Analyses of coronary graft patency after aprotinin use: results from the International Multicenter Aprotinin Graft Patency Experience (IMAGE) trial

Consensus Statement: Hemostasis Trial Outcomes in Cardiac Surgery and Mechanical Support

BACKGROUND

Research evaluating hemostatic agents for the treatment of clinically significant bleeding has been hampered by inconsistency and lack of standardized primary clinical trial outcomes. Clinical trials of hemostatic agents in both cardiac surgery and mechanical circulatory support, such as extracorporeal membrane oxygenation and ventricular assist devices, are examples of studies that lack implementation of universally accepted outcomes.

METHODS

A subgroup of experts convened by the National Heart, Lung, and Blood Institute and the US Department of Defense developed consensus recommendations for primary outcomes in cardiac surgery and mechanical circulatory support.

RESULTS

For cardiac surgery the primary efficacy endpoint of total allogeneic blood products (units vs mL/kg for pediatric patients) administered intraoperatively and postoperatively through day 5 or hospital discharge is recommended. For mechanical circulatory support outside the perioperative period the recommended primary outcome for extracorporeal membrane oxygenation is a 5-point ordinal score of thrombosis and bleeding severity adapted from the Common Terminology Criteria for Adverse Events version 5.0. The recommended primary endpoint for ventricular assist device is freedom from disabling stroke (Common Terminology Criteria for Adverse Events AE ≥ grade 3) through day 180.

CONCLUSIONS

The proposed composite risk scores could impact the design of upcoming clinical trials and enable comparability of future investigations. Harmonizing and disseminating global consensus definitions and management guidelines can also reduce patient heterogeneity that would confound standardized primary outcomes in future research.

Recommended primary outcomes for clinical trials evaluating hemostatic blood products and agents in patients with bleeding: Proceedings of a National Heart Lung and Blood Institute and US Department of Defense Consensus Conference

ABSTRACT

High-quality evidence guiding optimal transfusion and other supportive therapies to reduce bleeding is needed to improve outcomes for patients with either severe bleeding or hemostatic disorders that are associated with poor outcomes. Alongside challenges in performing high-quality clinical trials in patient populations who are at risk of bleeding or who are actively bleeding, the interpretation of research evaluating hemostatic agents has been limited by inconsistency in the choice of primary trial outcomes. This lack of standardization of primary endpoints or outcomes decreases the ability of clinicians to assess the validity of endpoints and compare research results across studies, impairs meta-analytic efforts, and, ultimately, delays the translation of research results into clinical practice. To address this challenge, an international panel of experts was convened by the National Heart Lung and Blood Institute and the US Department of Defense on September 23 and 24, 2019, to develop expert opinion, consensus-based recommendations for primary clinical trial outcomes for pivotal trials in pediatric and adult patients with six categories in various clinical settings. This publication documents the conference proceedings from the workshop funded by the National Heart Lung and Blood Institute and the US Department of Defense that consolidated expert opinion regarding clinically meaningful outcomes across a wide range of disciplines to provide guidance for outcomes of future trials of hemostatic products and agents for patients with active bleeding.

Decreasing Postoperative Blood Loss by Topical vs. Intravenous Tranexamic Acid in Open Cardiac Surgery (DEPOSITION) study: Results of a pilot study

BACKGROUND

Cardiac surgery patients are at high risk for postoperative bleeding. Intravenous (IV) tranexamic acid (TxA) is a commonly used antifibrinolytic drug, but is associated with postoperative seizures. We conducted this pilot randomized controlled trial (RCT) to determine the feasibility of a larger trial that will be designed to investigate the impact of TxA administration route, intrapericardial (IP) vs IV, on postoperative bleeding and seizures.

METHODS

In this single-center, double-blinded, pilot RCT we enrolled adult patients undergoing nonemergent on-pump cardiac operations through a median sternotomy. Participants were randomized to IP or IV TxA groups. The primary outcomes were cumulative chest tube drainage, transfusion requirements, and incidence of postoperative seizures.

RESULTS

A total of 97 participants were randomized to the intervention and control groups. Baseline characteristics were similar in both groups. Most participants underwent a CABG and/or aortic valve replacement. There was no statistical difference. The IP TxA group was found to have a tendency for less chest tube drainage in comparison to the IV TxA group, 500.5 (370.0-700.0) and 540.0 (420.0-700.0) mL, respectively, which was not statistically significant (P = 0.2854). Fewer participants in the IP TxA group with cardiac tamponade and/or required a reoperation for bleeding and fewer packed red blood cell transfusions. None of the IP TxA group developed seizure vs one from the IV TxA group.

