Neutrophil activation during cardiopulmonary bypass in paediatric and adult patients

Plasma S100A8/A9 heterodimer is an early prognostic marker of acute kidney injury associated with cardiac surgery

AIM

We investigated whether plasma levels of the inflammation marker S100A8/A9, could predict acute kidney injury (AKI) onset in patients undergoing cardiac surgery necessitating cardiopulmonary bypass (CPB).

PATIENTS & METHODS

Plasma levels of S100A8/A9 and other neutrophil cytosolic proteins were measured in 39 patients pre- and immediately post-CPB.

RESULTS

All markers increased significantly post-CPB with S100A8/A9, S100A12 and myeloperoxidase levels significantly higher in patients who developed AKI within 7 days. S100A8/A9 had good prognostic utility for AKI, with an area under the receiver operating characteristic curve of 0.81 (95% CI: 0.676-0.949) and a cut-off value of 10.6 μg/ml (85.7% sensitivity and 75% specificity) irrespective of age.

CONCLUSION

Plasma S100A8/A9 levels immediately after cardiac surgery, can predict onset of AKI, irrespective of age.

Leucocyte filtration of residual heart-lung machine blood in children undergoing congenital heart surgery

Cardiopulmonary bypass (CPB) leads to a generalized inflammatory reaction, resulting in increased postoperative leucocyte counts and decreased pulmonary function. In adults, removal of leucocytes from the residual heart - lung machine blood after CPB improved postoperative oxygenation. In children, however, the clinical effects of leucocyte filtration of the residual heart - lung machine blood are unknown. Therefore, we measured postoperative leucocyte counts and arterial blood oxygenation in children undergoing congenital cardiac surgery in a randomized prospective study. Anaesthesia and CPB were standardized. After CPB, the residual heart-lung machine blood was collected as usual. In a group of 25 children, this blood was filtered with a leucocyte depletion filter before transfusion. A control group of 25 children received this blood unfiltered. We found that the postoperative leucocyte counts were significantly lower in the filter group than in the control group ( p=0.02, repeated measurements ANOVA). This difference reached a maximum on the second postoperative day (12.9×109/L filter versus 15.9×109/L control, p=0.02, Student’s t-test). Values for the arterial blood oxygenation on the first postoperative day were not different between the two groups (15.5±1 kPa filter versus 14.6±1.3 kPa control, p=0.57, Student’s t-test). We conclude that leucocyte filtration of the residual heart-lung machine blood reduced systemic leucocyte counts, but did not improve arterial blood oxygenation in children after congenital heart surgery.

Transfusion protocol for implantation and explantation of cardiac devices in an academic medical center

Few reports in the literature describe the transfusion support needed for implantation and explantation of cardiac assist devices. Because such devices are frequently used at this institution, we have established a protocol to support these patients. We reviewed blood bank records to document the usage of blood components in all patients on cardiac assist devices from 1989 to 2005 (n = 215). The data were separated into components given at the time of implantation and explantation of the device. Implantation data on 214 patients showed the mean use as follows: red blood cells (RBC), 5.7 U; platelets (PLT), 2.4 U; fresh frozen plasma (FFP), 7.5 U; and cryoprecipitate, 0 U. Explantation data on 134 patients showed a mean use as follows: RBC, 7.7 U; PLT, 2.4 U; FFP, 9.9 U; and cryoprecipitate, 3.7 U. Our protocol for the preparation of blood components for implantation and explantation of a cardiac device is, implantation: RBC, 4 U; PLT, 1 U; FFP, 6 U; explantation: RBC, 8 U; PLT, 2 U; FFP, 8 U. Our data do not support the need for preparation of cryoprecipitate before implantation or explantation.

Levels of inflammatory markers in the blood processed by autotransfusion devices during cardiac surgery associated with cardiopulmonary bypass circuit

