High-dose aprotinin modulates the balance between proinflammatory and anti-inflammatory responses during coronary artery bypass graft surgery

Effects of interventions targeting the systemic inflammatory response to cardiac surgery on clinical outcomes in adults

BACKGROUND

Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.

OBJECTIVES

The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.

SELECTION CRITERIA

RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.

DATA COLLECTION AND ANALYSIS

Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL-6 and IL-8 concentrations in blood post-surgery. The primary clinical outcome was in-hospital or 30-day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta-analyses were performed using random effects models, and heterogeneity was assessed using I2.

MAIN RESULTS

A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL-6 (SMD -0.77, 95% CI -0.97 to -0.58, I2 = 92%) and IL-8 (SMD -0.92, 95% CI -1.20 to -0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in-hospital or 30-day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.

AUTHORS' CONCLUSIONS

A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.

Aprotinin-Drug against Respiratory Diseases

Aprotinin (APR) was discovered in 1930. APR is an effective pan-protease inhibitor, a typical "magic shotgun". Until 2007, APR was widely used as an antithrombotic and anti-inflammatory drug in cardiac and noncardiac surgeries for reduction of bleeding and thus limiting the need for blood transfusion. The ability of APR to inhibit proteolytic activation of some viruses leads to its use as an antiviral drug for the prevention and treatment of acute respiratory virus infections. However, due to incompetent interpretation of several clinical trials followed by incredible controversy in the literature, the usage of APR was nearly stopped for a decade worldwide. In 2015-2020, after re-analysis of these clinical trials' data the restrictions in APR usage were lifted worldwide. This review discusses antiviral mechanisms of APR action and summarizes current knowledge and prospective regarding the use of APR treatment for diseases caused by RNA-containing viruses, including influenza and SARS-CoV-2 viruses, or as a part of combination antiviral treatment.

Randomized controlled trials of aprotinin in cardiac surgery: could clinical equipoise have stopped the bleeding?

Background Aprotinin is a serine protease inhibitor used to limit perioperative bleeding and reduce the need for donated blood transfusions during cardiac surgery. Randomized controlled trials of aprotinin evaluating its effect on the outcome of perioperative transfusion have been published since 1987, and systematic reviews were conducted in 1992 and 1997.

Methods A systematic search was conducted for all RCTs of aprotinin that used placebo controls or were open-label with no active control treatment. Data collected included the primary outcome, objective of each study, whether a systematic review was cited or conducted as part of the background and/or rationale for the study and the number of previously published RCTs cited. Cumulative meta-analyses were performed.

Results Sixty-four randomized, controlled trials of aprotinin were found, conducted between 1987 and 2002, reporting an endpoint of perioperative transfusion. Median trial size was 64 subjects, with a range of 20 to 1784. A cumulative meta-analysis indicated that aprotinin greatly decreased the need for perioperative transfusion, stabilizing at an odds ratio of 0.25 (p, 10 2 6) by the 12th study, published in June of 1992. The upper limit of the confidence interval never exceeded 0.65 and results were similar in all subgroups. Citation of previous RCTs was extremely low, with a median of 20% of prior trials cited. Only 7 of 44 (15%) of subsequent reports referenced the largest trial (N 1/4 1784), which was 28 times larger than the median trial size.

Conclusions This study demonstrates that investigators evaluating aprotinin were not adequately citing previous research, resulting in a large number of RCTs being conducted to address efficacy questions that prior trials had already definitively answered. Institutional review boards and journals could reduce the number of redundant trials by requiring investigators to conduct adequate searches for prior evidence and conducting systematic reviews.

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.

