Severe anaphylactic reaction after primary exposure to aprotinin

Hemostatic strategies for uncontrolled bleeding: A comprehensive update

Uncontrolled bleeding remains the leading cause of morbidity and mortality across the entire macrocosm. It refers to excessive loss of blood that occurs inside of body, due to unsuccessful platelet plug formation at the injury site. It is not only limited to the battlefield, but remains the second leading cause of death amongst the civilians, as a result of traumatic injury. Startlingly, there are no effective treatments currently available, to cater the issue of internal bleeding, even though early intervention is of utmost significance in minimizing the mortality rates associated with it. The fatal issue of uncontrolled bleeding is ineffectively being dealt with the use of pressure dressings, tourniquet, and surgical procedures. This is not a practical approach in combat arenas or in emergency situations, where the traumatic injury inflicted is deep inside the body, and cannot be addressed externally, by the application of topical dressings. This review focuses on the traditional hemostatic agents that are used to augment the process of hemostasis, such as mineral zeolites, chitosan based products, biologically active agents, anti-fibrinolytics, absorbable agents, and albumin and glutaraldehyde, as well as the micro- and nano-based hemostatic agents such as synthocytes, thromboerythrocytes, thrombosomes, and the synthetic platelets.

Comparison of hemostatic agents used in vascular surgery

INTRODUCTION

Over the past 15 years, a wide range of agents have been developed for use in surgical procedures to achieve hemostasis. These agents can be divided into three broad categories: hemostats, sealants and adhesives. They vary widely related to their mechanism of action, composition, ease of application, adherence to wet or dry tissue, immunogenicity and cost.

AREAS COVERED

This article focuses on the agents used in vascular surgery to achieve hemostasis; agents involved in clinical trials are also covered.

EXPERT OPINION

When surgeons achieve rapid hemostasis, potential benefits include better visualization of the surgical area, shorter operative times, decreased requirement for transfusions, better management of an anticoagulated patient, decreased wound healing time and overall improvement in patient recovery time. The need for safe and efficacious hemostatic agents that can provide a range of benefits is clearly a significant surgical issue.

Natural and engineered plasmin inhibitors: applications and design strategies

The serine protease plasmin is ubiquitously expressed throughout the human body in the form of the zymogen plasminogen. Conversion to active plasmin occurs through enzymatic cleavage by plasminogen activators. The plasminogen activator/plasmin system has a well-established function in the removal of intravascular fibrin deposition through fibrinolysis and the inhibition of plasmin activity; this has found widespread clinical use in reducing perioperative bleeding. Increasing evidence also suggests diverse, although currently less defined, roles for plasmin in a number of physiological and pathological processes relating to extracellular matrix degradation, cell migration and tissue remodelling. In particular, dysregulation of plasmin has been linked to cancer invasion/metastasis and various chronic inflammatory conditions; this has prompted efforts to develop inhibitors of this protease. Although a number of plasmin inhibitors exist, they commonly suffer from poor potency and/or specificity of inhibition that either results in reduced efficacy or prevents clinical use. Consequently, there is a need for further development of high-affinity plasmin inhibitors that maintain selectivity over other serine proteases. This review summarises clearly defined and potential applications for plasmin inhibition. The properties of naturally occurring and engineered plasmin inhibitors are discussed in the context of current knowledge regarding plasmin structure, specificity and function. This includes design strategies to obtain the potency and specificity of inhibition in addition to controlled temporal and spatial distribution tailored for the intended use.

Mucosal sensitization to German cockroach involves protease-activated receptor-2

BACKGROUND

Allergic asthma is on the rise in developed countries. A common characteristic of allergens is that they contain intrinsic protease activity, and many have been shown to activate protease-activated receptor (PAR)-2 in vitro. The role for PAR-2 in mediating allergic airway inflammation has not been assessed using a real world allergen.