CONCLUSION

This is the first known pilot RCT to investigate the role of TxA route of administration in open cardiac surgery. Intrapericardial TxA shows promising results with decreased bleeding, transfusion requirements, reoperations, and postoperative seizures. A larger RCT is needed to confirm these results and lead to a change in practice.

Anticoagulation, bleeding and blood transfusion practices in Australasian cardiac surgical practice

We surveyed contemporary Australasian cardiac surgical and anaesthetic practice, focusing on antiplatelet and antifibrinolytic therapies and blood transfusion practices. The cohort included 499 sequential adult cardiac surgical patients in 12 Australasian teaching hospitals. A total of 282 (57%) patients received red cell or component transfusion. The median (IQR) red cell transfusion threshold haemogloblin levels were 66 (61-73) g/l intraoperative^ and 79 (74-85) g/l postoperatively. Many (40%) patients had aspirin within five days of surgery but this was not associated with blood loss or transfusion; 15% had Clopidogrel within seven days of surgery. In all, 30 patients (6%) required surgical re-exploration for bleeding. Factors associated with transfusion and excessive bleeding include pre-existing renal impairment, preoperative Clopidogrel therapy, and complex or emergency surgery. Despite frequent (67%) use of antifibrinolytic therapy, there was a marked variability in red cell transfusion rates between centres (range 17 to 79%, P <0.001). This suggests opportunities for improvement in implementation of guidelines and effective blood-sparing interventions. Many patients presenting for surgery receive antiplatelet and/or antifibrinolytic therapy, yet the subsequent benefits and risks remain unclear.

Hospital-Acquired Anemia: A Contemporary Review of Etiologies and Prevention Strategies

Advances in medicine have significantly improved lives and life spans globally. However, these practices have come with their own set of secondary consequences. Hospital-acquired anemia is one such consequence and is conferred by new medicines, operations, procedures, and tests. In this review, the authors will explore the data on this poorly considered phenomenon and discuss the etiologies, outcomes, and prevention strategies for some of the more prolific causes of hospital-acquired anemia. This study also will review the risks and benefits of treating hospital-acquired anemia.

Tranexamic Acid in Patients Undergoing Coronary-Artery Surgery

BACKGROUND

Tranexamic acid reduces the risk of bleeding among patients undergoing cardiac surgery, but it is unclear whether this leads to improved outcomes. Furthermore, there are concerns that tranexamic acid may have prothrombotic and proconvulsant effects.

METHODS

In a trial with a 2-by-2 factorial design, we randomly assigned patients who were scheduled to undergo coronary-artery surgery and were at risk for perioperative complications to receive aspirin or placebo and tranexamic acid or placebo. The results of the tranexamic acid comparison are reported here. The primary outcome was a composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery.

RESULTS

Of the 4662 patients who were enrolled and provided consent, 4631 underwent surgery and had available outcomes data; 2311 were assigned to the tranexamic acid group and 2320 to the placebo group. A primary outcome event occurred in 386 patients (16.7%) in the tranexamic acid group and in 420 patients (18.1%) in the placebo group (relative risk, 0.92; 95% confidence interval, 0.81 to 1.05; P=0.22). The total number of units of blood products that were transfused during hospitalization was 4331 in the tranexamic acid group and 7994 in the placebo group (P<0.001). Major hemorrhage or cardiac tamponade leading to reoperation occurred in 1.4% of the patients in the tranexamic acid group and in 2.8% of the patients in the placebo group (P=0.001), and seizures occurred in 0.7% and 0.1%, respectively (P=0.002 by Fisher's exact test).

CONCLUSIONS

Among patients undergoing coronary-artery surgery, tranexamic acid was associated with a lower risk of bleeding than was placebo, without a higher risk of death or thrombotic complications within 30 days after surgery. Tranexamic acid was associated with a higher risk of postoperative seizures. (Funded by the Australian National Health and Medical Research Council and others; ATACAS Australia New Zealand Clinical Trials Registry number, ACTRN12605000557639 .).

