Aprotinin Versus Placebo in Major Orthopedic Surgery: A Randomized, Double-Blinded, Dose-Ranging Study

Pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic and long bone fractures

BACKGROUND

Pelvic, hip, and long bone fractures can result in significant bleeding at the time of injury, with further blood loss if they are treated with surgical fixation. People undergoing surgery are therefore at risk of requiring a blood transfusion and may be at risk of peri-operative anaemia. Pharmacological interventions for blood conservation may reduce the risk of requiring an allogeneic blood transfusion and associated complications.

OBJECTIVES

To assess the effectiveness of different pharmacological interventions for reducing blood loss in definitive surgical fixation of the hip, pelvic, and long bones.

SEARCH METHODS

We used a predefined search strategy to search CENTRAL, MEDLINE, PubMed, Embase, CINAHL, Transfusion Evidence Library, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) from inception to 7 April 2022, without restrictions on language, year, or publication status. We handsearched reference lists of included trials to identify further relevant trials. We contacted authors of ongoing trials to acquire any unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of people who underwent trauma (non-elective) surgery for definitive fixation of hip, pelvic, and long bone (pelvis, tibia, femur, humerus, radius, ulna and clavicle) fractures only. There were no restrictions on gender, ethnicity, or age. We excluded planned (elective) procedures (e.g. scheduled total hip arthroplasty), and studies published since 2010 that had not been prospectively registered. Eligible interventions included: antifibrinolytics (tranexamic acid, aprotinin, epsilon-aminocaproic acid), desmopressin, factor VIIa and XIII, fibrinogen, fibrin sealants, and non-fibrin sealants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted data. We assessed the certainty of the evidence using GRADE. We did not perform a network meta-analysis due to lack of data.

MAIN RESULTS

We included 13 RCTs (929 participants), published between 2005 and 2021. Three trials did not report any of our predefined outcomes and so were not included in quantitative analyses (all were tranexamic acid versus placebo). We identified three comparisons of interest: intravenous tranexamic acid versus placebo; topical tranexamic acid versus placebo; and recombinant factor VIIa versus placebo. We rated the certainty of evidence as very low to low across all outcomes. Comparison 1. Intravenous tranexamic acid versus placebo Intravenous tranexamic acid compared to placebo may reduce the risk of requiring an allogeneic blood transfusion up to 30 days (RR 0.48, 95% CI 0.34 to 0.69; 6 RCTs, 457 participants; low-certainty evidence) and may result in little to no difference in all-cause mortality (Peto odds ratio (Peto OR) 0.38, 95% CI 0.05 to 2.77; 2 RCTs, 147 participants; low-certainty evidence).  It may result in little to no difference in risk of participants experiencing myocardial infarction (risk difference (RD) 0.00, 95% CI -0.03 to 0.03; 2 RCTs, 199 participants; low-certainty evidence), and cerebrovascular accident/stroke (RD 0.00, 95% CI -0.02 to 0.02; 3 RCTs, 324 participants; low-certainty evidence).  We are uncertain if there is a difference between groups for risk of deep vein thrombosis (Peto OR 2.15, 95% CI 0.22 to 21.35; 4 RCTs, 329 participants, very low-certainty evidence), pulmonary embolism (Peto OR 1.08, 95% CI 0.07 to 17.66; 4 RCTs, 329 participants; very low-certainty evidence), and suspected serious drug reactions (RD 0.00, 95% CI -0.03 to 0.03; 2 RCTs, 185 participants; very low-certainty evidence). No data were available for number of red blood cell units transfused, reoperation, or acute transfusion reaction. We downgraded the certainty of the evidence for imprecision (wide confidence intervals around the estimate and small sample size, particularly for rare events), and risk of bias (unclear or high risk methods of blinding and allocation concealment in the assessment of subjective measures), and upgraded the evidence for transfusion requirement for a large effect.  Comparison 2. Topical tranexamic acid versus placebo We are uncertain if there is a difference between topical tranexamic acid and placebo for risk of requiring an allogeneic blood transfusion (RR 0.31, 95% CI 0.08 to 1.22; 2 RCTs, 101 participants), all-cause mortality (RD 0.00, 95% CI -0.10 to 0.10; 1 RCT, 36 participants), risk of participants experiencing myocardial infarction (Peto OR 0.15, 95% CI 0.00 to 7.62; 1 RCT, 36 participants), cerebrovascular accident/stroke (RD 0.00, 95% CI -0.06 to 0.06; 1 RCT, 65 participants); and deep vein thrombosis (Peto OR 1.11, 95% CI 0.07 to 17.77; 2 RCTs, 101 participants).  All outcomes reported were very low-certainty evidence. No data were available for number of red blood cell units transfused, reoperation, incidence of pulmonary embolism, acute transfusion reaction, or suspected serious drug reactions. We downgraded the certainty of the evidence for imprecision (wide confidence intervals around the estimate and small sample size, particularly for rare events), inconsistency (moderate heterogeneity), and risk of bias (unclear or high risk methods of blinding and allocation concealment in the assessment of subjective measures, and high risk of attrition and reporting biases in one trial). Comparison 3. Recombinant factor VIIa versus placebo   Only one RCT of 48 participants reported data for recombinant factor VIIa versus placebo, so we have not presented the results here.

AUTHORS' CONCLUSIONS

We cannot draw conclusions from the current evidence due to lack of data. Most published studies included in our analyses assessed the use of tranexamic acid (compared to placebo, or using different routes of administration).  We identified 27 prospectively registered ongoing RCTs (total target recruitment of 4177 participants by end of 2023). The ongoing trials create six new comparisons: tranexamic acid (tablet + injection) versus placebo; intravenous tranexamic acid versus oral tranexamic acid; topical tranexamic acid versus oral tranexamic acid; different intravenous tranexamic acid dosing regimes; topical tranexamic acid versus topical fibrin glue; and fibrinogen (injection) versus placebo.

