Methylprednisolone inhibits increase of interleukin 8 and 6 during open heart surgery

Prophylactic corticosteroids for cardiopulmonary bypass in adult cardiac surgery

BACKGROUND

Cardiac surgery triggers a strong inflammatory reaction, which carries significant clinical consequences. Corticosteroids have been suggested as a potential perioperative strategy to reduce inflammation and help prevent postoperative complications. However, the safety and effectiveness of perioperative corticosteroid use in adult cardiac surgery is uncertain. This is an update of the 2011 review with 18 studies added.

OBJECTIVES

Primary objective: to estimate the effects of prophylactic corticosteroid use in adults undergoing cardiac surgery with cardiopulmonary bypass on the: - co-primary endpoints of mortality, myocardial complications, and pulmonary complications; and - secondary outcomes including atrial fibrillation, infection, organ injury, known complications of steroid therapy, prolonged mechanical ventilation, prolonged postoperative stay, and cost-effectiveness.

SECONDARY OBJECTIVE

to explore the role of characteristics of the study cohort and specific features of the intervention in determining the treatment effects via a series of prespecified subgroup analyses.

SEARCH METHODS

We used standard, extensive Cochrane search methods to identify randomised studies assessing the effect of corticosteroids in adult cardiac surgery. The latest searches were performed on 14 October 2022.

SELECTION CRITERIA

We included randomised controlled trials in adults (over 18 years, either with a diagnosis of coronary artery disease or cardiac valve disease, or who were candidates for cardiac surgery with the use of cardiopulmonary bypass), comparing corticosteroids with no treatments. There were no restrictions with respect to length of the follow-up period. All selected studies qualified for pooling of results for one or more endpoints.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were all-cause mortality, and cardiac and pulmonary complications. Secondary outcomes were infectious complications, gastrointestinal bleeding, occurrence of new post-surgery atrial fibrillation, re-thoracotomy for bleeding, neurological complications, renal failure, inotropic support, postoperative bleeding, mechanical ventilation time, length of stays in the intensive care unit (ICU) and hospital, patient quality of life, and cost-effectiveness. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

This updated review includes 72 randomised trials with 17,282 participants (all 72 trials with 16,962 participants were included in data synthesis). Four trials (6%) were considered at low risk of bias in all the domains. The median age of participants included in the studies was 62.9 years. Study populations consisted mainly (89%) of low-risk, first-time coronary artery bypass grafting (CABG) or valve surgery. The use of perioperative corticosteroids may result in little to no difference in all-cause mortality (risk with corticosteroids: 25 to 36 per 1000 versus 33 per 1000 with placebo or no treatment; risk ratio (RR) 0.90, 95% confidence interval (CI) 0.75 to 1.07; 25 studies, 14,940 participants; low-certainty evidence). Corticosteroids may increase the risk of myocardial complications (68 to 86 per 1000) compared with placebo or no treatment (66 per 1000; RR 1.16, 95% CI 1.04 to 1.31; 25 studies, 14,766 participants; low-certainty evidence), and may reduce the risk of pulmonary complications (risk with corticosteroids: 61 to 77 per 1000 versus 78 per 1000 with placebo/no treatment; RR 0.88, 0.78 to 0.99; 18 studies, 13,549 participants; low-certainty evidence). Analyses of secondary endpoints showed that corticosteroids may reduce the incidence of infectious complications (risk with corticosteroids: 94 to 113 per 1000 versus 123 per 1000 with placebo/no treatment; RR 0.84, 95% CI 0.76 to 0.92; 28 studies, 14,771 participants; low-certainty evidence). Corticosteroids may result in little to no difference in incidence of gastrointestinal bleeding (risk with corticosteroids: 9 to 17 per 1000 versus 10 per 1000 with placebo/no treatment; RR 1.21, 95% CI 0.87 to 1.67; 6 studies, 12,533 participants; low-certainty evidence) and renal failure (risk with corticosteroids: 23 to 35 per 1000 versus 34 per 1000 with placebo/no treatment; RR 0.84, 95% CI 0.69 to 1.02; 13 studies, 12,799; low-certainty evidence). Corticosteroids may reduce the length of hospital stay, but the evidence is very uncertain (-0.5 days, 0.97 to 0.04 fewer days of length of hospital stay compared with placebo/no treatment; 25 studies, 1841 participants; very low-certainty evidence). The results from the two largest trials included in the review possibly skew the overall findings from the meta-analysis.

AUTHORS' CONCLUSIONS

A systematic review of trials evaluating the organ protective effects of corticosteroids in cardiac surgery demonstrated little or no treatment effect on mortality, gastrointestinal bleeding, and renal failure. There were opposing treatment effects on cardiac and pulmonary complications, with evidence that corticosteroids may increase cardiac complications but reduce pulmonary complications; however, the level of certainty for these estimates was low. There were minor benefits from corticosteroid therapy for infectious complications, but the evidence on hospital length of stay was very uncertain. The inconsistent treatment effects across different outcomes and the limited data on high-risk groups reduced the applicability of the findings. Further research should explore the role of these drugs in specific, vulnerable cohorts.

Renal and Cerebral Hypoxia and Inflammation During Cardiopulmonary Bypass

Cardiac surgery-associated acute kidney injury and brain injury remain common despite ongoing efforts to improve both the equipment and procedures deployed during cardiopulmonary bypass (CPB). The pathophysiology of injury of the kidney and brain during CPB is not completely understood. Nevertheless, renal (particularly in the medulla) and cerebral hypoxia and inflammation likely play critical roles. Multiple practical factors, including depth and mode of anesthesia, hemodilution, pump flow, and arterial pressure can influence oxygenation of the brain and kidney during CPB. Critically, these factors may have differential effects on these two vital organs. Systemic inflammatory pathways are activated during CPB through activation of the complement system, coagulation pathways, leukocytes, and the release of inflammatory cytokines. Local inflammation in the brain and kidney may be aggravated by ischemia (and thus hypoxia) and reperfusion (and thus oxidative stress) and activation of resident and infiltrating inflammatory cells. Various strategies, including manipulating perfusion conditions and administration of pharmacotherapies, could potentially be deployed to avoid or attenuate hypoxia and inflammation during CPB. Regarding manipulating perfusion conditions, based on experimental and clinical data, increasing standard pump flow and arterial pressure during CPB appears to offer the best hope to avoid hypoxia and injury, at least in the kidney. Pharmacological approaches, including use of anti-inflammatory agents such as dexmedetomidine and erythropoietin, have shown promise in preclinical models but have not been adequately tested in human trials. However, evidence for beneficial effects of corticosteroids on renal and neurological outcomes is lacking. © 2021 American Physiological Society. Compr Physiol 11:1-36, 2021.

Population Pharmacokinetic/Pharmacodynamic Modeling of Methylprednisolone in Neonates Undergoing Cardiopulmonary Bypass

Methylprednisolone is used in neonates to modulate cardiopulmonary bypass (CPB)–induced inflammation, but optimal dosing and exposure are unknown. We used plasma methylprednisolone and interleukin (IL)‐6 and IL‐10 concentrations from neonates enrolled in a randomized trial comparing one vs. two doses of methylprednisolone to develop indirect response population pharmacokinetic/pharmacodynamic models characterizing the exposure–response relationships. We applied the models to simulate methylprednisolone dosages resulting in the desired IL‐6 and ‐10 exposures, known mediators of CPB‐induced inflammation. A total of 64 neonates (median weight 3.2 kg, range 2.2–4.3) contributed 290 plasma methylprednisolone concentrations (range 1.07–12,700 ng/mL) and IL‐6 (0–681 pg/mL) and IL‐10 (0.1–1125 pg/mL). Methylprednisolone plasma exposure following a single 10 mg/kg intravenous dose inhibited IL‐6 and stimulated IL‐10 production when compared with placebo. Higher (30 mg/kg) or more frequent (twice) dosing did not confer additional benefit. Clinical efficacy studies are needed to evaluate the effect of optimized dosing on outcomes.

