protection benefits (45.7% vs 35.8%, OR 0.66, 95% CI [0.45-0.97], P=0.041), but also demonstrated statistically significant reduction in ALI, the ICU and hospital LOS, and the duration of chest drainage (all P<0.05).

Conclusion

The perioperative NICD administration may confer myocardial protection in patients undergoing cardiac surgery with CPB. Furthermore, the preoperative utilization of NICD has the potential to mitigate the incidence of postoperative ALI, a reduction in the ICU and hospital LOS, and the duration of chest drainage.

Cytokine Storm Syndrome Triggered by Extracorporeal Membrane Oxygenation in Pediatric Patients

Cytokine storm syndrome (CSS) is a serious and potentially life-threatening condition caused by severe systemic inflammation, immune activation, and a positive feedback loop of cytokine release. Typically triggered by systemic infection, malignancy, monogenic or rheumatic disease, similar patterns of hyper-inflammation have been seen in patients undergoing cardiopulmonary bypass (CPB) and in patients treated with extracorporeal membrane oxygenation (ECMO). Typical treatments used for the prevention and treatment of CPB/ECMO-induced hyper-inflammation have not been shown to be substantially effective. Two patients suffering from ECMO-related CSS were identified by their severe hyper-inflammatory profile and life-threatening sequelae of vasodilatory shock and respiratory failure. Anakinra, an interleukin-1 receptor antagonist, was employed as specific cytokine-directed therapy for the treatment of CSS in these two patients to good effect, with significant improvement in hyper-inflammation and cardiorespiratory status. The use of cytokine-directed therapies in CPB/ECMO-related CSS has great potential to improve the treatment and outcomes of this serious condition.

Post-operative troponin levels and left ventricular function in patients with d-transposition of the great arteries following the arterial switch operation

The aim of this study was to assess the significance of post-operative troponin levels as a surrogate for left ventricular (LV) dysfunction measured by global longitudinal strain (GLS) in patients with dextro-transposition of the great arteries (d-TGA) who undergo an arterial switch operation (ASO), and to explore the LV GLS recovery in the mid-term follow-up period. Seventy-eight neonates were included, of whom 41 had troponin-I measurements and 37 had troponin-T measurements. The primary outcome of LV GLS was assessed and compared with healthy controls at the pre-operative stage and time of discharge, 3 months, 6 months and 12 months of age. Secondary outcomes included deaths or transplantations and other clinical markers such as length of hospital stay. D-TGA patients had worse LV GLS post-operatively compared to age-matched controls (p < 0.01) which improved by 12 months of age (p = 0.53). No association was found between changes in troponin-I or troponin-T levels and LV GLS at the time of discharge (r = 0.4, p = 0.64 and r = -0.5, p = 0.91, respectively). In addition, there were no deaths or transplantations in this cohort over a period of 12 months. LV GLS appears to worsen in the early post-operative period for d-TGA patients who undergo neonatal ASO but this recovers through the first post-operative year. Troponin levels have limited value in predicting early or midterm LV dysfunction and recovery.

microRNA Expression Levels Change in Neonatal Patients During and After Exposure to Cardiopulmonary Bypass

Background The systemic inflammation that occurs after exposure to cardiopulmonary bypass (CPB), which is especially severe in neonatal patients, is associated with poorer outcomes and is not well understood. In order to gain deeper insight into how exposure to bypass activates inflammatory responses in circulating leukocytes, we studied changes in microRNA (miRNA) expression during and after exposure to bypass. miRNAs are small noncoding RNAs that have important roles in modulating protein levels and function of cells. Methods and Results We performed miRNA-sequencing on leukocytes isolated from neonatal patients with CPB (n=5) at 7 time points during the process of CPB, including before the initiation of bypass, during bypass, and at 3 time points during the first 24 hours after weaning from bypass. We identified significant differentially expressed miRNAs using generalized linear regression models, and miRNAs were defined as statistically significant using a false discovery rate-adjusted P<0.05. We identified gene targets of these miRNAs using the TargetScan database and identified significantly enriched biological pathways for these gene targets. We identified 54 miRNAs with differential expression during and after CPB. These miRNAs clustered into 3 groups, including miRNAs that were increased during and after CPB (3 miRNAs), miRNAs that decreased during and after CPB (10 miRNAs), and miRNAs that decreased during CPB but then increased 8 to 24 hours after CPB. A total of 38.9% of the target genes of these miRNAs were significantly differentially expressed in our previous study. miRNAs with altered expression levels are predicted to significantly modulate pathways related to inflammation and signal transduction. Conclusions The unbiased profiling of the miRNA changes that occur in the circulating leukocytes of patients with bypass provides deeper insight into the mechanisms that underpin the systemic inflammatory response that occurs in patients after exposure to CPB. These data will help the development of novel treatments and biomarkers for bypass-associated inflammation.

Uni-ventricular palliation vs. bi-ventricular repair: differential inflammatory response

Background

To examine whether uni-ventricular palliation (UVP) and bi-ventricular repair (BVR) result in a different pattern of systemic inflammatory response to pediatric cardiac surgery with extra-corporeal circulation (ECC).

Methods

In 20 children (median age 39.5 months) undergoing either UVP (n = 12) or BVR (n = 8), plasma levels of the inflammatory cytokines TNF-α, IL-6, IL-10, and IL-12 and of procalcitonin (PCT), were measured before, during and after open cardiac surgery up to postoperative day (POD) 10.

Results

Epidemiologic, operative- and outcome variables were similar in both groups but post-operative central venous pressure that was higher in UVP. In the whole cohort, the inflammatory response was characterized by an early important, significant and parallel increase of IL-6 and IL-10 that reached their peak values either at the end of ECC (IL-10) or 4 h postoperatively (IL-6), respectively and by a significant and parallel decrease of TNF-α and IL-12 levels after connection to ECC, followed by a bi-phasic significant increase with a first peak 4 h after ECC and a second at POD 10, respectively. Patients after UVP showed a shift of the cytokine balance with lower IL-6- (p = 0.01) after connection to ECC, lower early post-operative TNF-α - (p = 0.02) and IL-12- (p = 0.04) concentrations and lower TNF-α/IL-10-ratio (p = 0.03) as compared with patients with BVR. Levels of PCT were similar in both groups.

Conclusions

UVP is associated with an anti-inflammatory shift of the inflammatory response to cardiac surgery that might be related to the particular hemodynamic situation of patients with UVP.

A perspective on the potential detrimental role of inflammation in pig orthotopic heart xenotransplantation

There is a critical shortage of deceased human donor organs for transplantation. The need is perhaps most acute in neonates and infants with life-threatening congenital heart disease, in whom mechanical support devices are largely unsuccessful. If orthotopic (life-supporting) heart transplantation (OHTx) were consistently successful in the genetically engineered pig-to-nonhuman primate (NHP) model, a clinical trial of bridging with a pig heart in such patients might be justified. However, the results of pig OHTx in NHPs have been mixed and largely poor. We hypothesise that a factor is the detrimental effects of the inflammatory response that is known to develop (a) during any surgical procedure that requires cardiopulmonary bypass, and (b) immediately after an NHP recipient is exposed to a pig xenograft. We suggest that the combination of these two inflammatory responses has a direct detrimental effect on pig heart graft function, but also, and possibly of more importance, on recipient baboon pulmonary function, which further impacts survival of the pig heart graft. In addition, the inflammatory response almost certainly adversely impacts the immune response to the graft. If our hypothesis is correct, the potential steps that could be taken to reduce the inflammatory response or its effects (with varying degrees of efficacy) include (a) white blood cell filtration, (b) complement depletion or inactivation, (c) immunosuppressive therapy, (d) high-dose corticosteroid therapy, (e) cytokine/chemokine-targeted therapy, (f) ultrafiltration or CytoSorb hemoperfusion, (g) reduction in the levels of endogenous catecholamines, (h) triiodothyronine therapy and (i) genetic engineering of the organ-source pig. Prevention of the inflammatory response, or attenuation of its effects, by judicious anti-inflammatory therapy may contribute not only to early survival of the recipient of a genetically engineered pig OHTx, but also to improved long-term pig heart graft survival. This would open the possibility of initiating a clinical trial of genetically engineered pig OHTx as a bridge to allotransplantation.