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

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

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

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

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

Blood Conservation Strategies in Cardiac Surgery

Perioperative bleeding in cardiac surgery is related to both surgical trauma of blood vessels and defects in the hemostatic mechanism caused, in part, by cardiopulmonary bypass. Blood transfusion therefore remains a significant risk of cardiac surgery with important health and economic consequences. Blood conservation strategies for cardiac surgery have advanced over the years and the following discussion will focus on the current practices at Toronto General Hospital.

Adverse Central Nervous System Outcomes After Cardiopulmonary Bypass: A Beneficial Effect of Aprotinin?

This review considers the evidence for potential central nervous system benefits associated with use of anti- protease therapy for patients undergoing procedures involving cardiopulmonary bypass. Unfortunately, few randomized, controlled clinical trials have assessed the lysine analogue class of antifibrinolytics (ie, ∈-amino caproic acid, tranexamic acid) compared with the num ber investigating the efficacy of the enzyme-inactivator class of antifibrinolytic typified by the nonspecific serine protease inhibitors aprotinin and nafamostat.

Topical application of aprotinin in cardiac surgery

The aim of our study was to compare a systemic and a local aprotinin application in patients during coronary artery bypass graft (CABG) surgery. The advantage of a topical aprotinin application is seen in the fact that this may not lead to systemic side effects. A prospective, randomized study comprising 97 patients was conducted. A dose of 5 106 KIU aprotinin was given systemically to 49 patients and four doses of 1.25 106 KIU aprotinin were applied topically to 48 patients by spraying the substance on the target area (A. mammaria interna region and pericardium). We determined markers for the inflammatory response, coagulation system, standard haematological markers and postoperative complications. Exclusion criteria were defined as surgical bleeding, redo operations, neurological, haematological, liver and kidney disorders. Sex, age, perfusion times, mortality, renal failure and strokes were identical in both groups. Biochemical markers and clinical outcome demonstrated no significant differences between the systemic and local applications. Interleukin 6 and elastase were tendentially higher ( p= 0.1) in the local group, but with a high standard deviation in each patient. Our results suggest that there is no difference between the perioperative application of 5 106 KIU systemically given aprotinin and 1.25 106 KIU locally applied aprotinin.

Local use of ankaferd blood clotter in emergent beating heart coronary artery bypass grafting

Background:

Severe beeding which requiring massive blood transfusion after emergent beating heart surgery is shown to be 1–3%. Therefore, complications and side effects of transfusion can be seen. The aim of this study was to investigate the effectiveness of Ankaferd blood clotter (ABC) as a new topical herbal blood clotter to decrease mediastinal bleeding in emergent beating heart CABG patients who medicated with clopidogrel and acetyl salisilic acite (ASA) prior to CABG surgery.

Materials and Methods:

25 CABG patients received a high dose clopidogrel (600 mgr) and 300 mgr ASA have been included into the study (ABC group). 25 patients have also been included into the study for comparison (placebo group, PG). After the administration of protamine sulphate, a 10 ml of ABC solution has been sprayed to the surgical area including mediastinum and epicardial sac. We compared mediastinal drenaige, reoperation due to tamponade, and required blood and blood products in both groups.

Results:

The mean amount of bleeding after operation was 230 ml in ABC group, and 490 ml in CG (P=0.001). In ICU, bleeding in ABC group and CG was 410ml and 680ml, respectively (P=0.0022). The mean total bleeding from mediastinum was 530±280 mL and 990±440 mL In ABC and CG group, respectively (P=0.001). The amount of autotransfusion was as follows: 175 mL in ABC group, and 290 mL in CG (P=0.002). No patient needed the surgical revision in ABC group, but four patients (16%) from CG group because of cardiac tamponade. Seventeen patients from CG required blood transfusion due to low hematocrite level postoperatively. In CG, the mean hematocrite level was 17±2,3. Transfusion of fresh frozen plasma and platelets in ABC group and CG were as follows: 0.2 and 0 in ABC group, and 0.3and 0.4 in CG.

Conclusion:

Our study showed that the local use of 10 mL ABC reduces bleeding significantly. Therefore, transfusion requirements of PRBC, platelets, and total blood units in patients on clopidogrel and ASA undergoing emergent beating heart CABG. To provide cardiac tamponade because of excessive mediastinal bleeding and requirement of blood transfusion after emergent CABG patients who previously administered clopidogrel and ASA, we propose local use of ABC solution as a potent coagulant agent.

