Pharmacological strategies to decrease excessive blood loss in cardiac surgery: a meta-analysis of clinically relevant endpoints

Fibrinogen concentrate in the treatment of severe bleeding after aortic aneurysm graft surgery

Aortic aneurysm graft surgery involving cardiopulmonary bypass is often associated with substantial coagulopathic perioperative bleeding, requiring hemostatic intervention with allogeneic blood products, such as fresh frozen plasma, platelet concentrate, and red blood cells. We conducted a pilot study to determine the effects of fibrinogen concentrate in patients with microvascular bleeding during aortic valve surgery with ascending aorta replacement. Dosing of fibrinogen concentrate was individualized based on thromboelastometry. First-line therapy with fibrinogen concentrate reduced the need for allogeneic blood product support, including transfusions of fresh frozen plasma, platelet concentrate, and red blood cells. Similar results were seen in a second cohort study conducted in patients undergoing thoraco-abdominal aortic aneurysm surgery: patients who received fibrinogen concentrate required significantly less allogeneic blood product support following surgery. These results prompted the initiation of a randomized placebo-controlled trial in patients undergoing thoraco-abdominal aortic aneurysm surgery, aortic valve surgery with ascending aorta replacement, or aortic arch surgery. Results are expected to be published soon. Larger, multicenter studies are needed to determine the exact role of fibrinogen concentrate in the management of perioperative bleeding following cardiac surgery and cardiopulmonary bypass.

A comprehensive appraisal of meta-analyses focusing on nonsurgical treatments aimed at decreasing perioperative mortality or major cardiac complications

PURPOSE

Millions of patients worldwide who undergo surgical procedures face significant morbidity and mortality risks. Several systematic reviews have been performed on ancillary treatments aimed at improving surgical outcomes, but their features and scholarly impact are unclear. We describe characteristics of meta-analyses on ancillary treatments aimed at improving surgical outcomes and explore factors associated with scholarly citations.

METHODS

Systematic reviews published up to 2008 were searched without language restrictions in MEDLINE/PubMed. Reviews focusing on nonsurgical treatments aimed at decreasing mortality or major cardiac complications were included. Associations between content, quality, and bibliometric details and scholarly citations in several indexes were systematically appraised.

RESULTS

From 2,239 citations, 84 systematic reviews were identified. Patients most commonly underwent cardiovascular surgery (40.2%), and were tested for cardiovascular drugs (25.8%), with placebo acting as control (38.1%). Internal validity appeared largely robust, as most (50.5%) reviews were at low risk of bias. Normalized yearly citations for the included reviews ranged between 5.6 in Google Scholar and 4.3 in Web of Science. Multivariable analysis showed that citations were significantly and positively associated with number of authors, North American corresponding author, number of studies included, number of patients included, noncardiothoracic surgical scope, explicit funding, and lack of competing interests (all p < 0.05).

CONCLUSIONS

Systematic reviews currently represent a key element in defining state of the art ancillary treatments of patients undergoing surgery. However, the citation success of available meta-analyses is not significantly associated with prognostically relevant findings or quality features.

Tranexamic acid reduces blood transfusions in elderly patients undergoing combined aortic valve and coronary artery bypass graft surgery: a randomized controlled trial

OBJECTIVE

To evaluate the effects of tranexamic acid on postoperative blood loss and transfusion requirements in elderly patients undergoing combined aortic valve replacement and coronary artery bypass graft surgery (CABG).

DESIGN

A prospective, randomized, double-blinded, placebo-controlled, parallel-group trial.

SETTING

A university hospital (single institution).

PARTICIPANTS

Sixty-four patients 70 years or older undergoing combined aortic valve replacement and CABG surgery were included. One patient was withdrawn from the study after randomization by the attending surgeon because of a change in the surgical procedure. The remaining 63 patients were analyzed as intention to treat.

INTERVENTIONS

The included patients were randomized to treatment with either tranexamic acid, 10 mg/kg, as a bolus injection before surgery followed by 1 mg/kg/h as an infusion during surgery, or a corresponding volume of 0.9% sodium chloride.

MEASUREMENTS AND MAIN RESULTS

Postoperative blood loss was recorded for 16 hours. The transfusion of blood products was recorded during the entire hospital stay. The number of packed red cell transfusions given to the patients was significantly lower in the tranexamic acid group compared with the placebo group (median, 3.0 [interquartile range, 2-5] v 5.0 [3-7], p = 0.049).

