Variability in transfusion practice for coronary artery bypass surgery persists despite national consensus guidelines: a 24-institution study. Institutions of the Multicenter Study of Perioperative Ischemia Research Group

Patient blood management - a new paradigm for transfusion medicine?

The saving of many lives in history has been duly credited to blood transfusions. What is frequently overlooked is the fact that, in light of a wealth of evidence as well as other management options, a therapy deemed suitable yesterday may no longer be the first choice today. Use of blood has not been based upon scientific evaluation of benefits, but mostly on anecdotal experience and a variety of factors are challenging current practice. Blood is a precious resource with an ever limiting supply due to the aging population. Costs have also continually increased due to advances (and complexities) in collection, testing, processing and administration of transfusion, which could make up 5% of the total health service budget. Risks of transfusions remain a major concern, with advances in blood screening and processing shifting the profile from infectious to non‐infectious risks. Most worrying though, is the accumulating literature demonstrating a strong (often dose‐dependent) association between transfusion and adverse outcomes. These include increased length of stay, postoperative infection, morbidity and mortality. To this end, a recent international consensus conference on transfusion outcomes (ICCTO) concluded that there was little evidence to corroborate that blood would improve patients’ outcomes in the vast majority of clinical scenarios in which transfusions are currently routinely considered; more appropriate clinical management options should be adopted and transfusion avoided wherever possible. On the other hand, there are patients for whom the perceived benefits of transfusion are likely to outweigh the potential risks. Consensus guidelines for blood component therapy have been developed to assist clinicians in identifying these patients and most of these guidelines have long advocated more conservative ‘triggers’ for transfusion. However, significant variation in practice and inappropriate transfusions are still prevalent. The ‘blood must always be good philosophy’ continues to permeate clinical practice. An alternative approach, however, is being adopted in an increasing number of centres. Experience in managing Jehovah’s Witness patients has shown that complex care without transfusion is possible and results are comparable with, if not better than those of transfused patients. These experiences and rising awareness of downsides of transfusion helped create what has become known as ‘patient blood management’. Principles of this approach include optimizing erythropoiesis, reducing surgical blood loss and harnessing the patient’s physiological tolerance of anaemia. Treatment is tailored to the individual patient, using a multidisciplinary team approach and employing a combination of modalities. Results have demonstrated reduction of transfusion, improved patient outcomes and patient satisfaction. Significant healthcare cost savings have also followed. Despite the success of patient blood management programmes and calls for practice change, the potential and actual harm to patients caused through inappropriate transfusion is still not sufficiently tangible for the public and many clinicians. This has to change. The medical, ethical, legal and economic evidence cannot be ignored. Patient blood management needs to be implemented as the standard of care for all patients.

Bloodless aortic valve and ascending aorta replacement surgery requiring circulatory arrest: two case studies

Blood and/or blood product transfusions are common during and after complicated cardiac procedures. Replacement of the aortic valve, ascending aorta, and coronary implantation requiring circulatory arrest are high-risk procedures. Blood product transfusions only add to the morbidity and mortality rates associated with these types of procedures. Perfusion strategies must be incorporated to decrease the effects of hemodiluton due to cardiopulmonary bypass (CPB), and preserve platelets and clotting factors needed for hemostasis, post-operatively. We are reporting two consecutive cases where the patients presented with aortic valve stenosis accompanying an ascending aortic aneurysm requiring surgical correction using circulatory arrest. Neither patient required any blood or blood product donation throughout their hospital stay. Our strategies included minimizing our bypass circuit, utilization vacuum-assisted venous drainage, plasma sequestration, total circuit retrograde autologous priming (RAP), and cell salvage.

Transfusion associated in-hospital mortality and morbidity in isolated Coronary Artery Bypass Graft surgery

Transfusion after cardiac surgery is very common. This rate varies between institutions and has remained high despite established transfusion guidelines. We analyzed our database of patients who underwent isolated CABG (Coronary Artery Bypass Graft) to determine the predictive factors of homologous transfusion and associated postoperative morbidity, mortality and resource utilization. All 14,152 patients who underwent first-time isolated CABG, with or without cardiopulmonary bypass (CPB) who had postoperative homologous transfusion between February 2002 and March 2008 in Tehran Heart Center, were evaluated retrospectively. Overall, 16.5% of patients received transfusion. Transfused patients demonstrated a significantly higher incidence of postoperative complications (cardiac, infectious, ischemic, reoperation) and mortality (p<0.001). Homologous blood transfusion effect on mortality, morbidity and resource utilization. By Multivariable logistic regression analysis adjusted for confounders: Homologous blood transfusion effect on Mortality (30-days) (OR=3.976, p<0.0001), Prolonged ventilation hours (OR=4.755, p<0.0001), Total ICU hours (β =14.599, p<0.0001), Hospital length of stay (β =1.141, p<0.0001), Post surgery length of stay (β =0.955, p<0.0001). We conclude that the isolated CABG patients receiving blood transfusion have significantly higher mortality, morbidity and resource utilization. Homologous blood transfusion is an independent factor of increased resource utilization, morbidity and mortality.

Hospital variation in transfusion and infection after cardiac surgery: a cohort study

BACKGROUND

Transfusion practices in hospitalised patients are being re-evaluated, in part due to studies indicating adverse effects in patients receiving large quantities of stored blood. Concomitant with this re-examination have been reports showing variability in the use of specific blood components. This investigation was designed to assess hospital variation in blood use and outcomes in cardiac surgery patients.