The effect of antifibrinolytic prophylaxis on postoperative outcomes in patients undergoing cardiac operations

Antifibrinolytic agents such as aprotinin and epsilon aminocaproic acid limit postoperative bleeding and blood transfusion in patients undergoing cardiac operations using cardiopulmonary bypass (CPB). Recent evidence suggests that these agents have adverse side effects that influence operative mortality and morbidity. We studied postoperative bleeding, transfusion rates, and operative outcomes in our patients in order to assess the efficacy of these agents during cardiac operations requiring CPB. We reviewed records of 520 patients undergoing a variety of cardiac operations between January 2005 and May 2009. We measured multiple variables including pre-operative risk factors, antifibrinolytic agent used, and outcomes of operation, such as measures of bleeding and blood transfusion, as well as serious operative morbidity and mortality. Postoperative bleeding rates varied significantly between patients receiving aprotinin and those receiving aminocaproic acid (P < 0.05). There was an associated 12% decrease in operative site bleeding in aprotinin-treated patients compared with aminocaproic acid. There was no significant difference in the transfusion rates of packed red blood cells between patients receiving aminocaproic acid or aprotinin (P > 0.05), though individuals in the aprotinin group did receive FFP more frequently than patients in the aminocaproic acid group (P < 0.05). There was no significant difference in morbidity and mortality rates between patients in either drug group (P > 0.05). Our study shows that aprotinin is more effective at controlling operative site bleeding than aminocaproic acid. Reduced operative site bleeding did not portend better outcome or differences in transfusion requirements. Aminocaproic acid remains a safe and cost-effective option for antifibrinolytic prophylaxis because of unavailability of aprotinin.

Aprotinin in cardiac surgery

Aprotinin is a naturally occurring serine protease inhibitor that is being used with increasing frequency in cardiac surgery and beyond to reduce blood loss and the need for perioperative blood transfusion. Through inhibition of serine proteases such as plasmin, aprotinin significantly reduces fibrinolysis, thereby aiding hemostasis during surgical procedures. In addition, aprotinin interacts with other factors in the coagulation and fibrinolytic cascade, creating a hemostatic balance, without increasing the risk of thrombosis. These proven benefits are supplemented by the anti-inflammatory properties of aprotinin, which may help curb some of the deleterious effects of cardiopulmonary bypass. This article will review the discovery of aprotinin, its mechanism of action, dosing and adverse effects, and highlight the major recent trials demonstrating its efficacy.

[Indications and use of prothrombin complex in cardiac surgery]

On of the most common, and serious, complications in cardiac surgery is postoperative bleeding. According to the majority of studies, between 10% and 92% of patients subjected to elective surgery require transfusions of blood products and blood derivatives. Transfusions and reinterventions are associated with longer stays in critical care units and a decrease in survival rates. There have been some important changes in the treatment of changes in haemostasis and post-surgical bleeding in the last few years, particularly with the introduction into clinical practice of working procedures backed up by clinical guidelines, as well as the appearance of new drugs. The aim of this work is to describe the main characteristics and update the use of prothrombin complexes that are currently available in Spain, with special emphasis on their use in cardiac surgery.

Near infrared fluorescence imaging with ICG in TECAB surgery using the da Vinci Si surgical system in a canine model

BACKGROUND

This study assessed the clinical utility of near-infrared fluorescence imaging using indocyanine green in off-pump beating heart total endoscopic and robotic-assisted coronary artery bypass using the fluorescence imaging system for the da Vinci Si on a canine model for vessel identification, graft patency, and correlation of graft patency with ultrasound transit-time flow measurement probe.

METHODS

Beating heart total endoscopic robotic-assisted coronary artery bypass was performed on eight canine using indocyanine green and fluorescence imaging to identify the internal mammary artery prior to harvesting, the coronary vessel anatomy, and the patency of the beating heart total endoscopic coronary artery bypass anastomosis. Three to four injections of indocyanine green with a dose of 1.25 mg to 2.5 mg were administered per animal. Transit-time flow was measured in each of the dogs.

RESULTS

High definition 3D images were obtained. The camera working distance, indocyanine green dosage, internal mammary artery visualization, coronary artery visualization, patency by indocyanine green injection, and patency by transit-time flow were recorded. Six cases were completed successfully, and all demonstrated correlation between indocyanine green measurements of flow, and the transit-time flow measurement.