Intraoperative blood salvage devices allowing a reinfusion of red blood cells (RBCs) after processing of shed blood and stagnant blood in the mediastinal cavity are more and more used to reduce homologous blood requirements in cardiac surgery with cardiopulmonary bypass (CPB). As the proinflammatory activity of the shed blood also contributes to morbidity during CPB, we conducted a prospective study in order to examine the quality of autologous blood before and after processing with five different devices [BRAT2, Sequestra, Compact Advanced, Cell Saver 5 (CS5), Continuous Autologous Transfusion System (CATS)]. All systems resulted in an excellent haemoconcentration, ranging from 53.7% (Compact) to 68.9% (CATS). The concentrations and elimination rates of several inflammatory markers [IL-1beta, IL-2, IL-8, TNFalpha, myeloperoxidase (MPO), elastase] were examined. Except for the Sequestra, an important increase in concentration of IL-1beta (between 30% and 220%) has been observed after processing with each device. In contrast, the attenuation rate of IL-6 and TNFalpha (95%) was optimal for all investigated blood salvages systems. Regarding IL-8, only the CATS and CS5 systems were able to attenuate this biological parameter with an excellent efficacy. The rate of attenuation in MPO and elastase, as markers of leukocyte activation, was higher than 80% for all devices. In conclusion, the different RBC washing systems tested in this study resulted in a significant attenuation of the inflammatory response. Increased levels of IL-1beta after processing remained, however, unclear. According to the type of protocol, based on inlet haematocrit, fill and wash speeds, and wash volumes, small variations in reducing the inflammatory response have been observed from one device to another.

Neutrophils and platelets accumulate in the heart, lungs, and kidneys after cardiopulmonary bypass in neonatal pigs

OBJECTIVE

Cardiac surgery with cardiopulmonary bypass elicits a systemic inflammatory response. An exaggerated response is associated with organ dysfunction and increased morbidity and mortality.

DESIGN

The aim of the present study was to investigate whether the cardiopulmonary bypass procedure in itself results in accumulation of isotope-labeled platelets, polymorphonuclear neutrophils, and fibrinogen at organ levels in neonatal pigs and to monitor changes in organ function.

SETTING

Pediatric cardiopulmonary bypass setup with 60 mins of aortic cross-clamp time and 120 mins of hypothermic cardiopulmonary bypass time.

SUBJECTS

Thirty piglets were allocated to sternotomy alone (sham group, n = 15) or to sternotomy and cardiopulmonary bypass (n = 15).

MEASUREMENTS AND MAIN RESULTS

Isotope-labeled autologous polymorphonuclear neutrophils, platelets, and commercially available fibrinogen were infused, and the specific accumulation at organ level was measured in a gamma counter 4 hrs after termination of cardiopulmonary bypass. Concomitant changes in oxygenation index and cardiac output were registered. Animals exposed to cardiopulmonary bypass showed a significantly higher technetium-99m-polymorphonuclear neutrophil accumulation in the lungs and kidneys, whereas indium-111-platelets accumulated in the heart and kidneys compared with the sham group. There was a significantly larger increase in oxygenation index and significantly larger decrease in cardiac output between the pre- and postcardiopulmonary bypass period in the cardiopulmonary bypass group compared with the sham group.

CONCLUSIONS

The cardiopulmonary bypass procedure without cardiac surgery elicits organ dysfunction in terms of impaired respiratory and hemodynamic function. Platelets and polymorphonuclear neutrophils were entrapped in the heart, lungs, and kidneys of cardiopulmonary bypass animals, indicating that cell accumulation may contribute to the developing organ dysfunction.

Inflammation After Cardiopulmonary Bypass: Therapy for the Postpump Syndrome

Cardiopulmonary bypass (CPB) is used in most, but not all, complex heart operations. CPB is associated with a systemic inflammatory response in adults and children. Many materials-dependent (exposure of blood to non- physiologic surfaces and conditions) and materials-in dependent (surgical trauma, ischemia-perfusion to the organs, changes in body temperature, and release of endotoxin) factors during CPB have been implicated in the etiology of this complex response. The mechanisms involved may include complement activation, release of cytokines, leukocyte activation with expression of ad hesion molecules, and production of various vasoactive and immunoactive substances. Postpump inflamma tion may lead to postoperative complications and may result in respiratory failure, renal dysfunction, bleeding disorders, neurologic dysfunction, altered liver func tion, and ultimately multiple organ failure. Significant efforts are being made to decrease the generation and effects of postpump inflammation. Interventions to this end have included avoiding CPB when possible, im proving the biocompatibility of the involved mechani cal devices, and administering medications that main tain cellular integrity. This article provides an overview of the etiology, pathophysiology, and treatment of postpump inflammation. Perhaps with additional in sight into this syndrome, CPB can be made a safer and more efficacious modality of cardiorespiratory support. Copyright© 2001 by W.B. Saunders Company.

Anti-inflammatory effects of 17beta-estradiol pretreatment in men after coronary artery surgery

OBJECTIVE

To investigate the anti-inflammatory and hemodynamic effects of 17beta-estradiol in men undergoing elective coronary artery bypass graft surgery (CABG).