Effect of the Ultrasonic Bone Scalpel on Blood Loss During Pediatric Spinal Deformity Correction Surgery

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Determine the effect of the ultrasonic bone scalpel (UBS) on intraoperative blood loss and surgical time.

SUMMARY OF BACKGROUND DATA

The UBS has shown beneficial effects in limiting blood loss in spinal surgery, but no study has examined its effect in patients with neuromuscular scoliosis.

METHODS

Clinical records were reviewed for patients aged 9-18 who underwent posterior spinal fusion surgery of five or more levels for scoliosis correction by the senior author from April 2013 until October 2016. Exclusion criteria included: vertebral column resections, previous spinal surgery, cell saver usage, cases complicated by signal loss on monitoring, and incomplete medical records. A total of 84 patients met the criteria and were included in data analysis. The UBS was routinely used for performing osteotomies and facetectomies for all cases operated after March 2015. These cases were compared to a control group who underwent surgery prior to this date in which the UBS was not used. The experimental and control groups were further divided into adolescent idiopathic (AIS) and neuromuscular (NMS) subgroups.

RESULTS

EBL in AIS patients decreased from 1,211 mL in the control group to 771 mL in the UBS group for an average total reduction of 440 mL (95% CI 106, 774, p = .01). In NMS patients, EBL fell from 2,171 mL in controls to 1228 mL in the study group for an average total reduction of 943 mL (95% CI 288, 1598, p < .01). On controlling for weight and number of levels fused, blood loss decreased 26.2% in AIS patients and 46.2% in NMS patients.

CONCLUSIONS

The ultrasonic bone scalpel is effective in reducing blood loss in AIS and NMS deformity correction surgery. Surgical time is not adversely affected by its use.

LEVEL OF EVIDENCE

Level II, cohort study.

Impact of balanced tetrastarch raw material on perioperative blood loss: a randomized double blind controlled trial

BACKGROUND

As 6% hydroxyethyl starch (HES) 130/0.40 or 130/0.42 can originate from different vegetable sources, they might have different clinical effects. The purpose of this prospective, randomized, double-blind controlled trial was to compare two balanced tetrastarch solutions, one maize-derived and one potato-derived, on perioperative blood loss in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

We randomly assigned 118 patients undergoing elective cardiac surgery into two groups, to receive either a maize- or a potato-derived HES solution. Study fluids were administered perioperatively (including priming of CPB) until the second postoperative day (POD#2) using a goal directed algorithm. The primary outcome was calculated postoperative blood loss up to POD#2. Secondary outcomes included short-term incidence of acute kidney injury (AKI), and long-term effect (up to one yr) on renal function.

RESULTS

Preoperative and intraoperative characteristics of the subjects were similar between groups. Similar volumes of HES were administered (1950 ml [1250-2325] for maize-HES and 2000 ml [1500-2700] for potato-HES; P=0.204). Calculated blood loss (504 ml [413-672] for maize-HES vs 530 ml [468-705] for potato-HES; P=0.107) and the need for blood components were not different between groups. The incidence of AKI was similar in both groups (P=0.111). Plasma creatinine concentration and glomerular filtration rates did vary over time, although changes were minimal.

CONCLUSIONS

Under our study conditions, HES 130/0.4 or 130/0.42 raw material did not have a significant influence on perioperative blood loss. Moreover, we did not find any effect of tetrastarch raw material composition on short and long-term renal function.

CLINICAL TRIAL REGISTRATION

EudraCT number: 2011-005920-16.

The current place of aprotinin in the management of bleeding

There is a considerable difference between the mechanism of action of the lysine analogues, tranexamic acid and epsilon-aminocaproic acid, and the serine protease inhibitor aprotinin. Aprotinin acts to inactivate free plasmin, but with little effect on bound plasmin, whereas the lysine analogues are designed to prevent excessive plasmin formation by fitting into plasminogen's lysine-binding site to prevent the binding of plasminogen to fibrin. Aprotinin is associated with a reduction in bleeding and transfusion requirements following major surgery, and has a dose-response profile, compared with no dose-response effect in the one study investigating tranexamic acid in cardiac surgical patients. Following its withdrawal in 2007, which is explained in detail in this review, the regulators have now licensed aprotinin for myocardial revascularisation only, which is relatively low-risk for bleeding.

Use of aprotinin to reduce blood loss and transfusion in major orthopedic surgery: a meta-analysis

BACKGROUD

Conflicting reports have been published regarding the effectiveness and safety of aprotinin in reducing blood loss and transfusion in patients undergoing orthopedic surgery. We performed a meta-analysis to evaluate the effectiveness and safety of aprotinin in reducing blood loss and transfusion in major orthopedic surgery.

MATERIALS AND METHODS

MEDLINE, PubMed, EMBASE and Cochrane databases were searched for relevant studies. Only randomized controlled trials were eligible for this study. The weighted mean difference in blood loss, and number of transfusions per patient and the summary risk ratio of transfusion requirements, and deep-vein thrombosis (DVT) were calculated in the aprotinin-treated group and the control group.

RESULTS

Eighteen randomized controlled trials involving 1276 patients were included. The use of aprotinin reduced total blood loss by a mean of 498.88 ml (95% confidence interval [CI]; -735.03 to -262.72), intra-operative blood loss by a mean of 246.11 ml (95% CI; -352.11 to -140.11), post-operative blood loss by a mean of 169.11 ml (95% CI; -234.06 to -105.55), the number of blood transfusions per patient by 0.93 units (95% CI; -1.36 to -0.51). Aprotinin led to a signficant reduction in transfusion requirements (RR 0.59; 95% CI; 0.51 to 0.69) and no increase in the risk of DVT (RR 0.58; 95% CI; 0.38 to 1.08).