CONCLUSION

Use of near-infrared fluorescence with indocyanine green was feasible in our study, and would be of great benefit during total endoscopic robotic-assisted coronary artery bypass using the fluorescence imaging-capable da Vinci Si system to help identify the internal mammary artery, delineate the coronary anatomy, and also determine patency of the anastomoses. This procedure correlated well with transit-time flow measurement.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Burden of blood transfusion in knee and hip surgery in the US and Belgium

OBJECTIVE

Transfusion services in orthopaedic surgery can lead to unnecessary complications and increased healthcare costs. The objective of this study was to assess treatments and costs associated with blood and blood product transfusions in a historical cohort of 189,457 inpatients in the US and 34,987 inpatients in Belgium undergoing knee or hip surgery.

METHODS

Descriptive analysis, logistic regression and ordinary least squares regression were used to describe the factors associated with the use and cost of allogeneic blood transfusion.

RESULTS

Hospitalisation costs for joint replacement surgery totalled $12,718 (SD=6,356) and averaged 4.33 days in the US, while costs in Belgium were $6,526 (SD=3,192) and averaged 17.1 days. The use of low molecular weight heparin and tranexamic acid was much higher in Belgium than the US (36% and 99% compared to 0% and 40%, respectively). Patients in the US spent 12.7 (p<0.0001) fewer days in the hospital, 0.3 (p<0.0001) fewer days in the intensive care unit and were 88% less likely to have allogeneic blood transfusions (OR=0.22, 95% CI 0.22-0.23), but incurred $6,483 (p<0.0001) more costs per hospitalisation than patients in Belgium.

CONCLUSIONS

While hospital costs for patients were greater in the US, length of stay was shorter and patients were less likely to have transfusion services than those patients in Belgium. While this study is limited by factors inherent to observational studies, such as omitted variable bias, misclassification, and disease comorbidity, there are substantial differences in the use of blood products between Belgium and the US.

Can local application of Tranexamic acid reduce post-coronary bypass surgery blood loss? A randomized controlled trial

Background

Diffuse microvascular bleeding remains a common problem after cardiac procedures.

Systemic use of antifibrinolytic reduces the postoperative blood loss.

The purpose of this study was to examine the effectiveness of local application of tranexamic acid to reduce blood loss after coronary artery bypass grafting (CABG).

Methods

Thirty eight patients scheduled for primary isolated coronary artery bypass grafting were included in this double blind, prospective, randomized, placebo controlled study.

Tranexamic acid (TA) group (19 patients) received 1 gram of TA diluted in 100 ml normal saline. Placebo group (19 patients) received 100 ml of normal saline only. The solution was purred in the pericardial and mediastinal cavities.

Results

Both groups were comparable in their baseline demographic and surgical characteristics. During the first 24 hours post-operatively, cumulative blood loss was significantly less in TA group (median of 626 ml) compared to Placebo group (median of 1040 ml) (P = 0.04). There was no significant difference in the post-op Packed RBCs transfusion between both groups (median of one unit in each) (P = 0.82). Significant less platelets transfusion required in TA group (median zero unit) than in placebo group (median 2 units) (P = 0.03). Apart from re-exploration for excessive surgical bleeding in one patient in TA group, no difference was found in morbidity or mortality between both groups.

Conclusion

Topical application of tranexamic acid in patients undergoing primary coronary artery bypass grafting led to a significant reduction in postoperative blood loss without adding extra risk to the patient.

Biochemical injury markers and mortality after coronary artery bypass grafting: a systematic review

The strength of the association between cardiac biomarker release and prognosis is uncertain. We performed a systematic literature search to find articles regarding these markers and death after coronary surgical interventions, and evaluated the results with meta-analytic methods. We found 23 articles concerning 29,483 patients that reported the MB fraction of creatine kinase (CK-MB) and troponin T and I. Heterogeneity of existing studies prevented the pooling of the results of troponin studies. The pooled data of the CK-MB studies suggest that after coronary artery bypass grafting, CK-MB release of more than five to eight times the upper limit of the reference range is associated with an increased risk of death during the next 40 months.