Clinical and Laboratory Predictors for the Development of Low Cardiac Output Syndrome in Infants Undergoing Cardiopulmonary Bypass: A Pilot Study

Cardiac surgery employing cardiopulmonary bypass exposes infants to a high risk of morbidity and mortality. The objective of this study was to assess the utility of clinical and laboratory variables to predict the development of low cardiac output syndrome, a frequent complication following cardiac surgery in infants. We performed a prospective observational study in the pediatric cardiovascular ICU in an academic children’s hospital. Thirty-one patients with congenital heart disease were included. Serum levels of nucleosomes and a panel of 20 cytokines were measured at six time points in the perioperative period. Cardiopulmonary bypass patients were characterized by increased levels of interleukin-10, -6, and -1α upon admission to the ICU compared to non-bypass cardiac patients. Patients developing low cardiac output syndrome endured longer aortic cross-clamp time and required greater inotropic support at 12 h postoperatively compared to bypass patients not developing the condition. Higher preoperative interleukin-10 levels and 24 h postoperative interleukin-8 levels were associated with low cardiac output syndrome. Receiver operating characteristic curve analysis demonstrated a moderate capability of aortic cross-clamp duration to predict low cardiac output syndrome but not IL-8. In conclusion, low cardiac output syndrome was best predicted in our patient population by the surgical metric of aortic cross-clamp duration.

Shear stress associated with cardiopulmonary bypass induces expression of inflammatory cytokines and necroptosis in monocytes

Cardiopulmonary bypass (CPB) is required during most cardiac surgeries. CBP drives systemic inflammation and multiorgan dysfunction that is especially severe in neonatal patients. Limited understanding of molecular mechanisms underlying CPB-associated inflammation presents a significant barrier to improve clinical outcomes. To better understand these clinical issues, we performed mRNA sequencing on total circulating leukocytes from neonatal patients undergoing CPB. Our data identify myeloid cells, particularly monocytes, as the major cell type driving transcriptional responses to CPB. Furthermore, IL-8 and TNF-α were inflammatory cytokines robustly upregulated in leukocytes from both patients and piglets exposed to CPB. To delineate the molecular mechanism, we exposed THP-1 human monocytic cells to CPB-like conditions, including artificial surfaces, high shear stress, and cooling/rewarming. Shear stress was found to drive cytokine upregulation via calcium-dependent signaling pathways. We also observed that a subpopulation of THP-1 cells died via TNF-α-mediated necroptosis, which we hypothesize contributes to post-CPB inflammation. Our study identifies a shear stress-modulated molecular mechanism that drives systemic inflammation in pediatric CPB patients. These are also the first data to our knowledge to demonstrate that shear stress causes necroptosis. Finally, we observe that calcium and TNF-α signaling are potentially novel targets to ameliorate post-CPB inflammation.

Myocardial Expression of Estrogen Receptor-mRNA Is Associated With Lower Markers of Post-operative Organ Damage in Young Patients With Congenital Cardiac Defect

Background: Estrogen receptors (ERs) relate to cardio-protection in adults, but their role in younger patients is not known. We aimed to assess the myocardial expression of ERα- and ERβ- mRNA in young patients with congenital cardiac disease and to analyze their putative protective role. Patients and Methods: Twenty children and young adults (seven females and 13 males) with a median age of 13.8 years (interquartile range: 12.3 years) were enrolled in this prospective study. The myocardial expression of ER-mRNA and genes involved in inflammation, growth, and stress response was assessed by real-time PCR and was correlated to post-operative (po) outcome. Results: ER-mRNA was detected in the myocardium of all patients, independently of gender and age. The expression of ER-mRNA correlated with that of mRNA coding for brain natriuretic peptide and for all cytokines tested. A higher ERα-mRNA expression correlated with lower troponin T concentrations at 24 h po (p = 0.032), higher PaO₂/FiO₂ ratio at 4 h po (p = 0.059), lower fluid retention at 4 h po (p = 0.048), and lower aspartate aminotransferase (AST) levels at 24 h po (p = 0.047). A higher ERβ-mRNA expression was also correlated with lower fluid retention at 24 h po (p = 0.048). Patients in whom the levels of ERα- and ERβ-mRNA were >P50 had lower troponin T (p = 0.003, respectively) and lower AST concentrations at 24 h po (p = 0.043, respectively) than the others. Conclusions: The expression of ERα- and ERβ-mRNA is present in the myocardium of children and young adults with congenital cardiac defect and is associated with lower markers of po organ damage. This suggests that ERs may provide perioperative organ protection in this population.

Extracorporeal life support and systemic inflammation

Extracorporeal life support (ECLS) encompasses a wide range of extracorporeal modalities that offer short- and intermediate-term mechanical support to the failing heart or lung. Apart from the daily use of cardiopulmonary bypass (CPB) in the operating room, there has been a resurgence of interest and utilization of veno-arterial and veno-venous extracorporeal membrane oxygenation (VA- and VV-ECMO, respectively) and extracorporeal carbon dioxide removal (ECCO₂R) in recent years. This might be attributed to the advancement in technology, nonetheless the morbidity and mortality associated with the clinical application of this technology is still significant. The initiation of ECLS triggers a systemic inflammatory response, which involves the activation of the coagulation cascade, complement systems, endothelial cells, leukocytes, and platelets, thus potentially contributing to morbidity and mortality. This is due to the release of cytokines and other biomarkers of inflammation, which have been associated with multiorgan dysfunction. On the other hand, ECLS can be utilized as a therapy to halt the inflammatory response associated with critical illness and ICU therapeutic intervention, such as facilitating ultra-protective mechanical ventilation. In addition to addressing the impact on outcome of the relationship between inflammation and ECLS, two different but complementary pathophysiological perspectives will be developed in this review: ECLS as the cause of inflammation and ECLS as the treatment of inflammation. This framework may be useful in guiding the development of novel therapeutic strategies to improve the outcome of critical illness.

C1 esterase inhibitor in pediatric cardiac surgery with cardiopulmonary bypass plays a vital role in activation of the complement system

Our prospective study was therefore designed to determine which part of the systemic inflammatory response after cardiac operations resulted from Cardiopulmonary bypass (CPB) in neonates and infants. After approval by the human ethical committee of the Gunma Children’s Medical Center (GCMC) and informed consent of the parents, 40 consecutive term congenital heart disease patients aged until 1 year who underwent long CPB time (> 3 h) at surgery were included in the prospective study between January 2012 and December 2014. C1 esterase inhibitor (C1-inh) drug (@Berinert) was generously provided by CSL Behring (King of Prussia, PA). The C1-inh (20 IU/kg) was given intravenously 60 min after CPB. Blood samples for complement factors were obtained before and 48 h after administration of C1-inh. Six patients did not survive and their data were not included. Of 34 patients included, median age was 6.5 months, median body weight was 6050 g, and 16 (47%) were female. According to the Mann–Whitney U test, there were no differences between the two groups concerning demographic and intraoperative data, postoperative chemical data. C1q concentration was only significant lower in patients with C1-inh non-treated group than in patients with C1-inh treated group. But, the consumption of C1q, C3, C4, CH₅₀, and C1-inh in patients with C1-inhibitor non-treated group was observed early postoperatively. There is a significant difference in the values before and after C1-inh treatment between the two groups. The lower value in the C1-inh-treated group is explained by the activation of the classical pathway through the replenishment of complements by C1-inh treatment. This study proposes the administration of C1-inh is an effective therapy to reduce the activation and improve the clinical capillary leak syndrome.