METHODS

Mice (wild type or PAR-2-deficient) were sensitized to German cockroach (GC) feces (frass) or protease-depleted GC frass by either mucosal exposure or intraperitoneal injection and measurements of airway inflammation (IL-5, IL-13, IL-17A, and IFNgamma levels in the lung, serum IgE levels, cellular infiltration, mucin production) and airway hyperresponsiveness were performed.

RESULTS

Following systemic sensitization, GC frass increased airway hyperresponsiveness, Th2 cytokine release, serum IgE levels, cellular infiltration and mucin production in wild type mice. Interestingly, PAR-2-deficient mice had similar responses as wild type mice. Since these data were in direct contrast to our finding that mucosal sensitization with GC frass proteases regulated airway hyperresponsiveness and mucin production in BALB/c mice (Page et. al. 2007 Resp Res 8:91), we backcrossed the PAR-2-deficient mice into the BALB/c strain. Sensitization to GC frass could now occur via the more physiologically relevant method of intratracheal inhalation. PAR-2-deficient mice had significantly reduced airway hyperresponsiveness, Th2 and Th17 cytokine release, serum IgE levels, and cellular infiltration compared to wild type mice when sensitization to GC frass occurred through the mucosa. To confirm the importance of mucosal exposure, mice were systemically sensitized to GC frass or protease-depleted GC frass via intraperitoneal injection. We found that removal of proteases from GC frass had no effect on airway inflammation when administered systemically.

CONCLUSIONS

We showed for the first time that allergen-derived proteases in GC frass elicit allergic airway inflammation via PAR-2, but only when allergen was administered through the mucosa. Importantly, our data suggest the importance of resident airway cells in the initiation of allergic airway disease, and could make allergen-derived proteases attractive therapeutic targets.

Textilinin-1, an alternative anti-bleeding agent to aprotinin: Importance of plasmin inhibition in controlling blood loss

Aprotinin has been used widely in surgery as an anti-bleeding agent but is associated with a number of side effects. We report that textilinin-1, a serine protease inhibitor from Pseudonaja textilis venom with sequence relatedness to aprotinin, is a potent but reversible plasmin inhibitor and has a narrower range of protease inhibition compared to aprotinin. Like aprotinin, textilinin-1 at 5 micromol/l gave almost complete inhibition of tissue plasminogen activator-induced fibrinolysis of whole blood clots. The activated partial thromboplastin time for plasma was markedly increased by aprotinin but unaffected by textilinin-1. In a mouse tail-vein bleeding model, intravenous textilinin-1 and aprotinin caused similar decreases in blood loss but time to haemostasis in the textilinin-treated animals was significantly shorter than in aprotinin-treated mice. Based on these data, textilinin-1 merits further investigation as a therapeutic alternative to aprotinin.

The use of aprotinin in children undergoing operative repair of isolated atrial septal defects

BACKGROUND

The purpose of this retrospective study was to examine the benefits, risks and costs associated with aprotinin use in children who underwent repair of an atrial septal defect (ASD). The primary aim was to determine whether the transfusion rate is lower in children who received aprotinin compared with those who did not during ASD repair. The use of aprotinin has been shown to reduce transfusion requirements for children undergoing primary or secondary repair of congenital cardiac anomalies. However, past studies have not reported the benefits of this agent during low complexity procedures such as ASD repair.

METHODS

All children who underwent ASD repair over 6 years (3 years pre- and postroutine use of aprotinin for all CPB cases in the institution) were identified, and their medical records reviewed. Children with multiple congenital cardiac lesions were excluded. The following data were recorded: demographics and baseline laboratory findings, intraoperative use of aprotinin, cardiopulmonary bypass information including details of ultrafiltration, all intraoperative and postoperative transfusions, postoperative bleeding and relevant laboratory findings.

RESULTS

One hundred and fifteen children were included, 66 of whom received aprotinin. Transfusion rates were not different between children who received aprotinin [n = 8 (12%)] and those who did not [n = 3 (6%)]. Furthermore, changes in hematocrit were not different between groups. These findings were similar when children </=15 kg were compared with those >15 kg.

CONCLUSIONS

This study suggests that aprotinin use offers no benefit for children undergoing isolated repair of an ASD.