CONCLUSION

Tranexamic acid reduced the number of packed red cell transfusions given to patients 70 years or older undergoing combined aortic valve replacement and CABG surgery.

Plasmin generation and fibrinolysis in pediatric patients undergoing cardiopulmonary bypass surgery

This prospective, single-centre cohort study aimed to evaluate plasmin generation and fibrinolysis during and after cardiopulmonary bypass (CPB) surgery in a cohort of children up to 6 years of age. Blood samples were drawn at eight time points: after induction of anesthesia, before unfractionated heparin (UFH), after UFH, after initiation of bypass, before protamine, after protamine, after chest closure, and 6 h after chest closure. The study identified an increase in fibrinolysis during CPB and particularly up to 6 h afterward in children. This could be the mechanism for the significant bleeding events observed in this young population after CPB. This study establishes the foundation for future studies in this area, particularly those focusing on clinical outcomes after CPB surgery.

Use of Topical Tranexamic Acid or Aminocaproic Acid to Prevent Bleeding After Major Surgical Procedures

OBJECTIVE:

To evaluate the literature describing topical use of tranexamic acid or aminocaproic acid for prevention of postoperative bleeding after major surgical procedures.

DATA SOURCES:

Literature was retrieved through MEDLINE (1946-September 2011) and International Pharmaceutical Abstracts(1970-September 2011) using the terms tranexamic acid, aminocaproic acid, antifibrinolytic, topical, and surgical. In addition, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION:

All identified articles in English were evaluated. Clinical trials, case reports, and meta-analyses describing topical use of tranexamic acid or aminocaproic acid to prevent postoperative bleeding were included.

DATA SYNTHESIS:

A total of 16 publications in the setting of major surgical procedures were included; the majority of data were for tranexamic acid. For cardiac surgery, 4 trials used solutions containing tranexamic acid (1-2.5 g in 100-250 mL of 0.9% NaCl), and 1 trial assessed a solution containing aminocaproic acid (24 g in 250 mL of 0.9% NaCl). These solutions were poured into the chest cavity before sternotomy closure. For orthopedic procedures, all of the data were for topical irrigation solutions containing tranexamic acid (500 mg-3 g in 50-100 mL of 0.9% NaCl) or for intraarticular injections of tranexamic acid (250 mg to 2 g in 20-50 mL of 0.9% sodium chloride, with or without carbazochrome sodium sulfate). Overall, use of topical tranexamic acid or aminocaproic acid reduced postoperative blood loss; however, few studies reported a significant reduction in the number of packed red blood cell transfusions or units given, intensive care unit stay, or length of hospitalization.

CONCLUSIONS:

Topical application of tranexamic acid and aminocaproic acid to decrease postsurgical bleeding after major surgical procedures is a promising strategy. Further data are needed regarding the safety of this hemostatic approach.

Early postoperative outcomes and blood product utilization in adult cardiac surgery: the post-aprotinin era

BACKGROUND

Aprotinin was a commonly used pharmacological agent for homeostasis in cardiac surgery but was discontinued, resulting in the extensive use of lysine analogues. This study tested the hypothesis that early postoperative adverse events and blood product utilization would affected in this post-aprotinin era.

METHODS AND RESULTS

Adult patients (n=781) undergoing coronary artery bypass, valve replacement, or both from November 1, 2005, to October 31, 2008, at a single institution were included. Multiple logistic regression modeling and propensity scoring were performed on 29 preoperative and intraoperative variables in patients receiving aprotinin (n=325) or lysine analogues (n=456). The propensity-adjusted relative risk (RR) for the intraoperative use of packed red blood cells (RR, 0.75; 95% confidence interval [CI], 0.57 to 0.99), fresh frozen plasma (RR, 0.37; 95% CI, 0.21 to 0.64), and cryoprecipitate (RR:0.06; 95% CI, 0.02 to 0.22) were lower in the aprotinin versus lysine analog group (all P<0.05). The risk for mortality (RR, 0.53; 95% CI, 0.16 to 1.79) and neurological events (RR, 0.87; 95% CI, 0.35 to 2.18) remained similar between groups, whereas a trend for reduced risk for renal dysfunction was observed in the aprotinin group.

CONCLUSIONS

In the post-aprotinin era, with the exclusive use of lysine analogues, the relative risk of early postoperative outcomes such as mortality and renal dysfunction have not improved, but the risk for the intraoperative use of blood products has increased. Thus, improvements in early postoperative outcomes have not been realized with the discontinued use of aprotinin, but rather increased blood product use has occurred with the attendant costs and risks inherent with this strategy.