METHODS

We evaluated outcomes in 24,789 Medicare beneficiaries in the state of Michigan, USA who received coronary artery bypass graft surgery from 2003 to 2006. Using a cohort design, patients were followed from hospital admission to assess transfusions, in-hospital infection and mortality, as well as hospital readmission and mortality 30 days after discharge. Multilevel mixed-effects logistic regression was used to calculate the intrahospital correlation coefficient (for 40 hospitals) and compare outcomes by transfusion status.

RESULTS

Overall, 30% (95 CI, 20% to 42%) of the variance in transfusion practices was attributable to hospital site. Allogeneic blood use by hospital ranged from 72.5% to 100% in women and 49.7% to 100% in men. Allogeneic, but not autologous, blood transfusion increased the odds of in-hospital infection 2.0-fold (95% CI 1.6 to 2.5), in-hospital mortality 4.7-fold (95% CI 2.4 to 9.2), 30-day readmission 1.4-fold (95% CI 1.2 to 1.6), and 30-day mortality 2.9-fold (95% CI 1.4 to 6.0) in elective surgeries. Allogeneic transfusion was associated with infections of the genitourinary system, respiratory tract, bloodstream, digestive tract and skin, as well as infection with Clostridium difficile. For each 1% increase in hospital transfusion rates, there was a 0.13% increase in predicted infection rates.

CONCLUSION

Allogeneic blood transfusion was associated with an increased risk of infection at multiple sites, suggesting a system-wide immune response. Hospital variation in transfusion practices after coronary artery bypass grafting was considerable, indicating that quality efforts may be able to influence practice and improve outcomes.

Bloodless cardiac surgery and the pediatric patient: a case study

Peri-operative transfusion of blood or blood products is associated with increased morbidity and mortality after cardiac surgery. However, excessive hemodilution as a result of avoiding the use of homologous blood products can also lead to decreased oxygen delivery to vital end organs and dilutional coagulopathy. This is particularly challenging in pediatric cardiac surgery where there is a large discrepancy between the patient circulating blood volume and the priming volume of the cardiopulmonary bypass (CPB) circuit. Strategies to avoid the use of homologous blood products during pediatric cardiac surgery must also incorporate miniaturization of the CPB circuit and other bypass techniques in order to avoid problems with excessive hemodilution. We report a 5.9 kg male infant who underwent successful surgical correction of a ventricular septal defect without the use of homologous blood transfusion. Our strategies included the pre-operative administration of erythropoietin and iron to increase red blood cell mass, acute normovolemic hemodilution (ANH) before the institution of CPB, retrograde autologous priming (RAP), cell salvage, continuous ultrafiltration, vacuum-assisted venous drainage to minimize the circuit size and priming volume, and the use of near infrared spectroscopy (NIRS) to monitor the patient during the entire procedure. The utilization of these strategies is now standard for our entire pediatric cardiac surgical population.

Predictors of packed red cell transfusion after isolated primary coronary artery bypass grafting--the experience of a single cardiac center: a prospective observational study

Background

Preoperative patients' characteristics can predict the need for perioperative blood component transfusion in cardiac surgical operations. The aim of this prospective observational study is to identify perioperative patient characteristics predicting the need for allogeneic packed red blood cell (PRBC) transfusion in isolated primary coronary artery bypass grafting (CABG) operations.

Patients and Methods

105 patients undergoing isolated, first-time CABG were reviewed for their preoperative variables and followed for intraoperative and postoperative data. Patients were 97 males and 8 females, with mean age 58.28 ± 10.97 years. Regression logistic analysis was used for identifying the strongest perioperative predictors of PRBC transfusion.

Results

PRBC transfusion was used in 71 patients (67.6%); 35 patients (33.3%) needed > 2 units and 14 (13.3%) of these needed > 4 units. Univariate analysis identified female gender, age > 65 years, body weight ≤ 70 Kg, BSA ≤ 1.75 m², BMI ≤ 25, preoperative hemoglobin ≤ 13 gm/dL, preoperative hematocrit ≤ 40%, serum creatinine > 100 μmol/L, Euro SCORE (standard/logistic) > 2, use of CPB, radial artery use, higher number of distal anastomoses, and postoperative chest tube drainage > 1000 mL as significant predictors. The strongest predictors using multivariate analysis were CPB use, hematocrit, body weight, and serum creatinine.

Conclusion

The predictors of PRBC transfusion after primary isolated CABG are use of CPB, hematocrit ≤ 40%, weight ≤ 70 Kg, and serum creatinine > 100 μmol/L. This leads to better utilization of blood bank resources and cost-efficient targeted use of expensive blood conservation modalities.

Increased mortality, morbidity, and cost associated with red blood cell transfusion after cardiac surgery

PURPOSE OF REVIEW

Literature since 2006 was reviewed to identify the harms and costs of red blood cell (RBC) transfusion.

RECENT FINDINGS

Several studies, in people having various cardiac surgery operations, found strong associations of RBC transfusion with mortality and postoperative morbidity. The effect on mortality was strongest close to the time of operation but extended to 5 years. Morbidity outcomes included serious wound and systemic infections, renal failure, prolonged ventilation, low cardiac index, myocardial infarction, and stroke. RBC transfusion was also strongly associated with increased cardiac intensive care unit and ward postoperative stay, and hence, increased cost of admission; available studies did not consider all resources used and the associated costs.

SUMMARY

The harms of RBC transfusion have potentially serious and long-term consequences for patients and are costly for health services. This evidence should shift clinicians' equipoise towards more restrictive transfusion practice. The immediate aim should be to avoid transfusing a small number of RBC units for general malaise attributed to anaemia, a practice that appears to occur in about 50% of transfused patients. Randomized trials comparing restrictive and liberal transfusion triggers are urgently needed to directly compare the benefits and harms from RBC transfusion.