Short- and midterm outcomes of coronary artery bypass surgery performed by surgeons in training

OBJECTIVE

The effect of training on outcomes in cardiac surgery is poorly studied. We aimed to study the results of coronary artery bypass grafting procedures performed by surgeons in training across our state with respect to short- and midterm postoperative outcomes.

METHODS

All coronary artery bypass grafting surgeries performed by trainee surgeons between July 2001 and December 2006 were compared with those performed by consultant surgeons using mandatory prospectively collected statewide data. Early mortality; prolonged ventilation or intensive care unit stay; return to operating theater for bleeding, stroke, myocardial infarction, or renal failure; and 5-year survival were compared using propensity score analysis.

RESULTS

A total of 7745 surgeries were included in this study. Trainees performed 983 (13%) surgeries. Trainee surgeries had longer perfusion and crossclamp times. Crude early postoperative outcomes were similar between trainee and consultant surgeries. After propensity score adjustment, early outcomes remained similar, with the exception of myocardial infarction (0.8% in trainee surgeries vs 0.4% in consultant surgeries, P = .046). Adjusted 1-, 3-, and 5-year survivals were similar between trainee and consultant surgeries: 95.3% versus 95.5%, 90.8% versus 92.0%, and 86.3% versus 87.1%, respectively.

CONCLUSION

Coronary artery bypass grafting performed by trainee surgeons within a supervised program is safe with acceptable short- and midterm outcomes.

The safety of aprotinin and lysine-derived antifibrinolytic drugs in cardiac surgery: a meta-analysis

BACKGROUND

Because of recent concerns about the safety of aprotinin, we updated our 2007 Cochrane review that compared the relative benefits and risks of aprotinin and the lysine analogues tranexamic acid and epsilon aminocaproic acid.

METHODS

We searched electronic databases, including CENTRAL, MEDLINE, EMBASE, Google and Google Scholar for trials of antifibrinolytic drugs used in adults scheduled for cardiac surgery. Searches were updated to January 2008. By comparing aprotinin and the 2 lysine analogues to control, we derived indirect head-to-head comparisons of aprotinin to the other drugs. We derived direct estimates of risks and benefits by pooling estimates from head-to-head trials of aprotinin and tranexamic acid or epsilon aminocaproic acid.

RESULTS

For indirect estimates, we identified 49 trials involving 182 deaths among 7439 participants. The summary relative risk (RR) for death with aprotinin versus placebo was 0.93 (95% confidence interval [CI] 0.69-1.25). In the 19 trials that included tranexamic acid, there were 24 deaths among 1802 participants. The summary RR was 0.55 (95% CI 0.24-1.25). From the risk estimates derived for individual drugs, we calculated an indirect summary RR of death with use of aprotinin versus tranexamic acid of 1.69 (95% CI 0.70-4.10). To calculate direct estimates of death for aprotinin versus tranexamic acid, we identified 13 trials with 107 deaths among 3537 participants. The summary RR was 1.43 (95% CI 0.98-2.08). Among the 1840 participants, the calculated estimates of death for aprotinin compared directly to epsilon aminocaproic acid was 1.49 (95% CI 0.98-2.28). We found no evidence of an increased risk of myocardial infarction with use of aprotinin compared with the lysine analogues in either direct or indirect analyses. Compared with placebo or no treatment, all 3 drugs were effective in reducing the need for red blood cell transfusion. The RR of transfusion with use of aprotinin was 0.66 (95% CI 0.61-0.72). The RR of transfusion was 0.70 (95% CI 0.61-0.80) for tranexamic acid, and it was 0.75 (95% CI 0.58-0.96) for use of epsilon aminocaproic acid. Aprotinin was also effective in reducing the need for re-operation because of bleeding (RR 0.48, 95% CI 0.34-0.67).

INTERPRETATION

The risk of death tended to be consistently higher with use of aprotinin than with use of lysine analogues. Aprotinin had no clear advantages to offset these harms. Either tranexamic acid or epsilon aminocaproic acid should be recommended to prevent bleeding after cardiac surgery.

Tranexamic acid reduces blood loss in off-pump coronary artery bypass surgery

OBJECTIVE

This study was designed to evaluate the hemostatic effect of tranexamic acid in off-pump coronary artery bypass surgery.

DESIGN

A prospective, randomized, double-blind, placebo-controlled study.

SETTING

The Department of Anesthesiology and Cardiac Surgery, Medical Sciences University.