[The "Seville" Consensus Document on Alternatives to Allogenic Blood Transfusion. Sociedades españolas de Anestesiología (SEDAR), Medicina Intensiva (SEMICYUC), Hematología y Hemoterapia (AEHH), Transfusión sanguínea (SETS) Trombosis y Hemostasia (SETH)]

The Consensus Document on Alternatives to Allogenic Blood Transfusion (AABT) has been drawn up by a panel of experts from 5 scientific societies. The Spanish Societies of Anesthesiology (SEDAR), Critical Care Medicine and Coronary Units (SEMICYUC), Hematology and Hemotherapy (AEHH), Blood Transfusion (SETS) and Thrombosis and Hemostasis (SETH) have sponsored and participated in this Consensus Document. Alternatives to blood transfusion have been divided into pharmacological and non-pharmacological, with 4 modules and 12 topics. The main objective variable was the reduction of allogenic blood transfusions and/or the number of transfused patients. The extent to which this objective was achieved by each AABT was evaluated using the Delphi method, which classifies the grade of recommendation from A (supported by controlled studies) to E (non-controlled studies and expert opinion). The experts concluded that most of the indications for AABT were based on middle or low grades of recommendation, "C", "D", or "E", thus indicating the need for further controlled studies.

Liver transplant in Jehovah's Witnesses patients

PURPOSE OF REVIEW

The Jehovah's Witness religion is a Christian movement, founded in the USA in the 1870s, with 6 million members worldwide (150,000 in the UK). Members of this faith have strong beliefs based upon passages from the Bible that are interpreted as prohibiting the 'consumption' of blood. Their beliefs prevent them from accepting transfusion of whole blood or its primary components. They also believe that blood that has been removed from the body is 'unclean' and should be disposed of. The use of procedures that involve the removal and storage of their own blood is often unacceptable.

RECENT FINDINGS

Biological hemostats, including collagen and cellulose pads (Kaltostat) and fibrin glues and sealants (Tisseal), aid coagulation and reduce blood loss. Strategies have been described to reduce the number of red cells lost during hemorrhage by the nonlinear reduction in packed cell volume achieved by hemodilution. With the cell-saver technique, shed blood is suctioned from the wound, centrifuged, washed, mixed with an additive/anticoagulant solution and then reinfused as required. Many coagulation factors are available as recombinant products, including factors VIII, IX and VIIa.

SUMMARY

In summary, major surgery can be performed safely in the Jehovah's Witness who refuses blood transfusion by utilizing preoperative and intraoperative techniques that decrease surgical blood loss, decrease oxygen consumption, and increase oxygen delivery. Even if significant intraoperative blood loss occurs, successful postoperative management is possible by utilizing techniques that minimize oxygen consumption and maximize oxygen delivery.

Bleeding and management of coagulopathy

Bleeding after cardiac surgery remains a significant problem, increasing both length of stay and mortality, and is caused by multiple factors including dilutional changes, ongoing fibrinolysis, and platelet dysfunction. The evaluation of coagulopathy is problematic because of the long turnaround time of standard coagulation tests. Algorithms involving point of care testing, including thromboelastography and thromboelastometry, have been published; all have the potential to reduce transfusion requirements. Massive transfusion coagulopathy that occurs in trauma can also be seen in complex aortic surgery and other massive bleeding patients and should prompt consideration of a transfusion protocol involving fixed ratios of fresh frozen plasma, platelets, and red blood cells. Pharmacologic agents such as antifibrinolytics are commonly administered, but a multimodal approach to management is important. Recombinant and purified coagulation products are being studied and provide clinicians specific agents to treat targeted deficiencies. A general multi-modal approach is required and recommendations are made for the management of bleeding and coagulopathy in cardiac surgical patients.

Patients with severe aortic valve stenosis and impaired platelet function benefit from preoperative desmopressin infusion

BACKGROUND

Patients with severe aortic valve stenosis have a markedly reduced platelet function as measured by a prolonged collagen adenosine diphosphate closure time (CADP-CT) determined by the platelet function analyzer PFA-100. We hypothesized that such patients may benefit from desmopressin when they present with prolonged CADP-CT due to the specific action of desmopressin on von Willebrand factor (VWF) and CADP-CT.

METHODS

In this double-blind, randomized placebo controlled trial, 43 patients undergoing aortic valve replacement (due to severe aortic valve stenosis with CADP-CT>170 seconds) were given desmopressin 0.3 μg/kg or saline intravenously after induction of anesthesia. Measurement of CADP-CT, factor VIII activity, von Willebrand factor antigen, GpIb binding activity, ristocetin cofactor activity, collagen-binding activity, and multimers were performed after induction of anesthesia, one hour after desmopressin infusion, and 24 hours postoperatively.

