Hemorrhage and the use of blood products after adult cardiac operations: myths and realities

Safety of Continuing Aspirin Use in Patients With Coronary Heart Disease Who Undergo Thyroid Surgery During the Perioperative Period

Objective: To investigate the safety of continuing aspirin use in patients with coronary heart disease undergoing thyroid surgery during the perioperative period. Methods: Forty-four patients with coronary heart disease who underwent thyroid surgery in our department from July 2019 to June 2023 were selected as the observation group, and the observation group continued to use aspirin during the perioperative period. Forty-four patients who underwent the same surgery during the same period without coronary heart disease and without anticoagulant or antiplatelet therapy were selected as control group 1. Another 44 patients with coronary heart disease who underwent the same surgery from August 2015 to June 2019 and used low molecular weight heparin bridging during the perioperative period were selected as control group 2. Clinical data from the 3 groups of patients were collected for retrospective analysis. Results: The age and proportion of male patients in the observation group and control group 2 were higher than those in control group 1, and the total hospital stay in control group 2 was longer than in the observation group and control group 1, with statistically significant differences (all P < .05). There were no statistically significant differences in surgical time, intraoperative blood loss, postoperative drainage volume, duration of drainage tube retention, postoperative hospital stay, and perioperative hemoglobin, platelet, and international normalized ratio between the 3 groups of patients (all P > .05). All patients in the 3 groups successfully completed surgery without serious complications or death during the perioperative period. Conclusion: Continuing to use aspirin in patients with coronary heart disease who undergo thyroid surgery during the perioperative period can safely complete surgery without increasing the risk of intraoperative and postoperative bleeding.

Autologous blood salvage in cardiac surgery: clinical evaluation, efficacy and levels of residual heparin

OBJECTIVE

Intraoperative blood salvage (cell saver technique) in cardiac surgery is universally used in surgical procedures with a marked risk of blood loss. The primary objectives of this study were to determine the concentration of residual heparin in the final product that is reinfused into the patient in the operating room and to evaluate the efficacy and safety of the cell saver technique.

METHOD

Twelve patients undergoing elective cardiac surgery were enrolled in this study. Using the XTRA Autotransfusion System, blood samples were collected from the cardiotomy reservoir, both prior to blood processing (pre-sample) and after it, directly from the bag with processed product (post-sample). Hematocrit and hemoglobin levels, the protein, albumin and residual heparin concentrations, hemolysis index, and the platelet, erythrocyte and leukocyte counts were measured.

RESULTS

Hematocrit and hemoglobin levels and red blood cell counts were higher in post-processing samples, with a mean variation of 54.78%, 19.81g/dl and 6.84×106/mm3, respectively (p<0.001). The mean hematocrit of the processed bag was 63.49 g/dl (range: 57.2-67.5). The residual heparin levels were ≤0.1IU/ml in all post-treatment analyses (p=0.003). No related adverse events were observed.

CONCLUSION

The reduced residual heparin values (≤0.1IU/ml) in processed blood found in this study are extremely important, as they are consistent with the American Association of Blood Banks guidelines, which establish target values below 0.5IU/ml. The procedure was effective, safe and compliant with legal requirements and the available international literature.

Association of Continued Preoperative Aspirin Use and Bleeding Complications in Patients Undergoing Thyroid Surgery

Importance

No evidence exists to direct the management of preoperative aspirin (acetylsalicylic acid) use in patients undergoing thyroid surgery. Nevertheless, a considerable number of patients interrupt receiving aspirin therapy during the preoperative period to minimize bleeding complications despite the increased risk of experiencing major adverse cardiac events.

Objective

To determine whether aspirin therapy continued preoperatively increases bleeding complications in patients undergoing thyroid surgery.

Design, Setting, and Participants

Retrospective analysis of a consecutive sample of 570 patients, aged 18 to 100 years, who underwent thyroid surgery for benign and malignant disease from January 1, 2010, to December 31, 2015, by a single surgeon at a tertiary referral hospital center in New Orleans, Louisiana.

Exposures

Patients receiving aspirin therapy and patients not receiving aspirin therapy (aspirin naive) preoperatively.

Main Outcomes and Measures

Comparison of estimated blood loss, substantial blood loss, operative hematoma, nonoperative hematoma, and recurrent laryngeal nerve injury.

Results

Of 570 patients who underwent thyroid surgery, 106 (18.6%) were performed in patients receiving aspirin; of these, 23 (21.7%) were men and 105 (99.1%) were older than 45 years. Those receiving aspirin therapy displayed a 14.4-year difference in age (95% CI, 11.6-17.1). The aspirin group displayed a 20.3% absolute increase (95% CI, 9.3-30.7) in African American patients. Aspirin therapy was not associated with a statistically significant or clinically meaningful increase in intraoperative blood loss (2.5 mL; 95% CI, -0.4 to 5.3). Aspirin therapy was associated with a statistically significant increase in total hematoma formation (3.3%; 95% CI, 0.4-9.0), but the results were inconclusive. Aspirin therapy was not associated with a statistically significant increase in recurrent laryngeal nerve injury (2.6%; 95% CI, -1.1 to 8.6), but the results were inconclusive.

Conclusions and Relevance

These results suggest that aspirin therapy can be maintained prior to thyroid surgery without increased intraoperative bleeding. Further research with a larger sample size and more outcome events are required to make definitive conclusions regarding the association between aspirin use and complications, including hematoma and recurrent laryngeal nerve injury.

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.

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.

Assessing the effectiveness of retrograde autologous priming of the cardiopulmonary bypass machine in isolated coronary artery bypass grafts

INTRODUCTION

Currently, around 35-80% of patients undergoing cardiac surgery in the UK receive a blood transfusion. Retrograde autologous priming (RAP) of the cardiopulmonary bypass circuit has been suggested as a possible strategy to reduce blood transfusion during cardiac surgery.