CONCLUSION

The meta-analysis shows that aprotinin could significantly reduce blood loss and blood transfusion requirements in patients undergoing orthopedic surgery, and it did not appear to increase the risk of DVT.

Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma

BACKGROUND

When performing minimally invasive spine surgery in trauma patients, a short operation time and a perfect positioning of pedicle screws are demanded. In this study, we show that a Minimally Invasive Pedicle Screw System allows both.

METHODS

One hundred and twenty-one patients (131 fractures) with fractures between Th 3 and L 5 were treated. The most common fracture type was A3. We treated 52 females and 69 men with a mean age of 56.7 years. In 72% of the cases, the procedure was performed by two experienced spine surgeons. Postoperatively, all patients were examined using a CT-scan. In 61 patients, an anterior stabilization was additionally performed in 33 patients, vertebroplasty or cyphoplasty was performed. Fifteen patients underwent laminectomy.

RESULTS

No patient postoperatively developed any additional neurological compromise. In total, 682 screws were placed. In the postoperative CT-scan, we found 16 screws (2.2%) in suboptimal position, 8 with medial and 8 with lateral deviation.

DISCUSSION

With the Minimally Invasive Pedicle Screw System used in this study, spinal fractures can be treated in a short operation time with percutaneous stabilization and a correct positioning of the pedicle screws in almost 98%. In our study, no screw was so much malpositioned that revision surgery would have been necessary.

LEVEL OF EVIDENCE

Level III - Case-control study.

Reducing perioperative blood loss and allogeneic blood transfusion in patients undergoing major spine surgery

At present, individual techniques, including intraoperative acute normovolemic hemodilution, use of tranexamic acid, use of intrathecal morphine, proper positioning, and modification of operative techniques, seem most promising for reducing perioperative blood loss and allogeneic blood transfusion in patients undergoing major spine surgery. Other techniques including preoperative autologous predonation; mandatory discontinuation of use of antiplatelet agents; intraoperative and postoperative red-blood-cell salvage; use of aprotinin, epsilon-aminocaproic acid, recombinant factor VIIa, or desmopressin; induced hypotension; avoidance of hypothermia; and minimally invasive operative techniques require additional studies to either establish their effectiveness or address safety considerations.

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.

Can we safely reduce blood loss during lumbar pedicle subtraction osteotomy procedures using tranexamic acid or aprotinin? A comparative study with controls

STUDY DESIGN

Retrospective, observational study.

OBJECTIVE

To compare the safety and efficacy of 2 pharmaceutical antifibrinolytic agents, aprotinin and tranexamic acid, in controlling blood loss during lumbar pedicle subtraction osteotomy (PSO) in adults.

SUMMARY OF BACKGROUND DATA

Reconstructive spinal surgeries, in particular lumbar PSOs, have been associated with large blood losses despite interventions (intraoperative blood salvaging, controlled hypotensive anesthesia). Since the 1990s, intraoperative administration of antifibrinolytics (aprotinin, tranexamic acid, e-aminocaproic acid) has gained popularity. This study assesses the safety and efficacy of 2 antifibrinolytics, aprotinin and tranexamic acid, during adult lumbar PSO procedures at one institution.

METHODS

A retrospective comparative analysis of 44 consecutive adults undergoing posterior spinal fusion procedures with lumbar PSO at one institution was performed. Patients were analyzed according to treatment group: controls (10), aprotinin (14), and tranexamic acid (20). There were no significant differences in demographic (gender, age, comorbidities) or surgical traits (length of surgery, levels fused/exposed, preoperative hematocrit, bone graft source, primary/revision) between the 3 groups.

RESULTS

The aprotinin group had significantly less intraoperative blood loss (1114 +/- 992 mL; P < 0.01) than the tranexamic acid and control group (2102 +/- 1076 mL and 2260 +/- 1580 mL, respectively). The aprotinin group received significantly less blood (577 +/- 806 mL; P < 0.002) during the surgical procedure than the tranexamic acid (1838 +/- 1096 mL) and the control group (1502 +/- 1241 mL). There were no major intraoperative complications for any of the treatment groups. There were no postoperative cases of seizures, MI, CVA, DVT, or PE with any of the treatment groups. There was one acute tubular necrosis event in the aprotinin group, which resolved before discharge but did required several days of dialysis.

CONCLUSION

The aprotinin treatment group lost significantly less blood and received significantly fewer blood transfusions than both the tranexamic acid and control groups without significant differences in intra- and postoperative complications. These results may justify further study of aprotinin and other antifibrinolytics for this specific indication (3-column lumbar osteotomies in the adult spinal deformity population). A multicenter randomized comparative analysis would be ideal.

Role of Amicar in surgery for neuromuscular scoliosis

STUDY DESIGN

A retrospective case-control study.

OBJECTIVE

Evaluate the effectiveness of Amicar in decreasing perioperative blood loss in patients with neuromuscular scoliosis undergoing posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI).

SUMMARY OF BACKGROUND DATA

Previously, a preliminary prospective; prospective randomized double-blind; same-day anterior and posterior spinal fusion; and fibrinogen studies have demonstrated Amicar to be effective in decreasing total perioperative blood loss and transfusion requirements in surgery for idiopathic scoliosis. Increased fibrinogen secretion is a possible explanation. We are now analyzing its effectiveness in neuromuscular scoliosis.

METHODS

Amicar was administered at 100 mg/kg over 15 minute not to exceed 5 g after anesthesia induction. Maintenance is 10 mg/kg/h until wound closure. There were 2 study groups: group 1 (n = 34), no Amicar and group 2 (n = 62) who received Amicar. The majority of patients in both groups had cerebral palsy. Total perioperative blood loss was determined from the estimated intraoperative blood loss and measured postoperative suction drainage. Total perioperative blood loss and transfusion requirements (cell saver and allogeneic) were compared using chi or Fisher exact test.