Aprotinin Reduces the Procalcitonin Rise Associated With Complex Cardiac Surgery and Cardiopulmonary Bypass

Aprotinin, a nonspecific serine protease inhibitor, has been primarily used as a haemostatic drug in cardiac surgery with cardio-pulmonary bypass (CPB). This study investigated the effect of Aprotinin on the post-operative levels of procalcitonin (PCT) and a set of cytokines in patients undergoing pulmonary artery endarterectomy (PEA). We analyzed 60 patients with chronic thromboembolic pulmonary hypertension undergoing PEA. 30 patients (Group A) were treated with Aprotinin (2000000 IU prior anesthesia, then 2000000 IU in CPB prime and 50000 IU per hour continuously); a further 30 patients (Group B) received Tranexamic Acid (1 g before anesthesia, 1 g after full heparin dose and 2 g in CPB prime). PCT, TNFα, IL-1β, IL-6, and IL-8 arterial concentrations were measured from before until 72 hours after surgery. Aprotinin significantly affected early post-PEA plasma PCT. Patients treated with Aprotinin (Group A) had lower peak PCT levels compared to patients in Group B (1.52 ng/ml versus 2.18, p=0.024). Postoperative peak values of PCT and IL-6 correlated closely in both groups (r=0.78, r=0.83 respectively). Aprotinin attenuates the post-PEA increase of PCT in the same manner as other pro-inflammatory cytokines. Significant correlation between PCT and IL-6 post-surgery may be indicative of an indirect IL-6-mediated pathway of PCT alteration.

Antifibrinolytics attenuate inflammatory gene expression after cardiac surgery

OBJECTIVES

Anti-inflammatory effects of tranexamic acid and aprotinin, used to abate perioperative blood loss, are reported and might be of substantial clinical relevance. The study of messenger ribonucleic acid synthesis provides a valuable asset in evaluating the inflammatory pathways involved.

METHODS

Whole-blood messenger ribonucleic acid expression of 114 inflammatory genes was compared pre- and postoperatively in 35 patients randomized to receive either placebo, tranexamic acid, or aprotinin. These results were further confirmed by reverse transcription-polymerase chain reaction.

RESULTS

Of the 23 genes exhibiting independently altered postoperative gene expression levels, 8 were restricted to the aprotinin group only (growth differentiation factor 3, interleukin 19, interleukin 1 family member 7, transforming growth factor α, tumor necrosis factor superfamily 10, tumor necrosis factor superfamily 12, tumor necrosis factor superfamily 13B, vascular endothelial growth factor α), whereas both aprotinin and tranexamic acid altered gene expression of 3 genes as compared with placebo (FMS-related tyrosine kinase 3 ligand, growth differentiation factor 5, interferon-α8). In general, less upregulation of pro-inflammatory, and more upregulation of anti-inflammatory, genes was observed for patients treated with antifibrinolytics. Gene expression affected by aprotinin coded mostly for proteins that function through serine proteases.

CONCLUSIONS

This study demonstrates that the use of tranexamic acid and aprotinin results in altered inflammatory pathways on the genomic expression level. We further demonstrate that the use of aprotinin leads to significant attenuation of the immune response, with several inhibitory effects restricted to the use of aprotinin only. The results aid in a better understanding of the targets of these drugs, and add to the discussion on which antifibrinolytic can best be used in the cardiac surgical patient.

Comparative analysis of antifibrinolytic medications in pediatric heart surgery

OBJECTIVES

Recent studies suggest adverse events associated with aprotinin in adults may not occur in children, and there is interest in further pediatric study of aprotinin. However, there are limited contemporary data comparing aprotinin with other available antifibrinolytics (aminocaproic acid [ACA] and tranexamic acid [TXA]) to guide current practice and aid in potential trial design. We performed a comparative analysis in a large multicenter cohort.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database (2004-2008) was linked to medication data from the Pediatric Health Information Systems Database. Efficacy and safety outcomes were evaluated in multivariable analysis adjusting for patient and center factors overall and in neonates and those undergoing redo sternotomy.