RESULTS

In the majority of patients, baseline values of von Willebrand factor related indices were normal, but increased one hour after infusion of desmopressin by 73% to 90% as compared with placebo. Selective loss of high molecular weight multimers was seen only in a minority of patients. The CADP-CT was greater than 170 seconds in 92% of screened patients, and desmopressin shortened CADP-CT by 48% versus baseline and reduced postoperative blood loss by 42% (p<0.001).

CONCLUSIONS

Prolonged CADP-CT indicates platelet dysfunction in severe aortic valve stenosis, and can guide the use of desmopressin as an effective prohemostatic agent in patients with severe aortic valve stenosis.

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.

Stabilization of fibrin clots by activated prothrombin complex concentrate and tranexamic acid in FVIII inhibitor plasma

Defective hemostasis in haemophilia patients with FVIII inhibitors results in a dramatic decrease in thrombin generation forming unstable fibrin clots that are susceptible to fibrinolyisis. In this study we tested whether the combination of plasma derived activated prothrombin complex concentrate (pd-aPCC) with tranexamic acid (TXA) may improve fibrin clot stability in FVIII inhibitor plasma. A microplate assay for clot lysis time was used to assess clot stability in FVIII inhibitor plasma. The effect of pd-aPCC on clot stability was first tested using the commercial FVIII inhibitor plasma. TXA (5 ~ 10 mg mL⁻¹) increased clot lysis time, but pd-aPCC (0.25 ~ 1.0 U mL⁻¹) had no effect on it. The combination of pd-aPCC and TXA significantly increased clot lysis time compared with TXA alone. The effect appeared to be limited to fibrin clot resistance to fibrinolysis, as TXA was found to have no effect on thrombin generation induced by pd-aPCC. The effect of pd-aPCC and TXA on clot stability was then tested and verified in plasma samples from ten patients with severe haemophilia A and inhibitors. The combination of TXA (10 mg mL⁻¹) and pd-aPCC (0.5 U mL⁻¹) significantly increased clot lysis time compared to TXA alone. Our results suggest that the combination of pd-aPCC with TXA improves clot stability in FVIII inhibitor plasma without additional increases in thrombin generation.

Transfusion-free anesthetic management for open heart surgery in a neonate -A case report-

In small infants or neonates, open heart surgery without transfusion can have many risks regarding inadequate oxygen delivery and coagulopathy. However, if parents refuse blood transfusion, cardiac surgery without transfusion should be considered. We report a case of bloodless cardiac surgery in a 2.89 kg neonate with Jehovah's Witness parents. Blood conserving strategies were used. Preoperatively, erythropoietin and iron were supplemented to increase the hemoglobin level. Intraoperatively, techniques for minimizing blood loss were used, such as reducing priming volume for cardiopulmonary bypass, a blood salvage system, and modified ultrafiltration. Postoperatively, pharmacologic agents were administered and blood sampling was minimized.

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.

Effects of tranexamic acid on blood loss during total hip arthroplasty

PURPOSE

To assess the effects of tranexamic acid (TA) in patients undergoing total hip arthroplasty (THA) for osteoarthritis.

METHODS

42 patients underwent primary THA for osteoarthritis by a single surgeon. 10 men and 11 women who did not receive TA were controls, whereas 9 men and 12 women who received TA constituted the treatment group. Both groups were matched for age, gender, body mass index, and American Society of Anesthesiologists grading. The type of prosthesis used (cemented or uncemented) was based on the surgeon's preference and patient age, activity level and demands. No hybrid prosthesis was used. 10 minutes prior to incision, a single dose of intravenous TA (10 mg per kg body weight) was given to patients in the treatment group. Comparison was made between both groups with regard to intra-operative blood loss, postoperative reduction in haemoglobin and haematocrit levels, blood transfusion, incidence of deep vein thrombosis, and the length of hospital stay.

RESULTS

The mean intra-operative blood loss (489 [SD, 281] vs. 339 [SD, 184] ml, p = 0.048) and the decrease in haemoglobin level (38 [SD, 12] vs. 29 [SD, 10] g/l, p=0.014) were significantly higher in the control than the treatment group. Two patients among the controls received a transfusion, compared to none in the TA group (p = 0.49, Fisher's exact test). The 2 patients who needed blood transfusion had blood losses of 600 and 690 ml, compared to a mean of 489 ml in the whole group. No patient in either group developed deep vein thrombosis or pulmonary embolism up to 3 months.