Effect of low-dose dexamethasone on extra vascular lung water in patients following on-pump elective primary coronary artery bypass graft surgery

Background

The primary objective was to compare the effect of a low-dose dexamethasone as against a saline placebo on extravascular lung water index (EVLWI) in patients undergoing elective primary coronary artery bypass surgery. The secondary endpoints were to assess the effect of dexamethasone on other volumetric parameters (pulmonary vascular permeability index, global end diastolic volume index, and intrathoracic blood volume index), Vasoactive Inotrope Scores, hemodynamic parameters and serum osmolality in both groups.

Settings and Design

Prospective observational study performed at a single tertiary cardiac care center.

Materials and Methods

Twenty patients were randomized to receive either dexamethasone (steroid group, n = 10) or placebo (nonsteroid group, n = 10) twice before the institution of cardiopulmonary bypass (CPB). EVLWI and other volumetric parameters were obtained with the help of VolumeView™ Combo Kit connected to EV 1000 clinical platform at predetermined intervals. Hemodynamic parameters, vasoactive-inotropic Scores, hematocrit values were recorded at the predetermined time intervals. Baseline and 1^st postoperative day serum osmolality values were also obtained.

Results

The two groups were evenly matched in terms of demographic and CPB data. Intra- and inter-group comparison of the baseline EVLWI including other volumetric and hemodynamic parameters with those recorded at subsequent intervals revealed no statistical difference and was similar. Generalized estimating equation model was obtained to compare the changes between the groups over the entire study period which showed that on an average the changes between the steroid and nonsteroid group in terms of all volumetric parameters were not statistically significant.

Conclusions

There were no beneficial effects of low-dose dexamethasone on EVLWI or other volumetric parameters in patients subjected to on-pump primary coronary bypass surgery. Hemodynamic parameters were also not affected. Probably, the advanced hemodynamic monitoring aided in optimal fluid management in the nonsteroidal group impacting EVLW accumulation.

The inflammatory response to cardiopulmonary bypass: a therapeutic overview

The demographic of cardiac surgery patients continues to evolve to include older, sicker candidates, all the while maintaining an expectation of excellent outcomes. These latter results can only be achieved by the parallel advancement and re-examination of the technology of cardiopulmonary bypass (CPB); the key tool used daily by surgical teams worldwide. In this review, we will provide an overview of integrated therapeutic strategies that can be utilized to minimize the complex and myriad changes related to inflammation after CPB with the understanding that this may abrogate the detrimental end-organ and systemic effects of blood activation. Therapeutic strategies specifically related to the technology can be classified into those targeting biomaterial dependent or independent processes. The former can be addressed by the utilization of currently available biocompatible surfaces such as with heparin-coated circuits, phosphorylcholine-coated circuits (‘biomembrane mimicry’) and circuits composed of copolymers containing surface-modifying additives. The most important strategies related to biomaterial independent activation include the modification of techniques related to cardiotomy blood management and blood filtration. Finally, all of these strategies must be integrated and tailored with complementary pharmacologic agents such as aprotinin and steroids to optimize anti-inflammatory synergism. Only if we are armed with a comprehensive knowledge of the molecular and cellular basis for these strategies will we be able to continue to evolve our treatment in parallel with our patients to achieve these goals.

Minor Infection Encouraged by Steroid Administration during Cardiac Surgery

The aim of this study was to investigate whether steroid administration would increase the risk of postoperative infection. Sixty adults who underwent elective cardiac surgery under cardiopulmonary bypass were prospectively randomized into two groups. Thirty-one patients received hydrocortisone (50 mg·kg−1) before and after cardiopulmonary bypass, the other 29 served as controls. Various hemodynamic and pulmonary measurements were obtained perioperatively, and the white blood cell counts and levels of C-reactive protein were checked up to the 14th postoperative day. Steroid administration did not have any favorable effects during the perioperative period. Re-administration of antibiotics was needed in 7 patients (22.6%) after the 7th postoperative day in the steroid group, and in 3 (10.3%) in the control group. The peak white cell counts and C-reactive protein levels after the 7th postoperative day were significantly higher in the steroid group. Steroid administration offered no clinical benefit to patients undergoing cardiac surgery with cardiopulmonary bypass, and it may encourage minor infections in the late postoperative period.

Hidrocortisona reduz as concentrações séricas dos biomarcadores inflamatórios séricos em pacientes submetidos a endarterectomia de carótida

ResumoContextoA hidrocortisona pode reduzir a concentração dos biomarcadores inflamatórios séricos e teciduais.ObjetivoAnalisar a atividade inflamatória da proteína C-reativa ultrassensível (PCR-US), do fator de necrose tumoral (FNT)-alfa e do fator de crescimento do endotélio vascular (FCEV) séricos e teciduais, mediante administração intraoperatória de hidrocortisona, após endarterectomia de artéria carótida (EAC).MétodoVinte e dois pacientes foram divididos em Grupo Controle (5 assintomáticos e 6 sintomáticos) – não foi administrada hidrocortisona – e Grupo 1 (4 assintomáticos e 7 sintomáticos) – foram administrados 500 mg intravenoso de hidrocortisona. O PCR-US, o FNT-alfa e o FCEV séricos foram dosados no pré-operatório e em 1 hora, 6 horas e 24 horas após a EAC. Na placa carotídea, mensuramos os níveis de FNT-alfa e FCEV.ResultadosO grupo 1 exibiu menor concentração sérica de FNT-alfa em 1 hora (p=0,031), 6 horas (p=0,015) e 24 horas (p=0,017) após a EAC, e menor concentração de FCEV em 1 hora (p=0,006) e 6 horas (p=0,005) após a EAC, em relação ao grupo controle. Os pacientes sintomáticos do grupo 1 exibiram menor concentração de FNT-alfa em 1 hora e 6 horas após a EAC, e menor concentração de FCEV em 1 hora após a EAC, em relação ao grupo controle. Não houve diferença estatística entre as concentrações teciduais de FNT-alfa e FCEV entre o grupo controle e o grupo 1.ConclusãoA hidrocortisona reduz as concentrações séricas pós-operatórias de FNT-alfa e FCEV, em especial nos sintomáticos; porém, não reduz os níveis teciduais destes biomarcadores.

Hydrocortisone supresses inflammatory activity of metalloproteinase-8 in carotid plaque

Objective

Matrix metalloproteinases are inflammatory biomarkers involved in carotid plaque instability. Our objective was to analyze the inflammatory activity of plasma and carotid plaque MMP-8 and MMP-9 after intravenous administration of hydrocortisone.

Methods

The study included 22 patients with stenosis ≥ 70% in the carotid artery (11 symptomatic and 11 asymptomatic) who underwent carotid endarterectomy. The patients were divided into two groups: Control Group - hydrocortisone was not administered, and Group 1 - 500 mg intravenous hydrocortisone was administered during anesthetic induction. Plasma levels of MMP-8 and MMP-9 were measured preoperatively (24 hours before carotid endarterectomy) and at 1 hour, 6 hours and 24 hours after carotid endarterectomy. In carotid plaque, tissue levels of MMP-8 and MMP-9 were measured.

Results

Group 1 showed increased serum levels of MMP- 8 (994.28 pg/ml and 408.54 pg/ml, respectively; P=0.045) and MMP-9 (106,656.34 and 42,807.69 respectively; P=0.014) at 1 hour after carotid endarterectomy compared to the control group. Symptomatic patients in Group 1 exhibited lower tissue concentration of MMP-8 in comparison to the control group (143.89 pg/ml and 1317.36 respectively; P=0.003). There was a correlation between preoperative MMP-9 levels and tissue concentrations of MMP-8 (P=0.042) and MMP-9 (P=0.019) between symptomatic patients in the control group.

Conclusion

Hydrocortisone reduces the concentration of MMP- 8 in carotid plaque, especially in symptomatic patients. There was an association between systemic and tissue inflammation.