RESULTS

There was statistically less estimated intraoperative blood loss, total perioperative blood loss, and transfusion requirements in group 2. Postoperative suction drainage was also less but did not reach statistical significance. In group 1, estimated intraoperative blood loss, measured postoperative suction drainage, and total perioperative blood loss were 2194 +/- 1626 mL, 903 +/- 547 mL, and 3055 +/- 1852 mL, whereas in group 2, it was 1125 +/- 715 mL, 695 +/- 489 mL, and 1805 +/- 940 mL. Transfusion requirements were 1548 +/- 962 mL in group 1 but only 660 +/- 589 mL in group 2 (P < 0.0001). Amicar was equally effective in all diagnoses. There were no complications related to the use of Amicar.

CONCLUSION

Amicar was highly effective in decreasing perioperative blood loss and transfusion requirements in patients with neuromuscular scoliosis undergoing PSF and SSI. It was most effective in decreasing estimated intraoperative blood loss. This results in decreased transfusion requirements, costs, and potential transfusion-related complications.

Use of antifibrinolytic therapy to reduce transfusion in patients undergoing orthopedic surgery: a systematic review of randomized trials

BACKGROUND

Minimizing bleeding and transfusion is desirable given its cost, complexity and potential for adverse events. Concerns have been heightened by recent data demonstrating that bleeding events may predict worse outcomes and by warnings about the safety of erythropoietic stimulating agents. Prior small studies suggest that antifibrinolytic agents may reduce bleeding and transfusion need in patients undergoing total hip replacement (THR) or total knee arthroplasty (TKA). However, no single study has been large enough to definitively determine if these agents are safe and effective. To address this issue we performed a systematic review of randomized trials describing the use of tranexamic acid, epsilon aminocaproic acid, or aprotinin administration in the perioperative setting.

METHODS

MEDLINE, EMBASE, CINAHL and the Cochrane databases were searched for relevant trials. Two independent reviewers abstracted total blood loss, transfusion requirements, and venous thromboembolism (VTE) rates. Data were combined using the Mantel-Haenszel method and dichotomous data expressed as relative risk (RR) with 95% confidence intervals (CI).

RESULTS

Patients receiving antifibrinolytic agents had reduced transfusion need (RR 0.52; 95% CI, 0.42 to 0.64; P<0.00001), reduced blood loss and no increase in the risk of VTE (RR 0.95% CI, 0.80 to 1.10, I(2)=0%, P=0.531).

CONCLUSIONS

We conclude that antifibrinolytic agents may reduce bleeding and transfusion in patients undergoing THR or TKA who receive appropriate antithrombotic prophylaxis. There is a need for a large, adequately powered prospective study to carefully examine the safety and efficacy of these agents.

Safety aspects of aprotinin therapy in cardiac surgery patients

Aprotinin is the only agent with Class A Level 1 evidence for reduction in rates of transfusion and return to operating theatre to control bleeding after heart surgery. Principal on the list of safety issues raised over the years are increased risk for: a) thrombosis; and b) renal dysfunction. With multiple administrations, hypersensitivity reactions have emerged as a further safety concern. This review discusses these issues, based on the examination of > 500 published articles. The article also specifically places in context the data presented recently from the observational McSPI database analysis. This report suggested that aprotinin should be withdrawn from human use as serious safety issues have been ignored or missed, an inference not in agreement with the majority of the human safety literature.

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.

Use of aprotinin in extrapleural pneumonectomy: effect on hemostasis and incidence of complications

BACKGROUND

The purpose of this study was to examine the effect of aprotinin on blood loss in extrapleural pneumonectomy and to identify potential treatment-related complications.

METHODS

Between March 1, 1999, and July 1, 2004, 27 (52%) of 52 patients who underwent extrapleural pneumonectomy received half-dose aprotinin (1 million kallikrein inhibition units load; 250,000 kallikrein inhibition units per hour infusion). A retrospective data review and analysis were performed.

RESULTS

The mean age was 59.8 +/- 11 years, and 45 of 52 patients (87%) were male. Indications for extrapleural pneumonectomy were malignant pleural mesothelioma (n = 50) and pleural-based sarcoma (n = 2). The administration of aprotinin had no significant effect on intraoperative blood loss (1,010 +/- 599 versus 1,182 +/- 688 mL; p = 0.34) or units of packed red blood cells transfused intraoperatively (2.0 +/- 1.7 versus 1.9 +/- 1.7 units; p = 0.86). None of the patients who received aprotinin required the use of non-packed red blood cells blood products, but 4 patients (16%) who did not receive aprotinin required such transfusion (p < 0.05). Postoperative chest tube output at 12 and 24 hours was lower in the aprotinin group (381 +/- 195 and 867 +/- 313 mL, respectively) compared with the control group (725 +/- 527 and 1,221 +/- 442 mL, respectively; p < 0.03). There was no significant difference in incidence of postoperative thromboembolic events between the aprotinin and the control group (5 versus 4 patients; p = 1.0), and 2 patients in each group experienced renal insufficiency (p = 1.0).

CONCLUSIONS

Half-dose aprotinin did not decrease intraoperative blood loss or packed red blood cells transfusion in extrapleural pneumonectomy. However, use of aprotinin was associated with decreased use of non-packed red blood cells blood products and lower postoperative chest tube output. Aprotinin administration was not associated with an increase in incidence of postoperative complications.

Effect of recombinant aprotinin on postoperative blood loss and coronary vascular function in a canine model of cardiopulmonary bypass

OBJECTIVE

Aprotinin is a widely used serine protease inhibitor during cardiopulmonary bypass to reduce blood loss and preserve platelet function. However, the bovine-derived aprotinin can induce hypersensitivity reaction with fatal complications. Furthermore, vascular effects of aprotinin are not completely elucidated. The current study is designed to investigate the effects of recently developed recombinant aprotinin on blood loss and coronary vascular function in a clinically relevant canine model of cardiopulmonary bypass without aortic cross-clamping and cardioplegia.