CONCLUSION

A single dose of intravenous TA (10 mg per kg body weight) given 10 minutes prior to THA is a cost-effective and safe means of minimising blood loss and reduction in haemoglobin concentrations as well as the need for allogenic blood transfusion, without increasing the risk of thromboembolic events.

Blood conservation in cardiac surgery

Cardiac surgery is one of the largest users of blood and blood products--currently estimated at 15% of U.K. blood stocks. While the blood supply could be considered to be the safest it has ever been, there are well recognised risks associated with the transfusion of red cells and blood products. It is appropriate that attempts should be made to decrease and optimise the transfusion of blood and blood products.

No effect of a homoeopathic combination of Arnica montana and Bryonia alba on bleeding, inflammation, and ischaemia after aortic valve surgery

AIMS

" Arnica montana is a popular homoeopathic treatment with potential haemostatic and anti-inflammatory properties. A homoeopathic combination of A. montana and Bryonia alba was used in aortic valve surgery to evaluate its effectiveness in reducing bleeding, inflammation, pain and myocardial ischaemia.

METHODS

One day before surgery, 92 adult patients were randomly assigned to a double-blind parallel trial with either homoeopathic granules or a matching placebo until 4 days after surgery. The primary outcome was the volume of blood/liquid in the drains at their removal. The secondary outcomes included postoperative blood/liquid losses at 12 and 24 h as well as C-reactive protein (CRP), pain, temperature and plasma troponin Ic.

RESULTS

At 12 h and 24 h after surgery, then at drain removal, blood losses in homoeopathy and placebo groups were not statistically significant (362 +/- 218, 520 +/- 269 and 640 +/- 297 ml vs. 456 +/- 440, 620 +/- 477 and 796 +/- 717 ml; P= 0.19, 0.23 and 0.35, respectively). The statistical modelling did not show significantly different patterns of CRP, troponin and body temperature changes or of pain perception. The number of transfused packed red cells was not significantly different either (P= 0.58). Two patients from each group died during the study period and the number of serious adverse events was not statistically different (six in homoeopathy vs. 10 in placebo groups; Fisher's exact test P= 0.41).

CONCLUSIONS

In the study setting, there was no evidence of effects of A. montana and B. alba combination on bleeding, inflammation, pain or myocardial ischaemia.

Mechanism of hemostasis defects and management of bleeding in patients with acute coronary syndromes

The main cause of the hemostasis defects and related bleeding complications in patients with acute coronary syndromes (ACS) are the intake of multiple antithrombotic drugs, alone or concomitantly with invasive procedures such as coronary angiography and percutaneous coronary intervention (PCI). Antithrombotic drugs that impair several phases of hemostasis (platelet function, coagulation, and fibrinolysis) are causing bleeding particularly in elderly patients, in those underweight and with comorbidities such as renal insufficiency, diabetes, hypertension and malignancy. Identification of patients at high risk of bleeding is the most important preventive strategy, because the choice and dosages of drugs may to some extent be tailored to the degree of risk. Transfusions of blood products, which may become necessary in patients with major bleeding, should be used with caution, because they are associated with adverse cardiovascular events. To reduce the need of transfusion, the hemostatic drugs that decrease blood loss and transfusion requirements in cardiac surgery (antifibrinolytic amino acids, desmopressin, and recombinant factor VIIa) might be considered. However, the efficacy of these drugs in the control of bleeding complications is not unequivocally established in ACS and there is concern for an increased risk of thrombosis. In conclusion, evidence-based recommendations for the management of bleeding in patients with ACS are currently lacking, so that prevention through accurate assessment of the individual risk is the most valid strategy.

Adverse drug events associated with disorders of coagulation

Disorders of coagulation are common adverse drug events encountered in critically ill patients and present a serious concern for intensive care unit (ICU) clinicians. Dosing strategies for medications used in the ICU are typically developed for use in noncritically ill patients and, therefore, do not account for the altered pharmacokinetic and pharmacodynamic properties encountered in the critically ill as well as the increased potential for drug-drug interactions, given the far greater number of medications ordered. This substantially increases the risk for coagulation-related adverse reactions, such as a bleeding or prothrombotic events. Although many medications used in the ICU have the potential to cause coagulation disorders, the exact incidence will vary based on the specific medication, dose, concomitant drug therapy, ICU setting, and patient-specific comorbidities. Clinicians must strongly consider these factors when evaluating the risk/benefit ratio for a particular therapy. This review surveys recent literature documenting the risk for adverse drug reactions specific to bleeding and/or clotting with commonly used medications in the ICU.