Rationale and design of the steroids in cardiac surgery trial

BACKGROUND

Steroids may improve outcomes in high-risk patients undergoing cardiac surgery with the use of cardiopulmonary bypass (CBP). There is a need\ for a large randomized controlled trial to clarify the effect of steroids in such patients.

METHODS

We plan to randomize 7,500 patients with elevated European System for Cardiac Operative Risk Evaluation who are undergoing cardiac surgery with the use of CBP to methylprednisolone or placebo. The first coprimary outcome is 30-day all-cause mortality, and the most second coprimary outcome is a composite of death, MI, stroke, renal failure, or respiratory failure within 30 days. Other outcomes include a composite of MI or mortality at 30 days, new onset atrial fibrillation, bleeding and transfusion requirements, length of intensive care unit stay and hospital stay, infection, stroke, wound complications, gastrointestinal complications, delirium, postoperative insulin use and peak blood glucose, and all-cause mortality at 6 months.

RESULTS

As of October 22, 2013, 7,034 patients have been recruited into SIRS in 82 centers from 18 countries. Patient's mean age is 67.3 years, and 60.4% are male. The average European System for Cardiac Operative Risk Evaluation is 7.0 with 22.1% having an isolated coronary artery bypass graft procedure, and 66.1% having a valve procedure.

CONCLUSIONS

SIRS will lead to a better understanding of the safety and efficacy of prophylactic steroids for cardiac surgery requiring CBP.

Prophylactic corticosteroids for cardiopulmonary bypass in adults

BACKGROUND

High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, however, remains controversial, as no trials are available that have been sufficiently powered to draw conclusions on their effect on major clinical outcomes.

OBJECTIVES

The objective of this meta-analysis was to estimate the effect of prophylactic corticosteroids in cardiac surgery on mortality, cardiac and pulmonary complications.

SEARCH STRATEGY

Major medical databases (CENTRAL, MEDLINE, EMBASE, CINAHL and Web of Science) were systematically searched for randomised studies assessing the effect of corticosteroids in adult cardiac surgery. Database were searched for the full period covered, up to December 2009. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials comparing corticosteroid treatment to either placebo treatment or no treatment in adult cardiac surgery were selected. There were no restrictions with respect to length of the follow-up period. All selected studies qualified for pooling of results for one or more end-points.

DATA COLLECTION AND ANALYSIS

The processes of searching and selection for inclusion eligibility were performed independently by two authors. Also, quality assessment and data-extraction of selected studies were independently performed by two authors. The primary endpoints were mortality, cardiac and pulmonary complications. The main effect measure was the Peto odds ratio comparing corticosteroids to no treatment/placebo.

MAIN RESULTS

Fifty-four randomised studies, mostly of limited quality, were included. Altogether, 3615 patients were included in these studies. The pooled odds ratio for mortality was 1.12 (95% CI 0.65 to 1.92), showing no mortality reduction in patients treated with corticosteroids. The odds ratios for myocardial and pulmonary complications were 0.95, (95% CI 0.57 to 1.60) and 0.83 (95% CI 0.49 to 1.40), respectively. The use of a random effects model did not substantially influence study results. Analyses of secondary endpoints showed a reduction of atrial fibrillation and an increase in gastrointestinal bleeding in the corticosteroids group.

AUTHORS' CONCLUSIONS

This meta-analysis showed no beneficial effect of corticosteroid use on mortality, cardiac and pulmonary complications in cardiac surgery patients.

Protective effects of steroids in cardiac surgery: a meta-analysis of randomized double-blind trials

OBJECTIVE

Cardiac surgery and cardiopulmonary bypass (CPB) induce an acute inflammatory response contributing to postoperative morbidity. The use of steroids as anti-inflammatory agents in surgery using CPB has been tested in many trials and has been shown to have good anti-inflammatory effects but no clear clinical advantages for the lack of an adequately powered sample size. The aim of this study was to evaluate the effects of steroid treatment on mortality and morbidity after cardiac surgery.

DESIGN

A systematic meta-analysis of randomized double-blind trials (RDBs).

SETTING

A university hospital.

PARTICIPANTS

Adult patients who underwent cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

A trial search was performed through PubMed and Cochrane databases from 1966 to January 2009. Among 104 clinical trials reviewed, 31 RDB trials (1,974 patients) were considered suitable to be analyzed. A quality assessment of the trials was performed using the Jadad score. The types of steroid used in these trials were methylprednisolone (51.4%), dexamethasone (34.3%), hydrocortisone (5.7%), prednisolone (2.9%), or a combination of methylprednisolone and dexamethasone (5.7%). Steroid prophylaxis provided a protective effect preventing postoperative atrial fibrillation (odds ratio = 0.56; confidence interval [CI] 0.44-0.72, p < 0.0001), reducing postoperative blood loss (mean difference = -204.2 mL; CI from -287.4 to -121 mL; p < 0.0001), and reducing intensive care unit (mean difference = -6.6 hours; CI from -10.5 to -2.7 hours, p = 0.0007) and overall hospital stay (mean difference = -0.8 days; CI from -1.4 to -0.2 days, p = 0.01). Steroid prophylaxis had no effect on postoperative mortality, mechanical ventilation duration, re-exploration for bleeding, and postoperative infection.

CONCLUSIONS

A systematic review of RDB trials reveals that steroid prophylaxis may reduce morbidity after cardiac surgery and does not increase the risk of postoperative infections.

Effect of ulinastatin on cytokine reaction during gastrectomy

Background

Inflammation plays an important role in the postoperative morbidity of organs, which is related to the activation of pro-inflammatory and anti-inflammatory cytokines. Ulinastatin (Urinary trypsin inhibitor, UTI) is a serine protease inhibitor found in human urine or serum that inhibits the activation of human leukocyte elastase. This study examined the effect of UTI on the inflammation response in patients undergoing a gastrectomy.

Methods

Thirty patients scheduled to undergo a gastrectomy were divided into two groups as follows: Control group (untreated, n = 15) and UTI group (100,000 units of UTI were continuously injected intravenously for 2 hours, n = 15). Arterial blood was sampled before surgery (T0), 10 minutes after its onset (T1), at its end (T2), and 1 hour after surgery (T3) to measure the level of cytokines.

Results

Both the control and treatment groups had higher interleukin (IL)-6 levels at T2 and T3 than T0, and the level increased with time. However, the increase was smaller in the treatment group. The IL-8 levels were not activated significantly in any of the groups.

Conclusions

UTI inhibits the secretion of IL-6, which is an inflammatory cytokine produced after a gastrectomy. This shows that UTI can decrease the inflammation reaction caused by surgical stress.

The efficacy and dosage effect of corticosteroids for the prevention of atrial fibrillation after cardiac surgery: a systematic review

BACKGROUND

Atrial fibrillation (AF) complicates up to 60% of patients after cardiac surgery. Current prophylactic measures are inadequate. Corticosteroids down-regulate activation of the proinflammatory response (including C-reactive protein) after cardiopulmonary bypass and have been suggested to reduce the risk of postoperative AF.

OBJECTIVE

The goal of this meta-analysis was to determine (i) the efficacy of corticosteroids in preventing AF after cardiac surgery and (ii) the impact of different dosage regimens on this outcome.

DATA SOURCES

Sources included MEDLINE, Embase, the Cochrane Database of Systematic Reviews, and citation review of relevant primary and review articles.

STUDY SELECTION

The study identified prospective, randomized, placebo-controlled clinical trials that evaluated the role of corticosteroids in preventing AF after cardiac surgery.

DATA EXTRACTION

Data were abstracted on study design, study size, type of cardiac surgery, corticosteroid dosage regimen, and the incidence of AF in the first 72 hours after surgery. The total cumulated dose of corticosteroid was classified as low dose (<200 mg/d), moderate dose (200-1000 mg/d), high dose (1001-10,000 mg/d), and very high dose (10,000 mg/d) of hydrocortisone equivalents. Meta-analytic techniques were used to analyze the data.