RESULTS

A total of 22,258 patients (25 centers) were included: median age, 7.6 months (interquartile range, 2.6-43.4 months). Aprotinin (vs no drug) was associated with a significant reduction in combined hospital mortality/bleeding requiring surgical intervention overall (odds ratio [OR], 0.81; 95% confidence intervals [CI], 0.68-0.91) and in the redo sternotomy subgroup (OR, 0.57; 95% CI, 0.40-0.80). There was no benefit in neonates and no difference in renal failure requiring dialysis in any group. In comparative analysis, there was no difference in outcome in aprotinin versus ACA recipients. TXA (vs aprotinin) was associated with significantly reduced mortality/bleeding requiring surgical intervention overall (OR, 0.47; 95% CI, 0.30-0.74) and in neonates (OR, 0.30; 95% CI, 0.15-0.58).

CONCLUSIONS

These observational data suggest aprotinin is associated with reduced bleeding and mortality in children undergoing heart surgery with no increase in dialysis. Comparative analyses suggest similar efficacy of ACA and improved outcomes associated with TXA.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. This version of the review includes a sensitivity analysis excluding trials authored by Prof. Joachim Boldt.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

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.

Safety of aprotinin in congenital heart operations: results from a large multicenter database

BACKGROUND

Aprotinin was used frequently in children undergoing congenital heart operations with the aim of reducing bleeding, until it was taken off the market after adult studies reported increased renal failure and death. We evaluated the safety of aprotinin in a large multicenter cohort of children undergoing congenital heart operations.

METHODS

The Pediatric Health Information Systems Database was used to evaluate aprotinin in children (aged 0 to 18 years) undergoing congenital heart operations at 35 children's hospitals from 2003 to 2007. Propensity scores were constructed to account for potential confounders of age, sex, race, prematurity, genetic syndrome, type of operation (Risk Adjustment in Congenital Heart Surgery-1 category), center, and center volume. Multivariable analysis, adjusting for propensity score and individual covariates was performed to evaluate in-hospital mortality, postoperative renal failure requiring dialysis, and length of stay. Subanalysis was performed in the high-risk cohort undergoing reoperation.

RESULTS

The study included 30,372 patients (56% male) who were a median age of 7 months (interquartile range, 36 days to 3.2 years). Overall, 44% received aprotinin. Multivariable analysis found no difference in postoperative mortality (odds ratio, 1.00; 95% confidence interval [CI], 0.99 to 1.01), dialysis (odds ratio, 1.00; 95% CI, 0.99 to 1.01), or length of stay (least square mean difference, -0.44 days; 95% CI, -1.01 to 0.13) between aprotinin recipients and nonrecipients. No difference was found in mortality or dialysis in patients undergoing reoperation. Aprotinin recipients in the reoperation subgroup had significantly reduced length of stay (least square mean difference, -2.05 days; 95% CI -3.29 to -0.81),

CONCLUSIONS

These data suggest aprotinin is not associated with increased mortality or dialysis in children undergoing congenital heart operations and that further evaluation of aprotinin in this population could be undertaken without undue risk.

Aprotinin exerts differential and dose-dependent effects on myocardial contractility, oxidative stress, and cytokine release after ischemia-reperfusion

BACKGROUND

Cardiac surgery can result in left ventricular ischemia and reperfusion (I/R), the release of cytokines such as tumor necrosis factor, and oxidative stress with release of myeloperoxidase. Although aprotinin has been used in cardiac surgery, the likely multiple effects of this serine protease inhibitor limit clinical utility. This study tested the hypothesis that different aprotinin doses cause divergent effects on left ventricular contractility, cytokine release, and oxidative stress in the context of I/R.

METHODS

Left ventricular I/R (30 minutes I, 60 minutes R) was induced in mice, and left ventricular contractility (maximal end-systolic elastance) determined. Mice were randomly allocated to 2 x 10(4) kallikrein inhibitory units (KIU)/kg aprotinin (n = 11), 4 x 10(4) KIU/kg aprotinin (n = 10), and vehicle (saline, n = 10). Based upon a fluorogenic assay, aprotinin doses of 2 and 4 x 10(4) KIU/kg resulted in plasma concentrations similar to those of the half and full Hammersmith doses, respectively.