Clopidogrel use and bleeding after coronary artery bypass graft surgery

BACKGROUND

Short-term use of clopidogrel plus aspirin among patients with acute coronary syndrome reduces ischemic events, but concerns about coronary artery bypass graft (CABG) surgery-related bleeding limit its early use.

METHODS

Using data from 4,794 consecutive CABG procedures in the Duke Databank for Cardiovascular Disease (January 1999 to December 2003), we developed multivariable models for associations with CABG-related bleeding defined as reoperation for bleeding, red cell transfusion, and a composite of reoperation/transfusion/hematocrit drop>or=15%. We examined clopidogrel use<or=5 days versus no clopidogrel<or=5 days before CABG in each model. Models were adjusted for propensity for clopidogrel use<or=5 days.

RESULTS

Of 4,794 CABG patients, 332 (6.9%) received clopidogrel<or=5 days before CABG, 127 (2.6%) had reoperation for bleeding, 3,277 (68.4%) received red cell transfusion, and 4,387 (91.5%) had the composite outcome. After adjustment, clopidogrel use<or=5 days was not significantly associated with reoperation (odds ratio [OR] 1.24, 95% CI 0.63-2.41) or the composite end point (OR 1.23, 95% CI 0.72-2.10). Clopidogrel<or=5 days was modestly associated with red cell transfusion (OR 1.40, 95% CI 1.04-1.89) but more weakly than other factors, including which surgeon performed the procedure.

CONCLUSION

Clopidogrel administration<or=5 days before CABG was not significantly associated with reoperation for bleeding or a bleeding composite, and only weakly with red cell transfusion after surgery. The impact of withholding clopidogrel acutely in those for whom clopidogrel has proven benefits and the impact of delaying CABG to prevent bleeding among patients treated with clopidogrel should be viewed in the context of other stronger determinants of bleeding.

Impact of genetic variation on perioperative bleeding

Variation in bleeding in the perioperative period is a complex and multifactorial event associated with immediate and delayed consequences for the patient and health care resources. Little is known about the complex genetic influences on perioperative bleeding. With the discovery of multiple variations in the human genome and ever-growing databases of well-phenotyped surgical patients, better identification of patients at risk of bleeding is becoming a reality. In this review, polymorphisms in the platelet receptor genes, plasminogen activator inhibitor, and angiotensin genes among others will be discussed. We will explore the nature, effects, and implications of the genetics that influence perioperative bleeding above and beyond surgical bleeding, particularly in cardiac surgery.

Autologous blood predonation in cardiac surgery

The risk of transfusion of allogeneic blood products on outcome is well documented. Autologous blood donation prior to elective cardiac surgery has repeatedly shown to be an effective practice to reduce the exposure to allogeneic blood, but was criticized because of the alleged high costs. We analyzed the data of 4878 patients undergoing elective open-heart surgery, in whom 18% underwent autologous donation. Overall, autologous blood donation reduced the incidence of allogeneic blood transfusion from 48 to 13% during hospitalization. Additionally, it is shown that diagnosis adjusted autologous blood donation is cost-effective. The higher the probability of transfusion the better is efficacy and cost-effectiveness of predonation. Cardiac surgery is a high-transfusion area, thus, it offers ideal conditions for autologous donation. Autologous blood donation still remains a promising and cost-effective alternative to reduce allogeneic blood transfusion in elective cardiac surgery.

The effect of aprotinin on outcome after coronary-artery bypass grafting

BACKGROUND

Aprotinin has recently been associated with adverse outcomes in patients undergoing cardiac surgery. We reviewed our experience with this agent in patients undergoing cardiac surgery at Duke University Medical Center.

METHODS

We retrieved data on 10,275 consecutive patients undergoing surgical coronary revascularization at Duke between January 1, 1996, and December 31, 2005. We fit data to a logistic-regression model predicting each patient's likelihood of receiving aprotinin on the basis of preoperative characteristics and to models predicting long-term survival (up to 10 years) and decline in renal function, as measured by increases in serum creatinine levels.

RESULTS

A total of 1343 patients (13.2%) received aprotinin, 6776 patients (66.8%) received aminocaproic acid, and 2029 patients (20.0%) received no antifibrinolytic therapy. All patients underwent coronary-artery bypass grafting, and 1181 patients (11.5%) underwent combined coronary-artery bypass grafting and valve surgery. In the risk-adjusted model, survival was worse among patients treated with aprotinin, with a main-effects hazard ratio for death of 1.32 (95% confidence interval [CI], 1.12 to 1.55) for the comparison with patients receiving no antifibrinolytic therapy (P=0.003) and 1.27 (95% CI, 1.10 to 1.46) for the comparison with patients receiving aminocaproic acid (P=0.004). As compared with the use of aminocaproic acid or no antifibrinolytic agent, aprotinin use was also associated with a larger risk-adjusted increase in the serum creatinine level (P<0.001) but not with a greater risk-adjusted incidence of dialysis (P=0.56).

CONCLUSIONS

Patients who received aprotinin had a higher mortality rate and larger increases in serum creatinine levels than those who received aminocaproic acid or no antifibrinolytic agent.

Experience of a network of transfusion coordinators for blood conservation (Ontario Transfusion Coordinators [ONTraC])

BACKGROUND

The experiences of the development of a provincial program to promote blood conservation are herein reported.