DATA SYNTHESIS

We identified 7 relevant studies that included 1046 patients. The corticosteroid regimen differed between all studies with the total cumulative dose varying from 160 to 21,000 mg of hydrocortisone equivalents; one study each used low-dose and very high-dose corticosteroid. Overall, the use of corticosteroids was associated with a significant reduction in the risk of postoperative AF, with an odds ratio of 0.42, 95% confidence interval of 0.27 to 0.68, and P = .0004. Significant heterogeneity was however noted between studies. When the low-dose and very high-dose studies were excluded, the treatment effect was highly significant (odds ratio, 0.32; 95% confidence interval, 0.21 to 0.50; P < .00001) with insignificant heterogeneity.

CONCLUSIONS

Moderate-dosage corticosteroid (hydrocortisone) should be considered for the prevention of AF in high-risk patients undergoing cardiac surgery. Although the optimal dose, dosing interval, and duration of therapy is unclear, a single dose given at induction may be adequate. The interaction between corticosteroids, beta-blockers, and amiodarone requires further study.

The changes and effects of the plasma levels of tumor necrosis factor after coronary artery bypass surgery with cardiopulmonary bypass

BACKGROUND

Systemic inflammatory response after cardiopulmonary bypass (CPB) is thought to result from contact of cellular and humoral blood components with the synthetic material of the extracorporeal circulation system, leukocyte and endothelial activation caused by ischemia and reperfusion or endotoxins, or by surgical trauma. Proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8, play an important role in the inflammatory processes after CPB and may induce cardiac and lung dysfunction. This study examined the association of the increased release of TNF-alpha with increased myocardial and lung injury after CPB and its effect on postoperative morbidity.

METHODS

Twenty patients undergoing elective coronary artery bypass grafting (CABG) were included in the study. Four intervals of blood samples were obtaind and assayed for TNF-alpha, white blood cells, C-reactive protein, and erythrocyte sedimentation rate.

RESULTS

All patients were similar with regards to preoperative and intraoperative characteristics, and clinical outcomes were comparable. Plasma levels of TNF-alpha rose more than 20 pg/mL during and after standard CPB in 13 patients (group 1), whereas the plasma levels were less than 20 pg/mL in the remaining 7 patients (group 2) after CPB. The patients of the first group had increased mediastinal bleeding and prolonged intubation time compared to the other group.

CONCLUSION

Cardiac surgery and CPB stimulate systemic inflammatory processes characterized clinically by changes in cardiovascular and pulmonary function. Significant morbidity is rare, but most patients undergoing CPB exhibit some degree of organ dysfunction due to activation of the inflammatory response. This study showed that there were no major clinical results of TNF-alpha and white blood cell level, C-reactive protein, and erythrocyte sedimentation rate after the operation, but in patients with a high level of TNF-alpha (more than 20 pg/mL), increased mediastinal bleeding and longer orotracheal intubation time was observed. A number of studies have shown the increase of TNF-alpha after open heart surgery; however, the specific level of TNF-alpha was first described as 20 pg/mL in this study.

Methylprednisolone increases urinary nitrate concentrations and reduces subclinical renal injury during infrarenal aortic ischemia reperfusion

OBJECTIVE

This study tests the hypothesis that methylprednisolone may influence eNOS activity in renal arterial and venous vascular beds and impede subclinical renal injury.

SUMMARY BACKGROUND DATA

Acute renal failure is a major complication of cardiovascular surgery. Renal damage arises in part from excessive vasoconstriction mediated by an imbalance of vasoconstrictive ET-1 and vasodilatory NO produced by eNOS. While methylprednisolone may reduce subclinical renal injury as measured by urinary N-acetyl-beta-D-glucosaminidase (beta-NAG), its effects upon eNOS activity in renal arterial and venous vascular beds, reflected by urinary nitrate levels, is unclear.

METHODS

A porcine model of normotensive, euvolemic infrarenal aortic ischaemia-reperfusion was used. Forty-two pigs underwent a 60-minute laparotomy followed by 150 minutes of infrarenal ischemia and 180 minutes of reperfusion. Animals were randomized to receive methylprednisolone 30 mg/kg or placebo after induction of general anesthesia. Urinary beta-NAG levels were assessed as an index of subclinical renal injury, whereas urinary nitrate was assessed as an indicator of eNOS activity in renal arterial and venous vascular beds.

RESULTS

Methylprednisolone treatment did not influence mean arterial, central venous, or pulmonary artery wedge pressures but suppressed plasma IL-6 levels. After the ischemia-induced rise from preanaesthetic baseline levels, urinary beta-NAG levels declined to significantly lower values in the MP group, indicative of MP renal protection (P < 0.05). Conversely, urinary nitrate levels indicative of vascular e-NOS activity remained significantly and persistently higher in MP-treated animals (P < 0.05).

CONCLUSION

This study, in a porcine model of renal ischaemia-reperfusion injury, shows the benefits of methylprednisolone pretreatment in enhancing urinary nitrate levels indicative of vascular eNOS activity and the reduction of urinary beta-NAG levels, which represent subclinical renal injury.

Pulse Low Dose Steroids Attenuate Post-Cardiopulmonary Bypass SIRS; SIRS I

BACKGROUND

Cardiopulmonary bypass (CPB) initiates inflammation that contributes to multiorgan dysfunction (SIRS). Steroids have been demonstrated to attenuate this response; however, resistance to use steroids remains because of potential adverse effects of the high doses used. This study examines a lower dose steroid protocol for safety and attenuation of SIRS.

METHODS

Sixty patients undergoing CPB were randomized to pulse low doses of methylprednisolone (250 mg given twice IV) or placebo in this RCT. Outcomes pertaining to hemodynamics, ventilator requirement, arrhythmia, and metabolic derangements were recorded. Post-operative glucose control and gastrointestinal prohylaxis was instituted in all patients.

RESULTS

IL-6 concentrations were lower in the steroid group at 4 and 8 h post-operatively (P < 0.0001). The steroid group demonstrated more normothermia (37.2 degrees C versus 37.6 degrees C, P = 0.002), better hemodynamic stability with less requirement for inotropes or vasopressors (0% versus 27.6%, P = 0.005), higher SVRIs (1840 versus 1340 DSm2/cm5, P = 0.002), and higher mean arterial pressures (79 versus 74 mmHg, P = 0.03). The steroid group had a shorter duration of intubation (7.7 versus 10.7 h, P = 0.02), a shorter length of ICU stay (1.0 versus 2.0 days, P = 0.03), and less blood loss (505 versus 690 ml, P = 0.04) with no difference in post-operative blood glucose levels or complications.

CONCLUSIONS

Patients undergoing cardiopulmonary bypass receiving low pulse dose steroids had better hemodynamics, shorter mechanical ventilation times, less blood loss, and required less time in the ICU compared to those receiving placebo. Therefore, this study demonstrates that prophylactic low dose steroids attenuate the SIRS response to CPB without resulting in any untoward side-effects.

Modulation of systemic inflammatory response after cardiac surgery

Cardiac surgery and cardiopulmonary bypass initiate a systemic inflammatory response largely determined by blood contact with foreign surfaces and the activation of complement. It is generally accepted that cardiopulmonary bypass initiates a whole-body inflammatory reaction. The magnitude of this inflammatory reaction varies, but the persistence of any degree of inflammation may be considered potentially harmful to the cardiac patient. The development of strategies to control the inflammatory response following cardiac surgery is currently the focus of considerable research efforts. Diverse techniques including maintenance of hemodynamic stability, minimization of exposure to cardiopulmonary bypass circuitry, and pharmacologic and immunomodulatory agents have been examined in clinical studies. This article briefly reviews the current concepts of the systemic inflammatory response following cardiac surgery, and the various therapeutic strategies being used to modulate this response.