DESIGN

Prospective, randomized, controlled.

SETTING

Operating room and intensive care unit in a university hospital.

PARTICIPANTS

Twenty-one men undergoing primary, elective CABG surgery.

INTERVENTION

17beta-estradiol, 2mg, was given orally twice in 14 hours before the operation.

MEASUREMENTS AND MAIN RESULTS

Leukocyte counts, plasma myeloperoxidase, tumor necrosis factor-alpha, interleukin (IL)-6, IL-8, and IL-10 were measured perioperatively. Leukocyte counts were lower in the 17beta-estradiol group than in controls at 6 hours (11.4 +/- 2.0 hours v 15.5 +/- 4.7 hours x 10(9)/L) and 20 hours (11.6 +/- 1.9 hours v 13.6 +/- 2.5 hours x 10(9)/L) after reperfusion (p = 0.03). The release of myeloperoxidase was lower in the 17beta-estradiol group than in controls (5 minutes; 634.4 +/- 213.1 microg/mL v 773.1 +/- 209.3 microg/mL; 4 hours, 305.0 +/- 108.0 microg/mL v 441.3 +/- 191.6 microg/mL; p = 0.02). Systemic vascular resistance index was lower just after cardiopulmonary bypass, and cardiac index was higher postoperatively in the 17beta-estradiol group as compared with controls.

CONCLUSION

Pretreatment with 17beta-estradiol can limit leukocyte activation in men after CABG surgery.

The systemic inflammatory response after cardiac surgery with cardiopulmonary bypass in children

Paediatric cardiac surgery often requires cardiopulmonary bypass (CPB) during the surgical intervention. CPB is known to elicit a systemic inflammatory response with activation of the complement and coagulation systems, stimulation of cytokine production, cellular entrapment in organs, neutrophil activation with degranulation, platelet activation, and endothelial dysfunction. These changes are associated with a risk of postoperative organ dysfunction and increased morbidity and mortality in the postoperative period. Clinical studies have concentrated on measurement of inflammatory markers and mediators in peripheral blood, where the systemic inflammatory response in the paediatric cardiac patient seems to be different from the adult case. Looking at the organ level, experimental studies have the advantage of providing information contributing to a better understanding of the pathological events that may lead to the deteriorated organ function. This review focuses on the systemic inflammatory response after cardiac surgery with CPB in children and experimental CPB models.

Cardiopulmonary bypass elicits a pro- and anti-inflammatory cytokine response and impaired neutrophil chemotaxis in neonatal pigs

BACKGROUND

Cardiopulmonary bypass (CPB) induces a systemic inflammatory response and organ dysfunction, especially in children. Plasma concentration of inflammatory markers are increased in response to the trauma of cardiac surgery and CPB. The aim of the present study was to investigate whether the CPB procedure in itself elicits increased levels of inflammatory markers in neonatal pigs.

METHODS

The inflammatory response was measured in piglets undergoing sternotomy alone (sham group, n=13) or sternotomy and CPB (n=14). Inflammatory mediators were measured at baseline and at fixed time-points during and after CPB. IL-8, IL-10 and TNF-alpha levels and C-reactive protein (CRP) concentrations were measured in plasma samples. Polymorphonuclear neutrophils (PMN) chemotaxis was measured ex vivo, and CD-18 expression using an immunofluorescence technique.

RESULTS

Immediately after the CPB procedure increased IL-8 levels were found in the CPB group, but not in sham operated animals (P=0.005). Simultaneously, a marked IL-10 response was measured in the CPB group. Concurrently, PMN chemotaxis decreased in CPB animals but not in the sham group (P=0.04). CD-18 expression and CRP levels were not significantly different between groups and TNF-alpha showed no changes in either group. The chemotactic response did not correlate with plasma IL-8 or IL-10, nor with CD-18 expression.

CONCLUSION

The CPB procedure elicited a systemic inflammatory response in terms of significantly elevated plasma levels of IL-8 and IL-10. Furthermore, a temporary and simultaneous decrease in PMN chemotaxis was observed immediately after CPB.