METHODS

Data from 101 consecutive patients undergoing isolated coronary artery bypass grafts (where RAP was used) were collected prospectively and compared with 92 historic patients prior to RAP use in our centre.

RESULTS

Baseline characteristics (ie age, preoperative haemoglobin [Hb] etc) were not significantly different between the RAP and non-RAP groups. The mean pump priming volume of 1,013ml in the RAP group was significantly lower (p<0.001) than that of 2,450ml in the non-RAP group. The mean Hb level at initiation of bypass of 9.1g/dl in patients having RAP was significantly higher (p<0.001) than that of 7.7g/dl in those who did not have RAP. There was no significant difference between the RAP and non-RAP groups in transfusion of red cells, platelets and fresh frozen plasma, 30-day mortality, re-exploration rate and predischarge Hb level. The median durations of cardiac intensive care unit stay and in-hospital stay of 1 day (inter-quartile range [IQR]: 1-2 days) and 5 days (IQR: 4-6 days) in the RAP group were significantly shorter than those of the non-RAP group (2 days [IQR: 1-3 days] and 6 days [IQR: 5-9 days]).

CONCLUSIONS

In the population group studied, RAP did not influence blood transfusion rates but was associated with a reduction in duration of hospital stay.

Antiplatelet therapy in ENT surgery: a review

INTRODUCTION

Antiplatelet agents such as aspirin and clopidogrel are increasingly encountered in clinical practice. Otorhinolaryngological surgeons are involved in the peri-operative decision of whether to continue treatment and risk haemorrhage or to discontinue treatment and risk thrombosis.

METHODS

Literature relating to the risk of spontaneous or operative haemorrhage was reviewed. The morbidity and mortality associated with cessation of agents was evaluated. Published guidelines were also evaluated. A protocol for the management of antiplatelet agents in the peri-operative period, with particular reference to ENT operations, is presented.

CONCLUSION

SIGNIFICANT morbidity and mortality is associated with the premature cessation of antiplatelet agents. Data from cardiac surgery suggest that operative blood loss only marginally increases in patients on aspirin and clopidogrel. However, the management of antiplatelet agents in the peri-operative period should be made after multidisciplinary consultation.

A randomised controlled pilot trial to evaluate and optimize the use of anti-platelet agents in the perioperative management in patients undergoing general and abdominal surgery--the APAP trial (ISRCTN45810007)

PURPOSE

Surgeons are increasingly confronted by patients on long-term low-dose acetylsalicylic acid (ASA). However, owing to a lack of evidence-based data, a widely accepted consensus on the perioperative management of these patients in the setting of non-cardiac surgery has not yet been reached. Primary objective was to evaluate the safety of continuous versus discontinuous use of ASA in the perioperative period in elective general or abdominal surgery.

METHODS

Fifty-two patients undergoing elective cholecystectomy, inguinal hernia repair or colonic/colorectal surgery were recruited to this pilot study. According to cardiological evaluation, non-high-risk patients who were on long-term treatment with low-dose ASA were eligible for inclusion. Patients were allocated randomly to continuous use of ASA or discontinuation of ASA intake for 5 days before until 5 days after surgery. The primary outcome was the incidence of major haemorrhagic and thromboembolic complications within 30 days after surgery.

RESULTS

A total of 26 patients were allocated to each study group. One patient (3.8%) in the ASA continuation group required re-operation due to post-operative haemorrhage. In neither study group, further bleeding complications occurred. No clinically apparent thromboembolic events were reported in the ASA continuation and the ASA discontinuation group. Furthermore, there were no significant differences between both study groups in the secondary endpoints.

CONCLUSIONS

Perioperative intake of ASA does not seem to influence the incidence of severe bleeding in non-high-risk patients undergoing elective general or abdominal surgery. Further, adequately powered trials are required to confirm the findings of this study.

Effect of tranexamic acid on blood loss in pediatric cardiac surgery: a randomized trial

PURPOSE

The benefit of tranexamic acid (TXA) in pediatric cardiac surgery on postoperative bleeding has varied among studies. It is also unclear whether the effects of TXA differ between cyanotic patients and acyanotic patients. The aim of this study was to test the benefit of TXA in pediatric cardiac surgery in a well-balanced study population of cyanotic and acyanotic patients.

METHODS

A total of 160 pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (81 cyanotic, 79 acyanotic) were included in this single-blinded, randomized trial at a tertiary care university-affiliated teaching hospital. Eighty-one children (41 cyanotic, 40 acyanotic) were randomly assigned to a TXA group, in which they received 50 mg/kg of TXA as a bolus followed by 15 mg/kg/h infusion and another 50 mg/kg into the bypass circuit. The other 79 patients were randomly assigned to a placebo group. The primary end point was the amount of 24-h blood loss.

RESULTS

The amount of 24-h blood loss was significantly less in the TXA group than in the placebo group [mean (95% confidence interval): 18.6 (15.8-21.4) vs. 23.5 (19.4-27.5) ml/kg, respectively; mean difference -4.9 (-9.7 to -0.01) ml/kg; p = 0.049]. This effect of TXA was already significant at 6 h [9.5 (7.5-11.5) vs. 13.2 (10.6-15.9) ml/kg, respectively; mean difference -3.47 (-7.0 to -0.4) ml/kg; p = 0.027]. However, there was no significant difference in the amount of blood transfusion between the groups. There was also no statistical difference in the effect of TXA in each cyanotic and acyanotic subgroup.

CONCLUSION

TXA can reduce blood loss in pediatric cardiac surgery but not the transfusion requirement (http://ClinicalTrials.gov number NCT00994994).

