A randomized, controlled trial of aprotinin in neonates undergoing open-heart surgery

Prophylactic Use of Antifibrinolytics During Pediatric Cardiac Surgery With Cardiopulmonary Bypass on Postoperative Bleeding and Transfusion: A Systematic Review and Meta-Analysis

OBJECTIVES

To determine the effect of intraoperative antifibrinolytics, including tranexamic acid (TXA), aminocaproic acid (EACA), or aprotinin, on bleeding in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).

DATA SOURCES

Relevant articles were systematically searched from Ovid MEDLINE, Ovid EMBASE, CINAHL, Cochrane Library, and Web of Science to November 15, 2021.

STUDY SELECTION

Abstracts were screened, and full texts were reviewed using predetermined inclusion and exclusion criteria using the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline.

DATA EXTRACTION

A standardized data extraction tool was used.

DATA SYNTHESIS

Sixty-eight studies including 28,735 patients were analyzed. TXA compared with placebo resulted in a mean decrease in chest tube output of 9.1 mL/kg (95% CI, 6.0-12.3 mL/kg), I2 equals to 65.2%, p value of less than 0.001, platelet requirement of 2.9 mL/kg (95% CI, 0.1-5.8 mL/kg), I2 =72.5%, p value less than 0.001 and plasma requirement of 4.0 mL/kg (95% CI, 0.6-7.2 mL/kg), I2 equals to 94.5%, p value less than0.001. Aprotinin compared with placebo resulted in a mean decrease in chest tube output of 4.3 mL/kg (2.4-6.2 mL/kg), I2 equals to 66.3%, p value of less than 0.001, platelet transfusion of 4.6 mL/kg (95% CI, 0.6-8.6 mL/kg), I2 equals to 93.6%, p value of less than 0.001, and plasma transfusion of 7.7 mL/kg (95% CI, 2.1-13.2 mL/kg), I2 equals to 95.3%, p value of less than 0.001. EACA compared with placebo resulted in a mean decrease in chest tube output of 9.2 mL/kg (2.3-21.0 mL/kg), I2 equals to 96.4%, p value of less than 0.001, RBC transfusion of 7.2 mL/kg (95% CI, 2.4-12.1 mL/kg), I2 equals to 94.5%, p value equals to 0.002, and platelet transfusion of 10.7 mL/kg (95% CI, 2.9-18.5 mL/kg), I2 equals to 0%, p value of less than 0.001. No statistical difference was observed in chest tube output when TXA was compared with aprotinin. Subgroup analysis of cyanotic patients showed a significant decrease in chest tube output, platelet requirement, and plasma requirement for patients receiving aprotinin. Overall, the quality of evidence was moderate.

CONCLUSIONS

Antifibrinolytics are effective at decreasing blood loss and blood product requirement in children undergoing cardiac surgery with CPB although the quality of evidence is only moderate.

Efficacy and safety of aprotinin in paediatric cardiac surgery: A systematic review and meta-analysis

BACKGROUND

The relicensing of aprotinin in Europe and Canada has stimulated discussions on its usefulness in paediatric cardiac surgery.

OBJECTIVE

To systematically evaluate the available evidence on the efficacy and safety of aprotinin in paediatric cardiac surgery.

DESIGN

Systematic review of all randomised and observational studies comparing aprotinin with tranexamic acid, epsilon aminocaproic acid, placebo or no drug in paediatric cardiac surgery. Meta-analyses were performed on efficacy and safety outcomes.

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Web of Science and Embase were searched from January 2000 to March 2021.

ELIGIBILITY CRITERIA

Studies that enrolled children under 18 years undergoing cardiac surgery with cardiopulmonary bypass.

RESULTS

Thirty-two studies enrolling a total of 63 894 paediatric cardiac procedures were included. Aprotinin significantly reduced total blood loss [mean difference -4.70 ml kg-1, 95% confidence interval (CI), -7.88 to -1.53; P = 0.004], postoperative transfusion requirements and the incidence of surgical re-exploration for bleeding [odds ratio (OR) 0.74, 95% CI, 0.56 to 0.97; P = 0.03]. Aprotinin had no effects on 30-day mortality (OR 1.02, 95% CI, 0.93 to 1.11; P = 0.73) and on other safety outcomes, except for the incidence of renal replacement therapy (RRT), which was significantly increased in patients given aprotinin (OR 1.29, 95% CI, 1.08 to 1.54; P = 0.006). Findings from observational and randomised controlled trials did not largely differ. A sub-group analysis in neonates showed that aprotinin significantly reduced packed red blood cell transfusions and the incidence of postoperative surgical re-exploration for bleeding and/or tamponade. When compared with lysine analogues, aprotinin was more effective at reducing bleeding and transfusion without increasing the risk of side effects.

CONCLUSION

This meta-analysis suggests that aprotinin is effective and well tolerated in paediatric cardiac surgery. Given the large heterogeneity of the results and the risk of selection bias in observational studies, large randomised controlled trials are warranted.

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.