Hemostatic agents and tissue glues in urologic injuries and wound healing

Biosurgical preparations designed to promote surgical hemostasis and tissue adhesion are now available to the urologist and are increasingly being used across all surgical disciplines. Fibrin sealant and gelatin thrombin matrix are the two most widely used bio-surgical adjuncts in urology. Complex reconstructive, oncologic, and laparoscopic genitourinary procedures are those most appropriate for sealant use. This article details the diverse urologic applications of biosurgical products in the management of urologic injuries and the promotion of wound healing.

Forty Years of Clinical Aprotinin Use: A Review of 124 Hypersensitivity Reactions

Since its clinical introduction, the anaphylactic potential of aprotinin has been a major concern. World wide, its use is expanding so there is an increased chance that patients have reexposure from various sources. The risk of anaphylaxis is approximately 2.8% in reexposed patients. From 1963 to 2003, 124 cases of aprotinin-induced anaphylaxis were reported in 61 publications. Eleven patients died. The reexposure interval was less than 3 months in 72% (38 of 53 patients). This review looks at the profile of patients at risk so preventive measures may be taken. Past and future exposures have to be taken into account before any aprotinin administration.

The effect of tranexamic acid in fibrin sealant on adhesion formation in the rat

The objective of the research was to determine the effect of the type, dose, and volume of anti-fibrinolytic agents (tranexamic acid, aprotinin) added to fibrin formulations, on adhesion development. Adhesions were induced in 228 male rats by creating apposing parietal and visceral peritoneal defects. Animals were randomized to receive no treatment or a fibrin formulation containing aprotinin or tranexamic acid. Seven days later the incidence of adhesions, and the force and energy required to detach them, were determined. Adhesions developed in 13/13 rats in the control and aprotinin groups. Treatment with fibrin (100 mg/ml tranexamic acid) resulted in adhesions in 4/14 rats (as strips, p < or = 0.0005), 4/10 rats (as spray, p < or = 0.0036), and 12/15 rats (by drip). The reduction of adhesions was dependent on the concentration of tranexamic acid with strip and spray application. Using commercial formulations, tranexamic-acid-containing fibrin (10/15, p = 0.042), but not aprotinin-containing fibrin (13/15), reduced the incidence of side-wall adhesions from 15/15 in controls. Fibrin containing either tranexamic or aprotinin reduced the incidence and severity of adhesions. This effect was greater when tranexamic acid was used and was dependent on the mode of administration, the volume, and to a degree, the concentration of tranexamic acid.

The Effect of Erythropoietin on Allogeneic Blood Requirement in Patients Undergoing Elective Liver Resection: A Model Simulation

We investigated whether recombinant human erythropoietin (rHuEPO) administration would reduce red blood cell (RBC) transfusion requirements in patients undergoing elective liver resection. We retrospectively investigated 200 patients undergoing elective liver resection. Factors likely to predict perioperative RBC transfusion were studied using a logistic regression analysis. A mathematical model was used to simulate RBC transfusion requirements if (a). transfusion thresholds had been predefined at a hemoglobin concentration of 7-8 g/dL, (b). preoperative hemoglobin concentrations had been increased to 15 g/dL by rHuEPO administration in patients with preoperative hemoglobin concentration in the range 10-13 g/dL, and (c). both interventions had been used. A cost/benefit evaluation of rHuEPO administration formed part of this simulation. RBC transfusion was correlated with major and median liver resection, total liver vascular exclusion, and a combined nonhepatic abdominal surgery but was not correlated with a preoperative hemoglobin concentration in the range 10-13 g/dL. Adherence to a small transfusion threshold or rHuEPO administration alone would have resulted in a slight reduction in transfusion requirements and transfusion rates for the whole population. However, the two interventions in combination would have significantly reduced both variables. One-hundred-eighteen patients undergoing median and major liver resection received 92% of RBC transfused. Sixty-six of these 118 patients had preoperative hemoglobin concentrations in the range 10-13 g/dL and could have received rHuEPO before surgery. rHuEPO alone would have avoided the transfusion of 63 RBC packs of 203 in this subgroup and 12 transfused patients of 31 (P = 0.02). rHuEPO administration to these 66 patients would have cost 186000 Euro. The 63 RBC saved would have cost 10,710 Euro.