A quality assurance programme for cell salvage in cardiac surgery

At the same time as cell salvage was introduced into our institution for all patients undergoing cardiac surgery with cardiopulmonary bypass, we established a supporting programme of quality assurance to reassure clinicians regarding safety and efficacy. Data collected in patients operated on between 2001 and 2007 included pre- and post-wash heparin concentration, haemoglobin concentration and free haemoglobin concentration. Cell salvage was used in 6826 out of a total of 7243 patients (94%). Post-wash heparin concentration was consistently low (always < 0.4 IU.ml(-1)). There was a significant decrease in post-wash haemoglobin concentration in 2003 compared to 2001, from a median (IQR [range]) of 19.6 (16.7-22.2 [12.9-25.5]) g.dl(-1) to 17.5 (13.6-20.8 [12.6-23.7]) g.dl(-1) (p < 0.015). In addition, there was a significant increase in free plasma haemoglobin in 2006 compared to 2001, from 0.5 (0.3-0.8 [0.1-2.6]) g.l(-1) to 0.8 (0.3-1.4 [0.3-5.2]) g.l(-1) (p < 0.001). This programme led to the detection of a change in operator behaviour in 2003 and progressive machine deterioration resulting in appropriate fleet replacement in 2006. You can respond to this article at http://www.anaesthesiacorrespondence.com.

Does transfusion of residual cardiopulmonary bypass circuit blood increase postoperative bleeding? A prospective randomized study in patients undergoing on pump cardiopulmonary bypass

OBJECTIVE

Homologous blood transfusion after open heart surgery puts a tremendous load on the blood banks. This prospective randomized study evaluates the efficacy of infusing back residual cardiopulmonary bypass (CPB) circuit i.e., pump blood as a means to reduce homologous transfusion after coronary artery bypass surgery (CABG) and whether its use increases postoperative drainage.

MATERIALS AND METHODS

Sixty-seven consecutive patients who underwent elective CABGs under CPB were randomized into 2 groups: (1) cases where residual pump blood was used and (2) controls where residual pump blood was not used. Patients were monitored for hourly drainage on the day of surgery and the 1(st) postoperative day and the requirements of homologous blood and its products. Data were matched regarding change in Hemoglobin, Packed Cell Volume and coagulation parameters till 1st postoperative day. All cases were followed up for three years.

RESULTS

There was a marginal reduction in bleeding pattern in the early postoperative period in the cases compared to controls. The requirement of homologous blood and its products were also reduced in the cases.

CONCLUSIONS

The use of CPB circuit blood is safe in the immediate postoperative period. The requirement of homologous blood transfusion can come down if strict transfusion criteria are maintained.

Recombinant factor VIIa (NovoSeven RT) use in high risk cardiac surgery

OBJECTIVE

The use of recombinant factor VIIa (rFVIIa) (NovoSeven RT(®)) to establish hemostasis during massive perioperative bleeding in cardiac surgery has been explored in several retrospective studies. While early results are promising, a paucity of data leaves many questions about its safety profile. We sought to further define its use and associated outcomes in a large cohort study at a single institution.

METHODS

A retrospective cohort study design was used, in which 236 patients received rFVIIa for bleeding after cardiac surgery. These patients were matched with a cohort of 213 subjects, who had similar operations during the same period of time. Primary end points included thrombo-embolic events, mortality, incidence of re-operation, use of blood products, and patient disposition at 30 days. Statistical significance was assessed at p < 0.05.

RESULTS

There was no statistically significant difference in the incidence of stroke (3.4%, 1.9%; p = 0.32), renal failure (8.5%, 7.0%; p = 0.57), or 30-day mortality (7.7%, 4.3%; p = 0.14) between the rFVIIa and the control groups, respectively. The rFVIIa group did experience a higher rate of re-operation for bleeding (11.0%, 1.9%; p = 0.0001) and had a two-fold increase in the use of each of the following: cryoprecipitate, fresh-frozen plasma, platelets, and packed red blood cells, relative to the control group (p < 0.00001).

CONCLUSIONS

rFVIIa is an effective hemostatic agent for intractable bleeding in high-risk cardiac surgery with an acceptable safety profile. rFVIIa does not appear to be associated with increased postoperative complications, including thrombo-embolic events and death.

Off-label use of recombinant activated factor VII in intractable haemorrhage after cardiovascular surgery: an observational study of practices in 23 French cardiac centres (2005-7)

OBJECTIVES

The study aimed to describe French off-label use of rFVIIa for intractable bleeding in major cardiovascular surgery.

METHODS

Retrospective observational analysis of data from 2005 to October 2007 (no formal guidelines were available) was employed. The collect request form was elaborated by a multidisciplinary committee.

RESULTS

Data on 109 patients--37 mechanical cardiac assist devices--were collected, with repeated injection for 24%. Bleeding stopped, decreased or continued in 43%, 37% and 20% of the cases, respectively. For patients treated in the intensive care unit (ICU), hourly bleeding decreased from 365 ± 212 to 115 ± 106 ml h(-1) (p<0.001). The median number of transfused products was 25 (2-90) before and 6 (0-48) after rFVIIa (p<0.001). Most patients had been well compensated with fibrinogen (>1g.l(-1)) and platelets (>50 G.l(-1)) before rFVIIa. The bleeding outcome (cessation, decrease or no change) was associated with the infused dose (81 ± 31, 71 ± 24, 64 ± 23 μg.kg(-1); p = 0.044) and did not differ whether rFVIIa was administered in the operating room (49%) or ICU (51%). Thrombotic events occurred in 13% of patients without assist devices and in 27% of those with them (but without obvious intra-device clotting). The overall 28-day survival rate was 60% and associated with bleeding outcome (p = 0.002).

CONCLUSIONS

rFVIIa rescue therapy was followed by control of bleeding in a substantial number of the patients with seemingly acceptable safety; however, thrombotic risk remains a matter of concern. Our observational study suggests that the dose to be tested prospectively is at least 80 μg.kg(-1).