Dexamethasone: Benefit and Prejudice for Patients Undergoing On-Pump Coronary Artery Bypass Grafting

STUDY OBJECTIVES

Cardiac surgery with cardiopulmonary bypass (CPB) results in perioperative organ damage caused by the systemic inflammatory response syndrome (SIRS) and ischemia/reperfusion injury. Administration of corticosteroids before CPB has been demonstrated to inhibit the activation of the systemic inflammatory response. However, the clinical benefits of corticosteroid therapy are controversial. This study was designed to document the effects of dexamethasone on cytokine release and perioperative myocardial, pulmonary, renal, intestinal, and hepatic damage, as assessed by specific and sensitive biomarkers.

DESIGN AND PATIENTS

A prospective, double-blind, placebo-controlled, randomized trial for dexamethasone was conducted in 20 patients receiving either dexamethasone (1 mg/kg before anesthesia induction and 0.5 mg/kg after 8 h; n = 10) or placebo (n = 10). Different markers were used to assess the SIRS: interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP), and tryptase; and organ damage: heart (plasma heart-type fatty acid binding protein, cardiac troponin I [cTnI], creatine kinase-MB), kidneys (N-acetyl-glucosaminidase [NAG], microalbuminuria), intestine (intestinal-type fatty acid binding protein [I-FABP]/liver-type fatty acid binding protein [L-FABP]), and liver (alpha-glutathione S-transferase).

RESULTS

Dexamethasone modulated the SIRS with lower proinflammatory (IL-6, IL-8) and higher antiinflammatory (IL-10) IL levels. CRP and tryptase were lower in the dexamethasone group. cTnI values were lower in the dexamethasone group at 6 h in the ICU (p = 0.009). Patients in the dexamethasone group had a longer time to tracheal extubation (18.86 +/- 1.13 h vs 15.01 +/- 0.99 h, p = 0.02 [mean +/- SEM]), with a lower oxygenation index at that time: Pa(O2)/fraction of inspired oxygen ratio, 37.17 +/- 1.8 kPa vs 29.95 +/- 2.1 kPa (p = 0.009). The postoperative glucose level (10.7 +/- 0.6 mmol/L vs 7.4 +/- 0.5 mmol/L, p = 0.005) was higher in the dexamethasone group. Serum glucose was independently associated with intestinal injury (urine I-FABP peak, R2 = 42.5%, beta = 114.4 +/- 31.4, significant at p = 0.002; urine L-FABP peak, R2 = 47.3%, beta = 7,714.1 +/- 1,920.9, significant at p = 0.001) and renal injury (urine NAG, R2 = 32.1%, beta = 0.21 +/- 0.07, significant at p = 0.009). Tryptase peaks correlated negatively with peaks of intestinal and renal injury biomarkers.

CONCLUSION

Even while inhibiting SIRS, dexamethasone treatment offered no protection against transient, subclinical, perioperative abdominal organ damage. Tryptase release could have a preconditioning effect, offering protection against perioperative intestinal and renal damage. Dexamethasone treatment resulted in more pronounced postoperative pulmonary dysfunction, prolonged time to tracheal extubation, and initiated postoperative hyperglycemia in patients undergoing elective on-pump coronary artery bypass graft surgery.

Effects of Methylprednisolone and a Biocompatible Copolymer Circuit on Blood Activation During Cardiopulmonary Bypass

BACKGROUND

Cardiopulmonary bypass (CPB) induces derangements in physiology characterized by activation of blood pathways that may contribute to multiorgan dysfunction. This trial addresses the efficacy of a biocompatible surface alone and in combination with steroids in inhibiting these changes.

METHODS

In a factorial design, patients undergoing coronary artery bypass grafting were randomized (four groups; n = 17 per group) to CPB utilizing control circuits or a circuit prepared with a surface modifying active copolymer (SMA-CPB), with or without methylprednisolone (MPSS, 1 g intravenous). Leukocyte and complement activation, cytokine release, and bradykinin generation were measured. Clinical outcomes (blood loss, transfusion, arterial pressure response, and postoperative cardiac and pulmonary functions) were also examined.

RESULTS

The SMA-CPB was associated with a significant inhibition of elastase release (p = 0.026) and bradykinin generation (p = 0.027) during CPB. Terminal complement complex (TCC) generation was inhibited as an effect of SMA-CPB (p = 0.047). There was an interaction of SMA-CPB and MPSS to decrease both TCC (p = 0.042) and bradykinin generation (p = 0.028). There were strong effects of MPSS in inhibiting release of interleukin 6 (IL-6) (p = 0.007) and IL-8 (p < 0.001) and tissue plasminogen activator over time (p = 0.009) as well as decreasing peak day 1 creatine kinase (CK, p = 0.015) levels. Clinical effects of MPSS included decreased atrial fibrillation (p = 0.02), improved cardiac index over time, increased pulmonary compliance, and increased insulin need.

CONCLUSIONS

This trial suggests a potential beneficial effect for combined strategies to minimize inflammation after CPB. The specific effect of MPSS in decreasing postoperative atrial fibrillation and CK warrants further investigation of its role as a potential myocardial protective agent.

The systemic inflammatory response syndrome and cardiopulmonary bypass

Cardiac surgery using cardiopulmonary bypass (CPB) provokes a systemic inflammatory response. This is mainly triggered by contact activation of blood by artificial surfaces of the extracorporeal circuit. Although often remaining sub-clinical and resolving promptly at the end of CPB, in its most extreme form this inflammatory response may be associated with the development of the systemic inflammatory response syndrome (SIRS) that can often lead to major organ dysfunction (MODs) and death. Here, we review the pathophysiology behind the development of this "whole body" inflammatory response and some of the methods currently used to minimise it.

Effects of Preinjury Administration of Corticosteroids on Pseudointimal Hyperplasia and Cytokine Response in a Rat Model of Balloon Aortic Injury

Restenosis occurs in approximately one-third of patients with coronary or peripheral vascular disease who undergo balloon angioplasty or a surgical bypass procedure primarily because of the development of pseudointimal hyperplasia (PIH). Corticosteroids were effective in suppressing PIH in several experimental studies, but no clinical studies have been reported. To resolve this discrepancy, we studied the effects of preinjury administration of several doses of methylprednisolone (MP) at targeted times in a rat model of balloon aortic injury. Rats were given either no treatment or an intravenous injection of MP (0.5, 5.0, 50, or 500 mg/kg) 2 hours before aortic injury. Four hours later interleukin-6 (IL-6), IL-10, and macrophage migration inhibitory factor (MIF) concentrations in serum and tissue of injured aortas were assessed. Two weeks after injury, damaged aortas were harvested and studied histopathologically. Compared with results in controls, MP at a dose of 5 mg/kg significantly inhibited increases in plasma and tissue levels of IL-6 and significantly reduced the pseudointimal area, pseudointimal/medial area ratio, and proliferating cell nuclear antigen index in injured vessels. Administration of MP had no significant effect on the IL-10 or MIF level. Thus in a rat model of balloon aortic injury, preinjury administration of MP 5 mg/kg mitigated the development of PIH and cell proliferation and suppressed the postinjury increase in serum and tissue IL-6 concentrations. These results suggest that there is an appropriate dosage as well as appropriate timing for MP administration to suppress PIH.

Microvascular Inflammatory Response in Cardiac Surgery

Cardiac surgical procedures, with or without cardiopulmonary bypass, elicit a systemic inflammatory response in patients that induces the elaboration of multiple cytokines, chemokines, adhesion molecules, and destructive enzymes. This inflammatory reaction involves multiple interdependent and redundant cell types and humoral cascades, which allows for amplification and positive feedback at numerous steps. This systemic inflammatory response ultimately results in a broad spectrum of clinical manifestations, with multiple organ failure being the most severe form. Investigative efforts have focused on understanding the mechanism of this systemic inflammatory response syndrome in order to develop potential therapeutic targets to inhibit it, thereby possibly decreasing postoperative morbidity and mortality. Multiple therapeutic methods have been investigated, including pharmacologic inhibitors and modifications of surgical technique and the cardiopulmonary bypass circuit. Although studies have demonstrated that the use of these therapies in experimental and clinical settings has attenuated the systemic inflammatory response, they have failed to conclusively show clinical benefit from these therapies. These therapies may be too specific to minimize the deleterious effects of a systemic inflammatory response that results from the activation of multiple, interdependent, and redundant inflammatory cascades and cell types. Hence, further studies that investigate the molecular and cellular events underlying the systemic inflammatory response syndrome and the resultant effects of anti-inflammatory therapies are warranted to ultimately achieve improvements in clinical outcome after cardiac surgical procedures.