Efficacy and Safety of Antifibrinolytic Drugs in Pediatric Surgery: A Systematic Review

Antifibrinolytic drugs are used to reduce blood loss and subsequent transfusions during surgery and following trauma, but the optimal dosing regimen in the pediatric population is still unresolved. The aim of this systematic review was to evaluate efficacy and safety of antifibrinolytic drugs in pediatric surgery and trauma to determine the optimal dosing regimen. A literature search was performed in PubMed, Embase, Cochrane, and Web of Science on May 3, 2020. We included randomized controlled studies investigating the effect of tranexamic acid (TXA), aprotinin, and epsilon-aminocaproic acid, in terms of reducing blood loss, blood transfusions, reoperations, and rebleeds in pediatric patients aged 0 to 18 years undergoing cardiac surgery, noncardiac surgery, or trauma. Fifty randomized controlled trials (RCTs) were included; 28 RCTs investigated cardiac surgery and 22 investigated noncardiac surgery. No RCTs regarding trauma met the inclusion criteria. All antifibrinolytic drugs reduced postoperative blood loss and transfusions when used in pediatric surgery. The dosing regimen varied between studies, but similar effect sizes were found in terms of reduced blood loss regardless of the cumulative dose used. Few studies found adverse events, and no difference in incidence or type of adverse events was seen between the antifibrinolytic and the placebo group. In conclusion, use of antifibrinolytics is efficient and safe in children undergoing surgery. We propose TXA as the drug of choice based on its level of evidence and safety profile; we recommend a dosing regimen composed of a loading dose of 10 to 15 mg/kg prior to surgery followed by 1 to 5 mg/kg/h as continuous infusion throughout surgery.

Aprotinin versus tranexamic acid in children undergoing cardiac surgery: an observational study

OBJECTIVES

The upcoming release of aprotinin in paediatric cardiac surgery prompted a re-evaluation of its use in comparison to tranexamic acid (TXA) focusing on their effect on exposure to blood transfusions as well as severe postoperative morbidity or mortality.

METHODS

This retrospective study was conducted in a tertiary children hospital from 2002 to 2015. Patients receiving aprotinin (Aprotinin group: 2002-2007) were compared with those receiving TXA group (2008-2015) using propensity score analysis. Primary outcome measures were 'exposure to blood products' and 'severe postoperative morbidity or mortality'. High-risk subgroups that included neonates, complex (Risk Adjusted Classification for Congenital Heart Surgery-1 ≥ 3) and redo surgery were also analysed.

RESULTS

The study included 2157 patients, 1136 in the Aprotinin group and 1021 in the TXA group. Exposure to blood products was significantly higher in the Aprotinin group (78% vs 60%; P < 0.001) as well as in the complex and redo surgery subgroups. Incidence of mortality and/or severe morbidity was higher in the Aprotinin group (33% vs 28%; P = 0.007), as well as in the neonate group. However, cardiopulmonary bypass priming volume and intraoperative fluid balance were significantly decreased, and the use of modified ultrafiltration significantly increased in the TXA group.

CONCLUSIONS

In our population, children receiving aprotinin were more frequently transfused and were at a higher risk of developing severe postoperative morbidity or mortality than those receiving TXA. Subgroups at high risk of bleeding or inflammation did not seem to benefit from aprotinin. These differences might be explained by a safer profile of TXA, but also attributed to major changes in our patient blood management strategies over years.

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.

Coagulation and the surgical neonate

Both coagulopathy and abnormal thrombosis can complicate the anesthetic and surgical management of neonatal patients; however, the patterns of bleeding and thrombosis in neonates differ from those in adults or older children. Severe coagulopathic bleeding most commonly occurs during heart surgery and almost certainly contributes to morbidity and mortality in this population. Such severe bleeding is rare during other surgery; the exception is babies presenting to the operating room with established coagulopathy secondary to severe sepsis. Alternatively, pathological thrombosis will mainly occur in association with indwelling vascular access devices or surgically created vascular shunts. There are important differences between the coagulation system in neonates and older patients. The implication of this is that therapies established in other patient groups will not be optimal for neonates without adaptation. While evidence from high-quality clinical trials is rarely available, an understanding of how coagulation in neonates differs can help to guide practice. This review will discuss important differences between the coagulation system of neonates and older patients and how these relate to newer models of coagulation. The emphasis will be on issues likely to impact on perioperative care. In particular, the management of severe bleeding, the manipulation of coagulation during heart surgery, and the management of coagulopathy in septic neonates will be discussed in detail.