RESULTS

After I/R, maximal end-systolic elastance fell by more than 40% from baseline (p < 0.05), and this effect was attenuated by 2 x 10(4) KIU/kg but not 4 x 10(4) KIU/kg aprotinin. Tumor necrosis factor increased by more than 60% from control (p < 0.05) with I/R, but was reduced with 4 x 10(4) KIU/kg aprotinin. Myeloperoxidase increased with I/R, and was reduced to the greatest degree by 2 x 10(4) KIU/kg aprotinin.

CONCLUSIONS

Aprotinin influences left ventricular contractility, cytokine release, and oxidative stress, which are dose dependent. These results provide mechanistic evidence that multiple pathways are differentially affected by aprotinin in a context relevant to cardiac surgery.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery and previous reviews have found them to be effective in reducing blood loss and the need for transfusion. Recently, questions have been raised regarding the comparative performance of the drugs and the safety of the most popular agent, aprotinin.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, and the internet. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 211 RCTs that recruited 20,781 participants. Data from placebo/inactive controlled trials, and from head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of operative blood loss, but the differences were small. Aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.61 to 0.71). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.54 to 0.69) and it was 0.75 (95% CI 0.58 to 0.96) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared superior in reducing the need for RBC transfusion: RR 0.83 (95% CI 0.69 to 0.99). Aprotinin reduced the need for re-operation due to bleeding: RR 0.48 (95% CI 0.35 to 0.68). This translates into an absolute risk reduction of just under 3% and a number needed-to-treat (NNT) of 37 (95% CI 27 to 56). Similar trends were seen with TXA and EACA, but the data were sparse and the differences failed to reach statistical significance. The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias. Evidence of publication bias was not observed in trials reporting re-operation rates. Adjustment for these effects reduced the magnitude of estimated benefits but did not negate treatment effects. However, the apparent advantage of aprotinin over the lysine analogues was small and may be explained by publication bias and non-equivalent drug doses. Aprotinin did not increase the risk of myocardial infarction (RR 0.92, 95% CI 0.72 to 1.18), stroke (RR 0.76, 95% CI 0.35 to 1.64) renal dysfunction (RR 1.16, 95% CI 0.79 to 1.70) or overall mortality (RR 0.90, 95% CI 0.67 to 1.20). The analyses of myocardial infarction and death included data from the majority of subjects recruited into the clinical trials of aprotinin. However, under-reporting of renal events could explain the lack of effect seen with aprotinin. Similar trends were seen with the lysine analogues but data were sparse. These results conflict with the results of recently published non-randomised studies.

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the need for allogeneic red cell transfusion. Based on the results of randomised trials their efficacy does not appear to be offset by serious adverse effects. In most circumstances the lysine analogues are probably as effective as aprotinin and are cheaper; the evidence is stronger for tranexamic acid than for aminocaproic acid. In high risk cardiac surgery, where there is a substantial probability of serious blood loss, aprotinin may be preferred over tranexamic acid. Aprotinin does not appear to be associated with an increased risk of vascular occlusion and death, but the data do not exclude an increased risk of renal failure. There is no need for further placebo-controlled trials of aprotinin or lysine analogues in cardiac surgery. The principal need is for large comparative trials to assess the relative efficacy, safety and cost-effectiveness of anti-fibrinolytic drugs in different surgical procedures.

Meta-analysis comparing the effectiveness and adverse outcomes of antifibrinolytic agents in cardiac surgery

BACKGROUND

Since the 1980s, antifibrinolytic therapies have assisted surgical teams in reducing the amount of blood loss. To date, however, serious questions remain regarding the safety and effectiveness of these agents.