Oxidative Stress and Neonatal Respiratory Extracorporeal Membrane Oxygenation

Oxidative stress is a frequent condition in critically ill patients, especially if exposed to extracorporeal circulation, and it is associated with worse outcomes and increased mortality. The inflammation triggered by the contact of blood with a non-endogenous surface, the use of high volumes of packed red blood cells and platelets transfusion, the risk of hyperoxia and the impairment of antioxidation systems contribute to the increase of reactive oxygen species and the imbalance of the redox system. This is responsible for the increased production of superoxide anion, hydrogen peroxide, hydroxyl radicals, and peroxynitrite resulting in increased lipid peroxidation, protein oxidation, and DNA damage. The understanding of the pathophysiologic mechanisms leading to redox imbalance would pave the way for the future development of preventive approaches. This review provides an overview of the clinical impact of the oxidative stress during neonatal extracorporeal support and concludes with a brief perspective on the current antioxidant strategies, with the aim to focus on the potential oxidative stress-mediated cell damage that has been implicated in both short and long-term outcomes.

Neutralizing IL-6 reduces heart injury by decreasing nerve growth factor precursor in the heart and hypothalamus during rat cardiopulmonary bypass

AIMS

To investigate whether the expression of nerve growth factor precursor (proNGF) changes during cardiopulmonary bypass (CPB) and whether neutralizing interleukin-6 (IL-6) during CPB has cardiac benefits.

MAIN METHODS

Thirty patients undergoing CPB were recruited and their serum proNGF and troponin-I (TNI) were detected. In addition, rats were divided into three groups: CPB group, CPB with cardiac ischemia-reperfusion (IR) group, and a control group. The pre-CPB standard deviation of N-N intervals (SDNN) and post-CPB SDNN were compared. At the end of CPB, nerve peptide Y (NPY), acetylcholinesterase, cell apoptosis, and proNGF protein expression were measured in the heart and hypothalamus. Another rat cohort undergoing CPB was divided into two groups: an anti-IL-6 group with IL-6 antibody and a control group with phosphate buffer solution. At the end of CPB, serum hs-troponin-T and cardiac caspases 3 and 9 were detected. NPY and proNGF in the heart and hypothalamus were detected.

KEY FINDINGS

In patients, serum proNGF increased during CPB, and the concentration was positively correlated with TNI. In rats, cardiac autonomic nervous function was disturbed during CPB. More apoptotic cells and higher levels of proNGF were found in the heart and hypothalamus in the CPB groups than in the control groups. Neutralizing IL-6 was beneficial to lower cardiac injury by decreasing proNGF and apoptosis.

SIGNIFICANCE

CPB induced changes in proNGF in the heart and hypothalamus. Suppressing inflammation attenuated myocardial apoptosis and autonomic nerve function disturbance in CPB rats, likely due in part to regulation of proNGF in the heart and hypothalamus.

Gene expression of cytokines, growth factors and apoptosis regulators in a neonatal model of pulmonary stenosis

BACKGROUND

Right ventricular remodeling due to pulmonary stenosis increases morbidity in children. Its pathophysiology needs to be clarified.

METHODS

Six newborn lambs underwent pulmonary arterial banding, seven sham operation. mRNA encoding for cytokines, growth factors and regulators of apoptosis was sequentially measured in myocardium and blood before and up to 12 weeks postoperatively.

RESULTS

Experimental animals showed hypertrophy and fibrosis of the right ventricular myocardium, myocardial over-expression of CT-1-mRNA and higher blood concentrations of mRNA encoding for VEGF, TGF-β, Bak and BcL-xL than controls, respectively.

CONCLUSION

Neonatal pulmonary stenosis leads to myocardial hypertrophy that is associated with CT-1 gene expression and with activation of growth- and apoptosis pathways in blood cells.

Hybrid closure of atrial septal defect: A modified approach

A 3.5-year-old girl underwent transcatheter closure of patent ductus arteriosus in early infancy during which time her secundum atrial septal defect (ASD) was left alone. When she came for elective closure of ASD, she was found to have bilaterally blocked femoral veins. The defect was successfully closed with an Amplatzer septal occluder (ASO; St. Jude Medical, Plymouth, MN, USA) using a hybrid approach via a sub-mammary mini-thoracotomy incision without using cardiopulmonary bypass. At the end of 1-year follow-up, the child is asymptomatic with device in a stable position without any residual shunt.

Adrenomedullin alterations related to cardiopulmonary bypass in infants with low cardiac output syndrome

BACKGROUND

Low cardiac output syndrome (LCOS) remains a major perioperative complications in infants subjected to open-heart surgery with cardiopulmonary bypass (CPB). The present study investigated whether perioperative blood assessment of a potent vasoactive peptide namely adrenomedullin (AM) can predict the risk of LCOS.

METHODS

We measured AM levels in 48 patients (LCOS: n = 9; controls: n = 39) undergone to open-heart surgery with CPB at five predetermined time points before, during and after the surgery. Clinical, laboratory and perioperative data were analyzed by a multiple logistic regression model.

RESULTS

AM significantly decreased (p < 0.01) during and after the surgical procedure exhibiting a dip at the end of the CPB. Multivariable analysis demonstrated significant correlations among LCOS, AM measured at the end of CPB (p < 0.001), and cooling duration (p < 0.05). AM at 27 pg/L cutoff achieved a sensitivity of 100% and a specificity of 64.1%, while cooling at 11-min cutoff combined a sensitivity of 55.6% and a specificity of 92.3% for LCOS prediction.

CONCLUSIONS

This study suggests that AM can constitute, alone or combined with standard parameters, a promising predictor of LCOS in infants subjected to open-heart surgery with CPB.

Dexamethasone pretreatment provides antiinflammatory and myocardial protection in neonatal arterial switch operation

BACKGROUND

This prospective double-blinded randomized study tested the hypothesis that preoperative treatment with dexamethasone would attenuate inflammatory priming of the myocardium, reduce the systemic inflammatory reaction upon cardiac operation, and provide organ protection in neonates.

METHODS

Twenty neonates (age, 8 to 21 days) with transposition of the great arteries scheduled for arterial switch operation were included. Nine received dexamethasone (1 mg/kg body weight) 4 hours before cardiopulmonary bypass, and 11 received natrium chloride. We studied intramyocardial messenger RNA expression of interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor-α (TNF-α), as well as IL-10 and expression of TNF-α on protein level in right atrial tissue taken before institution of CPB. We measured plasma levels of IL-6, IL-10, lipopolysaccharide binding protein, and cardiac troponin T. Cytokine expression was related to postoperative outcome.

RESULTS

Pretreatment with dexamethasone led to a significant decrease in myocardial expression of IL-6, IL-8, IL-1β, and TNF-α messenger RNA and to a decrease in protein synthesis of TNF-α. Plasma concentrations of IL-6 were significantly lower and those of IL-10 significantly higher in pretreated patients. This was associated with lower cardiac troponin T values and lower dobutamine requirement. Levels of lipopolysaccharide binding protein were significantly higher postoperatively in pretreated neonates.

CONCLUSIONS

Dexamethasone administration before arterial switch operation leads to a shift in the myocardial and systemic cytokine expression profile in neonates with transposition of the great arteries, with downregulation of proinflammatory and upregulation of antiinflammatory cytokines. Lower myocardial cell damage and lower catecholamine requirement suggest myocardial protection in treated patients.