Recombinant Factor VIIa: An Assessment of Evidence Regarding Its Efficacy and Safety in the Off-Label Setting

Recombinant human factor VIIa (rFVIIa) is approved by the US Food and Drug Administration for use in the setting of hemorrhage associated with factor VIII or factor IX inhibitors in patients with congenital or acquired hemophilia. This indication represents only a small number of bleeding conditions. Since it became available, rFVIIa has been increasingly used in the management of off-label indications, ranging from emergent hemostasis in traumatic hemorrhage to prophylactic hemostasis in patients undergoing major surgery. Prominent off-label indications include the management of patients with coagulopathies, such as occurs in trauma patients experiencing massive and uncontrolled hemorrhage, and in patients undergoing cardiovascular surgery with cardiopulmonary bypass. Other occasions for use occur in patients with intact coagulation systems, with nontraumatic intracranial hemorrhage being the most common in this group. Uncertainties regarding the efficacy and safety associated with use of rFVIIa in these off-label scenarios have led to evidence-based assessments of patient outcomes, including mortality, the rate of thromboembolic adverse events, and posttreatment functional status. We review the evidence regarding the efficacy and safety of this important, but controversial, hemostatic agent in the off-label setting.

The Management of Antiplatelet Therapy in Patients With Coronary Stents Undergoing Noncardiac Surgery

Whereas the development of coronary stents has been a major breakthrough in the treatment of coronary artery disease, stent thrombosis, associated with myocardial infarction and death, has introduced a new challenge in the care of patients with coronary stents undergoing noncardiac surgery. This review presents the authors’ recommendations regarding the optimal management of such patients. Elective surgery should be postponed for at least 6 weeks and optimally 3 months for a bare-metal stent and at least 1 year for a drug-eluting stent. On the other hand, managing a patient undergoing non-elective surgery is more difficult and necessitates a case-by-case assessment of bleeding risk versus thrombotic risk based on patient comorbidities, type of stents present, details of the coronary intervention, and type of surgical procedure. Patients with a risk of bleeding that outweighs the risk of stent thrombosis should discontinue at least clopidogrel, whereas all other patients should continue dual antiplatelet therapy throughout the perioperative period.

Safety of cardiac surgery without blood transfusion: a retrospective study in Jehovah's Witness patients

The aim of this retrospective study was to compare the utilisation of blood products and outcomes following cardiac surgery for 123 Jehovah's Witnesses and 4219 non-Jehovah's Witness patient controls. The study took place over a 7-year period at the Amphia Hospital in Breda, the Netherlands. A specific protocol was used in the management of Jehovah's Witness patients, while the control group received blood without restriction according to their needs. Patients' characteristics were comparable in both groups. Pre-operatively, the mean (SD) Euro Score was higher in the Jehovah's Witness group (3.2 (2.6) vs 2.7 (2.5), respectively; p < 0.02). Pre-operative haemoglobin concentration was higher in the Jehovah's Witness group (8.9 (0.7) vs 8.6 (0.9) g.dl(-1), respectively; p < 0.001). The total cardiopulmonary bypass time did not differ between groups. The requirement for allogenic blood transfusion was 0% in the Jehovah's Witness group compared to 65% in the control group. Postoperatively, there was a lower incidence of Q-wave myocardial infarction (2 (1.8%) vs 323 (7.7%), respectively; p < 0.02), and non Q-wave infarction (11 (9.8%) vs 559 (13.2%), respectively; p < 0.02) in the Jehovah's Witness group compared with controls. Mean (SD) length of stay in the intensive care unit (2.3 (3.2) vs 2.6 (4.2) days; p = 0.26), re-admission rate to the intensive care unit (5 (4.5%) vs 114 (2.7%); p = 0.163), and mortality (3 (2.7%) vs 65 (1.5%); p = 0.59), did not differ between the Jehovah's Witness and control groups, respectively.

Aspirin and Tranexamic Acid for Coronary Artery Surgery (ATACAS) Trial: rationale and design

BACKGROUND

Despite some concern that recent aspirin ingestion increases blood loss after coronary artery surgery, there is some evidence that this may reduce thrombotic complications. In contrast, antifibrinolytic drugs can reduce blood loss in this setting, but there is concern that they may increase thrombotic complications. Published guidelines are limited by a lack of large randomized trials addressing the risks and benefits of each of these commonly used therapies in cardiac surgery. The ATACAS Trial is a study comparing aspirin, tranexamic acid, or both, with placebo in patients undergoing on-pump or off-pump coronary artery surgery.

METHODS

We discuss the rationale for conducting ATACAS, a 4600-patient, multicenter randomized trial in at-risk coronary artery surgery, and the features of the ATACAS study design (objectives, end points, target population, allocation, treatments, patient follow-up, and analysis).

CONCLUSIONS

The ATACAS Trial will be the largest study yet conducted to ascertain the benefits and risks of aspirin and antifibrinolytic therapy in coronary artery surgery. Results of the trial will guide the routine clinical care of patients in this setting.

Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction

Recent clinical data show that the risk of coronary thrombosis after antiplatelet drugs withdrawal is much higher than that of surgical bleeding if they are continued. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is regarded as mandatory until the coronary stents are fully endothelialized, which takes 3 months for bare metal stents, but up to 1 yr for drug-eluting stents. Therefore, interruption of antiplatelet therapy 10 days before surgery should be revised. After reviewing the data on the use of antiplatelet drugs in cardiology and in surgery, we propose an algorithm for the management of patients, based on the risk of myocardial ischaemia and death compared with that of bleeding, for different types of surgery. Even if large prospective studies with a high degree of evidence are still lacking on different antiplatelet regimens during non-cardiac surgery, we propose that, apart from low coronary risk situations, patients on antiplatelet drugs should continue their treatment throughout surgery, except when bleeding might occur in a closed space. A therapeutic bridge with shorter-acting antiplatelet drugs may be considered.

Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline

BACKGROUND

A minority of patients having cardiac procedures (15% to 20%) consume more than 80% of the blood products transfused at operation. Blood must be viewed as a scarce resource that carries risks and benefits. A careful review of available evidence can provide guidelines to allocate this valuable resource and improve patient outcomes.

METHODS

We reviewed all available published evidence related to blood conservation during cardiac operations, including randomized controlled trials, published observational information, and case reports. Conventional methods identified the level of evidence available for each of the blood conservation interventions. After considering the level of evidence, recommendations were made regarding each intervention using the American Heart Association/American College of Cardiology classification scheme.

RESULTS

Review of published reports identified a high-risk profile associated with increased postoperative blood transfusion. Six variables stand out as important indicators of risk: (1) advanced age, (2) low preoperative red blood cell volume (preoperative anemia or small body size), (3) preoperative antiplatelet or antithrombotic drugs, (4) reoperative or complex procedures, (5) emergency operations, and (6) noncardiac patient comorbidities. Careful review revealed preoperative and perioperative interventions that are likely to reduce bleeding and postoperative blood transfusion. Preoperative interventions that are likely to reduce blood transfusion include identification of high-risk patients who should receive all available preoperative and perioperative blood conservation interventions and limitation of antithrombotic drugs. Perioperative blood conservation interventions include use of antifibrinolytic drugs, selective use of off-pump coronary artery bypass graft surgery, routine use of a cell-saving device, and implementation of appropriate transfusion indications. An important intervention is application of a multimodality blood conservation program that is institution based, accepted by all health care providers, and that involves well thought out transfusion algorithms to guide transfusion decisions.

CONCLUSIONS

Based on available evidence, institution-specific protocols should screen for high-risk patients, as blood conservation interventions are likely to be most productive for this high-risk subset. Available evidence-based blood conservation techniques include (1) drugs that increase preoperative blood volume (eg, erythropoietin) or decrease postoperative bleeding (eg, antifibrinolytics), (2) devices that conserve blood (eg, intraoperative blood salvage and blood sparing interventions), (3) interventions that protect the patient's own blood from the stress of operation (eg, autologous predonation and normovolemic hemodilution), (4) consensus, institution-specific blood transfusion algorithms supplemented with point-of-care testing, and most importantly, (5) a multimodality approach to blood conservation combining all of the above.

Factors associated with excessive bleeding in cardiopulmonary bypass patients: a nested case-control study

Introduction

Excessive bleeding (EB) after cardiopulmonary bypass (CPB) may lead to increased mortality, morbidity, transfusion requirements and re-intervention. Less than 50% of patients undergoing re-intervention exhibit surgical sources of bleeding. We studied clinical and genetic factors associated with EB.

Methods

We performed a nested case-control study of 26 patients who did not receive antifibrinolytic prophylaxis. Variables were collected preoperatively, at intensive care unit (ICU) admission, at 4 and 24 hours post-CPB. EB was defined as 24-hour blood loss of >1 l post-CPB. Associations of EB with genetic, demographic, and clinical factors were analyzed, using SPSS-12.2 for statistical purposes.

Results

EB incidence was 50%, associated with body mass index (BMI)< 26.4 (25–28) Kg/m², (P = 0.03), lower preoperative levels of plasminogen activator inhibitor-1 (PAI-1) (P = 0.01), lower body temperature during CPB (P = 0.037) and at ICU admission (P = 0.029), and internal mammary artery graft (P = 0.03) in bypass surgery. We found a significant association between EB and 5G homozygotes for PAI-1, after adjusting for BMI (F = 6.07; P = 0.02) and temperature during CPB (F = 8.84; P = 0.007). EB patients showed higher consumption of complement, coagulation, fibrinolysis and hemoderivatives, with significantly lower leptin levels at all postoperative time points (P = 0.01, P < 0.01 and P < 0.01).

Conclusion

Excessive postoperative bleeding in CPB patients was associated with demographics, particularly less pronounced BMI, and surgical factors together with serine protease activation.

Balancing the benefit and risk of oral antiplatelet agents in coronary artery bypass surgery

Concern about possible hemorrhagic complications arising from use of oral antiplatelet agents in immediate proximity to coronary artery bypass graft (CABG) surgery leads many clinicians to avoid or discontinue these agents preoperatively. Recent evidence suggests that aspirin and clopidogrel can be used with relative safety in the preoperative period; dual antiplatelet therapy in the 5 days immediately preceding CABG surgery results in a moderate and variable increase in the risk of procedural bleeding. This modest hemorrhagic risk may be acceptable, given the clinical benefits of sustained antiplatelet therapy in preventing graft occlusion and ischemic complications pre- and post-CABG. Because the bleeding risk with aspirin is dose dependent, use of a low dose is preferred post-CABG.

Morbidity and mortality risk associated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting

OBJECTIVE

Our objective was to quantify incremental risk associated with transfusion of packed red blood cells and other blood components on morbidity after coronary artery bypass grafting.

DESIGN

The study design was an observational cohort study.

SETTING

This investigation took place at a large tertiary care referral center.

PATIENTS

A total of 11,963 patients who underwent isolated coronary artery bypass from January 1, 1995, through July 1, 2002.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among the 11,963 patients who underwent isolated coronary artery bypass grafting, 5,814 (48.6%) were transfused. Risk-adjusted probability of developing in-hospital mortality and morbidity as a function of red blood cell and blood-component transfusion was modeled using logistic regression. Transfusion of red blood cells was associated with a risk-adjusted increased risk for every postoperative morbid event: mortality (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.67-1.87; p<.0001), renal failure (OR, 2.06; 95% CI, 1.87-2.27; p<.0001), prolonged ventilatory support (OR, 1.79; 95% CI, 1.72-1.86; p<.0001), serious infection (OR, 1.76; 95% CI, 1.68-1.84; p<.0001), cardiac complications (OR, 1.55; 95% CI, 1.47-1.63; p<.0001), and neurologic events (OR, 1.37; 95% CI, 1.30-1.44; p<.0001).