STUDY DESIGN AND METHODS

Transfusion coordinators were placed in 23 Ontario hospitals. Anonymized laboratory and clinical information was collected in a defined number of all consecutive patients admitted for three designated procedures: knee arthroplasty, abdominal aortic aneurysm (AAA), and coronary artery bypass graft (CABG) surgery (n approximately 1100, 300, and 300 at each time period, respectively).

RESULTS

Considerable interinstitutional variation was observed in the proportion of patients who received transfusions. At 12 months, and over the 24-month period of the project, most hospitals demonstrated decreased use of allogeneic blood; at 12 months an approximate 24 percent reduction in patients undergoing knee surgery, 14 percent in AAA, and 23 percent in CABG was obtained. In addition, patients who received transfusions received less allogeneic blood. Patients who did not receive allogeneic transfusions had lower postoperative infection rates (p < 0.05) and length of stay (p < 0.0001); allogeneic transfusion was an independent predictor of increased length of stay. The main blood conservation measures employed during this time were education, preoperative autologous donation, erythropoietin, and cell salvage.

CONCLUSION

The implementation of a provincial network of transfusion coordinators was feasible and allogeneic transfusion rates declined over the period the program has been in place.

ABO blood group and bleeding after coronary artery bypass graft surgery

Low circulating von Willebrand factor levels increase the risk of bleeding after cardiac surgery. Patients with blood group O may be at greatest risk owing to lower baseline levels of von Willebrand factor compared with patients with other blood groups, and perioperative hemodilution during cardiac surgery may reduce von Willebrand factor to critical levels in these patients. This study tested the hypothesis that patients with blood group O are at increased risk for postoperative bleeding following cardiac surgery, and determined whether the blood group affected perioperative assessment of primary hemostasis. Using multivariate linear regression models that included preoperative and intraoperative covariates, the risk factors for postoperative bleeding were evaluated in 877 patients undergoing primary, nonemergent coronary artery bypass surgery at a university hospital. In a subset of these patients, we measured perioperative in-vitro bleeding times (PFA-100 analyzer) to determine whether there were measurable differences in primary hemostasis between patients with blood type O and those with other blood groups. Patients with blood group O did not have increased bleeding after cardiac surgery compared with patients with other blood types. In addition, while blood group O patients had laboratory evidence for abnormal primary hemostasis before surgery, there were no measurable differences in postoperative primary hemostasis in patients with different blood types. In conclusion, although we identified clinical and procedural factors that were independently associated with bleeding, blood group was not one of these factors.

Increased mortality, postoperative morbidity, and cost after red blood cell transfusion in patients having cardiac surgery

BACKGROUND

Red blood cell transfusion can both benefit and harm. To inform decisions about transfusion, we aimed to quantify associations of transfusion with clinical outcomes and cost in patients having cardiac surgery.

METHODS AND RESULTS

Clinical, hematology, and blood transfusion databases were linked with the UK population register. Additional hematocrit information was obtained from intensive care unit charts. Composite infection (respiratory or wound infection or septicemia) and ischemic outcomes (myocardial infarction, stroke, renal impairment, or failure) were prespecified as coprimary end points. Secondary outcomes were resource use, cost, and survival. Associations were estimated by regression modeling with adjustment for potential confounding. All adult patients having cardiac surgery between April 1, 1996, and December 31, 2003, with key exposure and outcome data were included (98%). Adjusted odds ratios for composite infection (737 of 8516) and ischemic outcomes (832 of 8518) for transfused versus nontransfused patients were 3.38 (95% confidence interval [CI], 2.60 to 4.40) and 3.35 (95% CI, 2.68 to 4.35), respectively. Transfusion was associated with increased relative cost of admission (any transfusion, 1.42 times [95% CI, 1.37 to 1.46], varying from 1.11 for 1 U to 3.35 for >9 U). At any time after their operations, transfused patients were less likely to have been discharged from hospital (hazard ratio [HR], 0.63; 95% CI, 0.60 to 0.67) and were more likely to have died (0 to 30 days: HR, 6.69; 95% CI, 3.66 to 15.1; 31 days to 1 year: HR, 2.59; 95% CI, 1.68 to 4.17; >1 year: HR, 1.32; 95% CI, 1.08 to 1.64).

CONCLUSIONS

Red blood cell transfusion in patients having cardiac surgery is strongly associated with both infection and ischemic postoperative morbidity, hospital stay, increased early and late mortality, and hospital costs.

Coronary artery surgery: cardiotomy suction or cell salvage?

Coronary artery bypass grafting (CABG) today results in what may be regarded as acceptable levels of blood loss with many institutions avoiding allogeneic red cell transfusion in over 60% of their patients. The majority of cardiac surgeons employ cardiotomy suction to preserve autologous blood during on-pump coronary artery bypass surgery; however the use of cardiotomy suction is associated with a more pronounced systemic inflammatory response and a resulting coagulopathy as well as exacerbating the microembolic load. This leads to a tendency to increased blood loss, transfusion requirement and organ dysfunction. Conversely, the avoidance of cardiotomy suction in coronary artery bypass surgery is not associated with an increased transfusion requirement. There is therefore no indication for the routine use of cardiotomy suction in on-pump coronary artery surgery.

Bloodless cardiac surgery: not just possible, but preferable

Blood transfusions after cardiac surgery are very common, and the rates are highly variable among institutions. Transfusion carries the risk of infectious and noninfectious hazards and is often clinically unnecessary. This article discusses the history of bloodless cardiac surgery, the hazards of transfusion, the benefits of reducing or eliminating transfusion, and strategies to conserve blood. It also provides a list of resources for those who are interested in learning more about bloodless care.