METHODS

Twenty-four dogs underwent cardiopulmonary bypass without aortic cross-clamping and cardioplegia. Dogs were divided into three groups in a blinded fashion: control animals (n=8) received placebo, aprotinin treatment groups received bovine (n=8) or recombinant aprotinin (n=8) according to the Hammersmith method. The doses of bovine and recombinant aprotinin were the same. Coagulation parameters and blood loss were measured regularly at different time points. Endothelium-dependent and -independent vasorelaxation were investigated in isolated left anterior descendent coronary arterial rings by using acetylcholine and bradykinin or sodium nitroprusside and adenosine, respectively.

RESULTS

Postoperative blood loss was significantly reduced in the aprotinin-treated groups in comparison to control and there was no significant difference between the two aprotinin-treated groups. Endothelium-dependent relaxation of coronary arteries to acetylcholine and bradykinin was unaffected in the aprotinin treatment groups. Both types of aprotinin significantly increased vasorelaxation to adenosine when compared with controls, but did not affect that to sodium nitroprusside.

CONCLUSIONS

The effectiveness of recombinant aprotinin on blood loss was equivalent to bovine-derived aprotinin. Neither types of aprotinin impaired endothelium-dependent relaxation in a canine model of cardiopulmonary bypass.

Fibrinogen levels following Amicar in surgery for idiopathic scoliosis

STUDY DESIGN

Prospective evaluation of fibrinogen levels before surgery and after surgery in patients with idiopathic scoliosis undergoing posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI) who received Amicar to decrease perioperative blood loss.

OBJECTIVES

To assess a possible association between postoperative fibrinogen levels and Amicar administration.

SUMMARY OF BACKGROUND DATA

Our previous randomized, double-blind (Amicar and control) study demonstrated a rise in fibrinogen levels on the first postoperative day in the Amicar group, but not in the control group. Fibrinogen levels were not measured on the remaining postoperative days. We subsequently measured fibrinogen levels on all postoperative days in 21 consecutive patients with idiopathic scoliosis and found a dramatic increase throughout the postoperative hospitalization. This study is a continuation of our analysis of postoperative fibrinogen levels.

METHODS

We analyzed fibrinogen levels before surgery and on all postoperative days (4 or 5 days) until discharge in 51 consecutive patients, including our 21 previously reported patients, who received Amicar and underwent a PSF and SSI. We also analyzed the same factors with respect to perioperative blood loss as in our previous Amicar studies.

RESULTS

There were 41 females and 10 males with a mean age at surgery of 14.2 +/- 1.8 years. Their mean hospitalization was 4.6 +/- 0.8 days. Their mean estimated intraoperative blood loss was 766 +/- 308 mL and postoperative suction drainage 532 +/- 186 mL for a total perioperative blood loss of 1297 +/- 311 mL. The perioperative transfusion requirements were 0.5 +/- 0.6 U per patient. The preoperative fibrinogen was 255.5 +/- 58.3 mg/dL, and it rose steadily throughout the postoperative period to 680.9 +/- 111.9 mg/dL on the fifth postoperative day. There were no complications related to the use of Amicar.

CONCLUSIONS

Fibrinogen levels rise steadily throughout the postoperative period. The significance of this increase is unknown. Was it due to the use of Amicar or just the effects of surgery itself? Further investigations will be necessary.

Full-dose aprotinin use in coronary artery bypass graft surgery: an analysis of perioperative pharmacotherapy and patient outcomes

BACKGROUND

Inappropriate activation of hemostasis and inflammation may contribute to postoperative morbidity and mortality. The serine protease inhibitor, aprotinin, has been shown to prevent tissue and organ injury in laboratory and animal studies. In this retrospective analysis, we evaluated the relationship of aprotinin therapy with organ dysfunction in humans undergoing coronary artery bypass graft surgery (CABG).

METHODS

Data from prospective randomized, double-blind, placebo-controlled studies evaluating the safety and efficacy of full-dose aprotinin (2 million KIU load, 2 million KIU pump prime, and 0.5 million KIU/h continuous infusion) to reduce blood loss and transfusion requirements in patients undergoing CABG (placebo, n = 861; aprotinin, n = 862) were examined retrospectively. Primary end-points were death, adverse cerebrovascular outcome, myocardial infarction (MI), and pharmacological interventions (inotropic drugs, vasopressors, and antiarrhythmics).

RESULTS

Univariate analysis showed that relative to placebo, full-dose aprotinin therapy was associated with significant effects on the incidence of adverse cerebrovascular outcome (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.19-0.93; P = 0.03) and use of inotropic drugs (OR 0.79, 95% CI 0.65-0.97; P = 0.02), vasopressors (OR 0.74, 95% CI 0.61-0.90; P < 0.01), and antiarrhythmics (OR 0.79, 95% CI 0.65-0.96; P = 0.02), but not death (OR = 1.00, 95% CI 0.54-1.85; P = 1.0) or MI (OR 0.92, 95% CI 0.64-1.31; P = 0.6). Multivariate analysis confirmed results of univariate analysis.

CONCLUSIONS

This retrospective analysis of data collected from prospective, randomized, placebo-controlled studies in CABG shows that full-dose aprotinin use was associated with a lower risk of adverse cerebrovascular outcomes and a reduced need for use of vasoactive drugs; the risk of death and perioperative MI was not affected by aprotinin therapy.

Pharmacological approaches to reducing blood loss and transfusions in the surgical patient

PURPOSE

To review the efficacy, effectiveness and safety of hemostatic drugs to reduce surgical blood loss.

METHODS

Analysis of randomized controlled trials and meta-analyses exploring the efficacy of desmopressin, aprotinin, lysine analogues and recombinant activated factor VII (rFVIIa) on clinically important endpoints.