CONCLUSIONS

Perioperative red blood cell transfusion is the single factor most reliably associated with increased risk of postoperative morbid events after isolated coronary artery bypass grafting. Each unit of red cells transfused is associated with incrementally increased risk for adverse outcome.

Antiplatelet agents and perioperative bleeding

PURPOSE

To briefly review the risks, in patients presenting for surgery, associated with the available antiplatelet agents, and to present the principles that should guide the evaluation of these risks and how to manage them.

METHODS

A narrative review of the current medical literature in English and French.

MAIN FINDINGS

Antiplatelet agents [mainly acetylsalicylic acid, clopidogrel and glycoprotein (GP) IIb/IIIa inhibitors] are used increasingly to prevent arterial thrombosis. Clinicians are confronted with the hemorrhagic risk associated with the continuation of antiplatelet agents throughout surgery or, conversely, with the thrombotic risk associated with their discontinuation. Most experts recommend surgery while maintaining acetylsalicylic acid for most vascular procedures and in several additional settings where the bleeding risk has been shown (or is likely) to be low. It is commonly recommended that clopidogrel be stopped five days before surgery to allow replacement of half the platelet pool. This approach has been associated with thrombotic events in patients waiting for urgent myocardial revascularization. In this context, aprotinin may reduce blood losses and transfusion requirements. Withdrawal of the competitive GPIIb/IIIa inhibitors at the beginning of surgery will decrease the risk of bleeding, less so for abciximab owing to its avid binding to platelet receptors. Platelets should not be transfused prophylactically, but only to those few patients with abnormal bleeding thought to be related to the persisting effect of antiplatelet therapy.

CONCLUSIONS

Unfortunately, data regarding the management of antiplatelet agent-treated patients undergoing surgery, especially non-cardiovascular, are scarce. Further clinical trials must be conducted to guide the clinical management of these patients.

Antithrombotic therapy in cardiac surgery

PURPOSE

To review the perioperative management of antithrombotic therapy in cardiac surgery, including the management of cardiopulmonary bypass (CPB) and off-pump surgery.

METHODS

A review of the relevant English literature over the period 1975-2005 was undertaken, in addition to a review of international practices in antithrombotic therapy in cardiac surgery.

PRINCIPAL FINDINGS

Cardiopulmonary bypass is required in most procedures and makes anticoagulation mandatory. Anticoagulation is, usually, achieved with unfractionnated heparin (UFH). Unfractionated heparin is monitored by point-of-care (POC) testing, such as the activated clotting time or the determination of heparin concentration. The target values of both tests remain empirical, with no clearly validated thresholds. The target value needs to be adjusted according to the POC test, given significant variations between devices and activators. After CABG, the need for antiplatelet therapy is well demonstrated, in order to limit the risk of postoperative death or ischemic events, and improve venous graft patency. Immediately after valvular surgery, antithrombotic therapy should take into account the specific risk carried by each patient and by each prosthetic device. The risk of venous thromboembolism, though poorly defined, is also present in the postoperative period and may require additional attention. Given the frequent exposure to UFH, occurrence of heparin-induced thrombocytopenia is not infrequent in these patients and requires careful individual management.

CONCLUSIONS

Antithrombotic therapy is an essential component of cardiac surgery. Yet, with the exception of antiplatelet agents in CABG patients, antithrombotic therapy is often based on the clinical experience of medical teams more than on an evidence-based assessment of the literature.

Effect of aprotinin on postoperative blood loss in off-pump coronary artery bypass surgery

BACKGROUND AND AIM OF THE STUDY

Off-pump coronary artery bypass (OPCAB) enables a reduction in postoperative complications, particularly bleeding and transfusion. Nevertheless, a significant percentage of patients still needs transfusion. The effect of antifibrinolytic therapy on postoperative bleeding as part of OPCAB is still not widely described. The purpose of this study was to investigate the potential benefit of aprotinin in OPCAB.

METHODS

We conducted a retrospective comparative study with a historical control group. Consecutive patients undergoing off-pump coronary bypass were divided in two groups: 40 patients were operated without any antifibinolytic drug (group C); 40 patients received aprotinin (group A) during surgery. Patients in group A received a bolus of 2 x 10(6) KIU during 30 minutes, followed by a continuous infusion of 0.5 x 10(6) KIU per hour until the end of surgery. The same protocol was used during the whole study period.

RESULTS

Preoperative data of the two groups did not differ except for the number of grafts performed, which was higher in group A. Prothrombin time and activated clotting time increased in both groups after surgery. The use of packed red blood cells or fresh frozen plasma was not significantly different between both groups. Postoperative blood loss was significantly reduced in the aprotinin group (540 mL +/- 320 vs. 770 mL +/- 390, p = 0.006). No increase in postoperative troponin values was found in group A.

CONCLUSIONS

Aprotinin significantly reduced postoperative blood loss without reducing the transfusion rate. Aprotinin was not associated with any increase in postoperative complications.

Hemodilution and surgical hemostasis contribute significantly to transfusion requirements in patients undergoing coronary artery bypass

OBJECTIVE

We sought to determine the incidence of and risk factors for the development of low intraoperative hematocrit levels and of excessive postoperative bleeding in patients undergoing coronary artery bypass grafting, whether the risk factors are the same, and their effect on blood product transfusions.

METHODS

We performed a prospective cohort study of 613 adult patients who underwent coronary artery bypass grafting in 3 tertiary, university-affiliated hospitals during the period from October 1, 2000, to March 31, 2001.