Strategy of transfusion in cardiac surgery: limits of hematocrit and how much is too low?

The use of blood and blood products in cardiac surgery is higher than necessary and a reduction is imperative due to complications and costs. Hemodilution is unavoidable in cardiopulmonary bypass and is the most likely pitfall when evaluating transfusion needs. Even patients with coexisting cardiovascular diseases tolerate perioperative hemodilution better than most anticipate. Hemodynamic monitoring is important to evaluate the association between hemoglobin level and organ function. Use of both mechanical and medical blood conservation strategies is required to reduce blood transfusion, and most of the methods have a positive cost-effectiveness and cost-benefit. By using the right strategy and policy, transfusion of blood and blood products can be reduced to less than 5% of cardiac patients.

Management of bleeding following major trauma: an updated European guideline

INTRODUCTION

Evidence-based recommendations are needed to guide the acute management of the bleeding trauma patient, which when implemented may improve patient outcomes.

METHODS

The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing a guideline for the management of bleeding following severe injury. This document presents an updated version of the guideline published by the group in 2007. Recommendations were formulated using a nominal group process, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence and based on a systematic review of published literature.

RESULTS

Key changes encompassed in this version of the guideline include new recommendations on coagulation support and monitoring and the appropriate use of local haemostatic measures, tourniquets, calcium and desmopressin in the bleeding trauma patient. The remaining recommendations have been reevaluated and graded based on literature published since the last edition of the guideline. Consideration was also given to changes in clinical practice that have taken place during this time period as a result of both new evidence and changes in the general availability of relevant agents and technologies.

CONCLUSIONS

This guideline provides an evidence-based multidisciplinary approach to the management of critically injured bleeding trauma patients.

Investigational vasopressin receptor modulators in the pipeline

The vasopressin system is complex and interacts with the central nervous, cardiovascular, renal, and hematological systems. Vasopressin plays an important role in the control of blood osmolarity and vascular tone, but is also involved in many other physiological events, which are mediated mainly via three types of vasopressin receptor: V1R, V2R, and V3R. V1R primarily mediate the vascular, and V2R the aquaretic, effects of vasopressin. Vasopressin may also interact with other receptors, like adrenergic and angiotensin-II receptors, or with distinct biological pathways, including those of nitric oxide and the K(ATP) channel. There are numerous clinical situations where vasopressin receptor modulators (agonists or antagonists) could be used. Currently, vasopressin and terlipressin are most commonly used to stimulate V1R in vasodilatory shock and cardiac arrest, while desmopressin, a synthetic analogue of vasopressin, acts on V2R; but new molecules are becoming available in the treatment of inappropriate antidiuretic hormone (ADH) secretion.

Perioperative blood conservation

This review examines the science and methodology of blood conservation in modern anaesthetic and surgical practice. Blood transfusion is associated with increased morbidity and mortality in all surgical patients, and the reduction or even elimination of transfusion has been and continues to be the subject of much research. Blood substitutes, despite extensive investigation, have not been proved successful in trials to date, and none have entered clinical practice. Pharmacological treatments include antifibrinolytic drugs (although aprotinin is no longer in clinical use), recombinant factor VIIa, desmopressin, erythropoietin and topical haemostatic agents, and the role of each of these is discussed. Autologous blood transfusion has recently fallen in popularity; however, cell salvage is almost ubiquitous in its use throughout Europe. Anaesthetic and surgical techniques may also be refined to improve blood conservation. Blood transfusion guidelines and protocols are strongly recommended, and repetitive audit and education are instrumental in reducing blood transfusion.

Superior outcome of nafamostat mesilate as an anticoagulant in patients undergoing maintenance hemodialysis with intracerebral hemorrhage

AIMS

The incidence of complications associated with cerebrovascular diseases in patients who receive hemodialysis for a long-term period is higher than that of other complications. It is known that mortality due to cerebral hemorrhage is two times higher compared to non-dialysis patients. Anti-coagulants used for hemodialysis are essential. Accordingly, in cases in which the cerebral hemorrhage occurred, the selection of anti-coagulants for the prevention of further bleeding poses a great challenge to physicians. The change of hematoma and patient prognosis has a direct relationship. Many ongoing studies are conducted to examine the causative factors causing the increased hematoma and their related prognostic factors. In the current study, we examined the effect of nafamostat mesylate (a serine protease inhibitor) on the change of hematoma compared to heparin in hemodialysis patients.