METHODS AND RESULTS

We conducted a meta-analysis to compare aprotinin, epsilon-aminocaproic acid, and tranexamic acid with placebo and head to head on 8 clinical outcomes from 138 trials. Published randomized controlled trial data were collected from OVID/PubMed. Outcomes included total blood loss, transfusion of packed red blood cells, reexploration, mortality, stroke, myocardial infarction, dialysis-dependent renal failure, and renal dysfunction (0.5-mg/dL increase in creatinine from baseline). All agents were effective in significantly reducing blood loss by 226 to 348 mL and the proportion of patients transfused with packed red blood cells over placebo. Only high-dose aprotinin reduced the rate of reexploration (relative risk, 0.49; 95% CI, 0.33 to 0.73). There were no significant risks or benefits for any agent for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin significantly increased the risk of renal dysfunction (relative risk, 1.47; 95% CI, 1.12 to 1.94), 12.9% versus 8.4%. Compared head to head, high-dose aprotinin demonstrated significant reduction in total blood loss over epsilon-aminocaproic acid (-184 mL; 95% CI, -256 to -112) and tranexamic acid (-195 mL; 95% CI, -286 to -105). There were no significant differences among any agent when compared head to head on other outcomes.

CONCLUSIONS

All antifibrinolytic agents were effective in reducing blood loss and transfusion. There were no significant risks or benefits for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin was associated with a statistically significant increased risk of renal dysfunction.

Aprotinin reduces cardiac troponin I release and inhibits apoptosis of polymorphonuclear cells during off-pump coronary artery bypass surgery

OBJECTIVES

In addition to blood-sparing effects, aprotinin may have cardioprotective and anti-inflammatory effects during cardiopulmonary bypass-assisted cardiac surgery. In this study, the authors examined whether aprotinin had cardioprotective and/or anti-inflammatory effects in patients undergoing off-pump coronary artery bypass grafting.

DESIGN

A prospective randomized clinical trial.

SETTING

University hospital.

PARTICIPANTS

Fifty patients were randomized to control (n = 25) or aprotinin treatment (n = 25) groups.

INTERVENTIONS

Aprotinin was given as a loading dose (2 x 10(6) KIU) followed by a continuous infusion at 5 x 10(5) KIU/h until skin closure.

MEASUREMENTS AND MAIN RESULTS

Blood samples for cardiac troponin I; interleukin-6, interleukin-8, and interleukin-10; tumor necrosis factor alpha; and elastase were taken after anesthesia induction, completion of revascularization, and 6 hours, 12 hours, and 24 hours after revascularization. Blood samples were taken to assess for apoptosis in polymorphonuclear cells. Baseline plasma levels for cardiac troponin I did not differ between groups but were significantly lower in aprotinin-treated patients at the time of revascularization (p = 0.03) and 6 hours (p = 0.004) and 24 hours (p = 0.03) later. Aprotinin significantly reduced apoptosis in polymorphonuclear cells compared with control-treated patients (p = 0.04). There were no differences in plasma cytokine or elastase levels between groups.

CONCLUSIONS

The authors conclude that aprotinin reduces perioperative cardiac troponin I release and attenuates apoptosis in polymorphonuclear cells but has no significant effects on plasma cytokine levels in patients undergoing off-pump coronary artery bypass graft surgery.

Suppressive effect of phosphodiesterase type 4 inhibition on systemic inflammatory responses after cardiopulmonary bypass