RESULTS

Low intraoperative hematocrit levels (<19%) were found in 131 (24%) patients who had operations performed with extracorporeal circulation compared with in 3 (4%) patients with operations performed off pump. In multivariate analysis this was associated with older age, female sex, lower preoperative hemoglobin levels, lower body surface area, longer duration on bypass, and use of higher total volumes with more hydroxyethyl starch in the circuit. Low intraoperative hematocrit levels did not predict excessive postoperative hemorrhage (>1 L of mediastinal drainage in the first 12 hours). This occurred in 26% (n = 140) of patients undergoing on-pump operations and in 25% of patients undergoing off-pump operations and in multivariate analysis was associated with male sex, longer pump times, not receiving aprotinin, and operations performed by certain surgeons but not with total circuit or hydroxyethyl starch volume.

CONCLUSIONS

We observed that the risk factors for the development of a low intraoperative hematocrit level and excessive postoperative bleeding differed. Our results suggest that decreasing these outcomes in patients undergoing cardiac surgery requires a comprehensive approach, including limiting hemodilution, particularly in female subjects with lower preoperative hemoglobin levels, and careful attention to surgical hemostasis.

Effect of non-selective, non-steroidal anti-inflammatory drugs and cyclo-oxygenase-2 selective inhibitors on the PFA-100 closure time

The place of cyclo-oxygenase (COX)-2 selective non-steroidal anti-inflammatory drugs (NSAIDs) in the peri-operative period remains under discussion. Due to the absence of COX-2 in platelets, the risk of bleeding in patients who use selective NSAIDs is thought to be decreased. We studied the influence of aspirin, diclofenac, lornoxicam and rofecoxib on the in vitro bleeding time using the platelet function analyser (PFA-100). The PFA-100 simulates the process of platelet adhesion and aggregation after vascular injury in vitro. Measurements in 43 volunteers were performed at three time points: before, 3 h, and 12 h after oral ingestion of one of the randomly assigned study medications. Aspirin, diclofenac and lornoxicam had a significant effect on the in vitro closure time, while rofecoxib did not show this effect. This supports the use of COX-2 selective drugs in the peri-operative period to minimise the risk of bleeding.

Postoperative intravenous iron used alone or in combination with low-dose erythropoietin is not effective for correction of anemia after cardiac surgery

OBJECTIVES

The aim of this study was to examine whether intravenous iron III-hydroxide sucrose complex (IHSC) used alone was sufficient to provide rapid correction of anemia after cardiac surgery and whether additional stimulation of erythropoiesis is possible by means of a single low dose of recombinant-human erythropoietin (r-HuEPO) administration.

DESIGN

Prospective, randomized, double-blind study.

SETTING

The study was conducted in a university hospital.

PARTICIPANTS

One hundred twenty American Society of Anesthesiologists II or III patients, who underwent elective cardiac surgery using cardiopulmonary bypass and in whom postpump hemoglobin ranged between 7 and 10 g/dL.

INTERVENTIONS

Patients were divided into 3 groups: group I = control; group II received postoperative intravenous iron supplementation with an iron III-hydroxide sucrose complex (IHSC); and group III received IV iron and a single dose of r-HuEPO (300 U/kg).

MEASUREMENTS AND RESULTS

No significant difference in transfusion needs was observed among the 3 groups (22%, 25%, and 17% of patients transfused in groups I, II, and III, respectively). Hemoglobin levels, reticulocyte counts, and serum ferritin levels were evaluated at different time intervals (until day 30 postoperatively). No side effects because of iron administration were noted in the study. Reticulocyte counts increased rapidly at day 5 (2.24% +/- 1.11%, 1.99% +/- 1.44%, and 3.84% +/- 2.02% in groups I, II, and III, respectively) and decreased after day 15 in the 3 groups. Ferritin levels increased significantly at day 5 in the 2 treated groups (899.33 +/- 321.55 ng/mL in group II, 845.75 +/- 289.96 ng/mL in group III v 463.15 +/- 227.74 ng/mL in group I). In group I, ferritin levels, after a slight elevation on day 5, decreased at day 15 to lower than baseline levels. No significant difference in hemoglobin increase was noted among the 3 groups.

CONCLUSION

Postoperative intravenous iron supplementation alone or in combination with a single dose of r-HuEPO (300 U/kg) is not effective in correcting anemia after cardiac surgery.

[Non-opioid analgesics for perioperative pain therapy. Risks and rational basis for use]

Non-opioid analgesics play a central role in the management of postoperative pain. In this review, the pharmacology, the analgesic efficacy and the side-effects of non-opioid analgesics are summarized. First, the pharmacology of diclofenac, acetyl salicylic acid, dipyrone, acetaminophen and the COX-2 inhibitors is described. Second, the analgesic efficacy of non-opioid analgesics is analyzed for moderate pain (e.g. ambulatory surgery) and for moderate to severe pain (e.g. abdominal surgery-in combination with opioids). There is limited evidence for an additive analgesic effect of two non-opioid analgesics. Third, the major side-effects of non-opioid analgesics are discussed in relation to the pathophysiology, the frequency and the clinical relevance of these effects. In particular, side-effects on the gastrointestinal tract (ulcus formation), on coagulation (bleeding and thrombosis), on the renal (renal insufficiency), the pulmonary (bronchospasm) and the hematopoetic systems (agranulocytosis) are described. Recommendations for the clinical use of non-opioid analgesics for perioperative pain therapy are given.

Albumin administration--what is the evidence of clinical benefit? A systematic review of randomized controlled trials

BACKGROUND AND OBJECTIVE

The advantages of albumin over less costly alternative fluids continue to be debated. Meta-analyses focusing on survival have been inconclusive, and other clinically relevant end-points have not been systematically addressed. We sought to determine whether albumin confers significant clinical benefit in acute illness compared with other fluid regimens.

METHODS

Database searches (MEDLINE, EMBASE, Cochrane Library) and other methods were used to identify randomized controlled trials comparing albumin with crystalloid, artificial colloid, no albumin or lower-dose albumin. Major findings for all end-points were extracted and summarized. A quantitative meta-analysis was not attempted.