MAIN FINDINGS

Although potentially useful in surgical patients with mild hemophilia or type I von Willebrand's disease, desmopressin has no proven benefit in patients without previous hemostatic defects. Aprotinin has been studied extensively in cardiopulmonary bypass surgery, with evidence of a blood sparing effect. Additional benefits are suggested. The drug is less consistently effective in liver transplantation and major orthopedic surgery. Although rare, hypersensitivity reactions to aprotinin may occur, especially on re-exposure. Tranexamic acid can reduce blood transfusion in cardiac surgery, liver transplantation and total knee arthroplasty surgery with a satisfactory safety profile. Epsilon aminocaproic acid has not been investigated adequately, despite its widespread use. While rFVIIa may be beneficial in controlling massive coagulopathic bleeding in trauma and surgical patients, there is currently no evidence to support its prophylactic use in elective surgical patients.

CONCLUSION

Aprotinin and tranexamic acid are valuable pharmacologic options for reducing surgical bleeding. The expected benefit of these drugs is highly dependent on the actual blood usage for a given procedure at the institutional level. More studies using clinically significant endpoints are necessary to assess the relative efficacy and optimal dosing of these drugs.

Aprotinin in Major Orthopedic Surgery: A Systematic Review of Randomized Controlled Trials

Aprotinin therapy is a promising strategy for reducing blood loss and blood transfusion requirements. The efficacy and safety of aprotinin in orthopedic surgery, however, remain controversial. We searched electronic databases for randomized controlled trials on the efficacy and safety of the use of aprotinin in orthopedic surgery. Thirteen trials that included a total of 506 patients who underwent major orthopedic surgery were analyzed. The pooled intraoperative and perioperative blood loss was significantly less in the aprotinin-treated patients than in the control patients (weighted mean difference [WMD] for intraoperative blood loss = -229 mL, 95% confidence interval [CI] = -367 to -91 mL, P = 0.0011; WMD for perioperative blood loss = -557 mL; 95% CI = -860 to -254 mL; P < 0.0001). The pooled amounts of red blood cell (RBC) units (U) transfused intraoperatively and perioperatively were significantly less in the aprotinin-treated patients than in the control patients (WMD for intraoperative RBC U = -1.1 U; 95% CI = -1.7 to -0.4 U; P = 0.0001; WMD for perioperative RBC U = -1.1 U; 95% CI = -1.7 to -0.5 U; P < 0.0001). Aprotinin was not associated with an increased incidence of deep vein thrombosis (odds ratio = 0.39; 95% CI = 0.14 to 1.05, P = 0.061). The authors conclude that aprotinin reduces the intraoperative and perioperative blood loss and allogeneic blood transfusion requirement and may not be associated with increased risk of deep vein thrombosis in the presence of pharmacological or mechanical prophylaxis in patients undergoing major orthopedic surgery.

The role of amicar in decreasing perioperative blood loss in idiopathic scoliosis

STUDY DESIGN

Four separate studies on the role of Amicar in decreasing perioperative blood loss in idiopathic scoliosis.

OBJECTIVES

To assess the efficacy and possible mechanisms of action for Amicar.

SUMMARY OF BACKGROUND DATA

Preliminary prospective, randomized double-blind and analysis of same-day anterior spinal fusion (ASF), fibrinogen, and posterior spinal fusion (PSF) studies have demonstrated Amicar to be effective in idiopathic scoliosis surgery. Increased fibrinogen secretion is a possible explanation.

METHODS

Amicar is administered at 100 mg/kg over 15 minutes not to exceed 5 g at anesthesia induction. Maintenance is 10 mg/kg per hour until wound closure.

RESULTS

Preliminary study: Amicar (N = 28) was effective compared with a control group (N = 31). Perioperative blood loss and transfusion following PSF were 1,604 +/- 517 mL and 1.1 +/- 1.0 U in the Amicar group compared with 2,312 +/- 994 mL and 2.1 +/- 1.1 U in the control group (P < 0.003). Prospective, randomized double-blind study confirmed this efficacy, although primarily in postoperative suction drainage: 1,391 +/- 212 mL and 1.1 +/- 1.0 U compared with 1,716 +/- 513 mL and 2.1 +/- 1.3 U (P < 0.002). A fibrinogen study (N = 21) demonstrated steady and excessive increase following PSF: before surgery it was 266 +/- 63 mg/dL and on the fifth postoperative day 699 +/- 94 mg/dL. In same-day anterior and posterior spinal surgery, Amicar was again effective, but primarily in decreasing chest tube drainage and during PSF. Group 1 (N = 15, no Amicar) 3,807 +/- 105 mL and 3.1 +/- 1.5 U; Group 2 (N = 27, Amicar for PSF only) 2,080 +/- 659 mL and 1.9 +/- 0.9 U; and Group 3 (N = 16, both ASF and PSF) 2,183 +/- 851 mL and 1.0 +/- 0.8 U.

CONCLUSIONS

Amicar appears highly effective in decreasing perioperative blood loss. This results in less autologous blood donation, blood transfusion, costs, and complications. Its mechanism of action is uncertain but may be related to increased fibrinogen secretion.

Aprotinin and epsilon aminocaproic acid are effective in reducing blood loss after primary total hip arthroplasty--a prospective randomized double-blind placebo-controlled study

A prospective randomized double-blind placebo-controlled study was undertaken to determine the efficacy and mechanism of action of two antifibrinolytic drugs aprotinin and epsilon aminocaproic acid (EACA) in reducing blood loss in primary unilateral total hip arthroplasty (THA). Aprotinin was administered as a bolus of 2 x 10(6) kallikrein inhibitor units (KIU) followed by 0.5 x 10(6) KIU h(-1) for 3 h, EACA was given as 10 g over 30 min followed by 5 g over 3 h. The median postoperative blood loss 24 h postoperatively was reduced from 450 mL in the placebo group to 180 mL for aprotinin (60% reduction, P < 0.001) and to 210 mL for EACA (53% reduction, P < 0.01). In this population, there was no reduction in the perioperative transfusion requirements. The mechanism of both drugs was independent of platelets as indicated by flow cytometric measurement of change of their expression of P-selectin, platelet-monocyte aggregates, V/Va and CD40 ligand. There were no thrombotic or infective complications and no adverse events were attributable to use of either drug. Infusion of either aprotinin or EACA at the doses described is a safe and effective means of reducing blood loss after THA. These therapies provide a means of reducing blood loss in THA patients.

