Aprotinin and the systemic inflammatory response after cardiopulmonary bypass

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

A randomized trial of the inflammatory cytokines levels and the blood transfusion rate between miniaturized tubing group and conventional tubing group in congenital heart disease open heart surgeries

INTRODUCTION

We aimed to compare the inflammatory cytokines levels of the miniaturized and conventional extracorporeal circuit system. The miniaturized extracorporeal circuit system may be fewer possible inflammation-induced or blood transfusion-related complications.

METHODS

We performed a prospective randomized controlled trial (RCT) of 101 patients undergoing congenital heart surgery with CPB (cardiopulmonary bypass, weight ≤15 kg, age ≤2 years). Patients were divided into two different CPB groups randomly by random data form. Blood samples at five different time points and the ultrafiltration fluid before and after CPB were collected in all patients. IL-6, IL-8, and TNF alpha were respectively tested with Abcam ELISA kit.

RESULTS

The IL-6 level of blood serum in two groups had no statistical differences between the two groups at all time points. The IL-8 level of blood serum in two groups had no statistical differences right after anesthesia and 5 min after CPB. However, IL-8 level was significantly higher in conventional extracorporeal circuit group than that in miniaturized extracorporeal circuit group at 6 h, 12 h and 24 h after CPB. Blood serum TNF alpha in conventional extracorporeal circuit group was significantly higher at 6 h after CPB than that in miniaturized extracorporeal circuit group. No statistical differences in TNF alpha were found between two groups right after anesthesia and at 5 min after CPB, 12 h and 24 h after CPB. In ultrafiltration fluid, no statistical differences were found in IL-6, IL-8 nor TNF alpha between two groups in all time. No statistical differences were found in ICU (intensive care unit) stay and mechanical ventilation time between the two groups. The blood transfusion rate was significantly lower in miniaturized extracorporeal circuit group.

CONCLUSION

Implementing the miniaturized extracorporeal circuit system could decrease the inflammatory cytokines at a certain level. The blood transfusion rate is significantly lower in miniaturized extracorporeal circuit group This indicates the miniaturized extracorporeal circuit system might be a safer CPB strategy with fewer possible inflammation-induced or blood transfusion-related complications.

Inflammatory Progression in Patients Undergoing Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is identified as a novel therapeutic strategy that offers short-term support to the metabolism of the heart and lungs in humans. Recently, the clinical centers, which provide ECMO has increased rapidly worldwide. The indications for the use of ECMO in daily clinical practice were broadened dynamically. However, even with the widespread adoption of ECMO, it still remains significant morbidity and mortality, and the underlying mechanisms are still not elucidated. Notably, one of the vital complications during ECMO was proposed as the inflammatory progression within the extracorporeal circulation. via the development of inflammatory response, patients with ECMO may further suffer from systemic inflammatory response syndrome (SIRS), posing serious risks to human health. Recently, growing evidence confirmed that through exposure of blood into the ECMO circuit could lead to the stimulation of the immune system which also facilitated the inflammatory response and systemic impaired. In the current review, the pathological development of inflammatory progression in patients with ECMO is well-listed. Furthermore, the relationship between immune-related activation and the development of inflammation is also summarized, which may further help us to decide the therapeutic strategies in daily clinical practice.

Anti-inflammatory effect of tranexamic acid on adult cardiac surgical patients: A PRISMA-compliant systematic review and meta-analysis

Objective

This study aims to evaluate the anti-inflammatory effect of tranexamic acid (TXA) on adult cardiac surgical patients.

Methods

PubMed, Embase, Ovid, Web of Science, CNKI, VIP, and WANFANG databases were systematically searched using the related keywords for cardiac surgical randomized controlled trials (RCTs) published from their inception to February 1, 2022. The primary outcomes were postoperative inflammatory biomarkers levels. The secondary outcomes were postoperative systemic inflammatory response syndrome and other major postoperative outcomes. The odds ratios and/or the weighted mean difference (WMD) with a 95% confidence interval (CI) were used to pool the data.

Results

Ten RCTs with 770 adult cardiac surgical patients were included. Compared with placebo, TXA achieved statistically significant inhibition of the postoperative interleukin (IL)-6 level (postoperative 6 h: n = 6 trials; WMD -31.66; 95% CI: -45.90, -17.42; p < 0.0001; I ²= 93%; postoperative 24 h: n =  8 trials; WMD, -44.06; 95% CI: -69.21, -18.91; p = 0.006; I ²= 100%); IL-8 level postoperative 24 h, TNF-α level postoperative 24 h, NE level postoperative 6 h: n = 3 trials; WMD, -36.83; 95% CI: -68.84, -4.83; p = 0.02; I ²= 95%); tissue necrosis factor alpha (TNF-α) level (postoperative 6 h: n = 3 trials; WMD, -7.21; 95% CI: -12.41, -2.01; p = 0.007; I ²= 47%; postoperative 24 h: n = 5 trials; WMD, -10.02; 95% CI: -14.93, -5.12; p < 0.0001; I ²= 94%); and neutrophil elastase (NE) level (postoperative 6 h: n = 3 trials; WMD, -66.93; 95% CI: -111.94, -21.92; p = 0.004; I ²= 86%). However, TXA achieved no statistically significant influence on the postoperative 24 h NE level.

Conclusions

TXA had a significant anti-inflammatory effect in adult cardiac surgical patients, as evidenced by the reduction of multiple postoperative proinflammatory biomarkers levels, but these results should be interpreted carefully and cautiously, as only a limited number of studies were included and there was high heterogeneity between them.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022312919.

Inflammation and Oxidative Stress in the Context of Extracorporeal Cardiac and Pulmonary Support

Extracorporeal circulation (ECC) systems, including cardiopulmonary bypass, and extracorporeal membrane oxygenation have been an irreplaceable part of the cardiothoracic surgeries, and treatment of critically ill patients with respiratory and/or cardiac failure for more than half a century. During the recent decades, the concept of extracorporeal circulation has been extended to isolated machine perfusion of the donor organ including thoracic organs (ex-situ organ perfusion, ESOP) as a method for dynamic, semi-physiologic preservation, and potential improvement of the donor organs. The extracorporeal life support systems (ECLS) have been lifesaving and facilitating complex cardiothoracic surgeries, and the ESOP technology has the potential to increase the number of the transplantable donor organs, and to improve the outcomes of transplantation. However, these artificial circulation systems in general have been associated with activation of the inflammatory and oxidative stress responses in patients and/or in the exposed tissues and organs. The activation of these responses can negatively affect patient outcomes in ECLS, and may as well jeopardize the reliability of the organ viability assessment, and the outcomes of thoracic organ preservation and transplantation in ESOP. Both ECLS and ESOP consist of artificial circuit materials and components, which play a key role in the induction of these responses. However, while ECLS can lead to systemic inflammatory and oxidative stress responses negatively affecting various organs/systems of the body, in ESOP, the absence of the organs that play an important role in oxidant scavenging/antioxidative replenishment of the body, such as liver, may make the perfused organ more susceptible to inflammation and oxidative stress during extracorporeal circulation. In the present manuscript, we will review the activation of the inflammatory and oxidative stress responses during ECLP and ESOP, mechanisms involved, clinical implications, and the interventions for attenuating these responses in ECC.