Blood transfusions in children: a multi-institutional analysis of practices and complications

BACKGROUND

Blood product transfusions are a valuable health-care resource. Guidelines for transfusion exist, but variability in their application, particularly in children, remains. The risk factors that threaten transfusion safety are well established, but because their occurrence in children is rare, single-institution studies have limited utility in determining the rates of occurrence. An epidemiologic approach that investigates blood transfusions in hospitalized children may help improve our understanding of transfused blood products in this vulnerable population.

STUDY DESIGN AND METHODS

This was a nonconcurrent cohort study of pediatric patients not more than 18 years of age hospitalized from 2001 to 2003 at 35 academic children's hospitals that are members of the Pediatric Health Information System (PHIS).

RESULTS

A total of 51,720 (4.8%) pediatric patients received blood product transfusions during the study period. Red blood cells (n = 44,632) and platelets (n = 14,274) were the two most frequently transfused products. The rate of transfusions was highest among children with neutropenia, agranulocytosis, and sickle cell crisis. Asian and American Indian patients had important differences in the rate of blood transfusions and their complications. Resource use in terms of length of stay and costs were higher in patients who received transfusion. Of those patients who received transfusions, 492 (0.95%) experienced a complication from the administered blood product. This accounted for a rate of complications of 10.7 per 1,000 units transfused.

CONCLUSIONS

The administration of blood products to children is a common practice in academic children's hospitals. Complications associated with these transfused products are rare.

Bloodless Cardiac Surgery is Associated With Decreased Morbidity and Mortality

BACKGROUND

Blood transfusion with cardiac surgery accounts for 20% of transfusions in the United States. The effect of perioperative transfusion on cardiac surgery outcomes is unknown. We hypothesized that cardiac surgery with perioperative blood transfusion was associated with worse outcomes.

METHODS

A prospectively maintained (Society of Thoracic Surgeons) institutional database was analyzed from 2000 to 2005. All patients undergoing coronary artery bypass and/or valve operations were evaluated for the association of preoperative and intraoperative risk factors with blood transfusion. The association of transfusion with postoperative complications and mortality was evaluated.

RESULTS

During the study period, 2691 patients met inclusion criteria. Sixty-four percent received transfusions. Preoperative risk factors associated with transfusion (p < 0.05) were lung disease, elevated creatinine, peripheral vascular disease, and previous cardiac interventions. Patients requiring transfusion were older (mean 65.2 vs. 61.2 years, p < 0.001). Transfusion was associated with longer cross-clamp (median 78 vs. 88 minutes, p < 0.001) and perfusion times (median 114 vs. 128 minutes, p < 0.001). Perioperative blood transfusion was associated with increased postoperative complications (53.5% vs. 30.5%, p < 0.001). Significant transfusion-associated complications were renal failure, prolonged ventilation time, pneumonia, cardiac arrest, gastrointestinal complications, atrial fibrillation, stroke, myocardial infarction, and bleeding requiring reoperation. Blood transfusion was associated with an increased operative mortality (3.4% vs. 1.7%, p = 0.005) and length of stay after surgery (median 6 vs. 5 days p < 0.001).

CONCLUSION

Identification and management of risk factors associated with transfusion may reduce the transfusion requirement, minimize perioperative complications and improve outcomes. Bloodless cardiac surgery is associated with a decreased morbidity and mortality.

Blood use in elective surgery: the Austrian benchmark study

BACKGROUND

Benchmarking transfusion activity may help to eliminate inappropriate use of blood products. The goal of this study was to measure and to compare the current transfusion practice and to identify predictors of transfusion in public hospitals to develop strategies to optimize transfusion practices.

STUDY DESIGN AND METHODS

This was a prospective observational study in 18 randomly selected public hospitals from April 2004 to February 2005. Primary outcome measures were the amount of intra- and postoperative blood components transfused and intercenter variability of transfusion rate. Secondary outcome measures were prevalence of preoperative anemia, calculated perioperative blood loss, and lowest measured perioperative hemoglobin (Hb) level.

RESULTS

Adult patients undergoing primary unilateral total hip replacement (THR, n = 1401), primary unilateral knee replacement (TKR, n = 1296), hemicolectomy (HECOC, n = 148), and coronary artery bypass graft (CABG) surgery (n = 777) were enrolled. Due to the small number, data of HECOC patients were not fully analyzed. In the remaining procedures, there was a large intercenter variability in the percentage of patients who received transfusions: THR 16 to 85 percent, TKR 12 to 87 percent, and CABG 37 to 63 percent. In the patients who received transfusions, the number of red blood cells (RBC) units transfused varied significantly. There was also a considerable intercenter variability in RBC loss. The prevalence of preoperative anemia was 19 percent and identical in both sexes. The incidence of preoperative anemia was three times higher in patients who received transfusions compared to those who did not.

CONCLUSION

This study demonstrates a high intercenter variability in RBC transfusions and RBC loss in standard surgical procedures. Whereas the variability in blood loss remains largely unexplained, the main predictors for allogeneic RBC transfusions are preoperative and nadir Hb and surgical RBC loss.

Erythropoietic therapy: Cost efficiency and reimbursement

PURPOSE

The practice of blood conservation is aimed at improving patient outcomes by avoiding allogeneic transfusions via a coordinated multidisciplinary, multipronged approach. The numerous blood conservation techniques and transfusion alternatives now available are described.