Cardiac function and circulating cytokines after endotoxin exposure in neonatal mice

Complications after cardiac surgery in neonates can occur because of activation of the inflammatory system. This study used lipopolysaccharide (LPS) endotoxin exposure to cause cytokine activation in neonatal mice and examine left ventricular (LV) function and the effects of antioxidant treatment on cytokine levels. Neonatal mice (6 d old) were injected with either 25 mg/kg LPS (n = 13) or PBS (n = 14), and LV function (echocardiography) was measured at 4 h. Plasma levels of TNF-α, IL-4, IL-6, and IL-10 were measured at 30 min, 1, 2, and 4 h after injection (n = 5 mice per group). Effects of pretreatment with N-acetylcysteine (NAC, 50 mg/kg) on cytokine levels were examined at 2 and 4 h after PBS or LPS (n = 5 mice per group). Four hours after LPS, heart rate was increased (434 ± 14 versus 405 ± 14 bpm, p < 0.05). LV end-diastolic dimension and ejection time were reduced with LPS (both p < 0.05). LPS exposure increased plasma TNF-α, IL-6, and IL-10 levels. NAC pretreatment attenuated the increases in TNF-α and IL-6 levels, but augmented IL-10 levels at 2 h post-LPS. LPS exposure altered cardiac performance and activated cytokines in neonatal mice, which may be ameliorated using antioxidants.

Initial Single-Center Experience With Levosimendan Infusion for Perioperative Management of Univentricular Heart With Ductal-Dependent Systemic Circulation

The aim of this study was to evaluate the safety and the efficacy of levosimendan, a novel calcium sensitizer agent, on postoperative hemodynamic and metabolic parameters of neonates affected by single ventricle anatomy. Twenty consecutive neonates scheduled for the Norwood procedure with Blalock Taussig shunt were prospectively enrolled. All patients received an infusion of levosimendan at 0.1 μg/kg/min commencing 24 hours before surgery, and the infusion was continued for 48 hours after surgery. No side effects (intolerance to the drug, hypotension, arrhythmias) were shown. A median inotropic score (IS) of 37 was necessary to maintain a mean arterial pressure between 45 and 50 mm Hg at intensive care unit (ICU) admission: IS was significantly reduced after 72 hours ( P < .05). Brain natriuretic peptide values decreased significantly from 1210 to 459 pg/mL in 72 hours ( P < .05). Median SvO2 increased significantly from 38% to 59% during the evaluated period ( P < .05). Cerebral near-infrared spectroscopy values were close to 40% at ICU admission with a significant stable increase to 50% after 12 hours ( P < .05). Median lactate level was 13 mmol/L at ICU admission but showed a trend to a rapid and significant decrease after 12 hours ( P < .05). Median urine output was surprisingly elevated, always remaining between 5.2 and 6.2 mL/kg/h throughout the postoperative period. Survival rate was 85% at 30 days (17/20 patients) and 75% (15/20) at hospital discharge. Levosimendan infusion in a cohort of neonates with univentricular anatomy was safe and potentially beneficial on postoperative hemodynamic and metabolic parameters.

The relationship between inflammatory activation and clinical outcome after infant cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass (CPB) induces a systemic inflammatory response. The magnitude and consequences in infants remain unclear. We assessed the relationship between inflammatory state and clinical outcomes in infants undergoing CPB.

METHODS

Plasma concentrations of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor α, IL-1β, and C-reactive protein (CRP) were measured pre-CPB and immediately post-CPB, and at 6, 12, and 24 hours post-CPB in infants ≤9 months old. Perioperative clinical data were collected prospectively.

RESULTS

Diagnoses of 93 patients included transposition of the great arteries (40), tetralogy of Fallot (28), ventricular septal defect (21), truncus arteriosus (2), and complete atrioventricular canal (2). The median age was 37 days (range = 2 to 264). Pre-CPB IL-6 and CRP were higher in younger infants but were not associated with postoperative inflammatory mediator concentrations or measured clinical outcomes. IL-6 increased post-CPB (median 3.2 pg/mL pre-CPB, 24.2 post-CPB, 95.4 at 6 hours, and 90.3 at 24 hours; all P < 0.001). CRP increased post-CPB, peaking at 24 hours (median 27.5 at 24 hours, 0.3 pre-CPB; P < 0.001). IL-10 and IL-8 increased immediately post-CPB. After adjusting for age and diagnosis, postoperative IL-6 and IL-8 correlated with intensive care unit length of stay and postoperative blood product administration and, for IL-8, 24-hour lactate.

CONCLUSIONS

Greater preoperative cytokine and CRP production in younger infants did not correlate with postoperative outcomes; correlation between postoperative inflammatory mediator production and clinical course was statistically significant but clinically modest. We conclude that in infants undergoing low-to-moderate-complexity cardiac surgery in a single high-volume center, the contribution of inflammatory mediator production to postoperative morbidity is relatively limited.

Intravenous omega-3, a technique to prevent an excessive innate immune response to cardiac surgery in a rodent gut ischemia model

OBJECTIVES

Neutrophil infiltration of tissues as part of the inflammatory response to cardiac surgery is one of the major mediators of postoperative multiple-organ dysfunction. Omega-3 fatty acids markedly attenuate endothelial cell inflammatory responses, including upregulation of neutrophil adhesion molecules. The efficacy of a clinically safe form of omega-3 to produce this effect in vivo was examined.

METHODS

Rat gut intravital microscopic analysis was used to visualize neutrophil transmigration from the microcirculation into the tissues of the gut. Inflammatory activation was in the form of 30 minutes of ischemia and 90 minutes of reperfusion. Sham, control (0.9% saline infusion over 4 hours), and omega-3 (Omegaven [Fresenius Kabi, Bad Homburg, Germany] infusion over 4 hours) pretreatments were compared.

RESULTS

Ischemia-reperfusion resulted in a 4-fold increase in neutrophil adherence to the endothelium (baseline: 4.3 ± 0.2 vs control group: 19.2 ± 3.5 adherent neutrophils per 100 μm, P < .01), which intravenous omega-3 suppressed (7.8 ± 1.7 adherent neutrophils per 100 μm, P < .01). Omega-3 pretreatment also reduced neutrophil transmigration into the tissues after reperfusion (sham group: 6.3 ± 0.8 vs control group: 13.2 ± 1.4 vs omega-3 group: 9.4 ± 0.9 neutrophils per field, P = .037). Gut tissue levels of the neutrophil-released enzyme myeloperoxidase were similarly markedly reduced with omega-3 pretreatment (sham group: 10.5 ± 1.6 vs control group: 19.0 ± 3.3 vs omega-3 group: 10.1 ± 1.2 U/g, P = .03).

CONCLUSIONS

Four hours' pretreatment with a relatively safe form of intravenous omega-3 suppressed neutrophil adherence and tissue infiltration, resulting in lower levels of the tissue-damaging enzyme myeloperoxidase. This suggests a possible strategy for diminishing postoperative multiple-organ dysfunction.

The effects of normoxic versus hyperoxic cardiopulmonary bypass on oxidative stress and inflammatory response in cyanotic pediatric patients undergoing open cardiac surgery: a randomized controlled trial

OBJECTIVES

This study investigates the effects of controlled reoxygenation cardiopulmonary bypass on oxidative stress, inflammatory response, and organ function in children undergoing repair of cyanotic congenital heart defects.

METHODS

Sixty-seven cyanotic patients (median age 15 months, interquartile range 6-49 months) undergoing corrective cardiac surgery were randomized to receive either controlled normoxic (50-0 mm Hg; n = 35) or hyperoxic (150-180 mm Hg; n = 32) cardiopulmonary bypass. Troponin I and 8-isoprostane, C3a, interleukins 6, 8, and 10, cortisol, protein S100, and alpha-glutamate transferase were measured preoperatively and 10 and 30 minutes after starting bypass, on removal of the aortic crossclamp, and 12 and 24 hours thereafter.

RESULTS

Overall, troponin I and 8-isoprostane levels were lower in the controlled normoxic group (-29%, 95% CI -48% to -3%, P = .03, and -26%, 95% CI -44% to -2%, P = .03, respectively). Protein S100 release was also lower in the normoxic group 10 minutes after starting bypass (-26%, 95% CI -40% to -9%, P = .005) and 10 minutes after aortic crossclamp removal (-23%, 95% CI -38% to -3%, P = .02, respectively), but similar at other time points in the two groups (P >or= .17). The alpha-glutamate transferase release was significantly lower in the normoxic group 10 minutes after aortic crossclamp removal (-28%, 95% CI -44% to -9%, P = .006, respectively) but was similar at other times (P >or= .11). Release of C3a, interleukins 6, 8, and 10, and cortisol was similar in the two groups throughout (P >or= .15).