Effect of an intraosseous injection of depo-medrol on pulpal concentrations of PGE2 and IL-8 in untreated irreversible pulpitis

The purpose of this prospective, randomized, double-blind study was to evaluate the pulpal concentrations of prostaglandin E2 (PGE2) and interleukin-8 (IL-8) in untreated teeth with irreversible pulpitis after the administration of an intraosseous injection of Depo-Medrol. Forty emergency patients with a clinical diagnosis of irreversible pulpitis experiencing moderate to severe pain participated. After receiving local anesthesia, patients randomly received, in a double-blind manner, an intraosseous injection of either 1 ml of Depo-Medrol (40 mg) (20 patients) or 1 ml of sterile saline placebo (control) (20 patients). No endodontic treatment was initiated. At 1 or 3 days after the intraosseous injection, the teeth were extracted and the pulpal tissue harvested. Prostaglandin E2 and interleukin-8 concentrations were determined by enzyme immunoassay. Results demonstrated a significantly (p < 0.05) lower concentration of prostaglandin E2 compared to the saline group at day 1. There were no significant (p > 0.05) differences between the two groups at day 3. The pulpal concentrations of prostaglandin E2 were reduced at 1 day after the intraosseous injection of Depo-Medrol.

Perioperative and postoperative course of cytokines and the metabolic activity of neutrophils in human cardiac operations and heart transplantation

OBJECTIVES

The purpose of this study was to compare systemic inflammatory responses after heart transplantation and nontransplant cardiac operations, both involving cardiopulmonary bypass with a focus on the role of polymorphonuclear leukocytes.

METHODS

Lipid peroxidation, blood phagocyte radical production, and interleukin 6, 8, and 10 plasma concentrations during surgical intervention and on the first and seventh postoperative days were evaluated in patients undergoing heart transplantation (n = 24) and in patients not undergoing transplantation (n = 30).

RESULTS

Levels of interleukin 6, 8, and 10 increased in both groups of patients during early reperfusion. They normalized within the first postoperative day in the transplant group, whereas the nontransplant group's interleukin 6 and 8 levels remained increased on the seventh day after the operation. Interleukin 10 plasma levels were higher in the heart transplant group during reperfusion. Lipid peroxidation was increased after the operation in both groups of patients. Phagocyte activity was enhanced at reperfusion and at all other sampling times only in the nontransplant group. On the other hand, phagocyte activity oscillated around the preoperative level during heart transplantation, or it was even decreased.

CONCLUSION

Both cardiac operations involving heart transplantation and those without transplantation are associated with increased oxidative stress and an enhanced production of proinflammatory and anti-inflammatory cytokines. Differences in interleukin 10 production and phagocyte activity could be caused mainly by the immunosuppressive therapy in heart transplant operations.

Corticosteroids and cardiopulmonary bypass : a review of clinical investigations

Traditionally, corticosteroids have been administered to patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) to ward off detrimental physiologic alterations associated with activation of the systemic inflammatory response, yet few well-controlled investigations exist, and use of these drugs in this setting remains controversial. This review article critically examines the results of clinical investigations in this area, and certain conclusions are suggested. The constellation of findings indicate that corticosteroids offer no clinical benefits to patients undergoing cardiac surgery with CPB and in fact may be detrimental. Further directions for clinical research in this area are also suggested.

The effects of aprotinin and steroids on generation of cytokines during coronary artery surgery

OBJECTIVE

To compare the efficacy of aprotinin and methylprednisolone in reducing cardiopulmonary bypass (CPB)-induced cytokine release, to evaluate the effect of myocardial cytokine release on systemic cytokine levels, and to determine the influence of cytokine release on perioperative and postoperative hemodynamics.

DESIGN

Prospective, randomized clinical trial.

SETTING

University teaching hospital and clinics.

PARTICIPANTS

Thirty patients undergoing elective coronary artery bypass graft surgery.

INTERVENTION

Patients were randomly allocated into groups treated with aprotinin (n = 10) or methylprednisolone (n = 10) or into an untreated control group (n = 10). Aprotinin-treated patients received aprotinin as a high-dose regimen (6 x 10(6) KIU), and methylprednisolone-treated patients received methylprednisolone (30 mg/kg intravenously) before CPB.

MEASUREMENTS AND MAIN RESULTS

Patients were analyzed for hemodynamic changes and alveolar-arterial PO2 difference (AaDO2) until the first postoperative day. Plasma levels of proinflammatory cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-6, and IL-8) were measured in peripheral arterial blood immediately before the induction of anesthesia, 5 minutes before CPB, 3 minutes after the start of CPB, 2 minutes after the release of the aortic cross-clamp, 1 hour after CPB, 6 hours after CPB, and 24 hours after CPB; and in coronary sinus blood immediately before CPB and 2 minutes after the release of the aortic cross-clamp. The hemodynamic parameters did not differ among the groups throughout the study. After CPB, AaDO2 significantly increased (p < 0.05) in all groups. A significant decrease in AaDO2 was observed in aprotinin-treated patients at 24 hours after CPB compared with the other groups (p < 0.05). TNF-alpha level from peripheral arterial blood significantly increased in control patients 1 hour after CPB (p < 0.01) and did not significantly increase in methylprednisolone-treated patients throughout the study. In all groups, IL-6 levels increased after the release of the aortic cross-clamp and reached peak values 6 hours after CPB. At 6 hours after CPB, the increase in IL-6 levels in methylprednisolone-treated patients was significantly less compared with levels measured in control patients and aprotinin-treated patients (p < 0.001). In control patients, IL-8 levels significantly increased 2 minutes after the release of the aortic cross-clamp (p < 0.05), and peak values were observed 1 hour after CPB (p < 0.01). IL-8 levels in control patients were significantly higher compared with patients treated with aprotinin and patients treated with methylprednisolone 1 hour after CPB (p < 0.05).

CONCLUSION

This study showed that methylprednisolone suppresses TNF-alpha, IL-6, and IL-8 release; however, aprotinin attenuates IL-8 release alone. Methylprednisolone does not produce any additional positive hemodynamic and pulmonary effects. An improved postoperative AaDO2 was observed with the use of aprotinin.

Risks and benefits of preoperative high dose methylprednisolone in surgical patients: a systematic review

BACKGROUND

A single preoperative high dose of methylprednisolone (15 to 30 mg/kg) has been advocated in surgery, because it may inhibit the surgical stress response and thereby improve postoperative outcome and convalescence. However, these potential clinical benefits must be weighed against possible adverse effects.

OBJECTIVE

To conduct a risk-benefit analysis using a meta-analysis, to compare complication rates and clinical advantages associated with the use of high dose methylprednisolone in surgical patients.

METHODS

Randomised controlled trials of high dose methylprednisolone in elective and trauma surgery were systematically searched for in various literature databases. Outcome data on adverse effects, postoperative pain and hospital stay were extracted and statistically pooled in fixed-effects meta-analyses.

RESULTS

We located 51 studies in elective cardiac and noncardiac surgery, as well as traumatology. Pooled data failed to show any significant increase in complication rates. In patients treated with corticosteroids, nonsignificantly more gastrointestinal bleeding and wound complications were observed; the 95% confidence interval boundaries of the numbers-needed-to-harm were 59 and 38, respectively. The only significant finding was a reduction of pulmonary complications (risk difference -3.5%; 95% confidence interval -1.0 to -6.1), mainly in trauma patients.

CONCLUSION

For patients undergoing surgical procedures, a perioperative single-shot administration of high dose methylprednisolone is not associated with a significant increase in the incidence of adverse effects. In patients with multiple fractures, limited evidence suggests promising benefits of glucocorticoids on pulmonary complications.