The effect of aprotinin on blood loss in bilateral total knee arthroplasty

Twenty-five patients undergoing bilateral total knee arthroplasty were given aprotinin (1-2 million units) in doses adjusted for weight, infused at the end of the first arthroplasty. Blood management was compared with our previous series of 68 patients who were not treated with aprotinin. Blood drained and re-transfused in the first 6 h was significantly less in the aprotinin group (323 ml, S.D. 320) than the untreated group (1033 ml, S.D. 539, p<0.0005). The total blood drained was also less in the aprotinin group (713 ml compared to 1613 ml, p<0.0005) but this was accounted for soley by the difference in early blood loss. The use of other blood products was less in the aprotinin group (360 ml, S.D. 357 compared to 827 ml, S.D. 434, p<0.0005). The mean postoperative haemoglobin on the day following surgery was similar at around 10 g. There were no complications or adverse reactions to the use of aprotinin. We conclude that aprotinin significantly reduces early blood loss after bilateral knee arthroplasty. In our hands, we have found it to be safe. Further work is required to determine whether postoperative use may further reduce the need for blood transfusion.

Perioperative systemic haemostatic agents

Skilful surgery combined with blood-saving methods and careful management of blood coagulation will all help reduce unnecessary blood loss and transfusion requirements. Excessive surgical bleeding causes hypovolaemia, haemodynamic instability, anaemia and reduced oxygen delivery to tissues, with a subsequent increase in postoperative morbidity and mortality. The role of anaesthetists in managing surgical blood loss has increased greatly in the last decade. Position of the patient during surgery and the provision of a hypotensive anaesthetic regimen were once considered the most important contributions of the anaesthetist to decreasing blood loss. Now, several pharmacological haemostatic agents are being used by anaesthetists as blood-saving agents. After a brief discussion of the physiology of haemostasis, this article will review the evidence for the role of such agents in reducing perioperative blood loss and transfusion requirements.

What is the evidence for using hemostatic agents in surgery?

The pharmacological methods used to achieve systemic hemostasis have generated much discussion due to concerns of serious adverse effects (e.g., thromboembolic complications) and costs of therapy in addition to efficacy considerations. There are a limited number of well-controlled trials involving pharmacological hemostasis for spine surgery. In the largest double-blinded randomized controlled trial to date involving spine surgery, there was a trend toward reduced homologous transfusion in patients receiving aprotinin, but the only statistically significant result ( p<0.001) was a reduction in autologous red cell donations. The findings of this trial are important, since the investigators used a number of restrictive transfusion strategies (e.g., autologous donation, low hematocrit trigger for transfusion, blood-salvaging procedures with the exception of no cell saver) that were not always employed in earlier trials involving hemostatic agents. Smaller studies involving antifibrinolytic agents other than aprotinin have demonstrated reductions in blood loss and transfusion requirements in patients undergoing spine surgery, although the results were not always statistically significant. A very large randomized trial would be required to address comparative medication- and transfusion-related adverse events; such a trial involving patients undergoing cardiac surgery is currently being performed. Additionally, cost-effectiveness analyses are needed to help define the role of these agents based on the data that is available.

Aprotinin and major orthopedic surgery

Aprotinin is a potent pharmacological agent that reduces bleeding and limits blood transfusion requirements in current surgical practice. Many studies have been conducted in orthopedic surgery. In several trials performed in total hip replacement (THR) and total knee replacement (TKN) patients, aprotinin only moderately decreased blood-loss-replacement requirements. Conversely, when aprotinin was used in patients at high risk for bleeding (cancer, sepsis, redone surgery), it developed a potent hemostatic activity and decreased blood transfusion significantly. No increase in deep vein thrombosis and pulmonary embolism was observed. The only major side effect could be the potential occurrence of an anaphylactoid reaction. Prophylactic administration of aprotinin should be considered in extensive spine surgery and in high-risk major orthopedic operations. The decision to use aprotinin should be guided by a risk/benefit analysis.

An overview of blood-sparing techniques used in spine surgery during the perioperative period

The problems linked to blood loss and blood-sparing techniques in spine surgery have been less studied than in other fields of orthopedics, such as joint-replacement procedures. Decreasing bleeding is not only important for keeping the patient's hemodynamic equilibrium but also for allowing a better view of the surgical field. In spine surgery the latter aspect is especially important because of the vicinity of major and highly fragile neurologic structures. The techniques and agents used for hemostasis and blood sparing in spinal procedures are mostly similar to those used elsewhere in surgery. Their use is modulated by the specific aspects of spinal approach and its relation to the contents of the spinal canal. Blood-sparing techniques can be divided into two categories based on their goals: either they are aimed at decreasing the bleeding itself, or they are aimed at decreasing the need for homologous transfusion. Various hemodynamic techniques, as well as systemic and local drugs and agents, can be used separately or in combination, and their use in the field of spine surgery is reported. The level of evidence for the efficacy of many of those methods in surgery as a whole is limited, and there is a lack of evidence for most of them in spine surgery. However, several blood-saving procedures and drugs, as well as promising new agents, appear to be efficient, although their efficacy has yet to be assessed by proper randomized controlled trials.