CONCLUSION

Controlled reoxygenation on starting cardiopulmonary bypass is associated with reduced myocardial damage, oxidative stress, and cerebral and hepatic injury compared with hyperoxic bypass and similar whole body inflammatory and stress response in cyanotic children undergoing open cardiac surgery.

A neutrophil elastase inhibitor, sivelestat, improved respiratory and cardiac function in pediatric cardiovascular surgery with cardiopulmonary bypass

PURPOSE

Several reports indicate that a neutrophil elastase inhibitor, sivelestat, may have prophylactic efficacy against a systemic inflammatory response after cardiovascular surgery with cardiopulmonary bypass (CPB). We evaluated the clinical pulmonary and cardiac effects of sivelestat.

METHODS

We performed a retrospective study of 25 pediatric patients who underwent elective cardiovascular surgery with CPB for ventricular septal defect with pulmonary hypertension. Ten patients received 0.2 mg x kg(-1) x h(-1) sivelestat; the other is patients were the control group. There were no significant differences in demographic characteristics between the two groups. The P(a)O(2)/fractional inspired oxygen (F(I)O(2); P/F) ratio, the respiratory index (RI), and the fractional area change (FAC) of the left ventricle (LV) in the postoperative course were measured.

RESULTS

The P/F ratio was higher in the sivelestat group compared with the control group and there were significant differences between the two groups immediately after weaning form CPB, and at 12 h after weaning from CPB (P < 0.05). The RI was lower in the sivelestat group compared with the control group and there were significant differences between the two groups at immediately after weaning from CPB, and at 6 h and 12 h after CPB (P < 0.05). The FAC of the LV was significantly better in the sivelestat group and there was a significant difference between the two groups on postoperative day (POD) 3 (P < 0.05).

CONCLUSION

We have shown that pediatric patients who underwent cardiovascular surgery with CPB who received sivelestat had a higher P/F ratio, a lower RI, and better FAC of the LV in the postoperative course.

Anti-inflammatory activities of new succinic and maleic derivatives from the fruiting body of Antrodia camphorata

Six new compounds, trans-3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]pyrrolidine-2,5-dione (1), trans-1-hydroxy-3-(4-hydroxyphenyl)-4-isobutylpyrrolidine-2,5-dione (2), cis-3-(4-hydroxyphenyl)-4-isobutyldihydrofuran-2,5-dione (3), 3-(4-hydroxyphenyl)-4-isobutyl-1H-pyrrole-2,5-dione (4), 3-(4-hydroxyphenyl)-4-isobutylfuran-2,5-dione (5), and dimethyl 2-(4-hydroxyphenyl)-3-isobutylmaleate (6), together with one known compound, 3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]furan-2,5-dione (7), were isolated from the fruiting bodies of Antrodia camphorata. The structures of the compounds were elucidated by analysis of their spectroscopic data. To investigate the immunomodulatory potential of the compounds, RAW264.7 macrophage cells were treated with the compounds. Compound 1 significantly increased spontaneous TNF-alpha secretion from unstimulated RAW264.7 cells but suppressed IL-6 production [50% inhibition concentration value (IC50) = 10 microg/mL] in LPS-stimulated cells. Compounds 3, 4, and 6 also suppressed IL-6 production with IC50 values of 17, 18, and 25 microg/mL, respectively, suggesting that these four compounds may have an anti-inflammatory effect on macrophage-mediated responses. Of the six compounds, compound 1 was the most effective, exerting both immunostimulatory and anti-inflammatory effects.

Arterial Switch Operation: Troponin T Does Not Predict Ventilation Requirements

The aim of this study was to assess whether postoperative cardiac troponin T levels could predict ventilation requirements in infants undergoing the arterial switch operation. Cardiac troponin T was measured 6 hours after aortic cross clamping and prior to tracheal extubation in 20 consecutive patients; 10 had simple and 10 had complex (with ventricular septal defect) transposition of the great arteries. The mean plasma troponin T level prior to extubation did not differ significantly in patients who were re-intubated and those who were successfully extubated. The initial cardiac troponin T levels in the complex defect group was significantly higher than in the simple transposition group. There was no correlation between initial cardiac troponin T levels and the duration of mechanical ventilation. There was no difference in mean duration of ventilation between the 2 groups. It was concluded that the postoperative cardiac troponin T level is not a predictor of successful extubation or prolonged artificial ventilation in this subset.

Risk stratification in neonates and infants submitted to cardiac surgery with cardiopulmonary bypass: a multimarker approach combining inflammatory mediators, N-terminal pro-B-type natriuretic peptide and troponin I

Low cardiac output syndrome (LCOS) is a common problem following cardiac surgery with cardiopulmonary bypass (CPB) in neonates and infants, and its early recognition remains a challenging task. We aimed to test whether a multimarker approach combining inflammatory and cardiac markers provides complementary information for prediction of LCOS and death in children submitted to cardiac surgery with CPB. Forty-six children younger than 18 months with congenital heart defects were prospectively enrolled. No intervention was made. Blood samples were collected pre-operatively, during CPB and post-operatively (PO) for measurement of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, cardiac troponin I (cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Clinical data and outcome variables were recorded. Logistic regression was used to identify predictors of LCOS and death. Multivariate logistic regression identified pre-operative NT-proBNP and IL-8 4h PO as independent predictors of LCOS, while cTnI 4h PO and CPB length were independent predictors of death. The use of inflammatory and cardiac markers in combination improved sensitivity, negative predictive value and accuracy of the models. In conclusion, the combined assessment of inflammatory and cardiac biochemical markers can be useful for identifying young children at increased risk for LCOS and death after heart surgery with CPB.

Children undergoing cardiac surgery for complex cardiac defects show imbalance between pro- and anti-thrombotic activity

Introduction

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with the activation of inflammatory mediators that possess prothrombotic activity and could cause postoperative haemostatic disorders. This study was conducted to investigate the effect of cardiac surgery on prothrombotic activity in children undergoing cardiac surgery for complex cardiac defects.

Methods

Eighteen children (ages 3 to 163 months) undergoing univentricular palliation with total cavopulmonary connection (TCPC) (n = 10) or a biventricular repair (n = 8) for complex cardiac defects were studied. Prothrombotic activity was evaluated by measuring plasma levels of prothrombin fragment 1+2 (F1+2), thromboxane B₂ (TxB2), and monocyte chemoattractant protein-1 (MCP-1). Anti-thrombotic activity was evaluated by measuring levels of tissue factor pathway inhibitor (TFPI) before, during, and after cardiac surgery.

Results

In all patients, cardiac surgery was associated with a significant but transient increase of F1+2, TxB2, TFPI, and MCP-1. Maximal values of F1+2, TxB2, and MCP-1 were found at the end of CPB. In contrast, maximal levels of TFPI were observed at the beginning of CPB. Concentrations of F1+2 at the end of CPB correlated negatively with the minimal oesophageal temperature during CPB. Markers of prothrombotic activity returned to preoperative values from the first postoperative day on. Early postoperative TFPI levels were significantly lower and TxB2 levels significantly higher in patients with TCPC than in those with biventricular repair. Thromboembolic events were not observed.

Conclusion

Our data suggest that children with complex cardiac defects undergoing cardiac surgery show profound but transient imbalance between pro- and anti-thrombotic activity, which could lead to thromboembolic complications. These alterations are more important after TCPC than after biventricular repair but seem to be determined mainly by low antithrombin III.