RESULTS

Seventy-nine randomized trials with a total of 4755 patients were included. No significant treatment effects were detectable in 20/79 (25%) trials. In cardiac surgery, albumin administration resulted in lower fluid requirements, higher colloid oncotic pressure, reduced pulmonary oedema with respiratory impairment and greater haemodilution compared with crystalloid and hydroxyethylstarch increased postoperative bleeding. In non-cardiac surgery, fluid requirements, and pulmonary and intestinal oedema were decreased by albumin compared with crystalloid. In hypoalbuminaemia, higher doses of albumin reduced morbidity. In ascites, albumin reduced haemodynamic derangements, morbidity and length of stay and improved survival after spontaneous bacterial peritonitis. In sepsis, albumin decreased pulmonary oedema and respiratory dysfunction compared with crystalloid, while hydroxyethylstarch induced abnormalities of haemostasis. Complications were lowered by albumin compared with crystalloid in burn patients. Albumin-containing therapeutic regimens improved outcomes after brain injury.

CONCLUSIONS

Albumin can bestow benefit in diverse clinical settings. Further trials are warranted to delineate optimal fluid regimens, in particular indications.

Post-operative course of coronary artery bypass surgery patients who pre-donate autologous blood

BACKGROUND

Pre-operative autologous blood donation is used to reduce the need of allogeneic blood in patients undergoing coronary bypass surgery operations, but it is not clear what impact the blood donation has on the post-operative course of these patients.

METHODS

We studied the post-operative course of 210 patients who pre-donated autologous blood before their coronary bypass operation (donors) and of 67 patients who were eligible to pre-donate but did not (controls).

RESULTS

The clinical variables and the technical operative parameters of the patients in the two groups were similar. There was no significant difference between the duration of assisted ventilation post-operatively (756 +/- 197 vs. 802 +/- 395 min; P=0.54) or length of stay in the intensive care unit (1.8 +/- 1.1 vs. 1.7 +/- 0.9 days; P=0.52) of the two groups. The number of autologous units of packed red cells and of fresh frozen plasma (FFP) received by the donors was significantly higher than the number of units of allogeneic packed red cells (1.5 +/- 0.9 vs. 0.3 +/- 0.9; P=0.001) and the units of homologous FFP received by the controls (2.3 +/- 0.8 vs. 0.6 +/- 1; P=0.001).

CONCLUSIONS

We found no evidence that autologous blood donation exerted a negative influence on the post-operative course of patients undergoing coronary bypass surgery. Patients who pre-donated blood received no allogeneic blood products, but the number of autologous blood products received by donors was higher than the number of blood products received by patients who did not pre-donate.

Vacuum-assisted venous return reduces blood usage

OBJECTIVE

To determine whether vacuum-assisted venous return has clinical advantages over conventional gravity drainage apart from allowing the use of smaller cannulas and shorter tubing.

METHODS

A total of 150 valve operations were performed at our institution between February and July 1999 using vacuum-assisted venous return with small venous cannulas connected to short tubing. These were compared with (1) 83 valve operations performed between April 1997 and January 1998 using the initial version of vacuum-assisted venous return, and (2) 124 valve operations performed between January and April of 1997 using conventional gravity drainage. Priming volume, hematocrit value, red blood cell usage, and total blood product usage were compared multivariably. These comparisons were covariate and propensity adjusted for dissimilarities between the groups and confirmed by propensity-matched pairs analysis.

RESULTS

Priming volume was 1.4 +/- 0.4 L for small-cannula vacuum-assisted venous return, 1.7 +/- 0.4 L for initial vacuum-assisted venous return, and 2.0 +/- 0.4 L for gravity drainage (P <.0001). Smaller priming resulted in higher hematocrit values both at the beginning of cardiopulmonary bypass (27% +/- 5% compared with 26% +/- 4% and 25% +/- 4%, respectively, P <.0001) and at the end (30% +/- 4% compared with 28% +/- 4% and 27% +/- 4%, respectively, P <.0001). Red cell transfusions were used in 17% of the patients having small-cannula vacuum-assisted venous return, 27% of the initial patients having vacuum-assisted venous return, and 37% of the patients having gravity drainage (P =.001); total blood product usage was 19%, 27%, and 39%, respectively (P =.002). Although ministernotomy also was associated with reduced blood product usage (P <.004), propensity matching on type of sternotomy confirmed the association of vacuum-assisted venous return with lowered blood product usage.

CONCLUSIONS

Vacuum-assisted venous return results in (1) higher hematocrit values during cardiopulmonary bypass and (2) decreased red cell and total blood product usage.

Volume expansion with albumin decreases mortality after coronary artery bypass graft surgery

OBJECTIVES

Albumin and nonprotein colloids (starches, dextran, and others) are used frequently as blood volume expanders in coronary artery bypass graft (CABG) surgery. The objective of this study was to determine differences between colloids with regard to patient characteristics and mortality rates.

DESIGN AND SETTING

Discharge data collected in the Solucient Clinical Pathways Database from 19,578 patients undergoing CABG surgery were analyzed.

MEASUREMENTS

Patients receiving albumin and nonprotein colloids were compared with regard to baseline patient characteristics. A multiple regression model was developed to determine if albumin use was independently associated with mortality rates.

RESULTS

Albumin was used in 8,084 cases (41.3%). The use of albumin and nonprotein colloids was not related to patient characteristics. Mortality was lower in the albumin group compared to the nonprotein colloid group (2.47% vs 3.03%, p = 0.02). In the multivariable logistic regression analysis, albumin use was associated with 25% lower odds of mortality compared to nonprotein colloid use (odds ratio, 0.80; 95% confidence interval, 0.67 to 0.96).

CONCLUSION

Colloid administration in CABG surgery was unrelated to patient characteristics. Albumin use appears to be associated with lower incidence of mortality after CABG surgery compared to nonprotein colloid use.