Single automated donor plateletpheresis increases the plasma level of proinflammatory cytokine tumor necrosis factor-alpha which does not associate with endothelial release markers von Willebrand factor and fibronectin

The effect of plateletpheresis on endothelium, which has strong effects on blood coagulation, fibrinolysis and platelet function, is not known. Activation of leukocytes and subsequent generation of proinflammatory cytokines during the extracorporeal circulation may activate the endothelium. To test this hypothesis we measured plasma levels of tumor necrosis factor (TNF)-alpha as a prototype of the proinflammatory cytokines, and von Willebrand factor (vWF) and fibronectin as endothelial release/damage markers before and after a single plateletpheresis procedure on an intermittent-flow machine Haemonetics MCS 3p in 17 healthy donors. We found a significant increase in median plasma level of TNF-alpha following plateletpheresis (3.5 vs 26.5 pg/ml, P=0.02). Such increases in vWF and fibronectin were not observed. The increase in plasma TNF-alpha indicates that a single plateletpheresis procedure causes leukocyte activation which does not seemingly impair endothelial cell function. The relation of plateletpheresis-induced proinflammatory cytokine release to some adverse effects observed in both donors and recipients, and the effect of repeated plateletpheresis on endothelium deserve further studies.

Heparin-coated cardiopulmonary bypass circuit: clinical effects in pediatric cardiac surgery

OBJECTIVES

Heparin-coated cardiopulmonary bypass (CPB) circuits have been reported to reduce complement activation and the inflammatory response associated with CPB. We retrospectively compared patients utilizing heparin-coated perfusion circuits with those using noncoated circuits to determine the clinical effects of the different circuits in pediatric cardiac surgery.

METHODS

Between July 1995 and July 1997, 203 patients weighing < 10 kg underwent cardiac surgery, 153 patients using heparin-coated bypass circuits and 50 patients using noncoated circuits. The 50 patients operated on with the noncoated circuit (Group N) were matched to 100 patients operated on with coated circuits (Group H) in age, weight, and type of procedure. Urine output during bypass, blood products used after bypass, postoperative ventilation days, hospital stay, morbidity, and mortality were compared between these groups.

RESULTS

Body weight, perfusion time, and procedure time were not different between the two groups. Urine output during bypass was notably greater in Group H than in Group N (11.3 +/- 10.5 mL/kg per hour vs 4.8 +/- 3.1 mL/kg per hour, respectively, p < 0.0001). Postoperative mechanical ventilation markedly decreased in Group H (Group H vs N = 2.8 +/- 2.7 days vs 5.1 +/- 7.5 days, respectively, p < 0.05). Red blood cell usage, hospital stay, morbidity, and mortality were not statistically different, although there was a tendency toward decreased transfusion of red cell and platelets in Group H (Group H vs N = 61.2 +/- 121.1 mL/kg vs 102.0 +/- 176.7 mL/kg, respectively, in red cell, p = 0.15; and Group H vs N = 7.9 +/- 13.7 mL/kg vs 13.2 +/- 24.5 mL/kg, respectively, in platelets, p = 0.16).

CONCLUSIONS

Patients operated on with the use of heparin-coated circuits had increased urine output during bypass and required less time postoperatively on the ventilator. These results suggest a reduction in the acute inflammatory response, capillary leakage, and overall systemic edema. We now routinely use coated circuits on all pediatric pump cases.

Comparison of Sarns 3M heparin bonded to Duraflo II and control circuits in a porcine model: macro- and microanalysis of thrombi accumulation in circuit arterial filters

Heparin-bonded perfusion circuits have been reported to reduce the thrombus formation during various levels of systemic heparinization. The goal of this study was to compare the efficacy of thrombo-resistance of the Sarns 3M heparin-bonded circuit to Baxter Duraflo II and untreated control in a porcine model. Fifteen Yorkshire pigs (60-65 kg) were anesthetized, heparinized with 3000 IU, intravenously (i.v.) and surgically cannulated with an internal jugular outflow and a femoral vein inflow. All circuits consisted of a 22-Fr venous cannula, centrifugal pump, arterial filter, an 18-Fr cannula for return and connected with equal lengths of 3/8" polyvinyl chloride tubing. The flows were maintained at 2.0 l/min for 4 h. Thrombus formation in filter samples were morphometrically analyzed through macro-densitometry, light microscopy, and scanning electron microscopy (SEM). Our findings revealed that the 3M circuit had significantly less gross thrombus (p < 0.001), 66% and 84% less microscopic thrombi and fivefold less SEM-measured aggregates (p = 0.03) compared to the Duraflo II and uncoated groups. This study demonstrated that the 3M heparin-bonded circuit had significantly reduced the formation of micro- and macro-thrombi in the minimally heparinized pig model compared to the Duraflo II and untreated control circuits.