The use of moderate hypothermia during cardiac surgery is associated with repression of tumour necrosis factor-alpha via inhibition of activating protein-1: an experimental study

Introduction

The use of moderate hypothermia during experimental cardiac surgery is associated with decreased expression of tumour necrosis factor (TNF)-α in myocardium and with myocardial protection. In order to identify the cellular mechanisms that lead to that repression, we investigated the effect of hypothermia during cardiac surgery on both main signalling pathways involved in systemic inflammation, namely the nuclear factor-κB (NF-κB) and activating protein-1 pathways.

Method

Twelve female pigs were randomly subjected to standardized cardiopulmonary bypass with moderate hypothermia or normothermia (temperature 28°C and 37°C, respectively; six pigs in each group). Myocardial probes were sampled from the right ventricle before, during and 6 hours after bypass. We detected mRNA encoding TNF-α by competitive RT-PCR and measured protein levels of TNF-α, inducible nitric oxide synthase and cyclo-oxygenase-2 by Western blotting. Finally, we assessed the activation of NF-κB and activating protein-1, as well as phosphorylation of p38 mitogen-activated protein kinase by electrophoretic mobility shift assay with super shift and/or Western blot.

Results

During and after cardiac surgery, animals subjected to hypothermia exhibited lower expression of TNF-α and cyclo-oxygenase-2 but not of inducible nitric oxide synthase. This was associated with lower activation of p38 mitogen-activated protein kinase and of its downstream effector activating protein-1 in hypothermic animals. In contrast, NF-κB activity was no different between groups.

Conclusion

These findings indicate that the repression of TNF-α associated with moderate hypothermia during cardiac surgery is associated with inhibition of the mitogen-activated protein kinase p38/activating protein-1 pathway and not with inhibition of NF-κB. The use of moderate hypothermia during cardiac surgery may mitigate the perioperative systemic inflammatory response and its complications.

Characterizing the Inflammatory Response to Cardiopulmonary Bypass in Children

Cardiopulmonary bypass is known to trigger a global inflammatory response. Age-dependent differences in the inflammatory response, the increased susceptibility to injury of immature organ systems, and the larger extracorporeal circuit to patient size ratio results in greater susceptibility of younger and smaller patients to the damaging effects of cardiopulmonary bypass. In this review the components of the inflammatory response to cardiopulmonary bypass are reviewed with special reference to the pediatric age group, including the age-specific impact on organ systems. In addition the current and evolving strategies to prevent, limit, and treat the inflammatory response to cardiopulmonary bypass in children are examined.

Perioperative serum interleukins in neonates with hypoplastic left-heart syndrome and transposition of the great arteries

OBJECTIVE

The primary study objective was to examine the impact of diagnosis on the inflammatory response in neonates with congenital heart disease undergoing cardiac surgery. The secondary objective was to study the impact of the inflammatory response on postoperative outcome in these neonates.

DESIGN

Observational study.

SETTING

Tertiary care children's hospital heart center.

PATIENTS

Neonates with hypoplastic left-heart syndrome (HLHS) undergoing stage I repair and patients with transposition of the great arteries (TGA) undergoing arterial switch operation.

MEASUREMENTS AND MAIN RESULTS

There were 24 neonates with HLHS and 21 neonates with TGA. Serum samples to measure interleukin (IL)-6 and -10 were obtained before and after CPB at 1, 3, 6, and 24 hours postoperatively. Time to extubation, intensive care unit (ICU) length of stay, and peritoneal fluid drainage were compared between the groups. Serum IL-6 and IL-10 concentrations increased after CPB when compared to the preoperative concentration. Preoperative concentrations of IL-6 were significantly elevated in the HLHS group (HLHS: 32 [21.1, 69.6] pg/mL v TGA: 7.2 [3.6, 22.5] pg/mL [median, 25th, and 75th percentile], p = 0.003) and remained elevated immediately after CPB, and at 3 and 6 hours postoperatively. The IL-10 to IL-6 ratio was lower in the HLHS group preoperatively and immediately after CPB. ICU length of stay was significantly longer in the HLHS group (TGA 4 [3-6] days v HLHS 6 [5-8] days, p = 0.031). Mortality in the HLHS group (4/24) was associated with significantly higher IL-6 postoperatively (IL-6 immediately postoperatively: HLHS survivors 59.9 [34.3, 65.7] pg/mL v nonsurvivors 98.7 [94.4, 104.5] pg/mL, p < 0.011).

CONCLUSIONS

All neonates with TGA or HLHS have a significant inflammatory response after CPB. Neonates with HLHS have evidence of an activated inflammatory response before CPB, which remains significant in the postoperative period. Accelerated interleukin expression and an abnormal cytokine balance correlate with longer time to extubation, longer ICU length of stay, and increased peritoneal fluid volume.

Interleukin-10, T-lymphocytes, and cardiac output in children after ventricular septal defect repair: a pilot study

OBJECTIVE

To evaluate the acute inflammatory response and cardiac output in children after surgery for ventricular septal defect.

DESIGN AND SETTING

Prospective, observational study in a level III multidisciplinary neonatal and pediatric intensive care unit.

PATIENTS

Ten children undergoing open-heart surgery for ventricular septal defect.

INTERVENTIONS

All children received methylprednisolone (30 mg/kg) in cardiopulmonary bypass (CPB) prime.

MEASUREMENTS AND RESULTS

Before and after cardiopulmonary bypass, plasma interleukin-10 and tumor necrosis factor alpha were measured by enzyme-linked immunosorbent assay, and lymphocyte subsets in peripheral blood by flow cytometry. Relative values (post-/pre-CPB) of interleukin-10 and tumor necrosis factor alpha were calculated. The cardiac index (CI) was measured continuously beat-to-beat by a pulse contour analysis (PiCCO). Children above the cutoff value (median cardiac index value 3.0 l min(-1) m(-2)) were designated as the normal CI group and those below this value as the low CI group. In the normal CI group the relative values of interleukin-10 remained almost seven times higher than pre-CPB values at 24 h while in the low CI group they decreased almost to pre-CPB values. Furthermore, the normal CI group, but not the low CI group, exhibited more than threefold decrease in T-lymphocytes (lymphocyte T-cells, T-helper cells, and cytotoxic T-cells) 24 h after CPB.

CONCLUSIONS

Children operated on for ventricular septal defect developed either a normal or low CI. The higher relative values of interleukin-10 and lower counts of lymphocyte T-cells, T-helper and cytotoxic T-cells differentiated the normal CI group from the low CI group at 24 h after cardiopulmonary bypass.

Hypothermic Low-Flow Cardiopulmonary Bypass Impairs Pulmonary and Right Ventricular Function More Than Circulatory Arrest

BACKGROUND

Hypothermic circulatory arrest (HCA) is used during surgical treatment of certain congenital heart defects. The possibility of ischemic neurologic injury associated with HCA has led some surgeons to use low-flow cardiopulmonary bypass (CPB) during the hypothermic interval (hypothermic low flow [HLF]). This study investigates the inflammatory response to HCA and HLF, and reports the consequences of this response on pulmonary and right ventricular function.

METHODS

Piglets (3.1 to 6.6 kg) were cooled to 16 degrees to 18 degrees C using CPB, and randomized: HCA for 60 minutes (n = 7), or HLF (50 cc.kg(-1).min(-1)) for 60 minutes (n = 6). The piglets were rewarmed to 36 degrees C and weaned from CPB. Serum tumor necrosis factor-alpha (TNF-alpha) concentration, percent lung water, and pulmonary and cardiac function were measured before and after CPB.

RESULTS

Tumor necrosis factor-alpha was higher after HLF (2,990.5 +/- 884.5 pg/mL), compared with HCA (347.6 +/- 89.2 pg/mL; p = 0.03). The percent lung water was higher after HLF (84.8% +/- 0.3%) than HCA (82.0% +/- 0.4%; p < 0.001). The alveolar to arterial oxygen gradient was worse after HLF (457 +/- 42 mm Hg) than HCA (285.8 +/- 45 mm Hg; p = 0.02). Pulmonary vascular resistance was greater after HLF (36.08 +/- 8.28 mm Hg.mL(-1).m(-2).min(-1)) than HCA (14.55 +/- 3.46 mm Hg. mL(-1).m(-2).min(-1); p = 0.049). The right ventricular pressure waveform peak derivative, corrected for systolic pulmonary artery pressure, was lower after HLF (14.1 +/- 1.4 sec(-1)), than HCA (23.8 +/- 2.7 sec(-1); p = 0.01).