Lung injury after cardiopulmonary bypass: Alternative treatment prospects

Although the lung injury caused by cardiopulmonary bypass (CPB) has been extensively investigated, the incidence and mortality of lung injury after CPB remain a prominent clinical problem. The poor outcome has been attributed to multifactorial etiology, including the systemic inflammatory response and ischemia reperfusion (I/R) injury during CPB. Lung injury after CPB is a complex pathophysiological process and has many clinical manifestations of mild to severe disease. Which is associated with prognosis. To alleviate this lung injury, interventions that address the pathogenesis are particularly important. This review summarizes the pathogenesis, mechanism and treatment options of lung injury after CPB, such as lung protection with intralipid.

Protective effect of dexmedetomidine on intestinal mucosal barrier function in rats after cardiopulmonary bypass

Cardiopulmonary bypass can result in damage to the intestines, leading to the occurrence of systemic inflammatory response syndrome. Dexmedetomidine is reported to confer anti-inflammatory properties. Here, the purpose of this study is to investigate the effect of dexmedetomidine on the intestinal mucosa barrier damage in a rat model of cardiopulmonary bypass. It was observed that cardiopulmonary bypass greatly decreased the levels of hemodynamic parameters than SHAM group, whereas dexmedetomidine pretreatment in a cardiopulmonary bypass model rat prevented this reduction. Also, it showed that compared with control animals, cardiopulmonary bypass caused obvious mucosal damage, which was attenuated in dexmedetomidine + cardiopulmonary bypass group. The above findings were in line with that of dexmedetomidine pretreatment, which increased the expression of tight junction proteins, but it decreased the levels of DAO, D-LA, FABP2, and endotoxin. Moreover, the results demonstrated that due to pre-administration of dexmedetomidine, the level of pro-inflammatory factors was decreased, while the level of anti-inflammatory cytokine was increased. Also, it showed that dexmedetomidine suppressed TLR4/JAK2/STAT3 pathway that was activated by cardiopulmonary bypass. Together, these results revealed that dexmedetomidine pretreatment relieves intestinal microcirculation, attenuates intestinal damage, and inhibits the inflammatory response of cardiopulmonary bypass model rats, demonstrating that in CPB-induced damage of intestinal mucosal barrier function, dexmedetomidine pretreatment plays a protective role by inactivating TLR4/JAK2/STAT3-mediated inflammatory pathway.

Antifibrinolytic Drugs for the Prevention of Bleeding in Pediatric Cardiac Surgery on Cardiopulmonary Bypass: A Systematic Review and Meta-analysis

BACKGROUND

Bleeding is one of the commonest complications affecting children undergoing cardiac surgery on cardiopulmonary bypass. Antifibrinolytic drugs are part of a multifaceted approach aimed at reducing bleeding, though sufficiently sized pediatric studies are sparse, and dosing algorithms are heterogeneous. Our objective was to evaluate the efficacy and safety of antifibrinolytic agents as well as the effectiveness of different dosing regimens in pediatric cardiac surgery using cardiopulmonary bypass.

METHODS

We performed a systematic review and meta-analysis evaluating randomized controlled trials published between 1980 and 2019, identified by searching the databases MEDLINE, EMBASE, PubMed, and CENTRAL. All studies investigating patients <18 years of age without underlying hematological disorders were included. The primary outcome was postoperative bleeding; secondary end points included blood product transfusion, mortality, and safety (thromboses, anaphylaxis, renal or neurological dysfunction, and seizures). Different dosing regimens were compared. Studies were dual appraised, outcomes were reported descriptively and, if appropriate, quantitatively using the Review Manager 5 (REVMAN 5) software (The Cochrane Collaboration).

RESULTS

Thirty of 209 articles were included, evaluating the following drugs versus control: aprotinin n = 14, tranexamic acid (TXA) n = 12, and epsilon-aminocaproic acid (EACA) n = 4. The number of participants per intervention group ranged from 11 to 100 (median, 25; interquartile range [IQR], 20.5) with a wide age span (mean, 13 days to 5.8 years) and weight range (mean, 3.1-26.3 kg). Methodological quality was low to moderate.All agents reduced mean 24-hour blood loss compared to control: aprotinin by 6.0 mL/kg (95% confidence interval [CI], -9.1 to -3.0; P = .0001), TXA by 9.0 mL/kg (95% CI, -11.3 to -6.8; P < .00001), and EACA by 10.5 mL/kg (95% CI, -21.1 to 0.0; P = .05). Heterogeneity was low for TXA (I2 = 29%; P = .19), moderate for aprotinin (I2 = 41%; P = .11), and high for EACA (I2 = 95%; P = <.00001). All agents also reduced 24-hour blood product transfusion. There was no clear dose-response effect for TXA nor aprotinin. Studies were underpowered to detect significant differences in mortality, thromboses, anaphylaxis, and renal or neurological dysfunction.

CONCLUSIONS

The available data demonstrate efficacy for all 3 antifibrinolytic drugs. Therefore, the agent with the most favorable safety profile should be used. As sufficient data are lacking, large comparative trials are warranted to assess the relative safety and appropriate dosing regimens in pediatrics.

Effect of Aprotinin and Avifavir® Combination Therapy for Moderate COVID-19 Patients

COVID-19 is a contagious multisystem inflammatory disease caused by a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We studied the efficacy of Aprotinin (nonspecific serine proteases inhibitor) in combination with Avifavir^® or Hydroxychloroquine (HCQ) drugs, which are recommended by the Russian Ministry of Health for the treatment therapy of moderate COVID-19 patients. This prospective single-center study included participants with moderate COVID-19-related pneumonia, laboratory-confirmed SARS-CoV-2, and admitted to the hospitals. Patients received combinations of intravenous (IV) Aprotinin (1,000,000 KIU daily, 3 days) and HCQ (cohort 1), inhalation (inh) treatment with Aprotinin (625 KIU four times per day, 5 days) and HCQ (cohort 2) or IV Aprotinin (1,000,000 KIU daily for 5 days) and Avifavir (cohort 3). In cohorts 1–3, the combination therapy showed 100% efficacy in preventing the transfer of patients (n = 30) to the intensive care unit (ICU). The effect of the combination therapy in cohort 3 was the most prominent, and the median time to SARS-CoV-2 elimination was 3.5 days (IQR 3.0–4.0), normalization of the CRP concentration was 3.5 days (IQR 3–5), of the D-dimer concentration was 5 days (IQR 4 to 5); body temperature was 1 day (IQR 1–3), improvement in clinical status or discharge from the hospital was 5 days (IQR 5–5), and improvement in lung lesions of patients on 14 day was 100%.

Transient perioperative inflammation following lung transplantation and major thoracic surgery with elective extracorporeal support: a prospective observational study

Background

The clinical relevance of inflammation induced by elective perioperative extracorporeal membrane oxygenation (ECMO) usage as an integral part of modern lung transplantation (LUTX) remains elusive. The aim of this study was to determine the perioperative cytokine response accompanying major thoracic surgery employing different extracorporeal devices comprising ECMO, cardiopulmonary bypass (CPB), or no extracorporeal circulation in relation to inflammation, clinically tangible as increased sequential organ failure assessment (SOFA) score, called SOFA.

Methods

In this prospective, observational pilot study 42 consecutive patients with end-stage pulmonary disease undergoing LUTX; 15 patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing pulmonary endarterectomy and 15 patients with lung cancer undergoing major lung resections were analysed. Cytokine serum concentrations and SOFA were determined before, at end of surgery and in the following postoperative days.