SUMMARY

Ongoing concerns exist regarding the availability of the nation's and the world's blood supply. In addition, the number of measures required to ensure blood safety has led to increases in the price of blood and blood products over the past 10-15 years. Moreover, blood transfusion carries inherent risks even under the most favorable circumstances. Investigations have established that injudicious transfusion is associated with development of ventilator-associated pneumonia, nosocomial infection, and organ dysfunction. Because most single blood-conservation techniques reduce blood usage by a mere 1-2 units, a series of integrated conservation approaches are required. These include preoperative autologous donation, use of erythropoietic agents, blood conservation techniques such as acute normovolemic hemodilution, individualized assessment of anemia tolerance, implementation of conservative transfusion thresholds, meticulous surgical techniques, and judicious use of phlebotomy and pharmacologic agents for limiting blood loss. Erythropoietic agents such as epoetin alfa have been used successfully to increase hemoglobin and decrease transfusion requirements, and are appropriate when used in advance of elective surgical procedures. Acquisition costs of erythropoietic stimulating agents versus costs of blood justify economic evaluation by hospitals to make the most cost-effective choice under current economic constraints.

CONCLUSION

Initiating a blood management program requires planning and support from those who are concerned about blood usage reduction and outcomes improvement. Launching a vigorous and ongoing educational program to raise awareness about the risks and hazards associated with blood transfusion is an important step in helping to reshape the medical staffs' attitudes about transfusion and the most cost-effective way to achieve clinical goals.

Blood tranfusion in critically ill patients: state of the art

Anemia is one of the most common abnormal findings in critically ill patients, and many of these patients will receive a blood transfusion during their intensive care unit stay. However, the determinants of exactly which patients do receive transfusions remains to be defined and have been the subject of considerable debate in recent years. Concerns and doubts have emerged regarding the benefits and safety of blood transfusion, in part due to the lack of evidence of better outcomes resulting from randomized studies and in part related to the observations that transfusion may increase the risk of infection. As a result of these concerns and of several studies suggesting better or similar outcomes with a lower transfusion trigger, there has been a general tendency to decrease the transfusion threshold from the classic 10 g/dL to lower values. In this review, we focus on some of the key studies providing insight into current transfusion practices and fueling the current debate on the ideal transfusion trigger.

Blood management

CONTEXT

We provide an overview of the principles of blood management: the appropriate use of blood and blood components, with a goal of minimizing their use.

OBJECTIVE

To review the strategies that exploit combinations of surgical and medical techniques, technologic devices, and pharmaceuticals, along with an interdisciplinary team approach that combines specialists who are expert at minimizing allogeneic blood transfusion.

DATA SOURCES

A search on Medline and PubMed for the terms English and humans used in articles published within the last 20 years.

CONCLUSIONS

Blood management is most successful when multidisciplinary, proactive programs are in place so that these strategies can be individualized to specific patients.

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.

Meta-analysis comparing the effectiveness and adverse outcomes of antifibrinolytic agents in cardiac surgery

BACKGROUND

Since the 1980s, antifibrinolytic therapies have assisted surgical teams in reducing the amount of blood loss. To date, however, serious questions remain regarding the safety and effectiveness of these agents.

METHODS AND RESULTS

We conducted a meta-analysis to compare aprotinin, epsilon-aminocaproic acid, and tranexamic acid with placebo and head to head on 8 clinical outcomes from 138 trials. Published randomized controlled trial data were collected from OVID/PubMed. Outcomes included total blood loss, transfusion of packed red blood cells, reexploration, mortality, stroke, myocardial infarction, dialysis-dependent renal failure, and renal dysfunction (0.5-mg/dL increase in creatinine from baseline). All agents were effective in significantly reducing blood loss by 226 to 348 mL and the proportion of patients transfused with packed red blood cells over placebo. Only high-dose aprotinin reduced the rate of reexploration (relative risk, 0.49; 95% CI, 0.33 to 0.73). There were no significant risks or benefits for any agent for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin significantly increased the risk of renal dysfunction (relative risk, 1.47; 95% CI, 1.12 to 1.94), 12.9% versus 8.4%. Compared head to head, high-dose aprotinin demonstrated significant reduction in total blood loss over epsilon-aminocaproic acid (-184 mL; 95% CI, -256 to -112) and tranexamic acid (-195 mL; 95% CI, -286 to -105). There were no significant differences among any agent when compared head to head on other outcomes.

CONCLUSIONS

All antifibrinolytic agents were effective in reducing blood loss and transfusion. There were no significant risks or benefits for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin was associated with a statistically significant increased risk of renal dysfunction.

Evaluation of a new platelet function analyzer in cardiac surgery: a comparison of modified thromboelastography and whole-blood aggregometry

OBJECTIVES

Impaired hemostasis of multiple etiologies are often present in patients undergoing cardiopulmonary bypass (CPB) surgery. Platelet dysfunction is considered to be important in the early postoperative period. Therefore, a new whole-blood platelet function analyzer was compared with thromboelastography in predicting postoperative hemostatic outcomes as measured by blood loss and blood product use.

DESIGN

Prospective study.

SETTING

Teaching hospital.

PARTICIPANTS

The study enrolled 54 patients scheduled for coronary artery bypass surgery with CPB.

INTERVENTIONS

Coagulation and platelet function were assessed preoperatively, after CPB, at 3 hours, and at 24 hours after surgery by using thromboelastography and impedance aggregometry. Patients were divided into a transfused and nontransfused group on the basis of postoperative transfusion requirements. Postoperative blood loss and requirements of blood transfusions were documented until 24 hours postoperatively.