CONCLUSIONS

Hypothermic low flow extends exposure to CPB, and is associated with an increased inflammatory response compared with HCA. The greater inflammatory response after HLF may result in substantial nonneurologic morbidity in the postoperative period, demonstrated by pulmonary and right ventricular dysfunction. Interventions that attenuate the inflammatory response to CPB may prevent pulmonary and right ventricular dysfunction after HLF.

Myocardial dysfunction in meningococcal septic shock

PURPOSE OF REVIEW

The underlying pathophysiology of sepsis has long been disputed. Systemic vasodilatation is important in the development of shock and, in septic critically ill adults who have been volume resuscitated, the systemic pressure is often low and the cardiac output high. In septic children however, and especially in those with meningococcal septic shock, poor cardiac output as a consequence of depressed myocardial function seems to be important, often being the cause of death in these patients. There is much evidence for disturbance of myocardial performance, yet despite the literature, there is still no consensus on how best to manage this complication of meningococcal disease.

RECENT FINDINGS

Many mediators have been proposed as the cause of the reduced myocardial performance, most recently interleukin-6 has emerged as a possible candidate involved in the pathophysiology of the myocardial dysfunction. Cardiac troponin I has been shown to be a marker of myocardial injury and may be used to monitor left ventricular function. Newer treatments emerging to manage the dysfunction include reports of success with phosphodiesterase inhibitors.

SUMMARY

Accepting that myocardial dysfunction may be an important cause of the shock state in overwhelming meningococcal disease, the approach to management may need to be tailored appropriately. Although presently there is no targeted treatment, it may be that therapy focused on inhibiting or antagonising interleukin-6 will be helpful in the future. Regardless of the importance of myocardial depression, fluid resuscitation remains a cornerstone in the management of severe meningococcal disease.

Effect of dexamethasone on postoperative cardiac troponin T production in pediatric cardiac surgery

OBJECTIVE

Pediatric cardiac surgery is associated with a temporary rise in cardiac troponin T (cTnT) during the postoperative period. We examined whether dexamethasone given before cardiopulmonary bypass has myocardial protective effects as assessed by the postoperative production of cTnT.

DESIGN AND SETTING

Prospective randomized interventional study in the pediatric intensive care unit in a university hospital.

INTERVENTIONS

Patients were randomly allocated to act as controls or receive a single dose of dexamethasone (1 mg/kg) during induction of anesthesia.

MEASUREMENTS AND RESULTS

cTnT was measured four times postoperatively: immediately after admission to the pediatric intensive care unit (PICU) and 8, 15, and 24 h thereafter. The two groups had similar mean cTnT concentrations on PICU admission: those receiving dexamethasone 1.85 ng/ml (1.55-2.15) and those not receiving it 2 ng/ml (95% confidence interval 1.56-2.51). Concentrations of cTnT 8 h after admission to the PICU differed significantly after 8 h: 1.99 ng/ml (1.53-2.45) in those receiving dexamethasone and 3.08 ng/ml (2.46-3.69) in those not receiving it. After subgroup statistical analysis differences between the two groups remained significant only at 8 h, not those after 15 or 24 h.

CONCLUSIONS

The use of dexamethasone (1 mg/kg) before cardiopulmonary bypass is associated with a brief but significant reduction in postoperative cTnT production. The clinical significance of this effect is unclear.

Administration of steroids in pediatric cardiac surgery: impact on clinical outcome and systemic inflammatory response

Cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response. Pre-bypass steroid administration may modulate the inflammatory response, resulting in improved postoperative recovery. We performed a prospective study in the departments of cardiovascular surgery and pediatric intensive care medicine of two university hospitals that included 50 infants who underwent heart surgery. Patients received either prednisolone (30 mg/kg) added to the priming solution of the cardiopulmonary bypass circuit (steroid group) or no steroids (nonsteroid group). Clinical outcome parameters include therapy with inotropic drugs, oxygenation, blood lactate, glucose, and creatinine, and laboratory parameters of inflammation include leukocytes, C-reactive protein, and interleukin-8. Postoperative recovery (e.g., the number, dosage, and duration of inotropic drugs as well as oxygenation) was similar in patients treated with or without steroids when corrected for the type of cardiac surgery performed. After CPB, there was an inflammatory reaction, especially in patients with a long CPB time. Postoperative plasma levels of interleukin-8 were correlated with the duration of CPB time (r = 0.62, p < 0.001). Administration of steroids had no significant impact on the laboratory parameters of inflammation. Administration of prednisolone into the priming solution of the CPB circuit had no measurable influence on postoperative recovery and did not suppress the inflammatory response.

Randomized Comparison Between Normothermic and Hypothermic Cardiopulmonary Bypass in Pediatric Open-Heart Surgery

BACKGROUND

The purpose of this study is to investigate the effect of cardiopulmonary bypass (CPB) temperature on myocardial reperfusion injury, oxidative stress, and inflammatory response in pediatric open heart surgery.

METHODS

Fifty-nine children (median age 78 months; interquartile range, 39-130) undergoing correction of simple congenital heart defects were randomized to receive either hypothermic (28 degrees C) or normothermic (35-37 degrees C) CPB. Troponin I and 8-isoprostane, complement activation C3a, interleukin (IL) -6, -8, and -10, were measured preoperatively, on removal of the aortic cross clamp, 30 minutes, 6, and 24 hours postoperatively.

RESULTS

Troponin I and 8-isoprostane were significantly raised, compared to baseline, in both groups, and remained high at 24 hours. Overall, troponin I and 8-isoprostane levels were 37% and 84% higher in the hypothermic than in the normothermic group, respectively (ratio 1.37, 95% CI 1.00 to 1.88, p = 0.053 and 1.84, 95% CI 1.22 to 2.78, p = 0.0045, respectively), and there was no evidence to suggest the treatment effect changed significantly over the time points measured (p = 0.63). Adjusting for aortic cross-clamp time reduced the effect of hypothermia on troponin (p = 0.18) but not on 8-isoprostane levels (p = 0.0028). The C3a, IL-6, and IL-8 release was similar in the two groups. The IL-10 release between the groups changed over time (p = 0.059) and examining differences at individual time points highlighted a statistically significant difference at the end of the cross-clamp time (p = 0.0079).

CONCLUSIONS

Normothermic CPB is associated with reduced oxidative stress compared with hypothermic CPB, and similar myocardial reperfusion injury and whole body inflammatory response, in children undergoing open heart surgery. A larger study with clinical outcomes as primary end points is now warranted.

Does cardiac surgery in newborn infants compromise blood cell reactivity to endotoxin?

Introduction

Neonatal cardiac surgery is associated with a systemic inflammatory reaction that might compromise the reactivity of blood cells against an inflammatory stimulus. Our prospective study was aimed at testing this hypothesis.

Methods

We investigated 17 newborn infants with transposition of the great arteries undergoing arterial switch operation. Ex vivo production of the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), of the regulator of the acute-phase response IL-6, and of the natural anti-inflammatory cytokine IL-10 were measured by enzyme-linked immunosorbent assay in the cell culture supernatant after whole blood stimulation by the endotoxin lipopolysaccharide before, 5 and 10 days after the operation. Results were analyzed with respect to postoperative morbidity.

Results

The ex vivo production of TNF-α and IL-6 was significantly decreased (P < 0.001 and P < 0.002, respectively), whereas ex vivo production of IL-10 tended to be lower 5 days after the operation in comparison with preoperative values (P < 0.1). Ex vivo production of all cytokines reached preoperative values 10 days after cardiac surgery. Preoperative ex vivo production of IL-6 was inversely correlated with the postoperative oxygenation index 4 hours and 24 hours after the operation (P < 0.02). In contrast, postoperative ex vivo production of cytokines did not correlate with postoperative morbidity.