PARTICIPANTS

One hundred eight patients undergoing off-pump coronary artery bypass surgery were enrolled into the study. Eight patients were withdrawn, and 100 patients were divided into 2 groups.

INTERVENTIONS

Fifty patients received tranexamic acid (bolus 1 g before skin incision and followed by maintenance dose of 400 mg/h during surgery), and 50 patients received saline.

MEASUREMENT AND MAIN RESULTS

Hematologic parameters, volume of blood loss, blood transfusion, and other clinical data were recorded throughout the perioperative period. Twenty-four-hour postoperative blood loss was significantly less in the tranexamic acid group compared with the control group (471 +/- 182 v 844 +/- 303). Patients in the tranexamic acid group received significantly less allogeneic blood (8 v 31 units).

CONCLUSION

Bleeding and hemorrhagic complications and the consequent need for allogeneic transfusion are still major problems after off-pump coronary artery bypass surgery. Tranexamic acid appears to be effective in reducing postoperative bleeding and the need for allogeneic blood products.

Serine protease inhibitor nafamostat given before reperfusion reduces inflammatory myocardial injury by complement and neutrophil inhibition

Animal data strongly support a role for inflammation in myocardial ischemia reperfusion injury. Attempts at cardioprotection by immunomodulation (such as with the specific C5 antibody pexelizumab) in humans have been disappointing. We hypothesized that a broader spectrum antiinflammatory agent might yield successful cardioprotection. The serine protease inhibitor nafamostat (FUT-175), which is already in clinical use, is a potent antiinflammatory synthetic serine protease inhibitor with anticomplement activity that we tested in a well-established rabbit model of 1 hour of myocardial ischemia followed by 3 hours of reperfusion. Compared to vehicle-treated animals, nafamostat (1 mg/kg of body weight) administered 5 minutes before reperfusion significantly reduced myocardial injury assessed by plasma creatine kinase activity (38.1 +/- 6.0 versus 57.9 +/- 3.7I U/g protein; P < 0.05) and myocardial necrosis (23.6 +/- 3.1% versus 35.7 +/- 1.0%; P < 0.05) as well as myocardial leukocyte accumulation (P < 0.05). In parallel in vitro studies, Nafamostat was a significantly more potent broad spectrum complement suppressor than C1 inhibitor. Nafamostat appears to have capability as an inhibitor of both complement pathways and as a broad-spectrum antiinflammatory agent by virtue of its serine protease inhibition. Administration of nafamostat before myocardial reperfusion after ischemia produced significant, dose-dependent cardioprotection. Reduced leukocyte accumulation and complement activity seem involved in the mechanism of this cardioprotective effect.

Is aprotinin safe to use in a cohort at increased risk for thrombotic events: results from a randomized, prospective trial in off-pump coronary artery bypass

BACKGROUND

Multiple randomized trials have established a favorable safety profile for aprotinin use during cardiac surgery, but recent database analyses suggest an increased risk of adverse thrombotic events. Our group previously demonstrated that off-pump coronary artery bypass (OPCAB) is linked to a postoperative hypercoagulable state. In this study, we tested whether aprotinin influences thrombotic events after OPCAB.

METHODS

Patients randomly received saline (n = 61) or aprotinin (2 x 10(6) kallikrein inhibiting units (KIU) loading dose, 0.5 x 10(6) KIU/hour [n = 59]) during OPCAB. Aprotinin levels (KIU/mL) were analyzed before, and 30 minutes (peak) and 4 hours after the loading dose. Estimated glomerular filtration rate (eGFR) was calculated daily based on Cockcroft equation with acute kidney injury (AKI) defined as eGFR less than 75% of baseline. Major adverse cardiac and cerebrovascular events (MACCE) were monitored during the first year, including acute graft failure by predischarge computed tomographic angiography.

RESULTS

Compared with placebo, the aprotinin group developed a significantly lower eGFR on day 3 (p < 0.006), but this difference resolved by day 5. Peak aprotinin level correlated with the degree of eGFR decline noted on day 3 (r = 0.56, p < 0.03) and independently predicted postoperative AKI (odds ratio 8.8, p < 0.008). The receiver operating characteristic analysis demonstrated that peak aprotinin level strongly predicts AKI (area under the curve = 0.86, 95% confidence interval 0.69 to 1.00). The percentage of patients reaching the composite MACCE endpoint was significantly reduced in the aprotinin versus placebo group (12 vs 34%, p = 0.01).