Results

LUTX on ECMO and pulmonary endarterectomy (PEA) on CPB triggered an immediate increase in cytokine serum concentrations at end of surgery: IL-6: 66-fold and 71-fold, IL-10: 3-fold and 2.5-fold, ST2/IL-33R: 5-fold and 4-fold and SOFA: 10.5±2.8 and 10.7±1.7, that decreased sharply to baseline levels from postoperative day 1–5. Despite low perioperative mortality (3 patients, 4.1%) extremely high SOFA ≥13 was associated with mortality after LUTX. Delta-SOFA distinguished survivors from non-survivors: −4.5±3.2 vs. −0.3±1.5 (P=0.001). Increased IL-6 serum concentrations were predictive for increased SOFA (sensitivity: 97%, specificity: 80%). Peak cytokine serum concentrations correlated with ECC duration, maximal lactate, transfusion of red-blood-cells, fresh-frozen-plasma, and catecholamine support.

Conclusions

LUTX and PEA on extracorporeal circulation with an excellent outcome triggered an immediate rise and concomitant fall of inflammation as observed in cytokine serum concentrations and SOFA. High absolute SOFA in the presence of an uncomplicated postoperative course may pertain to specific management strategies rather than organ failure.

Association of temporal trends in neutrophil lymphocyte ratio on left ventricular assist device patient outcomes

Neutrophil to lymphocyte ratio (NLR) can predict mortality/complications in left ventricular assist device (LVAD) patients; however, the prognostic value of longitudinal NLR measurements has not been well studied. Here, we examine the mortality/complication incidence in patients with chronically increased NLR verses patients with acutely elevated NLR as a predictor of patient outcomes. This retrospective analysis included 102 patients who underwent LVAD implantation from 2016 to 2018 at a single center. The NLR was calculated at the time of surgery, and at 30 and 90 days after surgery. The NLR values were grouped into categorical data: low, normal (put in range), and high. Patients were classified in 2 groups based on change in their NLR values from surgery to 90 days; the H90 group had sustained increase of NLR over 90-days and the N90 group had normalization of NLR at 90-days. Actuarial survival the between study groups was measured using Kaplan-Meier curves. The N90 group had 50 patients (median age 58 (48-66) years, 21% female) at the time of LVAD placement. Group H90 had 52 patients (median age 64 (52-68) years, 16% female). Median age, body mass index (BMI), bilirubin, creatinine, and BNP at time of implant as well as type of device and implant strategy were comparable between the study groups. The post implant survival for N90 group was significantly better than the H90 group at 1 year (93% vs. 80%) and 2 years (90% vs. 67%) (log-rank P = .001). Early post LVAD survival in patients with elevated NLR over 90 days postoperatively was significantly worse compared to patients who normalized the NLR at 90 days.

Targeting Crucial Host Factors of SARS-CoV-2

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide since its first incidence in Wuhan, China, in December 2019. Although the case fatality rate of COVID-19 appears to be lower than that of SARS and Middle East respiratory syndrome (MERS), the higher transmissibility of SARS-CoV-2 has caused the total fatality to surpass other viral diseases, reaching more than 1 million globally as of October 6, 2020. The rate at which the disease is spreading calls for a therapy that is useful for treating a large population. Multiple intersecting viral and host factor targets involved in the life cycle of the virus are being explored. Because of the frequent mutations, many coronaviruses gain zoonotic potential, which is dependent on the presence of cell receptors and proteases, and therefore the targeting of the viral proteins has some drawbacks, as strain-specific drug resistance can occur. Moreover, the limited number of proteins in a virus makes the number of available targets small. Although SARS-CoV and SARS-CoV-2 share common mechanisms of entry and replication, there are substantial differences in viral proteins such as the spike (S) protein. In contrast, targeting cellular factors may result in a broader range of therapies, reducing the chances of developing drug resistance. In this Review, we discuss the role of primary host factors such as the cell receptor angiotensin-converting enzyme 2 (ACE2), cellular proteases of S protein priming, post-translational modifiers, kinases, inflammatory cells, and their pharmacological intervention in the infection of SARS-CoV-2 and related viruses.

Patient Blood Management in Pediatric Cardiac Surgery: A Review

Efforts to reduce blood product transfusions and adopt blood conservation strategies for infants and children undergoing cardiac surgical procedures are ongoing. Children typically receive red blood cell and coagulant blood products perioperatively for many reasons, including developmental alterations of their hemostatic system, and hemodilution and hypothermia with cardiopulmonary bypass that incites inflammation and coagulopathy and requires systemic anticoagulation. The complexity of their surgical procedures, complex cardiopulmonary interactions, and risk for inadequate oxygen delivery and postoperative bleeding further contribute to blood product utilization in this vulnerable population. Despite these challenges, safe conservative blood management practices spanning the pre-, intra-, and postoperative periods are being developed and are associated with reduced blood product transfusions. This review summarizes the available evidence regarding anemia management and blood transfusion practices in the perioperative care of these critically ill children. The evidence suggests that adoption of a comprehensive blood management approach decreases blood transfusions, but the impact on clinical outcomes is less well studied and represents an area that deserves further investigation.

Risk stratification with longitudinal neutrophil to lymphocyte ratio assessment after left ventricular assist device implantation

Introduction:

Inflammatory processes are well-characterized risk factors in cardiovascular disease including advanced heart failure. Previous studies have utilized individual white cell subtypes in risk analysis, and a recent study has focused on the efficacy of the neutrophil-to-lymphocyte ratio in evaluating negative outcomes following left ventricular assist device implantation. To investigate the interaction between the left ventricular assist device and white cell counts, we assessed longitudinal changes in neutrophil-to-lymphocyte ratio following left ventricular assist device implantation.

Methods:

This retrospective study included 100 patients who underwent left ventricular assist device implantation between 2012 and 2013. The neutrophil-to-lymphocyte ratio was calculated prior to left ventricular assist device implantation, daily for the first 30 postoperative days, and at the first two postoperative outpatient visits. Preoperative demographic and clinical data were collected for all patients.

Results:

The mean neutrophil-to-lymphocyte ratio immediately before left ventricular assist device implantation was 5.2 ± 4.9. After surgery, the neutrophil-to-lymphocyte ratio decreased asymptotically, from a peak of 29.2 on postoperative day 1 to 4.1 at the second outpatient visit ( p < 0.001). Lack of improvement in the neutrophil-to-lymphocyte ratio at postoperative day 10 was associated with increased length of stay, right heart failure, and a trend toward worsened survival.

Conclusion:

Our results indicate a significant inflammatory response to implantation of the left ventricular assist device, a known effect. The magnitude of this response may be effectively and easily monitored over time using the neutrophil-to-lymphocyte ratio. In general, approximately 30 days is required for the neutrophil-to-lymphocyte ratio to return to preoperative levels. After several months, the neutrophil-to-lymphocyte ratio improves to below preoperative levels. It is possible that this reduction reflects the reversal of various heart failure–mediated inflammatory processes following left ventricular assist device implantation.

The effect of air exposure on leucocyte and cytokine activation in an in-vitro model of cardiotomy suction

Introduction:

Cardiopulmonary bypass (CPB) is known to cause a systemic inflammatory and immune response.

Objective:

An in-vitro model of cardiotomy suction was designed to quantify the effects of incrementally increased air-blood exposure on leucocyte marker CD11b and cytokine activation in two common anticoagulants, heparin and citrate.

Methods:

Fresh human blood was exposed to increasing amounts of air flow for ten minutes. Leucocyte and cytokine levels were measured prior to and after ten minutes of air flow. Cytokine levels were also measured after air exposure when incubated for 24 hours at 37oC.