Conclusion

Our results show that cardiac surgery in newborn infants is associated with a transient but significant decrease in the ex vivo production of the pro-inflammatory cytokines TNF-α and IL-6 together with a less pronounced decrease in IL-10 production. This might indicate a transient postoperative anti-inflammatory shift of the cytokine balance in this age group. Our results suggest that higher preoperative ex vivo production of IL-6 is associated with a higher risk for postoperative pulmonary dysfunction.

Effect of three different anaesthetic agents on the postoperative production of cardiac troponin T in paediatric cardiac surgery

BACKGROUND

Paediatric cardiac surgery is associated with some degree of myocardial injury. Ischaemic preconditioning (IP) has been investigated widely in the adult population. Volatile agents have been shown to simulate IP providing extra protection to the myocardium during adult cardiopulmonary bypass (CPB) while propofol seems to act through different mechanisms. IP has not been investigated in the paediatric population to the same extent. Cardiac troponin T (cTnT) is a reliable marker of myocardial injury in neonates and children. We have investigated the relationship between three anaesthetic agents, midazolam, propofol, and sevoflurane, and postoperative production of cTnT.

METHODS

Ninety patients undergoing repair of congenital heart defect with CPB were investigated in a prospective randomized study. cTnT was measured four times during the first 24 h following admission to the paediatric intensive care unit. Other variables measured included arterial blood gases, lactate, fluid balance, use of inotropic drugs, PaO2/FiO2 ratio and ventilator hours.

RESULTS

cTnT was elevated in all three groups throughout the study period. The differences between the three groups were not statistically significant. Eight hours after admission to the intensive care unit cTnT concentrations tended to be higher in the midazolam group [mean (95% confidence intervals)]; 2.7 (1.9-3.5) ng ml(-1). Patients receiving a propofol-based anaesthesia had similar concentrations 2.6 (1.7-3.5) ng ml(-1) while those receiving sevoflurane tended to have a lower cTnT production 1.7 (1.3-2.2) ng ml(-1).

CONCLUSIONS

Midazolam, propofol, and sevoflurane appear to provide equal myocardial protection in paediatric cardiac surgery when using cTnT as a marker of myocardial damage.

Different Proinflammatory Cytokine Serum Pattern in Neonate Patients Undergoing Open Heart Surgery. Relevance of IL-8

The purpose of this work was to investigate the clinical significance of serum levels of proinflammatory cytokines in pediatric patients undergoing cardiopulmonary bypass. We divided the patients in two groups: 8 neonates, and 19 non-newborn children. IL-1beta, IL-6, IL-8, and TNF serum levels were quantified before sternotomy, at admission to the PICU (30 min postoperatively), 24 h after the onset of surgery and 3 days after the operation. Surgical cardiac stress elicits significant increments of IL-6, IL-8 and TNF serum concentrations in both neonates and non-neonates, regardless of their preoperative clinical condition. However, in newborns the magnitude of the proinflammatory cytokine increments was, in particular with IL-8, remarkably greater than in older children. Moreover, neonate and non-neonate patients showed clearly disparate patterns of serum concentrations over time of both IL-8 and TNF. There was a marked relationship between IL-8 levels and postoperative morbidity, evaluated by pulmonary dysfunction, days on inotropic support and days of PICU stay in both neonates and non-neonates patients. In contrast, we found no relationship between serum levels of IL-6 and TNF and postoperative clinical data. Newborn and non-newborn patients undergoing cardiopulmonary bypass exhibit dissimilar patterns of proinflammatory cytokines. IL-8 might be implicated in the multiorganic dysfunction related to cardiopulmonary bypass in pediatric patients.

Role of interleukin 6 in myocardial dysfunction of meningococcal septic shock

BACKGROUND

Myocardial failure has a central role in the complex pathophysiology of septic shock and contributes to organ failure and death. During the sepsis-induced inflammatory process, specific factors are released that depress myocardial contractile function. We aimed to identify these mediators of myocardial depression in meningococcal septic shock.

METHODS

We combined gene-expression profiling with protein and cellular methods to identify a serum factor causing cardiac dysfunction in meningococcal septic shock. We identified genes that were significantly upregulated in blood after exposure to meningococci. We then selected for further analysis those genes whose protein products had properties of a myocardial depressant factor--specifically a 12-25 kDa heat-stable protein that is released into serum shortly after onset of meningococcal infection.

FINDINGS

We identified 174 significantly upregulated genes in meningococcus-infected blood: six encoded proteins that were of the predicted size and had characteristics of a myocardial depressant factor. Of these, interleukin 6 caused significant myocardial depression in vitro. Removal of interleukin 6 from serum samples of patients with meningococcaemia and from supernatants of inflammatory cells stimulated by meningococci in vitro abolished the negative inotropic activity. Furthermore, concentrations in serum of interleukin 6 strongly predicted degree of myocardial dysfunction and severity of disease in children with meningococcal septic shock.

INTERPRETATION

Interleukin 6 is a mediator of myocardial depression in meningococcal disease. This cytokine and its downstream mediators could be a target for future treatment strategies.

Critical care in cardiovascular medicine

The field of cardiac intensive care is rapidly evolving with nearly simultaneous advances in surgical techniques and adjunctive therapies, respiratory care, intensive care technology and monitoring, pharmacologic research and development, and computing and electronics. The focus of care has now shifted toward reducing morbidity and improving "quality of life" while the survival of infants and children with congenital heart defects, including those with univentricular hearts has dramatically improved during the last three decades. Despite these advances, there remains a predictable fall in cardiac output after cardiopulmonary bypass. This article focuses on early identification and aggressive treatment of the low cardiac output syndrome peculiar to these patients. The authors also briefly review the recent advances in the treatment of pulmonary hypertension, mechanical support, and neurologic surveillance after cardiac surgery.

Intramyocardial synthesis of pro- and anti-inflammatory cytokines in infants with congenital cardiac defects

OBJECTIVES

We sought to test the hypothesis that cytokines would be expressed in the myocardium of infants with congenital cardiac defects and to identify the signaling pathways involved.

BACKGROUND

Mechanical stress upregulates pro-inflammatory cytokines in the myocardium.

METHODS

Fifteen infants with tetralogy of Fallot (TOF) (n = 7) or with ventricular septal defects (VSDs) (n = 8) were investigated. Concentrations of pro- and anti-inflammatory cytokines and of the inducible nitric oxide synthase (iNOS) were measured by enzyme-linked immunosorbent assay and/or Western blotting in the right ventricular myocardium taken during cardiac surgery. Activation of the nuclear factor-kappa-B (NF-kappa-B) and p38 mitogen-activated protein kinase (MAPK) pathways was assessed by electrophoretic mobility shift assay with supershift and/or Western blotting, respectively.

RESULTS

The pro-inflammatory cytokines tumor necrosis factor (TNF)-alpha, interleukin (IL)-1-beta, and IL-6 and the anti-inflammatory cytokine IL-10 were detected in the myocardium of all patients. Concentrations of the pro-inflammatory cytokines and also of phosphorylated p38 MAPK were higher in patients with TOF than in those with VSD and correlated with the degree of pressure overload of the right ventricle. Levels of phosphorylated I-kappa-B-alpha, iNOS, and IL-10 were similar in patients with TOF and in those with VSD.

CONCLUSIONS

Our results show intramyocardial synthesis of pro-inflammatory cytokines in infants with congenital cardiac defects. This is associated with activation of both the NF-kappa-B and p38 MAPK pathways. The latter could be particularly important for the transduction of mechanical signals in the infant's myocardium. Synthesis of IL-10 indicates an intramyocardial anti-inflammatory potential in this age group.