High oxygen concentration exacerbates cardiopulmonary bypass-induced lung injury

OBJECTIVE

To investigate the effect of ventilation with 100% oxygen on lung injury associated with surgery involving cardiopulmonary bypass (CPB).

DESIGN

A prospective randomized study.

SETTING

University hospital.

PARTICIPANTS

Thirty patients undergoing coronary artery bypass graft surgery with CPB.

INTERVENTIONS

Patients were randomized to receive 100% oxygen (Oxygen group) or 50% oxygen (Air group) throughout surgery. During CPB, patients' lungs in the Air group were flushed with air and in the Oxygen group with 100% oxygen.

MEASUREMENTS AND MAIN RESULTS

Lung injury was evaluated by arterial oxygen tension-inspired oxygen concentration (PaO2-FIO2) ratio and cytokine levels (tumor necrosis factor-alpha and interleukin-8) in blood and bronchoalveolar lavage fluid measured before and after CPB. The lowest PaO2-FIO2 value was observed after 40 minutes following the completion of CPB in both groups. PaO2-FIO2 values 6 hours after CPB were not different from baseline in the Air group but remained lower (359+/-63 mmHg and 298+/-78 mmHg; p = 0.013) in the Oxygen group. Blood cytokine levels rose during surgery in both groups. Bronchoalveolar lavage levels of interleukin-8 did not change, whereas tumor necrosis factor-alpha increased only in the Oxygen group (p = 0.035).

CONCLUSIONS

A significant decrease of oxygenation was observed in the early post-CPB period in both groups of patients, with delay in recovery in patients treated with 100% oxygen. A larger increase of the proinflammatory cytokines was found in patients treated with 100% oxygen. High oxygen concentrations during surgery with CPB should be used only when specifically required.

Cardiomyopathy in AIDS: a pathophysiological perspective

This report addresses issues of pathogenesis, pathophysiology, and epidemiology of an increasingly prevalent cardiomyopathy in acquired immunodeficiency syndrome (AIDS). As patient survival increases with more effective antiretroviral therapy, cardiomyopathy in AIDS will become more apparent. The interactions of cellular and organism factors in AIDS and their relationships to the development of cardiomyopathy are reviewed herein. Amongst the factors addressed in this review are: (1) comorbid conditions found with AIDS, (2) the role of inflammatory heart disease and cytokines in the development of AIDS cardiomyopathy, (3) the pathogenetic role of vascular cells and myocardial cells in the development of cardiomyopathy, (4) the role of myocardial retroviral infection in AIDS, and (5) the impact of toxicity from antiretroviral therapy on the development of cardiomyopathy. Because it is possible that more than 1 of these factors is present in a given patient inflicted with AIDS, a multifactorial pathogenesis in AIDS cardiomyopathy must be considered.

Reperfusion injury after focal myocardial ischaemia: polymorphonuclear leukocyte activation and its clinical implications

The only way to rescue ischaemic tissue is to re-instate the oxygen supply to the tissue. However reperfusion of the ischaemic area not only oxygenates the tissue but also initiates a cascade of processes, which may in some cases result in temporary dysfunction of the myocardium. In order to devise protective measures, it is essential to understand the mechanisms and the triggers of this reperfusion phenomenon. In this review we will mainly focus on the inflammatory response caused by reperfusion. We will cover the different steps of polymorphonuclear leukocyte activation and will briefly discuss the molecular biology of the receptors involved. The currently used pharmacological medications in acute cardiology will be reviewed and in particular their actions on polymorphonuclear leukocyte activation, adhesion and degranulation. This review is a compilation of the current knowledge in the field and the therapeutic progress in the prevention of reperfusion injury made today.

Corticosteroids during operations using cardiopulmonary bypass

Although corticosteroids have been used for more than 30 years in the context of extracorporeal circulation, there is an ongoing debate about the benefits of their routine application. Methylprednisolone was given as early as 1966 to reduce vasoconstriction during cardiopulmonary bypass (CPB) and to prevent low output syndrome thereafter. An explanation for these findings was recently published. Lipid mediators lead to vasoconstriction and inflammatory cytokine production during CPB. There is no doubt about the potential of corticosteroids to reduce inflammatory and enhance anti-inflammatory mediators, while their possible influence on clinical parameters and their side effects are controversial, as discussed in the literature. There have been contradictory results with respect to pulmonary oxygenation, while an increase in the patient's blood glucose levels, however clinically unimportant, could be demonstrated. The influence of other drugs affecting the inflammatory response has to be taken into account, leading to a patient-specific recommendation for the use of corticosteroids during operations requiring CPB.

Does high-dose methylprednisolone in aprotinin-treated patients attenuate the systemic inflammatory response during coronary artery bypass grafting procedures?

OBJECTIVE

To discover the possible effects of methylprednisolone on the systemic inflammatory response during aprotinin treatment.

DESIGN

Randomized, double-blinded study.

SETTING

University-affiliated heart center.

PARTICIPANTS

Fifty-two patients scheduled for elective coronary artery bypass grafting.

INTERVENTIONS

In the methylprednisolone group (n = 26), 1 g of methylprednisolone was administered 30 minutes before cardiopulmonary bypass (CPB). The 26 control patients received a placebo instead. High-dose aprotinin was administered to all participants.

MEASUREMENTS AND MAIN RESULTS

After CPB, the concentration of the proinflammatory cytokines, interleukin-6 and interleukin-8, was significantly less in the methylprednisolone group. The anti-inflammatory interleukin-10 concentration was, in contrast, greater. After CPB, PaO2 was greater in the methylprednisolone group (245+/-17 v 195+/-16 mmHg). Dynamic pulmonary compliance was also greater, whereas the alveolar-arterial oxygen difference was less (376+/-17 v 428+/-16 mmHg). On arrival in the intensive care unit, the oxygen delivery index was greater in the methylprednisolone group (62+/-2.7 v 54+/-2.3 mL/min/m2) and the oxygen extraction rate was less (25%+/-0.02% v 30%+/-0.02%). After CPB, the cardiac index was significantly greater in the methylprednisolone group (4.1+/-0.2 v 3.6+/-0.2 L/min/m2). These patients had less blood loss postoperatively (616+/-52 v 833+/-71 mL; p = 0.017) and a greater urine output (8,015+/-542 v 6,417+/-423 mL/24 h; p = 0.024).

CONCLUSION

The use of methylprednisolone attenuates the systemic inflammatory response during aprotinin treatment and improves clinical outcome parameters.

Influence of methylprednisolone on cytokine balance during cardiac surgery

OBJECTIVE

To determine the influence of methylprednisolone on the cytokine balance during cardiac surgery.

DESIGN

Prospective, randomized, nonblinded study.

SETTING

University hospital.

PATIENTS

Twenty-one patients on cardiopulmonary bypass undergoing aortocoronary bypass surgery.

INTERVENTIONS

According to a randomized sequence, the patients either received methylprednisolone (30 mg/kg) [corrected] before cardiopulmonary bypass and before declamping of the aorta (MPS group, n = 11) or received nothing (control group, n = 10).

MEASUREMENTS AND MAIN RESULTS

Serum proinflammatory cytokines (interleukin [IL]-8, IL-6) and anti-inflammatory cytokines (IL-10, IL-1ra) were measured by enzyme-linked immunosorbent assays. Serum IL-6 and IL-8 concentrations in the control group (15.2 +/- 4.1 and 14.1 +/- 1.9 pg/mL, preoperatively) increased to 242 +/- 70.1 and 97.3 +/- 18.3 pg/mL at 60 mins after declamping of the aorta (p < .01, p < .01, respectively). The increases were greater than those from 2.5 +/- 0.6 and 2.5 +/- 0.5 pg/mL to 109.5 +/- 29.0 and 33 +/- 4.1 pg/mL in the MPS group for IL-6 and IL-8, respectively. Serum IL-10 concentrations increased significantly 60 mins after declamping of the aorta compared with its preoperative value in the two groups (the control group, from 1.0 +/- 0 to 537.9 +/- 61.7 pg/mL; the MPS group, from 0.3 +/- 0.2 to 654.9 +/- 24 pg/mL [p < .01, p < .01, respectively]). No difference was found between the two groups. Similarly, serum IL-1ra concentrations in the two groups increased the preoperative value in the control group from 304 +/- 120 to 44,374 +/- 14,631 pg/mL and in the MPS group from 616.5 +/- 109.6 to 35,598 +/- 9,074 pg/mL at 60 mins after declamping of the aorta (p < .01, p < .01, respectively). There was no difference between the two groups.