Results:

Leucocyte activation, measured by CD11b, was elevated between baseline and air flow rates up to 50 mL/min. After 10 minutes of air exposure, no measured cytokine levels were elevated. After 24 hours of incubation, cytokine levels of TNFα, IL-10, IL-6, and IL-8 were elevated. However, only IL-8 was significantly elevated in citrated blood, but not in heparinized blood, when compared to baseline samples that were also incubated for 24 hours.

Conclusion:

This study investigates CD11b levels in response to an air stimulus in blood that was anticoagulated with citrate or heparin. Exposure to an air stimulus activates leucocytes. Activation of CD11b was less when using heparin as an anticoagulant compared to citrate. Cytokine activation occurs with air stimulation, but levels do not immediately rise, indicating that time is required to generate free cytokines.

Antifibrinolytic Therapy and Perioperative Considerations

Fibrinolysis is a physiologic component of hemostasis that functions to limit clot formation. However, after trauma or surgery, excessive fibrinolysis may contribute to coagulopathy, bleeding, and inflammatory responses. Antifibrinolytic agents are increasingly used to reduce bleeding, allogeneic blood administration, and adverse clinical outcomes. Tranexamic acid is the agent most extensively studied and used in most countries. This review will explore the role of fibrinolysis as a pathologic mechanism, review the different pharmacologic agents used to inhibit fibrinolysis, and focus on the role of tranexamic acid as a therapeutic agent to reduce bleeding in patients after surgery and trauma.

Effectiveness and Safety of Aprotinin Use in Thoracic Aortic Surgery

OBJECTIVE

To determine the effectiveness and safety of aprotinin use in adult patients undergoing thoracic aortic surgery.

DESIGN

Single-center, retrospective study.

SETTING

All cases performed at a single university hospital.

PARTICIPANTS

Between January 2004 and December 2014, 846 adult patients underwent thoracic aortic surgery. Due to missing or duplicated data on primary outcomes, 314 patients were excluded. The final sample of 532 patients underwent surgery on the thoracic aorta.

INTERVENTIONS

The patients were divided in the following 2 groups: 107 patients (20.1%) received aprotinin during the surgery, which represented the study group, whereas the remaining 425 patients (79.9%) underwent surgery without the use of aprotinin.

MEASUREMENTS AND MAIN RESULTS

To adjust for patient selection and preoperative characteristics, a propensity score-matched analysis was conducted. Mean total blood loss at 12 hours after surgery was similar between the 2 groups. The blood product transfusion rates did not differ in the 2 groups, except for the rate of fresh frozen plasma transfusion being significantly higher in the aprotinin group. Re-exploration for bleeding and the incidence of a major postoperative bleeding event were similar between the groups. Rates of in-hospital mortality, renal failure, and cerebrovascular accidents did not show any statistically significant difference. Aprotinin did not represent a risk factor for mortality over the long term (hazard ratio 1.14, 95% confidence interval 0.62-2.08, p = 0.66).

CONCLUSIONS

The use of aprotinin demonstrated a limited effect in reducing postoperative bleeding and prevention of major bleeding events. Aprotinin did not adversely affect early outcomes and long-term survival.

Polymer-coated cardiopulmonary bypass circuit attenuates upregulation of both proteases/protease inhibitors and platelet degranulation in pigs

Introduction:

Interaction of blood with a cardiopulmonary bypass (CPB) circuit activates the coagulation-fibrinolysis, complement and kinin-kallikrein systems that are mainly supported by proteases and their inhibitors.

Methods:

Biocompatibility of a new polymer-coated (SEC-coated) CPB circuit was globally evaluated and compared with that of a non-coated CPB circuit by quantitative proteomics, using isobaric tags for relative and absolute quantification labeling tandem mass spectrometry. Plasma samples were taken three times (5 min after initiation of CPB, just before declamping and just before termination of CPB) in 12 pigs undergoing 120 min of CPB with the SEC-coated CPB circuit or a non-coated CPB circuit (n = 6, respectively).

Results:

Identified were 224 proteins having high protein confidence (>99%) and false discovery rate (FDR) <5%. Among these proteins, there were 25 significantly upregulated proteins in the non-coated CPB group compared to those in the SEC-coated CPB group. Dominant protein functions were platelet degranulation, serine-type (cysteine-type) endopeptidase inhibitor activity and serine-type endopeptidase activity in the 25 proteins. Bioinformatics analysis similarly revealed upregulation of proteins belonging to platelet degranulation and negative regulation of endopeptidase activity in the non-coated CPB group; these upregulations were effectively attenuated in the SEC-coated CPB group.

Conclusion:

The new polymer (SEC)-coated CPB circuit effectively attenuated upregulation of proteins compared to the non-coated CPB circuit. These proteins were associated with both proteases/protease inhibitors and platelet degranulation.

Plasma Kallikrein Inhibitors in Cardiovascular Disease: An Innovative Therapeutic Approach

Plasma prekallikrein is the liver-derived precursor of the trypsin-like serine protease plasma kallikrein, and circulates in plasma bound to high molecular weight kininogen. Plasma prekallikrein is activated to plasma kallikrein by activated factor XII or prolylcarboxypeptidase. Plasma kallikrein regulates the activity of multiple proteolytic cascades in the cardiovascular system such as the intrinsic pathway of coagulation, the kallikrein-kinin system, the fibrinolytic system, the renin-angiotensin system, and the complement pathways. As such, plasma kallikrein plays a central role in the pathogenesis of thrombosis, inflammation, and blood pressure regulation. Under physiological conditions, plasma kallikrein serves as a cardioprotective enzyme. However, its increased plasma concentration or hyperactivity perpetuates cardiovascular disease (CVD). In this article, we review the biochemistry and cell biology of plasma kallikrein and summarize data from preclinical and clinical studies that have established important functions of this serine protease in CVD states. Finally, we propose plasma kallikrein inhibitors as a novel class of drugs with potential therapeutic applications in the treatment of CVDs.

Leukocyte filtration and aprotinin: synergistic anti-inflammatory protection

Cardiopulmonary bypass activates an array of cellular and humoral inflammatory mechanisms that culminate in diverse or organ-specific injury. A manifestation of inflammatory injury to the heart, atrial fibrillation ranks among the most frequent and potentially life-threatening postsurgical complications. Pulmonary manifestations of the inflammatory response are also of major concern. Neutrophils activated by passage through the extracorporeal circuit inflict local injury and provoke the inflammatory cascade by producing oxyradicals and proinflammatory factors. This study tested if a combination of leukocyte depletion and aprotinin suppression of neutrophils could minimize postbypass atrial fibrillation and pulmonary dysfunction. In part one, two randomized groups of 90 patients undergoing primary coronary artery bypass grafting received full Hammersmith aprotinin alone (control group) or combined with leukofiltration (study group) and were prospectively examined. The dual treatment decreased the incidence of postoperative atrial fibrillation (7 of 90, 7.8%) by 67% versus aprotinin alone (21 of 90, 23.3%). Respiratory gas exchange in these patients was assessed from pulmonary shunt fraction. In the first two hours postbypass, pulmonary shunt fraction in the dual treatment group increased 40% less than in the group receiving aprotinin alone (p = 0.002), and subsided more quickly and completely over the next six hours. In part two, the cardiopulmonary bypass group receiving aprotinin+leukofiltration was retrospectively compared with 45 patients undergoing off-pump coronary revascularization. A strong, albeit not statistically significant trend (p= 0.08) toward a lower incidence of atrial fibrillation was found in the dual treatment group versus the off-pump group (8 of 45, 17.8%). These findings suggest that combining mechanical and pharmacologic suppression of the systemic inflammatory response could mitigate its deleterious arrhythmic and pulmonary complications.