Cardiopulmonary bypass (CPB) induces excessive production of endogenous proinflammatory mediators such as cytokines and elastase, which are responsible for the subsequent development of systemic inflammatory response syndrome (SIRS). In this study, we investigated the protective effect of rolipram against SIRS after CPB. Rats were divided into three groups (n = 5 in each): control (C), rolipram (R), and sham (S). Rats in groups C and R underwent CPB for 60 min followed by 60 min of observation, while those in group S were observed for 120 min without CPB. In group R, 40 microg/kg/min of rolipram was intravenously administered throughout the experiment. CD11b expression on neutrophils was analyzed using flow cytometry. Serum concentrations of tissue necrosis factor alpha (TNF-alpha), interleukin 1beta (IL-1beta), macrophage inflammatory protein 2 (MIP-2), and elastase were also determined. CD11b expression at the end of the experiment was unchanged from the initial value in group R, whereas that in group C increased to almost double, and that in group S also showed a slight increase (P < 0.01). Serum TNF-alpha levels in groups R and S were lower than those observed in group C (P < 0.05). Serum IL-1beta and MIP-2 levels in groups C and R tended to be higher than those in group S, although the difference was not statistically significant. Regarding elastase, group R showed a significantly lower value than group C and a higher value than group S (P < 0.05). Phosphodiesterase type 4 inhibition seems to suppress CPB-induced SIRS through the regulation of proinflammatory mediators in this rat model.

Anti-inflammatory effect of high-dose insulin treatment after urgent coronary revascularization surgery

BACKGROUND

The administration of insulin has been shown to exert cardioprotective and immunomodulatory properties. Ischemia and inflammation are typical features of acute coronary syndrome, thus it was hypothesized that high-dose glucose-insulin-potassium (GIK) treatment could suppress the systemic inflammatory reaction and attenuate myocardial ischemia-reperfusion injury in patients with unstable angina pectoris after urgent coronary artery bypass surgery.

METHODS

Forty patients with unstable angina pectoris scheduled for urgent coronary artery bypass surgery and cardiopulmonary bypass were randomly assigned to receive either high-dose insulin treatment (short-acting insulin 1 IU/kg/h with 30% glucose 1.5 ml/kg/h administered separately) or control treatment (saline). Blood glucose levels were targeted to 6.0-8.0 mmol/l in both groups by adjusting the rate of glucose infusion in the GIK group and by additional insulin in the control group as needed.

RESULTS

High-dose insulin treatment was associated with significantly lower average C-reactive protein (23.8 vs. 40.1 mg/l, P= 0.008) and free fatty acid levels (0.22 vs. 0.41 mmol/l, P= < 0.001) post-operatively. Average blood glucose levels were comparable during the intensive care unit (ICU) stay (7.1 vs. 6.9 mmol/l, P= 0.5) and 95% of the control patients received supplemental insulin. The pro-inflammatory cytokine response [interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha)] did not differ between the groups and beneficial effects on myocardial injury were not detected.

CONCLUSIONS

High-dose insulin treatment has potential anti-inflammatory properties independent of its ability to lower blood glucose levels. Even profound suppression of free fatty acid levels, the attenuation of myocardial ischemia-reperfusion injury was not detected.

Aprotinin decreases ischemic damage during coronary revascularization

BACKGROUND AND AIM

This study sought to determine whether the favorable anti-inflammatory effects of aprotinin might limit ischemic damage during the revascularization of ischemic myocardium.

METHODS

Twenty pigs underwent 90 minutes of coronary occlusion followed by 45 minutes of blood cardioplegic arrest and 180 minutes of reperfusion. Ten animals received a loading dose of aprotinin (40,000 kallikrein inhibiting units/kg) during the start of coronary occlusion followed by an infusion of 20,000 kallikrein inhibiting units/kg/hour. Ten other animals received no aprotinin. Summary statistics are expressed as the mean +/- standard error.

RESULTS

The aprotinin-treated animals required less cardioversions for ventricular arrhythmias (1.0 +/- 0.7 vs. 3.6 +/- 0.6; p < 0.001), accumulated less lung water (1.0 +/- 0.2% change vs. 6.2 +/- 0.9% change; p = 0.038), had more complete coronary relaxation to bradykinin (34.1 +/- 5.9% change vs. 9.2 +/- 3.5% change; p = 0.01), and had reduced infarct size (area necrosis/area risk = 20 +/- 1.1% vs. 39 +/- 1.2%; p = 0.003).