METHODS

The current study was conducted in 17 hemodialysis patients who developed a cerebral hemorrhage. These patients were assigned to two groups based on the type of anti-coagulants that they used (i.e., nafamostat mesylate and heparin). Then, the factors affecting the change of hematoma following the onset of cerebral hemorrhage were examined. The prognosis of hematoma was assessed based on brain CT scans, which were performed two weeks after the onset of cerebral hemorrhage in four groups. Following this, groups 1 (the decreased hematoma) and 2 (the decreased delay) were merged to group A (resolving group), and groups 3 (the increased hematoma) and 4 (the death following the aggravation) were merged to group B (the expansion group) for further analysis.

RESULTS

There were no significant differences in baseline characteristics between the nafamostat group and the heparin group. A comparison between the resolving group and the expansion group also showed that there were no significant differences in baseline characteristics. In the anti-coagulants and the change of hematoma, however, there were significant differences between the two groups (p = 0.024). A comparison of the change of hematoma between the four groups was also made. This showed that platelet counts and BUN level were significant factors (Platelet; p = 0.042, BUN; p = 0.043 ANOVA with resolving group).

CONCLUSIONS

Nafamostat mesylate has a similar profile of anti-coagulative activity to heparin. It is assumed, however, that nafamostat has an affirmative effect on the recovery of damaged sites following the onset of cerebral hemorrhage. It is an anti-coagulant that can be safely used for hemodialysis following the onset of cerebral hemorrhage.

Perioperative Coagulopathy, Bleeding, and Hemostasis During Cardiac Surgery

Cardiac surgery patients use 10%-25% of the blood products transfused annually in the United States. The transfusion of red blood cells or blood products has been the subject of intense scrutiny over the past 10 years. Bleeding after cardiac surgery can be surgical or nonsurgical and lead to hemodynamic compromise and surgical reexploration. Because hemorrhage and blood product transfusions are associated with multiple negative outcomes, including increased mortality, it is prudent to understand the mechanisms responsible for nonsurgical bleeding. This review focuses on the physiology of the normal coagulation and fibrinolysis, risk factors associated with patients presenting for cardiac surgery, impairments of normal hemostasis associated with cardiac surgery and cardiopulmonary bypass (CPB), and potential interventions to reduce perioperative blood loss and blood transfusion.

Battlefield resuscitation

PURPOSE OF REVIEW

To bring together in one review article, the most current and relevant evidence relating to military trauma resuscitation.

RECENT FINDINGS

The main themes highlighted by this review are coagulopathy of trauma shock (CoTS), damage control resuscitation, haemostatic resuscitation, the management of massive transfusion, use of adjuvant drugs for haemostasis and use of an empiric massive transfusion protocol.

SUMMARY

The review aims to educate the readership in recent advances in trauma practice, culminating in a novel empiric massive transfusion algorithm seamlessly guiding the clinician through the initial resuscitation stage resulting in reduced mortality, morbidity, coagulopathy and decreased overall blood product usage.

Lessons learned in antifibrinolytic therapy: The BART trial

Despite nearly 2 decades of published reports and clinical trials demonstrating the relative safety and efficacy of aprotinin in adult cardiac surgical patients at increased risk of bleeding-culminating in an official endorsement of the usage of aprotinin in such patients from both cardiac surgery and anesthesiology subspecialty committees-several more recent studies have raised profound concerns regarding the safety of aprotinin in these same patients. These studies and the implications thereof have ultimately resulted in the withdrawal of aprotinin from clinical usage internationally. This article will briefly review these developments with the hope of understanding how this abrupt turnabout took place and will attempt to understand how such events can be avoided in the future.

Suction, salvage, sutures, and potions: blood management post-aprotinin

Hemostasis management of the cardiac surgical patient has changed following the withdrawal of aprotinin for use in cardiac surgical patients. The challenge to minimize blood loss and reduce exposure of cardiac surgical patients to blood products continues to grow with patients presenting being older and sicker and more complex procedures being performed. The cardiac surgery team has many options available for it to consider; although current recommendations strongly support the use of cell salvage as one process to assist in this challenge, other options need to be equally critically evaluated.