IMPLICATIONS

A mathematical model simulation suggests that the routine preoperative administration of erythropoietin to patients scheduled for major and median liver resection presenting with a preoperative hemoglobin concentration in the range 10-13 g/dL could reduce blood transfusion requirements. However, the cost/benefit ratio warrants consideration.

Impact of tranexamic acid vs. aprotinin on blood loss and transfusion requirements after cardiopulmonary bypass: a prospective, randomised, double-blind trial

INTRODUCTION

Aprotinin (AP) reduces blood loss and transfusions after cardiopulmonary bypass (CPB), but may sensitise patients and is expensive. Tranexamic acid (TA) has less side-effects, but data regarding its efficacy are controversial. The aim of our prospective, randomised, double-blind study was to compare the impact of AP vs. TA on drainage blood loss and transfusion requirements in patients undergoing first time CABG on CPB.

MATERIALS AND METHODS

One hundred and twenty adult patients were randomised to receive either high-dose AP according to Hammersmith or a total of 2 g TA. Perioperative blood products were transfused in a standardised fashion. Blood loss was measured up to 24 h. Demographic and clinical patient data were collected until hospital discharge.

RESULTS

The data from 118 patients (TA: n = 58, AP: n = 60) who completed the study according to protocol were analysed. Blood loss at 24 h postoperation in TA patients was significantly higher (896 +/- 354 ml) as compared to AP patients (756 +/- 347 ml; p = 0.03). TA patients received 1.5 +/- 1.5 units of red blood cells (AP: 1.5 +/- 1.7, p = 1.0), 1.3 +/- 2.0 units of fresh frozen plasma (AP: 1.0 +/- 2.0, p = 0.38) and 0.5 +/- 1.4 units of platelets (AP: 0.2 +/- 0.7, p = 0.15). Clinical data, including perioperative myocardial infarction rate, acute renal failure, mechanical ventilation, hospital stay and mortality, were not significantly different between either group.

CONCLUSION

Our data show a difference in blood loss between TA and high-dose AP. Although statistically significant, it has little clinical relevance, because perioperative transfusion requirements were similar for both groups. Thus, TA appears to be a cost-effective alternative to AP in primary CABG patients.

Age and left ventricular impairment predict reopening for bleeding

Statistical analysis of data collected prospectively from all patients undergoing surgery under cardiopulmonary bypass from September 1994 to November 1998 (group 1) was performed to identify preoperative risk factors for reopening for bleeding. Multiple logistic regression analysis of 19 preoperative variables was carried out with reoperation for bleeding as the endpoint. The protocol for intraoperative use of aprotinin was then changed to include high-risk patients. Data collected from all subsequent patients from May 1999 to March 2002 (group 2) were analyzed. Subgroup analyses on primary isolated coronary artery surgery were also performed. Data were obtained from 1,946 patients aged 22 to 88 years (mean, 62.5 years). Older age, severe left ventricular impairment, redo surgery, and chronic renal failure were the independent predictors of reopening for bleeding in group 1. There were no independent predictors of reopening in group 2. Older age and chronic renal failure were the predictors of reexploration for bleeding in patients undergoing primary isolated coronary artery grafting. Prophylactic measures to prevent excessive bleeding should be used in elderly patients and those with severe left ventricular impairment, redo surgery, and chronic renal failure.

Risk of anaphylaxis from aprotinin re-exposure during LVAD removal and heart transplantation

Aprotinin has been shown to reduce transfusion requirements in re-operative cardiac surgery and in implantation of long-term left ventricular assist devices (LVAD). However, it is an antigenic polypeptide and re-exposure is associated with a small incidence of anaphylaxis. This report describes 2 cases of anaphylactic response to aprotinin when the agent was employed for both the LVAD implant and for the subsequent explant and cardiac transplant. Early re-exposure to just the test dose was associated with a significant incidence of anaphylaxis.