A systematic review of the use of antifibrinolytic agents in pediatric surgery and implications for craniofacial use

A systematic review aimed to evaluate the efficacy and safety of aprotinin, epsilon-aminocaproic acid (EACA), and tranexamic acid (TXA) in reducing perioperative blood loss, risk for transfusion, and total perioperative transfusion volume in major pediatric surgery. Medline, Embase, and Cochrane Reviews were searched for relevant articles published from January 1990 to January 2012. Additional studies were identified by cross-referencing citations and extracting data from recent published reviews. Data were recorded and analyzed using Cochrane's RevMan5.1 software. Thirty-four studies were included in this review of which 21 provided level 1b evidence, 11 were level 2b, and two were level 3b. As compared to control groups, antifibrinolytics reduced perioperative blood loss by standardized mean difference (SMD) of -0.70 (-0.89, -0.50; p<0.00001), total transfusion volume by SMD of -0.78 (-0.95, -0.61; p < 0.00001), and Odds Ratio (OR) for transfusion was 0.39 (0.23, 0.64; p=0.002). The OR for adverse events attributable to treatment was not statistically significant across groups (OR = 0.96; p = 0.58). Antifibrinolytics are effective in reducing blood loss and transfusion requirements in major pediatric surgery. TXA and EACA also appear to have reasonable side-effect profiles. Application to craniofacial surgery is promising, though further investigation is necessary.

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.

Differential effects of aprotinin and tranexamic acid on outcomes and cytokine profiles in neonates undergoing cardiac surgery

OBJECTIVE

Factors contributing to postoperative complications include blood loss and a heightened inflammatory response. The objective of this study was to test the hypothesis that aprotinin would decrease perioperative blood product use, reduce biomarkers of inflammation, and result in improved clinical outcome parameters in neonates undergoing cardiac operations.

METHODS

This was a secondary retrospective analysis of a clinical trial whereby neonates undergoing cardiac surgery received either aprotinin (n = 34; before May 2008) or tranexamic acid (n = 42; after May 2008). Perioperative blood product use, clinical course, and measurements of cytokines were compared.

RESULTS

Use of perioperative red blood cells, cryoprecipitate, and platelets was reduced in neonates receiving aprotinin compared with tranexamic acid (P < .05). Recombinant activated factor VII use (2/34 [6%] vs 18/42 [43%]; P < .001), delayed sternal closure (12/34 [35%] vs 26/42 [62%]; P = .02), and inotropic requirements at 24 and 36 hours (P < .05) were also reduced in the aprotinin group. Median duration of mechanical ventilation was reduced compared with tranexamic acid: 2.9 days (interquartile range: 1.7-5.1 days) versus 4.2 days (2.9-5.2 days), P = .04. Production of tumor necrosis factor and interleukin-2 activation were attenuated in the aprotinin group at 24 hours postoperatively. No differential effects on renal function were seen between agents.

CONCLUSIONS

Aprotinin, compared with tranexamic acid, was associated with reduced perioperative blood product use, improved early indices of postoperative recovery, and attenuated indices of cytokine activation, without early adverse effects. These findings suggest that aprotinin may have unique effects in the context of neonatal cardiac surgery and challenge contentions that antifibrinolytics are equivalent with respect to early postoperative outcomes.

Aprotinin confers neuroprotection by reducing apoptotic cell death

Aprotinin has been used in pediatric cardiac surgery for its antiinflammatory and hemostatic benefits. We have reported that aprotinin has a direct cellular neuroprotective effect through reduction of excitotoxicity. The purpose of this study was to investigate whether aprotinin is neuroprotective against apoptotic cell death. Near-pure neuronal cultures containing <5% astrocytes were obtained from fetal mice. Serum deprivation was initiated at 7 days by transferring the cultures, which are dependent on serum for survival, into growth medium lacking serum for 24 h. Neuronal cell death was assessed by phase-contrast cell counting after staining with 0.4% trypan blue dye. Aprotinin at a clinically relevant concentration of 100 KIU.mL(-1) significantly reduced apoptotic neuronal cell death from 84.4% to 51.8%. This result suggests that aprotinin has the potential to reduce brain injury resulting from apoptotic cell death induced by an ischemic insult. Additional studies are needed to evaluate the potential of aprotinin to reduce neurological injury in patients at high risk of cerebral injury, including those undergoing circulatory arrest.

Pediatric pharmacology in the first year of life

PURPOSE OF REVIEW

Toxicity concerns and awareness during anesthesia issues continue to concern pediatric anesthesiologists. Most developmental pharmacokinetic, pharmacodynamic and pharmacogenomic changes occur within the first year of life. Understanding these early changes can improve drug use in this cohort.

RECENT FINDINGS

Growth and development are two major aspects of children not readily apparent in adults. Clearance in the pediatric population should be investigated using models that describe size, maturation and organ function influences. Glucuronide conjugation (hepatic phase II process) mirrors glomerular filtration maturation over the first year of life. Phase 1 processes appear more rapid, and differences attributable to single nuclear polymorphisms may be obvious by the end of the 4-week neonatal period in term infants.Pharmacodynamic differences in infancy remain poorly defined, and neonatal pharmacokinetic-pharmacodynamic analyses that might elucidate such differences are few, partly because of a paucity of effective pharmacodynamic measures.

SUMMARY

Mechanistic models create a framework for the study of pharmacokinetic changes in infancy. Understanding these changes allows a target concentration approach to therapy and potential for reduced toxicity. The target concentration may be undefined because of a paucity of effect measures.