MEASUREMENTS AND MAIN RESULTS

Twenty-five patients (46%) received postoperative blood transfusions. Impaired hemostasis occurred after CPB detected by thromboelastography (p < 0.01) and impedance aggregometry (p < 0.01). In contrast to thromboelastography, preoperative adenosine diphosphate-mediated aggregometry correlated with postoperative requirements for blood transfusion (Spearman r = -0.302, p < 0.05) and was significantly lower in patients receiving allogeneic blood transfusion compared with nontransfused patients (p < 0.05). Neither aggregometry nor thromboelastography was correlated with postoperative blood loss.

CONCLUSION

Impedance aggregometry as well as thromboelastography are able to detect impaired hemostasis after CPB. In contrast to thromboelastography, aggregometry using a new whole-blood aggregometer identified patients with a reduced risk for postoperative transfusion requirements.

Coronary artery bypass graft surgery—care globalization: The impact of national care on fatal and nonfatal outcome

OBJECTIVE

In an international, prospective, observational study, we contrasted adverse vascular outcomes among four countries and then assessed practice pattern differences that may have contributed to these outcomes.

METHODS

A total of 5065 patients undergoing coronary artery bypass graft surgery were analyzed at 70 international medical centers, and from this pool, 3180 patients from the 4 highest enrolling countries were selected. Fatal and nonfatal postoperative ischemic complications related to the heart, brain, kidney, and gastrointestinal tract were assessed by blinded investigators.

RESULTS

In-hospital mortality was 1.5% (9/619) in the United Kingdom, 2.0% (9/444) in Canada, 2.7% (34/1283) in the United States, and 3.8% (32/834) in Germany (P = .03). The rates of the composite outcome (morbidity and mortality) were 12% in the United Kingdom, 16% in Canada, 18% in the United States, and 24% in Germany (P < .001). After adjustment for difference in case-mix (using the European System for Cardiac Operative Risk Evaluation) and practice, country was not an independent predictor for mortality. However, there was an independent effect of country on composite outcome. The practices that were associated with adverse outcomes were the intraoperative use of aprotinin, intraoperative transfusion of fresh-frozen plasma or platelets, lack of use of early postoperative aspirin, and use of postoperative heparin.

CONCLUSIONS

Significant between-country differences in perioperative outcome exist and appear to be related to hematologic practices, including administration of antifibrinolytics, fresh-frozen plasma, platelets, heparin, and aspirin. Understanding the mechanisms for these observations and selection of practices associated with improved outcomes may result in significant patient benefit.

Does the Use of Preoperative Aspirin Increase the Risk of Bleeding in Patients Undergoing Coronary Artery Bypass Grafting Surgery? Systematic Review and Meta-Analysis

BACKGROUND

The traditional recommendation has been to stop Aspirin seven to 10 days prior to coronary artery bypass surgery to reduce the potential risk of bleeding. A few reports have shown that Aspirin did not increase the risk of bleeding and may be beneficial to be continued until the time of surgery. The objective of this review was to evaluate the effect of preoperative Aspirin on bleeding in patients undergoing elective bypass surgery.

METHODS

A meta-analysis of 10 randomized and nonrandomized studies reporting comparisons between Aspirin and control was undertaken. The primary outcome was the total amount of postoperative chest tube drainage. Secondary outcomes were the number of units of packed red blood cell transfusion, platelet transfusion, fresh frozen plasma transfusion, and number of patients reexplored for bleeding.

RESULTS

Ten studies, involving 1748 patients, met the inclusion criteria for this review of whom 913 were in the Aspirin group and 835 were in the control group. Pooling the results of all studies showed a significant increase in blood loss and transfusion of red blood cells and fresh frozen plasma in the Aspirin group (p < 0.05). There was no significant difference between the two groups in the rate of platelet transfusion, or the incidence of reexploration (p > 0.05). Included studies were heterogeneous and of low methodological quality.

CONCLUSION

Aspirin is associated with increased chest tube drainage and may be associated with a greater requirement for blood products. High-quality prospective studies are warranted to reassess the effect of Aspirin on important postoperative outcomes.

Myocardial infarction following coronary artery bypass graft surgery increases healthcare resource utilization

OBJECTIVE

To assess the health economic impact of perioperative myocardial infarction in a cohort of patients undergoing coronary artery bypass graft surgery.

DESIGN

Retrospective cohort analysis using data from hospital bills and uniform billing forms.

SETTING

A total of 147 geographically diverse hospitals in the United States.

PATIENTS

The study population consisted of 2,102 coronary artery bypass graft surgery patients enrolled in the PRIMO-CABG trial at U.S. sites between January 2002 and February 2003.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Resource utilization and costs during the index hospitalization and during a 6-month follow-up period were compared between patients who had a myocardial infarction by postoperative day 4 and those who did not. Linear regression was used to examine whether myocardial infarction by day 4 was associated with index hospitalization costs, after adjusting for baseline characteristics. Myocardial infarction occurred in 191 (9.1%) patients undergoing coronary artery bypass graft surgery. Myocardial infarction was associated with a doubling of intensive care unit time (3.5 days among patients with no myocardial infarction and 7.1 days among patients with myocardial infarction, p < .01) and a 48% increase in hospital length of stay. Myocardial infarction by day 4 was associated with a 43% increase in hospital costs, a 29% increase in physician service costs, a 41% increase in total costs during the index hospitalization, and a 38% increase in cumulative 6-month costs. After baseline adjustment, myocardial infarction continued to be associated with higher index hospitalization costs.