Aprotinin reduces blood loss and the need for transfusion in orthognathic surgery

A randomized, placebo-controlled, double-blind trial (n= 15 in each group) showed that patients given aprotinin intravenously (200 ml, [2000000 kallikrein inactivator units] before the operation and then 50 ml per h until the end of the operation) during simultaneous maxillary Le Fort 1 and mandibular sagittal split osteotomies, lost 52% less blood than controls (calculated by subtracting the volume of saline irrigant used from the volume of blood collected in the aspirator bottle and surgical drains). Patients given aprotinin lost a mean (SD) of 473 (190) ml compared with 986 (356) ml in controls. They also required significantly less transfused blood (1 was given 2 units in the aprotinin group compared with 9 given a mean of 1.5 units (range 1-4) in the control group). There were no complications attributable to this drug.

Antifibrinolytic agents and desmopressin as hemostatic agents in cardiac surgery

OBJECTIVE

To review the use of systemic hemostatic medications for reducing bleeding and transfusion requirements with cardiac surgery.

DATA SOURCES

Articles were obtained through computerized searches involving MEDLINE (from 1966 to September 2000). Additionally, several textbooks containing information on the diagnosis and management of bleeding associated with cardiac surgery were reviewed. The bibliographies of retrieved publications and textbooks were reviewed for additional references.

STUDY SELECTION

Due to the large number of randomized investigations involving systemic hemostatic medications for reducing bleeding associated with cardiac surgery, the article selection process focused on recent randomized controlled trials, metaanalyses and pharmacoeconomic evaluations.

DATA EXTRACTION

The primary outcomes extracted from the literature were blood loss and associated transfusion requirements, although other outcome measures such as mortality were extracted when available.

DATA SYNTHESIS

Although the majority of investigations for reducing cardiac bleeding and transfusion requirements have involved aprotinin, evidence from recent meta-analyses and randomized trials indicates that the synthetic antifibrinolytic agents, aminocaproic acid and tranexamic acid, have similar clinical efficacy. Additionally, aminocaproic acid (and to a lesser extent tranexamic acid) is much less costly. More comparative information of hemostatic agents is needed retative to other outcomes (eg., reoperation rates, myocardial infarction, stroke). There is insufficient evidence to recommend the use of desmopressin for reducing bleeding and transfusion requirements in cardiac surgery, although certain subsets of patients may benefit from its use.

CONCLUSIONS

Of the medications that have been used to reduce bleeding and transfusion requirements with cardiac surgery, the antifibrinolytic agents have the best evidence supporting their use. Aminocaproic acid is the least costly therapy based on medication costs and transfusion requirements.

Aprotinin Use in Pediatric Cardiac Surgery

Aprotinin is a serine protease inhibitor that inhibits kal likrein and plasmin. Aprotinin's plasmin inhibition accounts for its antifibrinolytic and platelet-sparing effects, which are important factors for its homeostatic efficacy. The kallikrein inhibition occurs at higher plasma levels and is the mecha nism accounting for its anti-inflammatory actions. Aprotinin has relatively large acquisition costs, but these costs are offset by potential reductions in transfusions and intensive care costs. This review summarizes the pediatric literature and develops generalized recommendations for the effica cious use of aprotinin.

Role of aprotinin in the management of patients during and after cardiac surgery

Management of patients undergoing cardiac surgery has evolved in recent years as more is understood about the physiological changes and responses that occur during and after cardiopulmonary bypass (CPB). In particular, our understanding of the mechanisms involved in haemostasis and in the inflammatory response to bypass surgery, has allowed significant refinements in patient management. Improvements in the pharmacological conservation of blood loss have been striking, particularly with the development of the serine protease inhibitor, aprotinin (Trasylol, Bayer). Aprotinin represents a significant improvement, especially for patients at high risk, since it reduces the need for allogeneic and (sometimes scarce) blood products. However, in view of its cost, making an appropriate selection of patients most at risk of serious blood loss is a major consideration in the use of aprotinin. While its mechanisms of action are not well understood, the use of aprotinin also appears to reduce inflammatory response to CPB.