Anti-inflammatory effects of propofol during cardiopulmonary bypass: a pilot study

Introduction:

Propofol has been suggested as a useful adjunct to cardiopulmonary bypass (CPB) because of its potential protective effect on the heart mediated by a decrease in ischemia-reperfusion injury and inflammation at clinically relevant concentrations. In view of these potentially protective properties, which modulate many of the deleterious mechanism of inflammation attributable to reperfusion injury and CPB, we sought to determine whether starting a low dose of propofol infusion at the beginning of CPB would decrease inflammation as measured by pro-inflammatory markers.

Materials and Methods:

We enrolled 24 patients undergoing elective coronary artery bypass graft (CABG). The study group received propofol at rate of 120 mcg/kg/min immediately after starting CPB and was maintained throughout the surgery and for the following 6 hours in the intensive care unit (ICU). The control group received propofol dose of 30-50 mcg/kg/min which was started at the time of chest closure with wires and continued for the next 6 hours in the ICU. Interleukins (IL) -6, -8 and -10 and tumor necrosis factor alpha (TNFalpha) were assayed.

Result:

The most significant difference was in the level of IL-6 which had a P value of less than 0.06. Starting a low dose propofol early during the CPB was not associated with significant hemodynamic instability in comparison with the control group.

Conclusion:

Our study shows that propofol may be suitable as an anti-inflammatory adjunct for patients undergoing CABG.

RECCAS - REmoval of Cytokines during CArdiac Surgery: study protocol for a randomised controlled trial

Background

On-pump cardiac surgery triggers a significant postoperative systemic inflammatory response, sometimes resulting in multiple-organ dysfunction associated with poor clinical outcome. Extracorporeal cytokine elimination with a novel haemoadsorption (HA) device (CytoSorb®) promises to attenuate inflammatory response. This study primarily assesses the efficacy of intraoperative HA during cardiopulmonary bypass (CPB) to reduce the proinflammatory cytokine burden during and after on-pump cardiac surgery, and secondarily, we aim to evaluate effects on postoperative organ dysfunction and outcomes in patients at high risk.

Methods/design

This will be a single-centre randomised, two-arm, patient-blinded trial of intraoperative HA in patients undergoing on-pump cardiac surgery. Subjects will be allocated to receive either CPB with intraoperative HA or standard CPB without HA. The primary outcome is the difference in mean interleukin 6 (IL-6) serum levels between the two study groups on admission to the intensive care unit. A total number of 40 subjects was calculated as necessary to detect a clinically relevant 30 % reduction in postoperative IL-6 levels. Secondary objectives evaluate effects of HA on markers of inflammation up to 48 hours postoperatively, damage to the endothelial glycocalyx and effects on clinical scores and parameters of postoperative organ dysfunction and outcomes.

Discussion

In this pilot trial we try to assess whether intraoperative HA with CytoSorb® can relevantly reduce postoperative IL-6 levels in patients undergoing on-pump cardiac surgery. Differences in secondary outcome variables between the study groups may give rise to further studies and may lead to a better understanding of the mechanisms of haemoadsorption.

Trial registration

German Clinical Trials Register number DRKS00007928 (Date of registration 3 Aug 2015)

Methylprednisolone in patients undergoing cardiopulmonary bypass (SIRS): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Cardiopulmonary bypass initiates a systemic inflammatory response syndrome that is associated with postoperative morbidity and mortality. Steroids suppress inflammatory responses and might improve outcomes in patients at high risk of morbidity and mortality undergoing cardiopulmonary bypass. We aimed to assess the effects of steroids in patients at high risk of morbidity and mortality undergoing cardiopulmonary bypass.

METHODS

The Steroids In caRdiac Surgery (SIRS) study is a double-blind, randomised, controlled trial. We used a central computerised phone or interactive web system to randomly assign (1:1) patients at high risk of morbidity and mortality from 80 hospital or cardiac surgery centres in 18 countries undergoing cardiac surgery with the use of cardiopulmonary bypass to receive either methylprednisolone (250 mg at anaesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients were assigned with block randomisation with random block sizes of 2, 4, or 6 and stratified by centre. Patients aged 18 years or older were eligible if they had a European System for Cardiac Operative Risk Evaluation of at least 6. Patients were excluded if they were taking or expected to receive systemic steroids in the immediate postoperative period or had a history of bacterial or fungal infection in the preceding 30 days. Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcomes were 30-day mortality and a composite of death and major morbidity (ie, myocardial injury, stroke, renal failure, or respiratory failure) within 30 days, both analysed by intention to treat. Safety outcomes were also analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00427388.

FINDINGS

Patients were recruited between June 21, 2007, and Dec 19, 2013. Complete 30-day data was available for all 7507 patients randomly assigned to methylprednisolone (n=3755) and to placebo (n=3752). Methylprednisolone, compared with placebo, did not reduce the risk of death at 30 days (154 [4%] vs 177 [5%] patients; relative risk [RR] 0·87, 95% CI 0·70-1·07, p=0·19) or the risk of death or major morbidity (909 [24%] vs 885 [24%]; RR 1·03, 95% CI 0·95-1·11, p=0·52). The most common safety outcomes in the methylprednisolone and placebo group were infection (465 [12%] vs 493 [13%]), surgical site infection (151 [4%] vs 151 [4%]), and delirium (295 [8%] vs 289 [8%]).

INTERPRETATION

Methylprednisolone did not have a significant effect on mortality or major morbidity after cardiac surgery with cardiopulmonary bypass. The SIRS trial does not support the routine use of methylprednisolone for patients undergoing cardiopulmonary bypass.

FUNDING

Canadian Institutes of Health Research.

The safety and efficacy of antifibrinolytic therapy in neonatal cardiac surgery

Background

Neonates undergoing open-heart surgery are particularly at risk of postoperative bleeding requiring blood transfusion. Aprotinin has attained high efficacy in reducing the requirement for a blood transfusion following a cardiopulmonary bypass, but is seldom studied in the neonatal age group. The aim of this study was to compare the efficacy and adverse effects of aprotinin and tranexamic acid in neonates undergoing open-heart surgery at a single centre.

Methods

Between October 2003 and March 2008, perioperative data of 552 consecutive neonatal patients undergoing open-heart surgery in Children’s Hospital Boston were reviewed. Among them, 177 did not receive antifibrinolytic therapy (Group A); 100 were treated with tranexamic acid only (Group B); and 275 patients received aprotinin with or without tranexamic acid (Group C). Except for antifibrinolytic therapy, the anaesthesiological and surgical protocols remained identical. Postoperative complications and in-hospital mortality were the primary study endpoints.

Results

Body weight and Risk Adjustment for Congenital Heart Surgery (RACHS-1) scores were statistically comparable among the three groups. No statistically significant differences were observed between the duration of hospitalization, chest tube drainage, reexploration for bleeding, and kidney function impairment. In Group C, less blood was transfused within 24 hours than in GroupB. Operative mortality was similar among the three groups.

Conclusion

No further risk and kidney injury were observed in the use of aprotinin in neonatal cardiac surgery, aprotinin demonstrated a reduced requirement for blood transfusion compared with tranexamic acid. Our data provide reasonable evidence that aprotinin and tranexamic acid are safe and efficacious as antifibrinolytic modalities in neonatal patients undergoing cardiac surgery.