CONCLUSIONS

Compared with placebo, aprotinin use was associated with less MACCE but more AKI after OPCAB. The strong relationship between the peak aprotinin level and subsequent AKI suggests weight-based protocols for dosing aprotinin may reduce this risk.

Perioperative management of aspirin resistance after off-pump coronary artery bypass grafting: possible role for aprotinin

BACKGROUND

Aspirin is the only drug proven to reduce saphenous vein graft (SVG) failure, but aspirin resistance (ASA-R) frequently occurs after off-pump coronary artery bypass grafting (OPCAB). The factors, mechanism, and best means for preventing and/or treating ASA-R have not been established. This study hypothesizes that thrombin production during OPCAB stimulates this acquired ASA-R.

STUDY DESIGN AND METHODS

A nonrandomized prospective cohort of 255 patients (n=465 SVG) who underwent OPCAB with varied use of aprotinin (21%) and different SVG preparation techniques (standard, 56% vs. low-pressure, 44%) was analyzed. A surplus SVG segment was obtained to assess endothelial integrity. ASA-R was determined at baseline, after surgery, and on Days 1 and 3 by three assays. The effects of aprotinin on thrombin responsiveness were analyzed by means of whole-blood aggregometry, SVG tissue factor (TF) activity, and transcardiac thrombin production (i.e., F1.2 levels in aorta versus coronary sinus). SVG patency was assessed on Day 5 with multichannel CT angiography.

RESULTS

ASA-R developed in 42 percent of patients after OPCAB. Multivariate analysis showed that ASA-R, endothelial integrity, and target size independently predicted early SVG failure. Aprotinin use was associated with: 1) reduced postoperative ASA-R (15%); 2) decreased platelet (PLT) response to thrombin; 3) reduced TF activity within SVG segments; 4) decreased transcardiac thrombin gradient; and 5) improved SVG patency.

CONCLUSION

ASA-R is a common post-OPCAB event whose frequency may be reduced by intraoperative use of aprotinin, possibly via TF and thrombin suppression. Improved perioperative PLT function after OPCAB may also inadvertently enhance the clinical relevance of these potential antithrombotic effects.

Tranexamic acid and primary coronary artery bypass surgery: a prospective study

Tranexamic acid was used to reduce postoperative drainage and allogenic blood transfusion requirements in patients undergoing on-pump primary coronary bypass surgery. Over 12 months, 222 patients participated in this prospective, randomized, placebo-controlled, double-blind study conducted at a tertiary center. Half of the patients were randomly allocated to receive tranexamic acid as a bolus (10 mg x kg(-1)) prior to sternotomy, followed by an infusion (1 mg x kg(-1) x hr(-1)) up to the time of starting of protamine. The other 111 patients received a saline bolus and infusion. Postoperative drainage and transfusion requirements were measured in all patients. Markers of graft patency, hemostasis, hemodynamic stability, and fibrinolysis were evaluated. Chest closure time, renal function parameters, allergic reactions, incidence of stroke, re-exploration, and hospital mortality were also noted. Postoperative drainage was significantly less and blood conservation considerably better when tranexamic acid was used. Post-bypass hemostasis was achieved faster, fibrinolysis was less, and there was no evidence of increased incidence of graft occlusion in the group given tranexamic acid.

Guideline on antiplatelet and anticoagulation management in cardiac surgery

This document presents a professional view of evidence-based recommendations around the issues of antiplatelet and anticoagulation management in cardiac surgery. It was prepared by the Audit and Guidelines Committee of the European Association for Cardio-Thoracic Surgery (EACTS). We review the following topics: evidence for aspirin, clopidogrel and warfarin cessation prior to cardiac surgery; perioperative interventions to reduce bleeding including the use of aprotinin and tranexamic acid; the use of thromboelastography to guide blood product usage; protamine reversal of heparin; the use of factor VIIa to control severe bleeding; anticoagulation after mechanical, tissue valve replacement and mitral valve repair; the use of antiplatelets and clopidogrel after cardiac surgery to improve graft patency and reduce thromboembolic complications and thromboprophylaxis in the postoperative period. This guideline is subject to continuous informal review, and when new evidence becomes available. The formal review date will be at 5 years from publication (September 2013).