Effect of cardiopulmonary bypass and heparin on plasma levels of Lp(a) and Apo(a) fragments

Fragments of apolipoprotein(a) [apo(a)], the distinctive glycoprotein of lipoprotein(a) [Lp(a)], are present in human plasma and urine and have been implicated in the development of atherosclerosis. The mechanism responsible for the generation of apo(a) fragments in vivo is poorly understood. In this study, we examined the plasma levels of Lp(a) and apo(a) fragments [or free apo(a)] and urinary apo(a) in 15 subjects who underwent cardiac surgery necessitating cardiopulmonary bypass. We also measured the plasma concentration and activity of polymorphonuclear elastase, an Lp(a)-cleaving enzyme in vitro, and plasma levels of C-reactive protein. Despite a marked activation of polymorphonuclear cells and a pronounced inflammatory response, as documented by an 8-fold and a 35-fold increase in plasma levels of polymorphonuclear elastase and C-reactive protein, respectively, the proportion of plasma free apo(a) to Lp(a) and urinary excretion of apo(a) remained unchanged over a 7-day period after surgery, and polymorphonuclear elastase activity remained undetectable in plasma. No fragmentation of apo(a) was observed ex vivo in plasma samples collected before and after surgery. These data indicate that in this model, apo(a) is not fragmented in plasma and are consistent with the hypothesis that apo(a) fragments result from a constitutively active tissue mechanism that is not modified by cardiac surgery with cardiopulmonary bypass.

Heparin-coated bypass circuits: effects on inflammatory response in pediatric cardiac operations

BACKGROUND

This study was designed to investigate whether clinical signs of the inflammatory response in pediatric cardiac patients are reduced by heparin-coated cardiopulmonary bypass circuits and how this could be explained by differences in the pathophysiologic mechanisms involved.

METHODS

In a randomized, prospective study 19 patients underwent cardiopulmonary bypass either with Carmeda BioActive Surface bypass circuits (n = 9) or with identical noncoated circuits (control, n = 10). Clinical parameters were recorded during the first 48 hours after the start of operation. Blood samples for determination of terminal complement complex, soluble form of E-selectin, and beta-thromboglobulin were obtained perioperatively up to 24 hours after operation.

RESULTS

All clinical and inflammatory mediators showed a tendency in favor of the group with heparin-coated circuits. When analyzed on a point-by-point basis there were significant differences in postoperative central body temperature, soluble E-selectin levels, and beta-thromboglobulin levels (all p < 0.05).

CONCLUSIONS

These data suggest that the use of heparin-coated cardiopulmonary bypass offers clinical benefit and tends to reduce the release of inflammatory mediators.

Effect of collection and preprocessing methods on neutrophil elastase plasma concentrations

OBJECTIVES

Elevated plasma levels of the elastase alpha 1-proteinase inhibitor complex (E-alpha 1 PI) have been proposed as a marker of bacterial infection and neutrophil activation. Liberation of elastase from neutrophils after collection of blood may cause falsely elevated results. Collection methods have not been validated for critically ill neonates and children. We evaluated the influence of preanalytical methods on E-alpha 1 PI results including the recommended collection into EDTA tubes.

DESIGN AND METHODS

First, we compared varying acceleration speeds and centrifugation times. Centrifugation at 1550 g for 3 min resulted in reliable preparation of leukocyte free plasma. Second, we evaluated all collection tubes under consideration for absorption of E-alpha 1 PI. Finally, 12 sets of samples from healthy adults and 42 sets obtained from critically ill neonates and children were distributed into the various sampling tubes. Samples were centrifuged within 15 min of collection and analyzed with a new turbidimetric assay adapted to routine laboratory analyzers.

RESULTS

One of the two tubes containing a plasma-cell separation gel absorbed 22.1% of the E-alpha 1 PI content. In the remaining tubes without absorption of E-alpha 1 PI no differences were observed for samples from healthy adult patients. However, in samples from critically ill neonates or children, significantly higher results were obtained for plain Li-heparin tubes (mean = 183 micrograms/L), EDTA tubes (mean = 93 micrograms/L), and citrate tubes (mean = 88.5 micrograms/L) than for the Li-hep tube with cell-plasma separation gel and no absorption of E-alpha 1 PI (mean = 62.4 micrograms/L, p < 0.01).

CONCLUSION

Contrary to healthy adults, E-alpha 1 PI results in plasma samples from critically ill neonates and children depend on the type of collection tube.