Lung inflammatory response syndrome after cardiac-operations and treatment of lornoxicam

The majority of patients survive after extracorporeal circulation without any clinically apparent deleterious effects. However, disturbances exist in various degrees sometimes, which indicate the harmful effects of cardiopulmonary bypass (CPB) in the body. Several factors during extracorporeal circulation either mechanical dependent (exposure of blood to non-biological area) or mechanical independent (surgical wounds, ischemia and reperfusion, alteration in body temperature, release of endotoxins) have been shown to trigger the inflammatory reaction of the body. The complement activation, the release of cytokines, the leukocyte activation and accumulation as well as the production of several "mediators" such as oxygen free radicals, metabolites of arachidonic acid, platelet activating factors (PAF), nitric acid, and endothelin. The investigation continues today on the three metabolites of lornoxicam (the hydroxylated metabolite and two other metabolites of unknown chemical composition) to search for potential new pharmacological properties and activities.

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.

Recombinant bovine pancreatic trypsin inhibitor protects the liver from carbon tetrachloride-induced chronic injury in rats

CONTEXT

Bovine pancreatic trypsin inhibitor (BPTI) has been reported to relieve liver ischemia-reperfusion-induced injury in rats.

OBJECTIVE

This study was designed to determine whether the recombinant BPTI (rBPTI) can prevent the chronic liver injury induced by CCl4 in rats.

MATERIALS AND METHODS

Fifty male Wistar rats were divided into five groups. Rats were treated with 40% CCl4 at a dose of 2 ml/kg body weight twice a week subcutaneously for 12 weeks. In the 8th week, they were administered intraperitoneally with rBPTI (80 MU/kg), BPTI (80 MU/kg) or hepatocyte growth-promoting factor (pHGF; 100 mg/kg) daily for the next 4 weeks.

RESULTS

rBPTI significantly prevented the disruption of liver function of alanine aminotransferase (ALT; 172.7 ± 18.16 versus 141.2 ± 15.28, p=0.003), aspartate aminotransferase (AST; 225.10 ± 36.54 versus 170.06 ± 27.14, p=0.007) and hydroxyproline (Hyp; 1.14 ± 0.27 versus 0.62 ± 0.17, p=0.001). rBPTI significantly decreased the level of thiobarbituric acid reactive substances (TBARS; 1.15 ± 0.16 versus 0.87 ± 0.15, p=0.003) and increased the activities of superoxide dismutase (SOD; 6.07 ± 0.95 versus 7.75 ± 1.12, p=0.007). rBPTI reduced the production of cytokines of IL-1β and TGF-β. The hepatocyte necrosis, fibrosis, fatty degeneration and inflammatory cell infiltration were ameliorated by rBPTI administration.

CONCLUSION

This study demonstrated that rBPTI exerted a hepatoprotective effect on chronic liver fibrosis induced by CCl4, which suggests that rBPTI may have the potential application for chronic liver injury induced by drugs metabolism and toxic substances.

Probiotics can alleviate cardiopulmonary bypass-induced intestinal mucosa damage in rats

BACKGROUND

Cardiopulmonary bypass (CPB) is commonly applied to support circulation during heart surgery but frequently causes adverse effects.

AIMS

The purpose of this study was to examine the potential of probiotics to improve small intestinal mucosa barrier function after CPB.

METHODS

Twenty-four adult male SD rats were randomly divided into sham-operated (S), CPB-operated (CPB), and probiotic-fed (Y) groups. Diamine oxidase (DAO) activity and concentrations of D-lactic acid, endotoxin, TNFα, and IL-6 were measured in portal vein blood. IgA concentrations were determined in plasma and the small intestine. Vena cava blood and tissue samples were used to monitor bacterial growth. Intestinal epithelial ultrastructure was analyzed by transmission electron microscopy (TEM). Occludin and ZO-1 expression levels in the intestinal epithelium were detected by western blotting and immunohistochemistry, respectively.

RESULTS

D-lactic acid, endotoxin, TNFα and IL-6 levels, DAO activity, and bacterial translocation rate were increased (P < 0.05) in CPB and Y compared to the S group. The above indices were relatively lower (P < 0.05) in Y than in CPB. Plasma and small intestinal IgA levels were significantly lower (P < 0.05) in CPB, while in Y they were significantly increased (P < 0.05) but lower than in S (P < 0.05). These results were confirmed by TEM. Consistently, occludin and ZO-1 expression levels were significantly higher in Y than in CPB (P < 0.05) but still lower compared to S (P < 0.05).

CONCLUSION

Pre-administration of probiotics can improve, to some extent, intestinal barrier function after CPB in rats, and this effect is likely related to inhibition of the CPB-induced inflammatory response, improvement in local intestinal immune function, and increased expression of intestinal epithelial tight junction proteins.

A comparative study of the immune modulating properties of antifibrinolytics in cardiac surgery

PURPOSE

Antifibrinolytics, used in cardiac surgery to abate postoperative blood loss, share anti-inflammatory properties by suppression of pro-inflammatory D-dimer and plasmin levels. Additional drug specific immune modulating qualities are often mentioned in the discussion on which antifibrinolytic can best be used. To determine the extent and relevance of these effects, we investigated cytokine and growth factor plasma levels in cardiac surgery patients randomized to receive either tranexamic acid, aprotinin, or placebo. Corticosteroid-treated patients served to put the effects in perspective.

METHODS

Using a biochip immunoassay, plasma of 36 cardiac surgery patients was quantified for 12 cytokines and growth factors, assessed preoperatively and 6, 12, 24, and 48 h after the start of cardiopulmonary bypass. Eight patients were treated with tranexamic acid, nine with aprotinin, and nine received placebo. Ten placebo-treated patients received corticosteroids.

RESULTS

IL-1ß, IL-6, IL-8, IL-10, IFN-γ, TNF-α, VEGF, MCP-1, and EGF plasma concentrations significantly changed over time across all patients. Aprotinin-treated patients showed decreased pro-inflammatory TNF-α and peak MCP-1 plasma levels when compared with placebo. However, corticosteroids attenuated the inflammatory response to a much larger extent, lowering postoperative IL-6, IL-10, IFN-γ, and VEGF concentrations also.

CONCLUSIONS

Aprotinin attenuates postoperative pro-inflammatory levels TNF-α and MCP-1 whereas tranexamic acid does not. The majority of plasma proteins studied, however, were not affected by the use of antifibrinolytics when compared with placebo. A clinically relevant common anti-inflammatory effect through inhibition of fibrinolysis seems therefore unlikely.

High-dose aprotinin, blood product transfusions, and short-term outcome in neonates and infants: a pediatric cardiac surgery center experience

BACKGROUND

The efficacy of aprotinin, the most popular antifibrinolytic agent in congenital cardiac surgery, was still uncertain in small infants when its prophylactic use was suspended for safety reasons. The aim of this study is to describe associations between the prophylactic use of high-dose aprotinin, the need for blood product transfusions, and short-term outcome in neonates and infants with cardiac surgery.

METHODS/MATERIALS

This retrospective study included all patients younger than 1 year undergoing surgery with cardiopulmonary bypass through 42 months, before and after withdrawal of aprotinin. Each patient who received aprotinin was matched with a control with similar baseline and surgical characteristics, who have not received any antifibrinolytic agent. Associations between the use of aprotinin and the exposure to red blood cells, fresh frozen plasma, and platelet transfusions were estimated from a logistic regression model, and the exposure to additional transfusions from a polytomous regression model.

RESULTS

Matching resulted in two groups of 283 patients each, well balanced except for the priming volume and the ultrafiltration rate, larger in the aprotinin group. After adjustment for the priming volume and ultrafiltration rate, there was no significant association between the use of aprotinin, the exposure to any blood product transfusion, or the exposure to additional transfusions, the rate of re-exploration for bleeding, and short-term outcome. Two patients in the control group required re-exploration for bleeding.