Intraoperative blood management in joint replacement surgery

Interest is growing in blood conservation and avoidance of transfusion in patients undergoing orthopedic surgery, especially in the field of joint replacement. Several methods have proven successful in reducing intraoperative blood loss, which can translate into lessened allogeneic and autologous transfusion requirements. Available techniques include acute normovolemic hemodilution, hypotensive anesthesia, intraoperative blood salvage, specialized cautery, topical hemostatic agents, and pharmacologic agents given in the perioperative period. The greatest potential benefit arises in operations with greater expected blood loss or in special situations such as in patients with religious issues, bilateral joint replacement, coagulation disorders, or significant preoperative anemia.

A direct antifibrinolytic agent in major orthopedic surgery

Aprotinin is a potent pharmacological agent that reduces bleeding. In current surgical practices, the rate of blood transfusions has decreased with the use of aprotinin. Recently, studies using aprotinin have been conducted in orthopedic surgery. Several trials have been performed in patients undergoing total hip replacement and total knee replacement. Aprotinin moderately decreased blood loss in these patients. When aprotinin was used in patients with a high-risk of bleeding (ie, patients with cancer, sepsis, or undergoing reoperation), potent hemostatic activity occurred and the rate of blood transfusions significantly decreased. No increase in deep vein thrombosis and pulmonary embolism was observed. One adverse effect was the potential occurrence of an anaphylactoid reaction. Prophylactic administration of aprotinin should be considered in extensive spine surgery and in high-risk orthopedic operations. The decision to use aprotinin can be guided by a risk/benefit analysis.

Blood management in patients with deep prosthetic hip and knee infections

Patients undergoing treatment for infected hip and knee replacements often have significant blood loss and require allogeneic blood transfusions. In the setting of sepsis, traditional methods of blood management such as preoperative blood donations, cell savers, and reinfusion drains are contraindicated. Pharmacologic agents can minimize transfusion requirements by increasing erythropoiesis, or minimize perioperative blood loss. This article reviews the use of these agents in the management of patients with deep prosthetic hip and knee infections.

Tranexamic acid reduces the need for allogenic red blood cell transfusions in patients undergoing total hip replacement

PURPOSE

This prospective randomized double-blind trial evaluates the efficacy of tranexamic acid (TA) to decrease blood losses and red blood cell transfusions in patients undergoing primary unilateral total hip replacement (THR).

METHODS

Forty ASA class I to III patients received either iv TA 10 mg.kg(-1) bolus before surgery plus a 1 mg.kg(-1).hr(-1) infusion until wound closure (Group TA) or a placebo (Group P). Red blood cell transfusions were administered according to a standardized protocol.

RESULTS

One patient of Group P was excluded because of an erroneous diagnosis at enrollment. Total measured blood losses (Group TA: 1308 +/- 462 mL vs Group P: 1469 +/- 405 mL), preoperative hemoglobin levels (Group TA: 130.4 +/- 12.5 g.L(-1) vs Group P: 131.4 +/- 12.8 vs g.L(-1)), and seven-day postoperative hemoglobin values (Group TA: 97.8 +/- 11.8 g.L(-1) vs Group P: 102.9 +/- 12.2 g.L(-1)) were similar. Autologous whole blood was available in five patients of Group P and seven patients of Group TA. Fewer patients in Group TA required red blood cells (Group TA: 6/20 vs Group P: 13/19; P = 0.026) and allogenic red blood cell transfusions (Group TA: 0/20 vs Group P: 8/19; P = 0.0012). The median number of transfused unit per patient was also significantly less in patients of Group TA (0 unit) than in Group P (2 units; P = 0.03).

CONCLUSION

TA did not change measured blood losses but reduced red blood cell transfusion requirements in patients undergoing primary unilateral THR.

Pharmacological strategies to decrease transfusion requirements in patients undergoing surgery

Surgical procedures are inevitably associated with bleeding. The amount of blood loss may vary widely between different surgical procedures and depends on surgical as well as non-surgical factors. Whereas adequate surgical haemostasis may suffice in most patients, pro-haemostatic pharmacological agents may be of additional benefit in patients with (diffuse) surgical bleeding or in patients with a specific underlying haemostatic defect. In general, surgical haemostasis and pharmacological therapies can be complementary in controlling blood loss. The use of pharmacological therapies to reduce blood loss and blood transfusions in surgery has historically been restricted to a few drugs. Antifibrinolytic agents (aprotinin, tranexamic acid and aminocaproic acid) have the best evidence supporting their use, especially in cardiac surgery, liver transplantation and some orthopaedic surgical procedures. Meta-analyses of randomised, controlled trials in cardiac patients have suggested a slight benefit of aprotinin, compared with the other antifibrinolytics. Desmopressin is the treatment of choice in patients with mild haemophilia A and von Willebrand disease. It has also been shown to be effective in patients undergoing cardiac surgery who received aspirin up to the time of operation. However, overall evidence does not support a beneficial effect of desmopressin in patients without pre-existing coagulopathy undergoing elective surgical procedures. Topical agents, such as fibrin sealants have been successfully used in a variety of surgical procedures. However, only very few controlled clinical trials have been performed and scientific evidence supporting their use is still limited. Novel drugs, like recombinant factor VIIa (eptacog alfa), are currently under clinical investigation. Recombinant factor VIIa has been introduced for the treatment of haemophilia patients with inhibitors, either in surgical or non-surgical situations. Preliminary data indicate that it may also be effective in surgical patients without pre-existing coagulation abnormalities. More clinical trials are warranted before definitive conclusions can be drawn about the safety and the exact role of this new drug in surgical patients. Only adequately powered and properly designed randomised, clinical trials will allow us to define the most effective and the safest pharmacological therapies for reducing blood loss and transfusion requirements in surgical patients. Future trials should also consider cost-effectiveness because of considerable differences in the costs of the available pro-haemostatic pharmacological agents.