Tranexamic acid compared with high-dose aprotinin in primary elective heart operations: effects on perioperative bleeding and allogeneic transfusions

OBJECTIVE

Since excessive fibrinolysis during cardiac surgery is frequently associated with abnormal perioperative bleeding, many authors have advocated prophylactic use of antifibrinolytic drugs to prevent hemorrhagic disorders. We compared the effects of tranexamic acid (a synthetic antifibrinolytic drug) with aprotinin (a natural derivative product with antifibrinolytic properties) on perioperative bleeding and the need for allogeneic transfusions.

METHODS

In a single-center prospective randomized unblinded trial, 1040 consecutive patients undergoing primary, elective cardiac operations with cardiopulmonary bypass received either high-dose aprotinin or tranexamic acid. The aprotinin group (518 patients) received 280 mg in 20 minutes before the skin incision, 280 mg in the priming solution of the extracorporeal circuit, and a continuous infusion of 70 mg/h throughout the operation. The tranexamic acid group (522 patients) received 1 g in 20 minutes before the skin incision, 500 mg in the priming solution of the extracorporeal circuit, and a continuous infusion of 400 mg/h during the operation. Postoperative bleeding, perioperative transfusions, and hematologic variables were evaluated at fixed times. Postoperative thrombotic complications, intubation time, intensive care unit stay, and hospital stay were recorded.

RESULTS

Postoperative bleeding was similar in the 2 groups: aprotinin 250 mL (150-400 mL) versus tranexamic acid 300 mL (200-450 mL) (median and 25th-75th quartiles), median difference of 50 mL (95% confidence intervals, 0-50 mL). The number of transfusions and the outcome did not differ.

CONCLUSIONS

Tranexamic acid and aprotinin show similar clinical effects on bleeding and allogeneic transfusion in patients undergoing primary elective heart operations. Since tranexamic acid is about 100 times cheaper than aprotinin, its use is preferable in this type of patient.

[Allergic risk of aprotinin]

OBJECTIVE

To analyse the risk of anaphylactic reaction with the administration of aprotinin, either by i.v. route or as a biological sealant application and to propose updated guidelines in accordance with current data of the literature.

DATA SOURCES

Search in the Medline data base of articles in French, English and German, published since 1960, using following key words: aprotinin, allergy, anaphylaxis.

STUDY SELECTION

All categories of articles on this topic have been selected.

DATA EXTRACTION

Articles have been analysed for history, incidence and mechanisms of anaphylactic reactions, symptomatology, factors of risk, diagnosis and precautions of use.

DATA SYNTHESIS

Aprotinin is widely used for decreasing preoperative bleeding, especially in cardiac and orthopaedic surgery. This heterologue protein can cause anaphylactic reactions in 0.5 to 5.8% of patients, depending of the inclusion criteria. They are mediated by IgG and IgE antibodies. Aprotinin has also a direct, non specific, histaminoliberation effect. The clinical presentation includes various degrees of severity, up to cardiac arrest. Documented factors of risk are a previous parotinin administration, 15 days to 6 months before, and intolerance to beef meat, white of egg, cheese and milk. The immediate biological diagnosis is obtained on assessing the degranulation of basophiles (histamine) and mastocytes (tryptase), as well as the concentration of anti-aprotinin antibodies (RAST IgE), with a test of inhibition. The secondary assessment, six weeks later, includes prick-tests and intradermoreactions if the former are negative. The mean precaution consists to search factors of risk at preanaesthetic assessment. The predictive value of systematic prick-tests has not yet been validated. Anti H1 and anti H2 premedication is inefficient. A test dose can trigger a severe reaction.

CONCLUSION

Considering a significant anaphylactic risk, aprotinin administration becomes only licit after a careful evaluation of the benefit-risk ratio.