CONCLUSIONS

No association was found between the prophylactic use of aprotinin, blood product transfusions, and short-term outcome in this population of neonates and infants.

Aortic valve replacement in a dialysis-dependent Jehovah's Witness: successful use of a minicircuit, microplegia, and multimodality blood conservation technique

We present the first reported case of an aortic valve replacement operation without blood transfusion in a 62-year-old Jehovah's Witness with dialysis-dependent chronic renal failure, severe anemia, severe aortic stenosis, and symptomatic angina with minimal exertion after an accident in which she suffered fractures of both her right arm and leg. She underwent successful valve replacement surgery after preoperative stabilization of her fractures and high-dose erythropoietin and iron supplement therapy preoperatively and postoperatively. The intraoperative blood conservation technique included a novel approach with a miniature cardiopulmonary bypass circuit and microplegia with limited hemodilution. High-risk valve surgery in patients who are Jehovah's Witnesses can be successful with a carefully planned multimodality blood conservation strategy.

Postoperative complications following the Fontan procedure: the role of aprotinin

OBJECTIVE

To determine how the anti-inflammatory properties of aprotinin impact on postoperative complications in children undergoing the Fontan procedure.

METHODS

We included all patients between 14 months and 18 years (n=56) undergoing a Fontan operation at our institution between January 2005 and June 2009. The study group (n=29) included patients from January 2005 through December 2007 all of whom received aprotinin. The control group (n=27) included all patients from January 2008 through June 2009 who did not receive aprotinin. We reviewed all medical records and collected preoperative, intraoperative and postoperative data. Duration and volume of chest tube drainage were the primary outcome measures.

RESULTS

Of the 20% of patients who had postoperative arrhythmias, multivariate logistic regression analysis demonstrated only aprotinin was associated with significantly decreased postoperative arrhythmias (P=0.01). Renal function and fenestration or Fontan thrombosis did not differ significantly; there was no statistically significant difference in volume or duration of chest tube drainage. Median duration of chest tube drainage was 7 days in the aprotinin group and 8 days for patients who did not receive aprotinin (P=0.36).

CONCLUSION

The anti-inflammatory properties of aprotinin may be protective against postoperative arrhythmias. Aprotinin does not confer increased risks of prolonged chest tube drainage, renal dysfunction or thrombosis in patients undergoing the Fontan procedure.

Biochemical characterization of a novel high-affinity and specific plasma kallikrein inhibitor

BACKGROUND AND PURPOSE

Kallikrein acts on high molecular weight kininogen (HK) to generate HKa (cleaved HK) and bradykinin (BK). BK exerts its effects by binding to B(2) receptors. The activation of B(2) receptors leads to the formation of tissue plasminogen activator, nitric oxide (NO) and prostacyclin (PGI(2) ). An elevated kallikrein-dependent pathway has been linked to cardiovascular disease risk. The aim of this study was to investigate whether our novel plasma kallikrein inhibitor abolishes kallikrein-mediated generation of BK from HK and subsequent BK-induced NO and PGI(2) formation, thereby influencing endothelial pathophysiology during chronic inflammatory diseases.

EXPERIMENTAL APPROACH

Kinetic analysis was initially used to determine the potency of PF-04886847. Biochemical ligand binding assays, immunological methods and calcium flux studies were used to determine the selectivity of the kallikrein inhibitor. In addition, the effect of PF-04886847 on BK-induced relaxation of the rat aortic ring was determined in a model of lipopolysaccharide-induced tissue inflammation.

KEY RESULTS

Evidence was obtained in vitro and in situ, indicating that PF-04886847 is a potent and specific inhibitor of plasma kallikrein. PF-04886847 efficiently blocked calcium influx as well as NO and PGI(2) formation mediated through the BK-stimulated B(2) receptor signalling pathway. PF-04886847 blocked kallikrein-induced endothelial-dependent relaxation of isolated rat aortic rings pre-contracted with phenylephrine.

CONCLUSIONS AND IMPLICATIONS

PF-04886847 was shown to be the most potent small molecule inhibitor of plasma kallikrein yet described; it inhibited kallikrein in isolated aortic rings and cultured endothelial cells. Overall, our results indicate that PF-04886847 would be useful for the treatment of kallikrein-mediated inflammatory disorders.

Continuous localized monitoring of plasmin activity identifies differential and regional effects of the serine protease inhibitor aprotinin: relevance to antifibrinolytic therapy

BACKGROUND

Antifibrinolytic therapy, such as the use of the serine protease inhibitor aprotinin, was a mainstay for hemostasis after cardiac surgery. However, aprotinin was empirically dosed, and although the pharmacological target was the inhibition of plasmin activity (PLact), this was never monitored, off-target effects occurred, and led to withdrawn from clinical use. The present study developed a validated fluorogenic microdialysis method to continuously measure PLact and tested the hypothesis that standardized clinical empirical aprotinin dosing would impart differential and regional effects on PLact.

METHODS/RESULTS

Pigs (30 kg) were instrumented with microdialysis probes to continuously measure PLact in myocardial, kidney, and skeletal muscle compartments (deltoid) and then randomized to high-dose aprotinin administration (2 mKIU load/0.5 mKIU/hr infusion; n = 7), low-dose aprotinin administration (1 mKIU load/0.250 mKIU/hr infusion; n = 6). PLact was compared with time-matched vehicle (n = 4), and PLact was also measured in plasma by an in vitro fluorogenic method. Aprotinin suppressed PLact in the myocardium and kidney at both high and low doses, indicative that both doses exceeded a minimal concentration necessary for PLact inhibition. However, differential effects of aprotinin on PLact were observed in the skeletal muscle, indicative of different compartmentalization of aprotinin.

CONCLUSIONS

Using a large animal model and a continuous method to monitor regional PLact, these unique results demonstrated that an empirical aprotinin dosing protocol causes maximal and rapid suppression in the myocardium and kidney and in turn would likely increase the probability of off-target effects and adverse events. Furthermore, this proof of principle study demonstrated that continuous monitoring of determinants of fibrinolysis might provide a novel approach for managing fibrinolytic therapy.

No effect of a homoeopathic combination of Arnica montana and Bryonia alba on bleeding, inflammation, and ischaemia after aortic valve surgery

AIMS

" Arnica montana is a popular homoeopathic treatment with potential haemostatic and anti-inflammatory properties. A homoeopathic combination of A. montana and Bryonia alba was used in aortic valve surgery to evaluate its effectiveness in reducing bleeding, inflammation, pain and myocardial ischaemia.

METHODS

One day before surgery, 92 adult patients were randomly assigned to a double-blind parallel trial with either homoeopathic granules or a matching placebo until 4 days after surgery. The primary outcome was the volume of blood/liquid in the drains at their removal. The secondary outcomes included postoperative blood/liquid losses at 12 and 24 h as well as C-reactive protein (CRP), pain, temperature and plasma troponin Ic.

RESULTS

At 12 h and 24 h after surgery, then at drain removal, blood losses in homoeopathy and placebo groups were not statistically significant (362 +/- 218, 520 +/- 269 and 640 +/- 297 ml vs. 456 +/- 440, 620 +/- 477 and 796 +/- 717 ml; P= 0.19, 0.23 and 0.35, respectively). The statistical modelling did not show significantly different patterns of CRP, troponin and body temperature changes or of pain perception. The number of transfused packed red cells was not significantly different either (P= 0.58). Two patients from each group died during the study period and the number of serious adverse events was not statistically different (six in homoeopathy vs. 10 in placebo groups; Fisher's exact test P= 0.41).