CONCLUSIONS

Myocardial infarction following coronary artery bypass graft surgery was associated with a significant increase in intensive care unit time, hospital length of stay, and overall costs, which contributed to greater hospital and physician service costs. Healthcare resource utilization is increased in patients sustaining a myocardial infarction following coronary artery bypass graft surgery.

Current practice of hemodynamic monitoring and vasopressor and inotropic therapy in post-operative cardiac surgery patients in Germany: results from a postal survey

BACKGROUND

In Germany, more than 100,000 patients are monitored and treated in 80 intensive care units (ICUs) following cardiac surgery each year. The controversies concerning the different methods of hemodynamic monitoring and the appropriate agents for volume therapy and inotropic support are well known. However, little is known about how monitoring and treatment are currently performed.

METHODS

A questionnaire with 39 questions was sent to the leading physicians of 80 ICUs in Germany, treating patients after cardiac surgery. The questions to be answered covered the current practice of hemodynamic monitoring, volume replacement, inotropic/vasopressor support and transfusions in patients after cardiac surgery.

RESULTS

Sixty-nine per cent of the questionnaires were completed and returned. All ICUs used basic monitoring as recommended by the societies. The use of advanced hemodynamic monitoring included the pulmonary artery catheter (58.2%), transesophageal echocardiography (38.1%) and transpulmonary dilution techniques (13%). Crystalloids (21.2%) and colloids (73%) were used for volume replacement. Epinephrine (41.8%) and dobutamine (30.9%) were the first-choice inotropic drugs for the treatment of low cardiac output syndrome, followed by phosphodiesterase inhibitors (14.5%). Second-choice drugs for the treatment of low cardiac output syndrome were enoximone (29%), milrinone (25%) and dobutamine (25%). A written transfusion protocol and a transfusion threshold for red blood cells existed in 59% and 79% of ICUs, respectively.

CONCLUSION

Hemodynamic monitoring and the variability in clinical practice with regard to volume replacement, transfusion triggers and the use of vasopressors/inotropes in cardiac surgery patients tend to follow the results of traditional experience rather than current scientific knowledge. Guidelines are therefore necessary to help to improve the standards of intensive care after cardiac surgery and thus the outcome of patients.

Does off-pump or minimally invasive coronary artery bypass reduce mortality, morbidity, and resource utilization when compared with percutaneous coronary intervention? A meta-analysis of randomized trials

OBJECTIVE

To determine, through meta-analysis, whether off-pump coronary artery bypass, including minimally invasive off-pump coronary artery bypass, improves short-term and midterm outcomes compared with percutaneous coronary intervention for single- or double-vessel coronary artery disease.

METHODS

The primary outcome was need for coronary reintervention at 1 to 5 years. Secondary outcomes included all major clinical morbidities and resource utilization. A comprehensive search was undertaken to identify all randomized trials of off-pump coronary artery bypass versus percutaneous coronary intervention. MEDLINE, Cochrane Library, EMBASE, and abstract databases were searched up to May 2006. All randomized trials comparing off-pump coronary artery bypass (sternotomy or minimally invasive) versus percutaneous coronary intervention and reporting at least one predefined outcome were included. Odds ratios (OR, 95% confidence intervals [CI]) and weighted mean differences (WMD, 95% CI) were analyzed.

RESULTS

Six trials involving 989 patients were included. Compared with percutaneous coronary intervention, off-pump coronary artery bypass decreased angina recurrence (OR 0.54, 95% CI 0.34-0.87) and need for reintervention at 1 to 5 years (OR 0.24, 95% CI 0.15-0.40). Major adverse coronary events were significantly reduced (OR 0.44, 95% CI 0.30-0.63) and event-free survival was significantly increased at 1 to 5 years (OR 2.32, 95% CI 1.62-3.32) for off-pump coronary artery bypass versus percutaneous coronary intervention. Coronary stenosis at 6 months was reduced with off-pump coronary artery bypass compared with percutaneous coronary intervention (OR 0.31, 95% CI 0.18-0.55). Hospital stay was significantly increased with off-pump coronary artery bypass versus percutaneous coronary intervention (WMD 4.03, 95% CI 2.37-5.70). Quality of life favored off-pump coronary artery bypass in some domains but was reported in few studies. Death, myocardial infarction, and stroke did not significantly differ.

CONCLUSIONS

In single- or double-vessel disease, off-pump coronary artery bypass improved short-term and midterm clinical outcomes compared with percutaneous coronary intervention but was associated with an increased length of hospital stay.

Anemia and morbidity and mortality in coronary bypass surgery

PURPOSE OF REVIEW

Anemia is associated with increased morbidity and mortality, in community-dwelling persons, in critically ill patients and perioperatively. The exact reasons and extent of the risks induced by anemia are not known, however, nor the optimal therapeutic approach. Based on the assumption that transfusion invariably counteracts the risks associated with perioperative anemia, most studies do not exclude the confounding effects of transfusion, and anemia is inconsistently defined. Cardiovascular disease was identified as a major additional risk for anemic patients, but the combined effects of decreasing hemoglobin and comorbidities in patients with coronary stenoses have not been determined exactly. This review integrates recent data to present a more differentiated understanding of mechanisms and risks of anemia in coronary artery bypass grafting surgery.

RECENT FINDINGS

Patients with many comorbidities are more susceptible to the effects of anemia. Some outcomes may primarily be caused by concomitant risk factors associated with anemia rather than by low hemoglobin per se. The precise interactions of anemia and comorbidities to produce worse outcomes are still unclear, as is the optimal therapeutic approach.

SUMMARY

The review highlights recent developments on anemia in heart surgery, and advocates new studies to institute individually adapted therapies.