Bleeding management with fibrinogen concentrate targeting a high-normal plasma fibrinogen level: a pilot study

BACKGROUND

Bleeding diathesis after aortic valve operation and ascending aorta replacement (AV-AA) is managed with fresh-frozen plasma (FFP) and platelet concentrates. The aim was to compare haemostatic effects of conventional transfusion management and FIBTEM (thromboelastometry test)-guided fibrinogen concentrate administration.

METHODS

A blood products transfusion algorithm was developed using retrospective data from 42 elective patients (Group A). Two units of platelet concentrate were transfused after cardiopulmonary bypass, followed by 4 u of FFP if bleeding persisted, if platelet count was < or =100 x 10(3) microl(-1) when removing the aortic clamp, and vice versa if platelet count was >100 x 10(3) microl(-1). The trigger for each therapy step was > or =60 g blood absorbed from the mediastinal wound area by dry swabs in 5 min. Assignment to two prospective groups was neither randomized nor blinded; Group B (n=5) was treated according to the algorithm, Group C (n=10) received fibrinogen concentrate (Haemocomplettan P/Riastap, CSL Behring, Marburg, Germany) before the algorithm-based therapy.

RESULTS

A mean of 5.7 (0.7) g fibrinogen concentrate decreased blood loss to below the transfusion trigger level in all Group C patients. Group C had reduced transfusion [mean 0.7 (range 0-4) u vs 8.5 (5.3) in Group A and 8.2 (2.3) in Group B] and reduced postoperative bleeding [366 (199) ml vs 793 (560) in Group A and 716 (219) in Group B].

CONCLUSIONS

In this pilot study, FIBTEM-guided fibrinogen concentrate administration was associated with reduced transfusion requirements and 24 h postoperative bleeding in patients undergoing AV-AA.

Living without aprotinin: the results of a 5-year blood saving program in cardiac surgery

BACKGROUND

After 20 years of regular use in cardiac surgery patients, aprotinin has recently been withdrawn from the market due to many concerns about its safety. For a number of reasons aprotinin has not been available in Italy since 1998. The present study presents an aprotinin-free treatment protocol applied at our institution during the last 5 years, and aims to verify the results of this protocol in terms of allogeneic blood product transfusions, postoperative blood loss and surgical re-exploration rate.

METHODS

Retrospective study on 7988 consecutive patients who underwent cardiac surgery during the years 2003-2007. All the patients received specific hemostasis/coagulation management based on (a) routine use of tranexamic acid, (b) heparin dose-response monitoring, thromboelastography, platelet (PLT) function analysis in a select population of patients, and (c) use of fresh frozen plasma (FFP), PLTs, and desmopressin according to the hemostasis/coagulation profile. Data retrieved from the institutional database were quantity of packed red cells (PRCs), FFP, PLT transfusion rate, blood loss in the first 12 postoperative hours, and surgical re-exploration rate.

RESULTS

PRCs were transfused in 40.4% of patients (with higher rates for selected high-risk subpopulations), FFP in 12.9% and PLTs in 2.6%. Surgical re-exploration rate was 3.7%. With respect to historical controls, a significant reduction of PRCs and FFP transfusions was obtained using closed circuits, point of care coagulation tests, and combination of the two.

CONCLUSION

This aprotinin-free blood saving program is an effective strategy for allogeneic blood products transfusion containment.

The aprotinin saga and the risks of conducting meta-analyses on small randomised controlled trials - a critique of a Cochrane review

Background

Aprotinin for reducing blood loss during coronary artery bypass surgery was withdrawn from the market after early termination of a large randomised controlled trial (RCT) showing excess mortality for patients receiving aprotinin compared to lysine analogues. Several meta-analyses of small RCTs did not show excess mortality and even indicated reduced mortality, while several observational studies showed excess mortality. The aim of this paper is to review the quality of the meta-analysis of a Cochrane report.

Methods

The 52 studies included in the meta-analysis of the Cochrane report were reviewed according to whether an objective to study mortality was formulated in advance, whether follow-up method or time were specified, and whether the study had statistical power to show any effect.

Results

The Cochrane report restricted the analysis to RCTs, but the largest study should not have been included given that it was a prospective observational study with 1 784 patients rather than an RCT. None of the RCTs had sufficient statistical power to detect differences in mortality. Most studies had fewer than 100 patients. Seven out of 51 RCTs had mortality outcome as one of their objectives. Only very few described follow-up method or time.

Conclusion

It is doubtful whether small studies should be included in meta-analyses if they do not have the purpose of studying the specified outcome and if the follow-up method or time are not adequately described. The aprotinin saga shows overconfidence in small RCTs of inferior quality compared to well-conducted observational studies.