CONCLUSIONS

In the study setting, there was no evidence of effects of A. montana and B. alba combination on bleeding, inflammation, pain or myocardial ischaemia.

Recombinant bovine pancreatic trypsin inhibitor protects the liver from carbon tetrachloride-induced acute injury in mice

OBJECTIVES

Toxicity caused by pharmacological and chemical substances, including carbon tetrachloride (CCl(4)), is a major pathological factor for liver injury. Therefore, strategies to prevent toxicity are needed for maintaining a healthy liver. This study was designed to determine whether recombinant bovine pancreatic trypsin inhibitor (rBPTI), a non-specific serine protease inhibitor, prevents CCl(4)-induced liver injury in mice.

METHODS

Mice were treated with CCl(4) in the presence or absence of co-treatment with rBPTI. Liver sections were prepared for histopathological assessment. Liver function was evaluated by detecting serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and liver index. Liver oxidative stress and inflammation were examined by detecting the liver malondialdehyde level and glutathione and superoxide dismutase activity, and serum tumour necrosis factor-alpha level, respectively.

KEY FINDINGS

CCl(4) induced hepatocyte necrosis, inflammatory cell infiltration and fatty degeneration, which were ameliorated by co-treatment with rBPTI in a concentration-dependent manner. Furthermore, rBPTI prevented CCl(4)-induced disruption of liver function. Importantly, rBPTI reduced CCl(4)-induced liver oxidative stress response and pro-inflammatory cytokine production.

CONCLUSIONS

These results indicated that rBPTI exerted a protective effect on CCl(4)-induced liver injury in mice. Thus, rBPTI may have potential application for prevention of liver injury induced by metabolism of drugs and toxic substances.

Circulating matrix metalloproteinase levels after ventricular septal defect repair in infants

BACKGROUND

Surgery for congenital heart disease initiates a complex inflammatory response that can influence the postoperative course. However, broad integration of the cytokine and proteolytic cascades (matrix metalloproteinases: MMPs), which may contribute to postoperative outcomes, has not been performed.

METHODS AND RESULTS

Using a low-volume (50-60 μL), high-sensitivity, multiplex approach, we serially measured a panel of cytokines (interleukins 2, 4, 6, 8, and 10, tumor necrosis factor alpha, interleukin 1β, and granulocyte-macrophage colony stimulating factor) and matrix metalloproteinases (matrix metalloproteinases 2, 3, 7, 8, 9, 12, and 13) in patients (n = 9) preoperatively and after repair of ventricular septal defect. Results were correlated with outcomes such as inotropic requirement, oxygenation, and fluid balance. Serial changes in perioperative plasma levels of the cytokines and matrix metalloproteinases exhibited distinct temporal profiles. Plasma levels of interleukins 2, 8, and 10 and matrix metalloproteinase 9 peaked within 4 hours, whereas levels of matrix metalloproteinase 3 and 8 remained elevated at 24 and 48 hours after crossclamp removal. Area-under-the-curve analysis of early cytokine levels were associated with major clinical variables, including inverse correlations between early interleukin 10 levels and cumulative inotrope requirement at 48 hours (r: -0.85; P < .005) and late matrix metalloproteinase 7 levels and cumulative fluid balance (r: -0.90; P < .001).

CONCLUSIONS

The unique findings of this study were that serial profiling a large array of cytokines and proteolytic enzymes after surgery for congenital heart disease can provide insight into relationships between changes in bioactive molecules to early postoperative outcomes. Specific patterns of cytokine and matrix metalloproteinase release may hold significance as biomarkers for predicting and managing the postoperative course after surgery for congenital heart disease.

Effects of aprotinin or tranexamic acid on proteolytic/cytokine profiles in infants after cardiac surgery

BACKGROUND

After cardiopulmonary bypass (CPB), elaboration of cytokines, and subsequent induction of interstitial proteases, such as matrix metalloproteinases (MMPs), can result in a complex postoperative course. The serine protease inhibitor, aprotinin, which has been used in congenital heart surgery putatively for modulating fibrinolysis is now unavailable, necessitating the use of lysine analogues such as tranexamic acid (TXA). The present study tested the hypothesis that distinctly different plasma profiles of signaling molecules and proteases would be differentially affected after the administration of aprotinin or TXA in the context of congenital cardiac surgery and CPB.

METHODS

Thirty-seven patients (age, 4.8 +/- 0.3 months) undergoing corrective surgery for ventricular septal defect and tetralogy of Fallot received either aprotinin (n = 22) or TXA (n = 15). Using a high throughput multiplex suspension immunoassay, plasma was serially quantified for cytokines and MMPs: before aprotinin or TXA (baseline), after separation from CPB, and 4, 12, 24, and 48 hours post-CPB.

RESULTS

Tumor necrosis factor-alpha increased initially after CPB in both the aprotinin and TXA groups, but at 24 and 48 hours post-CPB was approximately 50% lower in the aprotinin group (p < 0.05). The IL-10 levels were threefold higher in the TXA group compared with the aprotinin group immediately post-CBP (p < 0.05). Plasma levels of MMP types associated with inflammation, MMP-8, and MMP-9, were twofold higher in the late post-CPB period in the TXA group when compared with the aprotinin group.

CONCLUSIONS

After ventricular septal defect or tetralogy of Fallot repair in children, cytokine induction occurs, which is temporally related to the emergence of a specific MMP profile. Moreover, these unique findings demonstrated differential effects between the serine protease inhibitor aprotinin and the lysine analogue TXA with respect to cytokine and MMP induction in the early postoperative period. The different cytokine-proteolytic profile between these antifibrinolytics may in turn influence biologic processes in the postoperative period.

Effect of subzero-balanced ultrafiltration on postoperative outcome of patients after cardiopulmonary bypass

OBJECTIVE

To evaluate the effect of a new ultrafiltration technique - subzero-balanced ultrafiltration technique - on early postoperative outcomes of adult patients undergoing cardiac operations with cardiopulmonary bypass.

METHODS

A total of 120 patients who required cardiopulmonary bypass for cardiac surgery were randomized into two groups, 60 in each group. Patients in the treatment group received subzero-balanced ultrafiltration during cardiopulmonary bypass, while patients in the control group received routine cardiopulmonary bypass. Postoperative outcomes, including hospital mortality and morbidity of the two groups, were analyzed.

RESULTS

Hospital mortality was 0% (0 of 60) in the treatment group versus 1.8% (1 of 60) in the control group (P=1.000). Total hospital complications was lower in the treated patients (11 of 60 [18.3%] versus 22 of 60 [36.7%], P=0.025). Duration of intubation time was shorter and transfusion volume within 24 hours postoperatively was less in patients having received subzero-balanced ultrafiltration during cardiopulmonary bypass (14.35 + or - 1.66 versus 18.64 + or - 1.57 h, P=0.036 and 1.54 + or - 1.56 versus 3.64 + or - 2.67 U/patient, P=0.032). Length of stay on the intensive care unit, duration of hospital stay, need for infusion of inotropic agent and drainage volumes within 24 h postoperatively between the two groups were comparable.

CONCLUSIONS

Subzero-balanced ultrafiltration during cardiopulmonary bypass can effectively decrease the patients' hospital morbidity and the volume of blood transfusion: it also may promote early postoperative recovery of patients. Routine application of subzero-balanced ultrafiltration during adult cardiac operations should not be necessary, but the technique should be compared to other techniques, e.g. MUF, in further studies.