CONCLUSIONS

Methylprednisolone reduces the production of IL-6 and IL-8 but not that of IL-10 and IL-1ra. These results suggest that one of the mechanisms of the cytoprotective effect of methylprednisolone may be to make changes in the proinflammatory and anti-inflammatory cytokine balance.

Methylprednisolone reduces the inflammatory response to cardiopulmonary bypass in neonatal piglets: timing of dose is important

INTRODUCTION

Cardiopulmonary bypass produces an inflammatory response that can cause significant postoperative pulmonary dysfunction and total body edema. This study evaluates the efficacy of preoperative methylprednisolone administration in limiting this injury in neonates and compares the effect of giving methylprednisolone 8 hours before an operation to the common practice of adding methylprednisolone to the cardiopulmonary bypass circuit prime.

METHODS

A control group of neonatal pigs (control; n = 6) received no preoperative medication. One experimental group (n = 6) received methylprednisolone sodium succinate (30 mg/kg) both 8 and 1.5 hours before the operation. A second experimental group received no preoperative treatment, but methylprednisolone (30 mg/kg) was added to the cardiopulmonary bypass circuit prime. All animals underwent cardiopulmonary bypass and 45 minutes of deep hypothermic circulatory arrest. Hemodynamic and pulmonary function data were acquired before cardiopulmonary bypass and at 30 and 60 minutes after bypass.

RESULTS

In the control group, pulmonary compliance, alveolar-arterial gradient, and pulmonary vascular resistance were significantly impaired after bypass (P <.01 for each by analysis of variance). In the group that received methylprednisolone, compliance (P =.02), alveolar-arterial gradient (P =.0003), pulmonary vascular resistance (P =.007), and extracellular fluid accumulation (P =.003) were significantly better after bypass when compared with the control group. Results for the group that received no preoperative treatment fell between the control group and the group that received methylprednisolone.

CONCLUSIONS

When given 8 hours and immediately before the operation, methylprednisolone improves pulmonary compliance after bypass, alveolar-arterial gradient, and pulmonary vascular resistance compared with no treatment. The addition of methylprednisolone to the cardiopulmonary bypass circuit prime is beneficial but inferior to preoperative administration.

Glucocorticoid attenuates a decrease of antithrombin III following major surgery

BACKGROUND

Major surgery, such as esophagectomy, activates inflammatory responses and the coagulation system, and this activation is characterized by release of inflammatory cytokines and a decrease in antithrombin-III (AT-III), respectively. Preoperative glucocorticoid administration has been reported to suppress circulatory cytokine levels after major surgery.

PATIENTS AND METHODS

A total of 28 patients underwent esophagectomy for esophageal carcinoma; 14 of them were given 10 mg/kg of methylprednisolone intravenously upon induction of anesthesia and 14 served as controls. Circulating levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), polymorphonuclear (PMN) elastase, thrombin-antithrombin III complex (TAT), AT-III, and albumin were measured before and immediately after the operation and on postoperative days (PODs) 1, 3, 5, and 7.

RESULTS

TNF-alpha, IL-6, and TAT levels significantly increased after esophagectomy in both groups. AT-III and albumin decreased to their minimum levels on POD 1 and POD 3, respectively. Methylprednisolone treatment effectively inhibited the increases in TNF-alpha and IL-6 and the decreases in AT-III and albumin, but did not inhibit the increases in PMN-elastase and TAT levels. There were significant correlations between AT-III, IL-6, and albumin levels.

CONCLUSIONS

These results suggest that methylprednisolone pretreatment attenuates the decrease in AT-III by reducing IL-6 production postoperatively.

Cytokine and lipid mediator blood concentrations after coronary artery surgery

This study investigates whether increased levels of cytokines and lipid mediators may be associated with complications after coronary artery bypass grafting (CABG) with extracorporeal circulation (ECC). Hemodynamic measurements and blood samples were obtained in 32 patients before and after the end of ECC and at the 6th and the 24th postoperative hours. Coagulation and pulmonary and cardiovascular functions were specifically assessed postoperatively at the same time. Patients with cardiovascular dysfunction had higher interleukin 8 (IL-8) levels. Higher platelet-activating factor (PAF) and decreased PAF acetylhydrolase activity (AHA, the enzyme that inactivates PAF) levels were found in patients with moderate cardiovascular dysfunction. Interleukin 6 (IL-6), IL-8, and AHA levels correlated with most hemodynamic parameters and creatine phosphokinase myocardial band levels obtained after surgery. Patients with severe lung injury had lower PAF, 6-keto prostaglandin (Pg)F1alpha, and PgE2 levels and higher thromboxane (Tx) B2 concentrations compared with patients without lung injury. Increased IL6 levels were only associated with moderate lung injury. Impaired hemostasis was associated with higher IL6 levels. AHA, IL-6, and IL-8 seem to be associated with cardiovascular dysfunction. The IL-6 blood levels and the ratio of TxB2/6 keto-PgF1alpha blood levels are increased during post-CABG lung injury. These results identify an association between specific post-CABG complications and the systemic inflammatory response. The clinical significance of this association remains to be evaluated.

IMPLICATIONS

Patients with pulmonary, cardiovascular, or hemostasis dysfunction after cardiopulmonary bypass demonstrate aberrancies in a variety of cytokines and lipid mediators in arterial blood or plasma. The relationship between these findings and inflammatory response-induced complications remains to be determined.

Inflammatory response to cardiopulmonary bypass: mechanisms involved and possible therapeutic strategies

BACKGROUND

Recent study of the inflammatory reactions occurring during and after cardiopulmonary bypass (CPB) has improved our understanding of the involvement of the inflammatory cascade in perioperative injury. However, the exact mechanisms of this complex response remain to be fully determined.

METHODS

Literature on the inflammatory response to CPB was reviewed to define current knowledge on the possible pathways and mediators involved, and to discuss recent developments of therapeutic interventions aimed at attenuating the inflammatory response to CPB.

RESULTS

CPB has been shown to induce complement activation, endotoxin release, leukocyte activation, the expression of adhesion molecules, and the release of many inflammatory mediators including oxygen-free radicals, arachidonic acid metabolites, cytokines, platelet-activating factor, nitric oxide, and endothelins. Therapies aimed at interfering with the inflammatory response include the administration of pharmacologic agents such as corticosteroids, aprotinin, and antioxidants, as well as modification of techniques and equipment by the use of heparin-coated CPB circuits, intraoperative leukocyte depletion, and ultrafiltration.

CONCLUSIONS

Improved understanding of the inflammatory reactions to CPB can lead to improved patient outcome by enabling the development of novel therapies aimed at limiting this response.

The inflammatory response and extracorporeal circulation

Defining the cause of organ and tissue dysfunction associated with the use of perfusion systems will produce methods of prevention or treatment and improve patient outcome. The problem is the plethora of triggers, effectors, and mediators in this process, which can now be measured. Each new measureable compound becomes another biochemical "smoking gun" without physiological data to show any relevance to the human problem. This review critically compares and contrasts the role of certain, largely novel, initiation, amplification, and cytotoxic mechanisms in the inflammatory response of the myocardium and pulmonary systems after a period of cardiopulmonary bypass. The available evidence strongly points to the process being different for each of these tissue beds. These data suggest that ensuring normal lung and heart functions after surgery will require separate therapeutic strategies.