CONCLUSIONS

Aprotinin limits ischemic injury during acute coronary revascularization by decreasing ventricular arrhythmias and lung edema, preserving endothelial function, and minimizing myocardial necrosis.

Inflammatory response in an immunosuppressed patient with Wegener's granulomatosis

BACKGROUND

The use of cardiopulmonary bypass (CPB) triggers a systemic inflammatory response (IR), but it is not known if a similar response occurs in an immunosuppressed patient with autoimmune disease.

METHODS AND RESULTS

Observational study in a 56-year-old man receiving immunosuppressive therapy for Wegener's granulomatosis (WG) who underwent aortic valve replacement on CPB. The following markers for IR were studied in the perioperative period: C3a, C5a, neutrophil elastase (NE), interleukin eight (IL-8), white cell count (WCC) and C-reactive protein (CRP). Results were compared with published literature on the IR in patients undergoing coronary revascularisation with and without the use of CPB. All inflammatory markers increased in the perioperative period. The intensity of IR was markedly reduced compared to published literature for patients undergoing coronary revascularisation on CPB and the temporal patients and extend resembled that for off-pump.

CONCLUSION

In a patient with WG on immunosuppressive therapy the CPB-related IR is reduced.

Stroke after cardiac surgery: a retrospective analysis of the effect of aprotinin dosing regimens

BACKGROUND

Half-dose aprotinin (HDA) appears to be equivalent to full-dose aprotinin (FDA) in its ability to prevent bleeding. However, data regarding the potential effect of aprotinin use and dosage on other outcomes such as the occurrence of perioperative stroke are limited. It has been postulated that the higher level of kallikrein inhibition obtained with FDA dosing may be required for end-organ protection. Therefore, we performed a retrospective study in cardiac surgery patients at high risk for developing stroke to determine the relative effects of FDA and HDA regimens on the incidence of postoperative stroke.

METHODS

Records of 1,524 patients undergoing cardiac surgery over a 15-month period were reviewed. Patients at high risk for stroke were selected if they met all of the following predefined criteria: age greater than 70 years, history of hypertension, history of diabetes mellitus, history of stroke or transient ischemic attack, and presence of aortic atheroma. A validated preoperative stroke risk index was calculated for each patient. Postoperative stroke required confirmation by computed tomography or magnetic resonance imaging. Patients were divided into three groups according to whether they were administered no aprotinin, HAD, or FDA.

RESULTS

A total of 149 patients fulfilled the criteria for being at high risk for stroke. Stroke risk index was very similar (p = 0.56) in the three groups: those who received no aprotinin and served as a control group (124 +/- 15, n = 56), those who were given HDA (123 +/- 12, n = 67), and those who received FDA (122 +/- 11 n = 26). Preoperative and intraoperative characteristics were also similar between the three study groups. Overall, the incidence of stroke was 16% (24/149). The incidence of stroke differed (p < 0.05) among the three groups: no aprotinin 16% (9/56), HDA 22% (15/67), and FDA 0% (0/26).

CONCLUSIONS

In this retrospective study of cardiac surgery patients at high risk for postoperative stroke, the administration of FDA but not HDA was associated with a lower incidence of stroke.

Aprotinin and preservation of myocardial function after ischemia-reperfusion injury

Ischemia-reperfusion injury, a complex process involving the generation and release of inflammatory cytokines, accumulation and infiltration of neutrophils and macrophages, release of oxygen free radicals, activation of proteases, and generation of nitric oxide (NO), may result in myocardial dysfunction and possible injury to other major organs. Aprotinin, a nonspecific serine protease inhibitor used to reduce the blood loss and transfusion requirements accompanying cardiac surgery, has dose-dependent effects on coagulation, fibrinolytic, and inflammatory variables. Data indicate that aprotinin may provide protection from ischemia-reperfusion injury. In myocardial tissue models of ischemia and reperfusion, aprotinin has been shown to reduce uptake of tumor necrosis factor-alpha (TNF-alpha), generation of NO, and accumulation of leukocytes. Improved myocardial function has been observed with aprotinin treatment in animal models of ischemia-reperfusion injury. In humans, data indicate that integrin expression associated with leukocyte transmigration as well as markers of myocardial damage are reduced in patients receiving aprotinin. Further, data suggest that patients who receive aprotinin may have a reduced need for inotropic support and a decreased incidence of postoperative atrial fibrillation. In all, review of this topic indicates that aprotinin may reduce aspects of ischemia-reperfusion injury and prospective clinical studies are needed to evaluate the impact of aprotinin on associated patient outcomes.

Differential effects of aprotinin and tranexamic acid on endotoxin desensitization of blood cells induced by circulation through an isolated extracorporeal circuit

OBJECTIVE

To compare the effects of aprotinin and tranexamic acid on blood cytokine secretion induced by the circulation of blood through an isolated extracorporeal circuit.

DESIGN

Prospective, placebo-controlled study.

SETTING

University hospital.

PARTICIPANTS

Healthy volunteers (n = 18).

INTERVENTIONS

Blood (400 mL) first was drawn from volunteers, then circulated through an isolated extracorporeal circuit. Three groups were compared depending on the addition or not of an antifibrinolytic agent in the circuit (control group [n = 8], tranexamic group [n = 5], aprotinin group [n = 5]). Samples for measurement were taken before and at different time points after the start of circulation through the extracorporeal circuit. Cytokine (tumor necrosis factor-alpha, interleukin [IL]-6, IL-8, and IL-10) concentrations in the plasma and in the supernatant of lipopolysaccharide-stimulated whole blood cell cultures were analyzed.

MEASUREMENTS AND MAIN RESULTS

In the control and tranexamic acid groups, tumor necrosis factor-alpha, IL-6, and IL-10 secretion by whole blood cell cultures were rapidly decreased, whereas IL-8 secretion was unaffected. In the aprotinin group, IL-8 secretion was also decreased (p < 0.05).

CONCLUSION

These results show that aprotinin, but not tranexamic acid, modulates the inflammatory response by reducing the IL-8 secretion of blood cells activated by contact with foreign surfaces.

Effect of C1-esterase-inhibitor on capillary leak and inflammatory response syndrome during arterial switch operations in neonates

OBJECTIVE

To determine if prophylactic administration of C1-esterase-inhibitor would have a beneficial effect on postoperative weight gain and the inflammatory response in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB).

DESIGN

Randomized, double-blinded study.

SETTING

University-affiliated heart center.

PARTICIPANTS

Twenty-four neonates with transposition of the great arteries.

INTERVENTIONS

In group inhibitor (INH) patients (n = 12), 100 IU/kg of C1-esterase-inhibitor (Berinert) was given 30 minutes before CPB. In group placebo (P) patients (n = 12), placebo was administered instead. Interleukin (IL)-6, C3a anaphylatoxin, C1 activity, prekallikrein, Hageman factor, D-dimers, and clinical parameters were measured 6 times perioperatively.

MEASUREMENTS AND MAIN RESULTS

All 24 patients had an uneventful clinical course. Mean arterial pressure and pulmonary oxygenation after CPB were superior in group INH patients. The weight gain on postoperative days 1 to 4 was significantly less in group INH patients compared with group P (55 +/- 59 g vs. 340 +/- 121 g, day 1). The concentration of IL-6 (76 +/- 17 pg/mL vs. 262 +/- 95 pg/mL during CPB) was significantly lower in group INH patients compared with group P patients. In contrast, no influence on C3a anaphylatoxin and coagulation factors was found.

CONCLUSION

Prophylactic application of C1-esterase-inhibitor in neonates undergoing arterial switch operations produces less inflammatory response compared with placebo. This difference may have contributed to improved clinical parameters, including less weight gain postoperatively.